[PATCH v6 00/24] i2c mux cleanup and locking update

[PATCH v6 00/24] i2c mux cleanup and locking update

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Hi!

I have a pair of boards with this i2c topology:

                       GPIO ---|  ------ BAT1
                        |      v /
   I2C  -----+------B---+---- MUX
             |                   \
           EEPROM                 ------ BAT2

	(B denotes the boundary between the boards)

The problem with this is that the GPIO controller sits on the same i2c bus
that it MUXes. For pca954x devices this is worked around by using unlocked
transfers when updating the MUX. I have no such luck as the GPIO is a general
purpose IO expander and the MUX is just a random bidirectional MUX, unaware
of the fact that it is muxing an i2c bus. Extending unlocked transfers
into the GPIO subsystem is too ugly to even think about. But the general hw
approach is sane in my opinion, with the number of connections between the
two boards minimized. To put it plainly, I need support for it.

So, I observe that while it is needed to have the i2c bus locked during the
actual MUX update in order to avoid random garbage on the slave side, it
is not strictly a must to have it locked over the whole sequence of a full
select-transfer-deselect operation. The MUX itself needs to be locked, so
transfers to clients behind the mux are serialized, and the MUX needs to be
stable during all i2c traffic (otherwise individual mux slave segments
might see garbage).

This series accomplishes this by adding code to i2c-mux-gpio and
i2c-mux-pinctrl that determines if all involved devices used to update the
mux are controlled by the same root i2c adapter that is muxed. When this
is the case, the select-transfer-deselect operations should be locked
individually to avoid the deadlock. The i2c bus *is* still locked
during muxing, since the muxing happens as part of i2c transfers. This
is true even if the MUX is updated with several transfers to the GPIO (at
least as long as *all* MUX changes are using the i2c master bus). A lock
is added to i2c adapters that muxes on that adapter grab, so that transfers
through the muxes are serialized.

Concerns:
- The locking is perhaps too complex?
- I worry about the priority inheritance aspect of the adapter lock. When
  the transfers behind the mux are divided into select-transfer-deselect all
  locked individually, low priority transfers get more chances to interfere
  with high priority transfers.
- When doing an i2c_transfer() in_atomic() context or with irqs_disabled(),
  there is a higher possibility that the mux is not returned to its idle
  state after a failed (-EAGAIN) transfer due to trylock.
- Is the detection of i2c-controlled gpios and pinctrls sane (i.e. the
  usage of the new i2c_root_adapter() function in 18/24)?

To summarize the series, there's some i2c-mux infrastructure cleanup work
first (I think that part stands by itself as desireable regardless), the
locking changes are in 16/24 and after with the real meat in 18/24. There
is some documentation added in 19/24 while 20/24 and after are cleanups to
existing drivers utilizing the new stuff.

PS. needs a bunch of testing, I do not have access to all the involved hw.

Specifically, thank you Antti for testing v5, but I did not add any
Tested-by for v6 since I moved the lock from the mux itself to the mux
parent adapter. I did this to cope with the situation I described in
    http://marc.info/?l=linux-i2c&m=145875234525803&w=2
thus making it possible to get rid of the unlocked accesses in the
si2168 driver (patch 21/24). I also didn't add any Reviewed-by for
the parts of the rtl2832 driver changes that suffered the most from
driver updates since v4.5-rc7, so please review that again as well.

This series can also be pulled from github, if that is preferred:

---------------------
The following changes since commit f55532a0c0b8bb6148f4e07853b876ef73bc69ca:

  Linux 4.6-rc1 (2016-03-26 16:03:24 -0700)

are available in the git repository at:

  https://github.com/peda-r/i2c-mux.git mux-core-and-locking-6

for you to fetch changes up to 81830e43de2bc849848b939166103217ac444df5:

  [media] rtl2832: regmap is aware of lockdep, drop local locking hack (2016-04-03 09:35:52 +0200)
---------------------

v6 compared to v5:
- Rebase on top of v4.6-rc1
- Adjust to gpio subsystem overhaul.
- Adjust to changes in the inv_mpu6050 driver.
- Adjust to changes in the rtl2832 driver.
- Fix some new trivial checkpatch issues.
- Rename "self-locked" muxes "mux-locked" instead, since the lock has
  been moved to the parent adapter and is common for all muxes with
  the same parent adapter. The advantage is that address collisions
  behind sibling muxes are handled. Parent-locked muxes also grab this
  new mux-lock so that parent-locked and mux-locked siblings interact
  better.
- Firmware mutex added to the si2168 driver.

v5 compared to v4 (only published as a git branch):
- Rebase on top of v4.5-rc7.
- A new patch making me maintainer of i2c muxes (also sent separately).
- A new file Documentation/i2c/i2c-topology that describes various muxing
  issues.
- Rename "i2c-controlled" muxes "self-locked" instead, as it is perfectly
  reasonable to have i2c-controlled muxes that use the pre-existing locking
  scheme. The pre-existing locking scheme for i2c muxes is from here on
  called "parent-locked".
- Rename i2c-mux.c:i2c_mux_master_xfer to __i2c_mux_master_xfer since it
  calls __i2c_transfer, which leaves room for a new i2c_mux_master_xfer
  that calls i2c_transfer. Similar rename shuffle for i2c_mux_smbus_xfer.
- Use sizeof(*priv) instead of sizeof(struct i2c_mux_priv). One instance.
- Some follow-up patches that were posted in response to v2-v4 cleaning up
  and simplifying various i2c muxes outside drivers/i2c/, among those is
  an unrelated cleanup patch to drivers/media/dvb-frontends/rtl2832.c that
  I carry here since it conflicts (trivially) with this series. That
  unrelated patch is (currently) the last patch in the series.

v4 compared to v3:
- Rebase on top of v4.5-rc6.
- Update to add new i2c-mux interfaces in 01/18 including glue to implement
  the old interfaces in terms of the new interfaces, then change the
  mux users over to the new interfaces one by one (in 02/18 through 14/18),
  and finally removing the old interfaces in 15/18. I.e. the first 15
  patches of v4 replaces the first 5 patches of v3, with the following
  points describing changes in the end result. Each patch is now touching
  only one subsystem.
- Rename i2c_add_mux_adapter and i2c_del_mux_adapters to i2c_mux_add_adapter
  and i2c_mux_del_adapters (so that the old functions can live on during the
  transition).
- Make i2c_mux_alloc take a parent and the select/deselect ops as
  arguments. Also add a flags argument to prevent churn later on.
- Add a new interface i2c_mux_one_adapter(). Make use of it in suitable
  mux users with a single child adapter.
- Adjust to a rename in struct gpio_chip.
- Update a couple of comments to match the new code.

v3 compared to v2:
- Fix devm_kfree of a NULL pointer in i2c_mux_reserve_adapters().
- Remove device tree "i2c-controlled" property and determine this by walking
  the dev tree instead.
- Fix compile problems with inv_mpu_acpi.c
- Wait with adding the client pointer to patch 2/8 for pca9541 and pca954x.

v2 compared to v1:
- Allocate mux core and (optional) priv in a combined allocation.
- Kill dev_err messages triggered by memory allocation failure.
- Fix the device specific i2c muxes that I had overlooked.
- Rebase on top of v4.4-rc8 (was based on v4.4-rc6 previously).
- Drop the last two patches in the series.

Cheers,
Peter

Antti Palosaari (1):
  [media] si2168: change the i2c gate to be mux-locked

Peter Rosin (23):
  i2c-mux: add common data for every i2c-mux instance
  i2c: i2c-mux-gpio: convert to use an explicit i2c mux core
  i2c: i2c-mux-pinctrl: convert to use an explicit i2c mux core
  i2c: i2c-arb-gpio-challenge: convert to use an explicit i2c mux core
  i2c: i2c-mux-pca9541: convert to use an explicit i2c mux core
  i2c: i2c-mux-pca954x: convert to use an explicit i2c mux core
  i2c: i2c-mux-reg: convert to use an explicit i2c mux core
  iio: imu: inv_mpu6050: convert to use an explicit i2c mux core
  [media] m88ds3103: convert to use an explicit i2c mux core
  [media] rtl2830: convert to use an explicit i2c mux core
  [media] rtl2832: convert to use an explicit i2c mux core
  [media] si2168: convert to use an explicit i2c mux core
  [media] cx231xx: convert to use an explicit i2c mux core
  of/unittest: convert to use an explicit i2c mux core
  i2c-mux: drop old unused i2c-mux api
  i2c: allow adapter drivers to override the adapter locking
  i2c: muxes always lock the parent adapter
  i2c-mux: relax locking of the top i2c adapter during mux-locked muxing
  i2c-mux: document i2c muxes and elaborate on parent-/mux-locked muxes
  iio: imu: inv_mpu6050: change the i2c gate to be mux-locked
  [media] rtl2832: change the i2c gate to be mux-locked
  [media] rtl2832_sdr: get rid of empty regmap wrappers
  [media] rtl2832: regmap is aware of lockdep, drop local locking hack

 Documentation/i2c/i2c-topology               | 370 +++++++++++++++++++++++++++
 MAINTAINERS                                  |   1 +
 drivers/i2c/i2c-core.c                       |  66 +++--
 drivers/i2c/i2c-mux.c                        | 350 ++++++++++++++++++++-----
 drivers/i2c/muxes/i2c-arb-gpio-challenge.c   |  47 ++--
 drivers/i2c/muxes/i2c-mux-gpio.c             |  72 +++---
 drivers/i2c/muxes/i2c-mux-pca9541.c          |  55 ++--
 drivers/i2c/muxes/i2c-mux-pca954x.c          |  64 ++---
 drivers/i2c/muxes/i2c-mux-pinctrl.c          | 124 +++++----
 drivers/i2c/muxes/i2c-mux-reg.c              |  63 ++---
 drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c   |   2 +-
 drivers/iio/imu/inv_mpu6050/inv_mpu_core.c   |   1 -
 drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c    |  78 ++----
 drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h    |   3 +-
 drivers/media/dvb-frontends/m88ds3103.c      |  18 +-
 drivers/media/dvb-frontends/m88ds3103_priv.h |   2 +-
 drivers/media/dvb-frontends/rtl2830.c        |  17 +-
 drivers/media/dvb-frontends/rtl2830_priv.h   |   2 +-
 drivers/media/dvb-frontends/rtl2832.c        | 241 +++--------------
 drivers/media/dvb-frontends/rtl2832.h        |   4 +-
 drivers/media/dvb-frontends/rtl2832_priv.h   |   3 +-
 drivers/media/dvb-frontends/rtl2832_sdr.c    | 303 ++++++++++------------
 drivers/media/dvb-frontends/rtl2832_sdr.h    |   5 +-
 drivers/media/dvb-frontends/si2168.c         | 103 +++-----
 drivers/media/dvb-frontends/si2168_priv.h    |   3 +-
 drivers/media/usb/cx231xx/cx231xx-core.c     |   6 +-
 drivers/media/usb/cx231xx/cx231xx-i2c.c      |  47 ++--
 drivers/media/usb/cx231xx/cx231xx.h          |   4 +-
 drivers/media/usb/dvb-usb-v2/rtl28xxu.c      |   5 +-
 drivers/of/unittest.c                        |  40 ++-
 include/linux/i2c-mux.h                      |  64 ++++-
 include/linux/i2c.h                          |  29 ++-
 32 files changed, 1277 insertions(+), 915 deletions(-)
 create mode 100644 Documentation/i2c/i2c-topology

-- 
2.1.4

[PATCH v6 01/24] i2c-mux: add common data for every i2c-mux instance

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

All i2c-muxes have a parent adapter and one or many child
adapters. A mux also has some means of selection. Previously,
this was stored per child adapter, but it is only needed
to keep track of this per mux.

Add an i2c mux core, that keeps track of this consistently.

Also add some glue for users of the old interface, which will
create one implicit mux core per child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/i2c-mux.c   | 238 ++++++++++++++++++++++++++++++++++++++----------
 include/linux/i2c-mux.h |  47 ++++++++++
 2 files changed, 237 insertions(+), 48 deletions(-)

diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index d4022878b2f0..d95eb66e11bf 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -28,33 +28,34 @@
 #include <linux/slab.h>
 
 /* multiplexer per channel data */
+struct i2c_mux_priv_old {
+	void *mux_priv;
+	int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
+	int (*deselect)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
+};
+
 struct i2c_mux_priv {
 	struct i2c_adapter adap;
 	struct i2c_algorithm algo;
-
-	struct i2c_adapter *parent;
-	struct device *mux_dev;
-	void *mux_priv;
+	struct i2c_mux_core *muxc;
 	u32 chan_id;
-
-	int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
-	int (*deselect)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
 };
 
 static int i2c_mux_master_xfer(struct i2c_adapter *adap,
 			       struct i2c_msg msgs[], int num)
 {
 	struct i2c_mux_priv *priv = adap->algo_data;
-	struct i2c_adapter *parent = priv->parent;
+	struct i2c_mux_core *muxc = priv->muxc;
+	struct i2c_adapter *parent = muxc->parent;
 	int ret;
 
 	/* Switch to the right mux port and perform the transfer. */
 
-	ret = priv->select(parent, priv->mux_priv, priv->chan_id);
+	ret = muxc->select(muxc, priv->chan_id);
 	if (ret >= 0)
 		ret = __i2c_transfer(parent, msgs, num);
-	if (priv->deselect)
-		priv->deselect(parent, priv->mux_priv, priv->chan_id);
+	if (muxc->deselect)
+		muxc->deselect(muxc, priv->chan_id);
 
 	return ret;
 }
@@ -65,17 +66,18 @@ static int i2c_mux_smbus_xfer(struct i2c_adapter *adap,
 			      int size, union i2c_smbus_data *data)
 {
 	struct i2c_mux_priv *priv = adap->algo_data;
-	struct i2c_adapter *parent = priv->parent;
+	struct i2c_mux_core *muxc = priv->muxc;
+	struct i2c_adapter *parent = muxc->parent;
 	int ret;
 
 	/* Select the right mux port and perform the transfer. */
 
-	ret = priv->select(parent, priv->mux_priv, priv->chan_id);
+	ret = muxc->select(muxc, priv->chan_id);
 	if (ret >= 0)
 		ret = parent->algo->smbus_xfer(parent, addr, flags,
 					read_write, command, size, data);
-	if (priv->deselect)
-		priv->deselect(parent, priv->mux_priv, priv->chan_id);
+	if (muxc->deselect)
+		muxc->deselect(muxc, priv->chan_id);
 
 	return ret;
 }
@@ -84,7 +86,7 @@ static int i2c_mux_smbus_xfer(struct i2c_adapter *adap,
 static u32 i2c_mux_functionality(struct i2c_adapter *adap)
 {
 	struct i2c_mux_priv *priv = adap->algo_data;
-	struct i2c_adapter *parent = priv->parent;
+	struct i2c_adapter *parent = priv->muxc->parent;
 
 	return parent->algo->functionality(parent);
 }
@@ -102,30 +104,80 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)
 	return class;
 }
 
-struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
-				struct device *mux_dev,
-				void *mux_priv, u32 force_nr, u32 chan_id,
-				unsigned int class,
-				int (*select) (struct i2c_adapter *,
-					       void *, u32),
-				int (*deselect) (struct i2c_adapter *,
-						 void *, u32))
+int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters)
+{
+	struct i2c_adapter **adapter;
+
+	if (adapters <= muxc->max_adapters)
+		return 0;
+
+	adapter = devm_kmalloc_array(muxc->dev,
+				     adapters, sizeof(*adapter),
+				     GFP_KERNEL);
+	if (!adapter)
+		return -ENOMEM;
+
+	if (muxc->adapter) {
+		memcpy(adapter, muxc->adapter,
+		       muxc->max_adapters * sizeof(*adapter));
+		devm_kfree(muxc->dev, muxc->adapter);
+	}
+
+	muxc->adapter = adapter;
+	muxc->max_adapters = adapters;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_mux_reserve_adapters);
+
+struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
+				   struct device *dev, int sizeof_priv,
+				   u32 flags,
+				   int (*select)(struct i2c_mux_core *, u32),
+				   int (*deselect)(struct i2c_mux_core *, u32))
 {
+	struct i2c_mux_core *muxc;
+
+	muxc = devm_kzalloc(dev, sizeof(*muxc) + sizeof_priv, GFP_KERNEL);
+	if (!muxc)
+		return NULL;
+	if (sizeof_priv)
+		muxc->priv = muxc + 1;
+
+	muxc->parent = parent;
+	muxc->dev = dev;
+	muxc->select = select;
+	muxc->deselect = deselect;
+
+	return muxc;
+}
+EXPORT_SYMBOL_GPL(i2c_mux_alloc);
+
+int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
+			u32 force_nr, u32 chan_id,
+			unsigned int class)
+{
+	struct i2c_adapter *parent = muxc->parent;
 	struct i2c_mux_priv *priv;
 	char symlink_name[20];
 	int ret;
 
-	priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL);
+	if (muxc->adapters >= muxc->max_adapters) {
+		int new_max = 2 * muxc->max_adapters;
+
+		if (!new_max)
+			new_max = 1;
+		ret = i2c_mux_reserve_adapters(muxc, new_max);
+		if (ret)
+			return ret;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
-		return NULL;
+		return -ENOMEM;
 
 	/* Set up private adapter data */
-	priv->parent = parent;
-	priv->mux_dev = mux_dev;
-	priv->mux_priv = mux_priv;
+	priv->muxc = muxc;
 	priv->chan_id = chan_id;
-	priv->select = select;
-	priv->deselect = deselect;
 
 	/* Need to do algo dynamically because we don't know ahead
 	 * of time what sort of physical adapter we'll be dealing with.
@@ -159,11 +211,11 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 	 * Try to populate the mux adapter's of_node, expands to
 	 * nothing if !CONFIG_OF.
 	 */
-	if (mux_dev->of_node) {
+	if (muxc->dev->of_node) {
 		struct device_node *child;
 		u32 reg;
 
-		for_each_child_of_node(mux_dev->of_node, child) {
+		for_each_child_of_node(muxc->dev->of_node, child) {
 			ret = of_property_read_u32(child, "reg", &reg);
 			if (ret)
 				continue;
@@ -177,8 +229,9 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 	/*
 	 * Associate the mux channel with an ACPI node.
 	 */
-	if (has_acpi_companion(mux_dev))
-		acpi_preset_companion(&priv->adap.dev, ACPI_COMPANION(mux_dev),
+	if (has_acpi_companion(muxc->dev))
+		acpi_preset_companion(&priv->adap.dev,
+				      ACPI_COMPANION(muxc->dev),
 				      chan_id);
 
 	if (force_nr) {
@@ -192,33 +245,122 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 			"failed to add mux-adapter (error=%d)\n",
 			ret);
 		kfree(priv);
-		return NULL;
+		return ret;
 	}
 
-	WARN(sysfs_create_link(&priv->adap.dev.kobj, &mux_dev->kobj, "mux_device"),
-			       "can't create symlink to mux device\n");
+	WARN(sysfs_create_link(&priv->adap.dev.kobj, &muxc->dev->kobj,
+			       "mux_device"),
+	     "can't create symlink to mux device\n");
 
 	snprintf(symlink_name, sizeof(symlink_name), "channel-%u", chan_id);
-	WARN(sysfs_create_link(&mux_dev->kobj, &priv->adap.dev.kobj, symlink_name),
-			       "can't create symlink for channel %u\n", chan_id);
+	WARN(sysfs_create_link(&muxc->dev->kobj, &priv->adap.dev.kobj,
+			       symlink_name),
+	     "can't create symlink for channel %u\n", chan_id);
 	dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
 		 i2c_adapter_id(&priv->adap));
 
-	return &priv->adap;
+	muxc->adapter[muxc->adapters++] = &priv->adap;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_mux_add_adapter);
+
+struct i2c_mux_core *i2c_mux_one_adapter(struct i2c_adapter *parent,
+					 struct device *dev, int sizeof_priv,
+					 u32 flags, u32 force_nr,
+					 u32 chan_id, unsigned int class,
+					 int (*select)(struct i2c_mux_core *,
+						       u32),
+					 int (*deselect)(struct i2c_mux_core *,
+							 u32))
+{
+	struct i2c_mux_core *muxc;
+	int ret;
+
+	muxc = i2c_mux_alloc(parent, dev, sizeof_priv, flags, select, deselect);
+	if (!muxc)
+		return ERR_PTR(-ENOMEM);
+
+	ret = i2c_mux_add_adapter(muxc, force_nr, chan_id, class);
+	if (ret) {
+		devm_kfree(dev, muxc);
+		return ERR_PTR(ret);
+	}
+
+	return muxc;
+}
+EXPORT_SYMBOL_GPL(i2c_mux_one_adapter);
+
+static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc);
+
+	return priv->select(muxc->parent, priv->mux_priv, chan);
+}
+
+static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc);
+
+	return priv->deselect(muxc->parent, priv->mux_priv, chan);
+}
+
+struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
+					struct device *mux_dev, void *mux_priv,
+					u32 force_nr, u32 chan_id,
+					unsigned int class,
+					int (*select)(struct i2c_adapter *,
+						      void *, u32),
+					int (*deselect)(struct i2c_adapter *,
+							void *, u32))
+{
+	struct i2c_mux_core *muxc;
+	struct i2c_mux_priv_old *priv;
+
+	muxc = i2c_mux_one_adapter(parent, mux_dev, sizeof(*priv), 0,
+				   force_nr, chan_id, class,
+				   i2c_mux_select,
+				   deselect ? i2c_mux_deselect : NULL);
+	if (IS_ERR(muxc))
+		return NULL;
+
+	priv = i2c_mux_priv(muxc);
+	priv->select = select;
+	priv->deselect = deselect;
+	priv->mux_priv = mux_priv;
+
+	return muxc->adapter[0];
 }
 EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
 
-void i2c_del_mux_adapter(struct i2c_adapter *adap)
+void i2c_mux_del_adapters(struct i2c_mux_core *muxc)
 {
-	struct i2c_mux_priv *priv = adap->algo_data;
 	char symlink_name[20];
 
-	snprintf(symlink_name, sizeof(symlink_name), "channel-%u", priv->chan_id);
-	sysfs_remove_link(&priv->mux_dev->kobj, symlink_name);
+	while (muxc->adapters) {
+		struct i2c_adapter *adap = muxc->adapter[--muxc->adapters];
+		struct i2c_mux_priv *priv = adap->algo_data;
+
+		muxc->adapter[muxc->adapters] = NULL;
+
+		snprintf(symlink_name, sizeof(symlink_name),
+			 "channel-%u", priv->chan_id);
+		sysfs_remove_link(&muxc->dev->kobj, symlink_name);
+
+		sysfs_remove_link(&priv->adap.dev.kobj, "mux_device");
+		i2c_del_adapter(adap);
+		kfree(priv);
+	}
+}
+EXPORT_SYMBOL_GPL(i2c_mux_del_adapters);
+
+void i2c_del_mux_adapter(struct i2c_adapter *adap)
+{
+	struct i2c_mux_priv *priv = adap->algo_data;
+	struct i2c_mux_core *muxc = priv->muxc;
 
-	sysfs_remove_link(&priv->adap.dev.kobj, "mux_device");
-	i2c_del_adapter(adap);
-	kfree(priv);
+	i2c_mux_del_adapters(muxc);
+	devm_kfree(muxc->dev, muxc->adapter);
+	devm_kfree(muxc->dev, muxc);
 }
 EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
 
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index b5f9a007a3ab..0d97d7a3f03c 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -27,6 +27,32 @@
 
 #ifdef __KERNEL__
 
+struct i2c_mux_core {
+	struct i2c_adapter *parent;
+	struct i2c_adapter **adapter;
+	int adapters;
+	int max_adapters;
+	struct device *dev;
+
+	void *priv;
+
+	int (*select)(struct i2c_mux_core *, u32 chan_id);
+	int (*deselect)(struct i2c_mux_core *, u32 chan_id);
+};
+
+struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
+				   struct device *dev, int sizeof_priv,
+				   u32 flags,
+				   int (*select)(struct i2c_mux_core *, u32),
+				   int (*deselect)(struct i2c_mux_core *, u32));
+
+static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
+{
+	return muxc->priv;
+}
+
+int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters);
+
 /*
  * Called to create a i2c bus on a multiplexed bus segment.
  * The mux_dev and chan_id parameters are passed to the select
@@ -41,8 +67,29 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 					       void *mux_dev, u32 chan_id),
 				int (*deselect) (struct i2c_adapter *,
 						 void *mux_dev, u32 chan_id));
+/*
+ * Called to create a i2c bus on a multiplexed bus segment.
+ * The chan_id parameter is passed to the select and deselect
+ * callback functions to perform hardware-specific mux control.
+ */
+int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
+			u32 force_nr, u32 chan_id,
+			unsigned int class);
+
+/*
+ * Allocate an i2c_mux_core and add one adapter with one call.
+ */
+struct i2c_mux_core *i2c_mux_one_adapter(struct i2c_adapter *parent,
+					 struct device *dev, int sizeof_priv,
+					 u32 flags, u32 force_nr,
+					 u32 chan_id, unsigned int class,
+					 int (*select)(struct i2c_mux_core *,
+						       u32),
+					 int (*deselect)(struct i2c_mux_core *,
+							 u32));
 
 void i2c_del_mux_adapter(struct i2c_adapter *adap);
+void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
 
 #endif /* __KERNEL__ */
 
-- 
2.1.4

[PATCH v6 02/24] i2c: i2c-mux-gpio: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/muxes/i2c-mux-gpio.c | 54 ++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 33 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
index b8e11c16d98c..1bcc26737359 100644
--- a/drivers/i2c/muxes/i2c-mux-gpio.c
+++ b/drivers/i2c/muxes/i2c-mux-gpio.c
@@ -18,8 +18,6 @@
 #include <linux/of_gpio.h>
 
 struct gpiomux {
-	struct i2c_adapter *parent;
-	struct i2c_adapter **adap; /* child busses */
 	struct i2c_mux_gpio_platform_data data;
 	unsigned gpio_base;
 };
@@ -33,18 +31,18 @@ static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
 					val & (1 << i));
 }
 
-static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
+static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct gpiomux *mux = data;
+	struct gpiomux *mux = i2c_mux_priv(muxc);
 
 	i2c_mux_gpio_set(mux, chan);
 
 	return 0;
 }
 
-static int i2c_mux_gpio_deselect(struct i2c_adapter *adap, void *data, u32 chan)
+static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct gpiomux *mux = data;
+	struct gpiomux *mux = i2c_mux_priv(muxc);
 
 	i2c_mux_gpio_set(mux, mux->data.idle);
 
@@ -136,19 +134,19 @@ static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
 
 static int i2c_mux_gpio_probe(struct platform_device *pdev)
 {
+	struct i2c_mux_core *muxc;
 	struct gpiomux *mux;
 	struct i2c_adapter *parent;
-	int (*deselect) (struct i2c_adapter *, void *, u32);
 	unsigned initial_state, gpio_base;
 	int i, ret;
 
-	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
-	if (!mux) {
-		dev_err(&pdev->dev, "Cannot allocate gpiomux structure");
+	muxc = i2c_mux_alloc(NULL, &pdev->dev, sizeof(*mux), 0,
+			     i2c_mux_gpio_select, NULL);
+	if (!muxc)
 		return -ENOMEM;
-	}
+	mux = i2c_mux_priv(muxc);
 
-	platform_set_drvdata(pdev, mux);
+	platform_set_drvdata(pdev, muxc);
 
 	if (!dev_get_platdata(&pdev->dev)) {
 		ret = i2c_mux_gpio_probe_dt(mux, pdev);
@@ -180,24 +178,18 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	if (!parent)
 		return -EPROBE_DEFER;
 
-	mux->parent = parent;
+	muxc->parent = parent;
 	mux->gpio_base = gpio_base;
 
-	mux->adap = devm_kzalloc(&pdev->dev,
-				 sizeof(*mux->adap) * mux->data.n_values,
-				 GFP_KERNEL);
-	if (!mux->adap) {
-		dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
-		ret = -ENOMEM;
+	ret = i2c_mux_reserve_adapters(muxc, mux->data.n_values);
+	if (ret)
 		goto alloc_failed;
-	}
 
 	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
 		initial_state = mux->data.idle;
-		deselect = i2c_mux_gpio_deselect;
+		muxc->deselect = i2c_mux_gpio_deselect;
 	} else {
 		initial_state = mux->data.values[0];
-		deselect = NULL;
 	}
 
 	for (i = 0; i < mux->data.n_gpios; i++) {
@@ -223,11 +215,8 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 		u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
 		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
 
-		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
-						   mux->data.values[i], class,
-						   i2c_mux_gpio_select, deselect);
-		if (!mux->adap[i]) {
-			ret = -ENODEV;
+		ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
+		if (ret) {
 			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 			goto add_adapter_failed;
 		}
@@ -239,8 +228,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	return 0;
 
 add_adapter_failed:
-	for (; i > 0; i--)
-		i2c_del_mux_adapter(mux->adap[i - 1]);
+	i2c_mux_del_adapters(muxc);
 	i = mux->data.n_gpios;
 err_request_gpio:
 	for (; i > 0; i--)
@@ -253,16 +241,16 @@ alloc_failed:
 
 static int i2c_mux_gpio_remove(struct platform_device *pdev)
 {
-	struct gpiomux *mux = platform_get_drvdata(pdev);
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
+	struct gpiomux *mux = i2c_mux_priv(muxc);
 	int i;
 
-	for (i = 0; i < mux->data.n_values; i++)
-		i2c_del_mux_adapter(mux->adap[i]);
+	i2c_mux_del_adapters(muxc);
 
 	for (i = 0; i < mux->data.n_gpios; i++)
 		gpio_free(mux->gpio_base + mux->data.gpios[i]);
 
-	i2c_put_adapter(mux->parent);
+	i2c_put_adapter(muxc->parent);
 
 	return 0;
 }
-- 
2.1.4

[PATCH v6 03/24] i2c: i2c-mux-pinctrl: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/muxes/i2c-mux-pinctrl.c | 86 +++++++++++++------------------------
 1 file changed, 30 insertions(+), 56 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index b5a982ba8898..bbfabf4f52be 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -26,27 +26,22 @@
 #include <linux/of.h>
 
 struct i2c_mux_pinctrl {
-	struct device *dev;
 	struct i2c_mux_pinctrl_platform_data *pdata;
 	struct pinctrl *pinctrl;
 	struct pinctrl_state **states;
 	struct pinctrl_state *state_idle;
-	struct i2c_adapter *parent;
-	struct i2c_adapter **busses;
 };
 
-static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
-				  u32 chan)
+static int i2c_mux_pinctrl_select(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct i2c_mux_pinctrl *mux = data;
+	struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);
 
 	return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
 }
 
-static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
-				    u32 chan)
+static int i2c_mux_pinctrl_deselect(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct i2c_mux_pinctrl *mux = data;
+	struct i2c_mux_pinctrl *mux = i2c_mux_priv(muxc);
 
 	return pinctrl_select_state(mux->pinctrl, mux->state_idle);
 }
@@ -55,6 +50,7 @@ static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
 static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 				struct platform_device *pdev)
 {
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 	struct device_node *np = pdev->dev.of_node;
 	int num_names, i, ret;
 	struct device_node *adapter_np;
@@ -64,15 +60,12 @@ static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 		return 0;
 
 	mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
-	if (!mux->pdata) {
-		dev_err(mux->dev,
-			"Cannot allocate i2c_mux_pinctrl_platform_data\n");
+	if (!mux->pdata)
 		return -ENOMEM;
-	}
 
 	num_names = of_property_count_strings(np, "pinctrl-names");
 	if (num_names < 0) {
-		dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
+		dev_err(muxc->dev, "Cannot parse pinctrl-names: %d\n",
 			num_names);
 		return num_names;
 	}
@@ -80,23 +73,21 @@ static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 	mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
 		sizeof(*mux->pdata->pinctrl_states) * num_names,
 		GFP_KERNEL);
-	if (!mux->pdata->pinctrl_states) {
-		dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
+	if (!mux->pdata->pinctrl_states)
 		return -ENOMEM;
-	}
 
 	for (i = 0; i < num_names; i++) {
 		ret = of_property_read_string_index(np, "pinctrl-names", i,
 			&mux->pdata->pinctrl_states[mux->pdata->bus_count]);
 		if (ret < 0) {
-			dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
+			dev_err(muxc->dev, "Cannot parse pinctrl-names: %d\n",
 				ret);
 			return ret;
 		}
 		if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
 			    "idle")) {
 			if (i != num_names - 1) {
-				dev_err(mux->dev, "idle state must be last\n");
+				dev_err(muxc->dev, "idle state must be last\n");
 				return -EINVAL;
 			}
 			mux->pdata->pinctrl_state_idle = "idle";
@@ -107,13 +98,13 @@ static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 
 	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
 	if (!adapter_np) {
-		dev_err(mux->dev, "Cannot parse i2c-parent\n");
+		dev_err(muxc->dev, "Cannot parse i2c-parent\n");
 		return -ENODEV;
 	}
 	adapter = of_find_i2c_adapter_by_node(adapter_np);
 	of_node_put(adapter_np);
 	if (!adapter) {
-		dev_err(mux->dev, "Cannot find parent bus\n");
+		dev_err(muxc->dev, "Cannot find parent bus\n");
 		return -EPROBE_DEFER;
 	}
 	mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
@@ -131,19 +122,18 @@ static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 
 static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 {
+	struct i2c_mux_core *muxc;
 	struct i2c_mux_pinctrl *mux;
-	int (*deselect)(struct i2c_adapter *, void *, u32);
 	int i, ret;
 
-	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
-	if (!mux) {
-		dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
+	muxc = i2c_mux_alloc(NULL, &pdev->dev, sizeof(*mux), 0,
+			     i2c_mux_pinctrl_select, NULL);
+	if (!muxc) {
 		ret = -ENOMEM;
 		goto err;
 	}
-	platform_set_drvdata(pdev, mux);
-
-	mux->dev = &pdev->dev;
+	mux = i2c_mux_priv(muxc);
+	platform_set_drvdata(pdev, muxc);
 
 	mux->pdata = dev_get_platdata(&pdev->dev);
 	if (!mux->pdata) {
@@ -166,14 +156,9 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	mux->busses = devm_kzalloc(&pdev->dev,
-				   sizeof(*mux->busses) * mux->pdata->bus_count,
-				   GFP_KERNEL);
-	if (!mux->busses) {
-		dev_err(&pdev->dev, "Cannot allocate busses\n");
-		ret = -ENOMEM;
+	ret = i2c_mux_reserve_adapters(muxc, mux->pdata->bus_count);
+	if (ret)
 		goto err;
-	}
 
 	mux->pinctrl = devm_pinctrl_get(&pdev->dev);
 	if (IS_ERR(mux->pinctrl)) {
@@ -203,13 +188,11 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 			goto err;
 		}
 
-		deselect = i2c_mux_pinctrl_deselect;
-	} else {
-		deselect = NULL;
+		muxc->deselect = i2c_mux_pinctrl_deselect;
 	}
 
-	mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
-	if (!mux->parent) {
+	muxc->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
+	if (!muxc->parent) {
 		dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
 			mux->pdata->parent_bus_num);
 		ret = -EPROBE_DEFER;
@@ -220,12 +203,8 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 		u32 bus = mux->pdata->base_bus_num ?
 				(mux->pdata->base_bus_num + i) : 0;
 
-		mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
-						     mux, bus, i, 0,
-						     i2c_mux_pinctrl_select,
-						     deselect);
-		if (!mux->busses[i]) {
-			ret = -ENODEV;
+		ret = i2c_mux_add_adapter(muxc, bus, i, 0);
+		if (ret) {
 			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 			goto err_del_adapter;
 		}
@@ -234,23 +213,18 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 	return 0;
 
 err_del_adapter:
-	for (; i > 0; i--)
-		i2c_del_mux_adapter(mux->busses[i - 1]);
-	i2c_put_adapter(mux->parent);
+	i2c_mux_del_adapters(muxc);
+	i2c_put_adapter(muxc->parent);
 err:
 	return ret;
 }
 
 static int i2c_mux_pinctrl_remove(struct platform_device *pdev)
 {
-	struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
-	int i;
-
-	for (i = 0; i < mux->pdata->bus_count; i++)
-		i2c_del_mux_adapter(mux->busses[i]);
-
-	i2c_put_adapter(mux->parent);
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 
+	i2c_mux_del_adapters(muxc);
+	i2c_put_adapter(muxc->parent);
 	return 0;
 }
 
-- 
2.1.4

[PATCH v6 04/24] i2c: i2c-arb-gpio-challenge: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/muxes/i2c-arb-gpio-challenge.c | 47 +++++++++++++-----------------
 1 file changed, 20 insertions(+), 27 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
index 402e3a6c671a..a42827b3c672 100644
--- a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
+++ b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
@@ -28,8 +28,6 @@
 /**
  * struct i2c_arbitrator_data - Driver data for I2C arbitrator
  *
- * @parent: Parent adapter
- * @child: Child bus
  * @our_gpio: GPIO we'll use to claim.
  * @our_gpio_release: 0 if active high; 1 if active low; AKA if the GPIO ==
  *   this then consider it released.
@@ -42,8 +40,6 @@
  */
 
 struct i2c_arbitrator_data {
-	struct i2c_adapter *parent;
-	struct i2c_adapter *child;
 	int our_gpio;
 	int our_gpio_release;
 	int their_gpio;
@@ -59,9 +55,9 @@ struct i2c_arbitrator_data {
  *
  * Use the GPIO-based signalling protocol; return -EBUSY if we fail.
  */
-static int i2c_arbitrator_select(struct i2c_adapter *adap, void *data, u32 chan)
+static int i2c_arbitrator_select(struct i2c_mux_core *muxc, u32 chan)
 {
-	const struct i2c_arbitrator_data *arb = data;
+	const struct i2c_arbitrator_data *arb = i2c_mux_priv(muxc);
 	unsigned long stop_retry, stop_time;
 
 	/* Start a round of trying to claim the bus */
@@ -93,7 +89,7 @@ static int i2c_arbitrator_select(struct i2c_adapter *adap, void *data, u32 chan)
 	/* Give up, release our claim */
 	gpio_set_value(arb->our_gpio, arb->our_gpio_release);
 	udelay(arb->slew_delay_us);
-	dev_err(&adap->dev, "Could not claim bus, timeout\n");
+	dev_err(muxc->dev, "Could not claim bus, timeout\n");
 	return -EBUSY;
 }
 
@@ -102,10 +98,9 @@ static int i2c_arbitrator_select(struct i2c_adapter *adap, void *data, u32 chan)
  *
  * Release the I2C bus using the GPIO-based signalling protocol.
  */
-static int i2c_arbitrator_deselect(struct i2c_adapter *adap, void *data,
-				   u32 chan)
+static int i2c_arbitrator_deselect(struct i2c_mux_core *muxc, u32 chan)
 {
-	const struct i2c_arbitrator_data *arb = data;
+	const struct i2c_arbitrator_data *arb = i2c_mux_priv(muxc);
 
 	/* Release the bus and wait for the other master to notice */
 	gpio_set_value(arb->our_gpio, arb->our_gpio_release);
@@ -119,6 +114,7 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct device_node *parent_np;
+	struct i2c_mux_core *muxc;
 	struct i2c_arbitrator_data *arb;
 	enum of_gpio_flags gpio_flags;
 	unsigned long out_init;
@@ -134,12 +130,13 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
-	if (!arb) {
-		dev_err(dev, "Cannot allocate i2c_arbitrator_data\n");
+	muxc = i2c_mux_alloc(NULL, dev, sizeof(*arb), 0,
+			     i2c_arbitrator_select, i2c_arbitrator_deselect);
+	if (!muxc)
 		return -ENOMEM;
-	}
-	platform_set_drvdata(pdev, arb);
+	arb = i2c_mux_priv(muxc);
+
+	platform_set_drvdata(pdev, muxc);
 
 	/* Request GPIOs */
 	ret = of_get_named_gpio_flags(np, "our-claim-gpio", 0, &gpio_flags);
@@ -196,21 +193,18 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 		dev_err(dev, "Cannot parse i2c-parent\n");
 		return -EINVAL;
 	}
-	arb->parent = of_get_i2c_adapter_by_node(parent_np);
+	muxc->parent = of_get_i2c_adapter_by_node(parent_np);
 	of_node_put(parent_np);
-	if (!arb->parent) {
+	if (!muxc->parent) {
 		dev_err(dev, "Cannot find parent bus\n");
 		return -EPROBE_DEFER;
 	}
 
 	/* Actually add the mux adapter */
-	arb->child = i2c_add_mux_adapter(arb->parent, dev, arb, 0, 0, 0,
-					 i2c_arbitrator_select,
-					 i2c_arbitrator_deselect);
-	if (!arb->child) {
+	ret = i2c_mux_add_adapter(muxc, 0, 0, 0);
+	if (ret) {
 		dev_err(dev, "Failed to add adapter\n");
-		ret = -ENODEV;
-		i2c_put_adapter(arb->parent);
+		i2c_put_adapter(muxc->parent);
 	}
 
 	return ret;
@@ -218,11 +212,10 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 
 static int i2c_arbitrator_remove(struct platform_device *pdev)
 {
-	struct i2c_arbitrator_data *arb = platform_get_drvdata(pdev);
-
-	i2c_del_mux_adapter(arb->child);
-	i2c_put_adapter(arb->parent);
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 
+	i2c_mux_del_adapters(muxc);
+	i2c_put_adapter(muxc->parent);
 	return 0;
 }
 
-- 
2.1.4

[PATCH v6 05/24] i2c: i2c-mux-pca9541: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/muxes/i2c-mux-pca9541.c | 55 ++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 32 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
index d0ba424adebc..93bea073ed13 100644
--- a/drivers/i2c/muxes/i2c-mux-pca9541.c
+++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
@@ -73,7 +73,7 @@
 #define SELECT_DELAY_LONG	1000
 
 struct pca9541 {
-	struct i2c_adapter *mux_adap;
+	struct i2c_client *client;
 	unsigned long select_timeout;
 	unsigned long arb_timeout;
 };
@@ -217,7 +217,8 @@ static const u8 pca9541_control[16] = {
  */
 static int pca9541_arbitrate(struct i2c_client *client)
 {
-	struct pca9541 *data = i2c_get_clientdata(client);
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+	struct pca9541 *data = i2c_mux_priv(muxc);
 	int reg;
 
 	reg = pca9541_reg_read(client, PCA9541_CONTROL);
@@ -285,9 +286,10 @@ static int pca9541_arbitrate(struct i2c_client *client)
 	return 0;
 }
 
-static int pca9541_select_chan(struct i2c_adapter *adap, void *client, u32 chan)
+static int pca9541_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct pca9541 *data = i2c_get_clientdata(client);
+	struct pca9541 *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
 	int ret;
 	unsigned long timeout = jiffies + ARB2_TIMEOUT;
 		/* give up after this time */
@@ -309,9 +311,11 @@ static int pca9541_select_chan(struct i2c_adapter *adap, void *client, u32 chan)
 	return -ETIMEDOUT;
 }
 
-static int pca9541_release_chan(struct i2c_adapter *adap,
-				void *client, u32 chan)
+static int pca9541_release_chan(struct i2c_mux_core *muxc, u32 chan)
 {
+	struct pca9541 *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+
 	pca9541_release_bus(client);
 	return 0;
 }
@@ -324,20 +328,12 @@ static int pca9541_probe(struct i2c_client *client,
 {
 	struct i2c_adapter *adap = client->adapter;
 	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct i2c_mux_core *muxc;
 	struct pca9541 *data;
 	int force;
-	int ret = -ENODEV;
 
 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
-		goto err;
-
-	data = kzalloc(sizeof(struct pca9541), GFP_KERNEL);
-	if (!data) {
-		ret = -ENOMEM;
-		goto err;
-	}
-
-	i2c_set_clientdata(client, data);
+		return -ENODEV;
 
 	/*
 	 * I2C accesses are unprotected here.
@@ -352,34 +348,29 @@ static int pca9541_probe(struct i2c_client *client,
 	force = 0;
 	if (pdata)
 		force = pdata->modes[0].adap_id;
-	data->mux_adap = i2c_add_mux_adapter(adap, &client->dev, client,
-					     force, 0, 0,
-					     pca9541_select_chan,
-					     pca9541_release_chan);
-
-	if (data->mux_adap == NULL) {
+	muxc = i2c_mux_one_adapter(adap, &client->dev, sizeof(*data), 0,
+				   force, 0, 0,
+				   pca9541_select_chan, pca9541_release_chan);
+	if (IS_ERR(muxc)) {
 		dev_err(&client->dev, "failed to register master selector\n");
-		goto exit_free;
+		return PTR_ERR(muxc);
 	}
+	data = i2c_mux_priv(muxc);
+	data->client = client;
+
+	i2c_set_clientdata(client, muxc);
 
 	dev_info(&client->dev, "registered master selector for I2C %s\n",
 		 client->name);
 
 	return 0;
-
-exit_free:
-	kfree(data);
-err:
-	return ret;
 }
 
 static int pca9541_remove(struct i2c_client *client)
 {
-	struct pca9541 *data = i2c_get_clientdata(client);
-
-	i2c_del_mux_adapter(data->mux_adap);
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 
-	kfree(data);
+	i2c_mux_del_adapters(muxc);
 	return 0;
 }
 
-- 
2.1.4

[PATCH v6 06/24] i2c: i2c-mux-pca954x: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Add a mask to handle the case where not all child adapters should
cause a mux deselect to happen, now that there is a common deselect op
for all child adapters.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/muxes/i2c-mux-pca954x.c | 64 +++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 31 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index acfcef3d4068..1693d29c11a4 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -60,9 +60,10 @@ enum pca_type {
 
 struct pca954x {
 	enum pca_type type;
-	struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
 
 	u8 last_chan;		/* last register value */
+	u8 deselect;
+	struct i2c_client *client;
 };
 
 struct chip_desc {
@@ -146,10 +147,10 @@ static int pca954x_reg_write(struct i2c_adapter *adap,
 	return ret;
 }
 
-static int pca954x_select_chan(struct i2c_adapter *adap,
-			       void *client, u32 chan)
+static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct pca954x *data = i2c_get_clientdata(client);
+	struct pca954x *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
 	const struct chip_desc *chip = &chips[data->type];
 	u8 regval;
 	int ret = 0;
@@ -162,21 +163,24 @@ static int pca954x_select_chan(struct i2c_adapter *adap,
 
 	/* Only select the channel if its different from the last channel */
 	if (data->last_chan != regval) {
-		ret = pca954x_reg_write(adap, client, regval);
+		ret = pca954x_reg_write(muxc->parent, client, regval);
 		data->last_chan = regval;
 	}
 
 	return ret;
 }
 
-static int pca954x_deselect_mux(struct i2c_adapter *adap,
-				void *client, u32 chan)
+static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct pca954x *data = i2c_get_clientdata(client);
+	struct pca954x *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+
+	if (!(data->deselect & (1 << chan)))
+		return 0;
 
 	/* Deselect active channel */
 	data->last_chan = 0;
-	return pca954x_reg_write(adap, client, data->last_chan);
+	return pca954x_reg_write(muxc->parent, client, data->last_chan);
 }
 
 /*
@@ -191,17 +195,21 @@ static int pca954x_probe(struct i2c_client *client,
 	bool idle_disconnect_dt;
 	struct gpio_desc *gpio;
 	int num, force, class;
+	struct i2c_mux_core *muxc;
 	struct pca954x *data;
 	int ret;
 
 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
 		return -ENODEV;
 
-	data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL);
-	if (!data)
+	muxc = i2c_mux_alloc(adap, &client->dev, sizeof(*data), 0,
+			     pca954x_select_chan, pca954x_deselect_mux);
+	if (!muxc)
 		return -ENOMEM;
+	data = i2c_mux_priv(muxc);
 
-	i2c_set_clientdata(client, data);
+	i2c_set_clientdata(client, muxc);
+	data->client = client;
 
 	/* Get the mux out of reset if a reset GPIO is specified. */
 	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
@@ -220,6 +228,10 @@ static int pca954x_probe(struct i2c_client *client,
 	data->type = id->driver_data;
 	data->last_chan = 0;		   /* force the first selection */
 
+	ret = i2c_mux_reserve_adapters(muxc, chips[data->type].nchans);
+	if (ret)
+		return ret;
+
 	idle_disconnect_dt = of_node &&
 		of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
 
@@ -238,16 +250,13 @@ static int pca954x_probe(struct i2c_client *client,
 				/* discard unconfigured channels */
 				break;
 			idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
+			data->deselect |= (idle_disconnect_pd
+					   || idle_disconnect_dt) << num;
 		}
 
-		data->virt_adaps[num] =
-			i2c_add_mux_adapter(adap, &client->dev, client,
-				force, num, class, pca954x_select_chan,
-				(idle_disconnect_pd || idle_disconnect_dt)
-					? pca954x_deselect_mux : NULL);
+		ret = i2c_mux_add_adapter(muxc, force, num, class);
 
-		if (data->virt_adaps[num] == NULL) {
-			ret = -ENODEV;
+		if (ret) {
 			dev_err(&client->dev,
 				"failed to register multiplexed adapter"
 				" %d as bus %d\n", num, force);
@@ -263,23 +272,15 @@ static int pca954x_probe(struct i2c_client *client,
 	return 0;
 
 virt_reg_failed:
-	for (num--; num >= 0; num--)
-		i2c_del_mux_adapter(data->virt_adaps[num]);
+	i2c_mux_del_adapters(muxc);
 	return ret;
 }
 
 static int pca954x_remove(struct i2c_client *client)
 {
-	struct pca954x *data = i2c_get_clientdata(client);
-	const struct chip_desc *chip = &chips[data->type];
-	int i;
-
-	for (i = 0; i < chip->nchans; ++i)
-		if (data->virt_adaps[i]) {
-			i2c_del_mux_adapter(data->virt_adaps[i]);
-			data->virt_adaps[i] = NULL;
-		}
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 
+	i2c_mux_del_adapters(muxc);
 	return 0;
 }
 
@@ -287,7 +288,8 @@ static int pca954x_remove(struct i2c_client *client)
 static int pca954x_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
-	struct pca954x *data = i2c_get_clientdata(client);
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+	struct pca954x *data = i2c_mux_priv(muxc);
 
 	data->last_chan = 0;
 	return i2c_smbus_write_byte(client, 0);
-- 
2.1.4

[PATCH v6 07/24] i2c: i2c-mux-reg: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/muxes/i2c-mux-reg.c | 63 ++++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 39 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c
index 5fbd5bd0878f..3ac9a2dab111 100644
--- a/drivers/i2c/muxes/i2c-mux-reg.c
+++ b/drivers/i2c/muxes/i2c-mux-reg.c
@@ -21,8 +21,6 @@
 #include <linux/slab.h>
 
 struct regmux {
-	struct i2c_adapter *parent;
-	struct i2c_adapter **adap; /* child busses */
 	struct i2c_mux_reg_platform_data data;
 };
 
@@ -64,18 +62,16 @@ static int i2c_mux_reg_set(const struct regmux *mux, unsigned int chan_id)
 	return 0;
 }
 
-static int i2c_mux_reg_select(struct i2c_adapter *adap, void *data,
-			      unsigned int chan)
+static int i2c_mux_reg_select(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct regmux *mux = data;
+	struct regmux *mux = i2c_mux_priv(muxc);
 
 	return i2c_mux_reg_set(mux, chan);
 }
 
-static int i2c_mux_reg_deselect(struct i2c_adapter *adap, void *data,
-				unsigned int chan)
+static int i2c_mux_reg_deselect(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct regmux *mux = data;
+	struct regmux *mux = i2c_mux_priv(muxc);
 
 	if (mux->data.idle_in_use)
 		return i2c_mux_reg_set(mux, mux->data.idle);
@@ -87,6 +83,7 @@ static int i2c_mux_reg_deselect(struct i2c_adapter *adap, void *data,
 static int i2c_mux_reg_probe_dt(struct regmux *mux,
 					struct platform_device *pdev)
 {
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *adapter_np, *child;
 	struct i2c_adapter *adapter;
@@ -107,7 +104,7 @@ static int i2c_mux_reg_probe_dt(struct regmux *mux,
 	if (!adapter)
 		return -EPROBE_DEFER;
 
-	mux->parent = adapter;
+	muxc->parent = adapter;
 	mux->data.parent = i2c_adapter_id(adapter);
 	put_device(&adapter->dev);
 
@@ -169,18 +166,20 @@ static int i2c_mux_reg_probe_dt(struct regmux *mux,
 
 static int i2c_mux_reg_probe(struct platform_device *pdev)
 {
+	struct i2c_mux_core *muxc;
 	struct regmux *mux;
 	struct i2c_adapter *parent;
 	struct resource *res;
-	int (*deselect)(struct i2c_adapter *, void *, u32);
 	unsigned int class;
 	int i, ret, nr;
 
-	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
-	if (!mux)
+	muxc = i2c_mux_alloc(NULL, &pdev->dev, sizeof(*mux), 0,
+			     i2c_mux_reg_select, NULL);
+	if (!muxc)
 		return -ENOMEM;
+	mux = i2c_mux_priv(muxc);
 
-	platform_set_drvdata(pdev, mux);
+	platform_set_drvdata(pdev, muxc);
 
 	if (dev_get_platdata(&pdev->dev)) {
 		memcpy(&mux->data, dev_get_platdata(&pdev->dev),
@@ -190,7 +189,7 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
 		if (!parent)
 			return -EPROBE_DEFER;
 
-		mux->parent = parent;
+		muxc->parent = parent;
 	} else {
 		ret = i2c_mux_reg_probe_dt(mux, pdev);
 		if (ret < 0) {
@@ -215,55 +214,41 @@ static int i2c_mux_reg_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	mux->adap = devm_kzalloc(&pdev->dev,
-				 sizeof(*mux->adap) * mux->data.n_values,
-				 GFP_KERNEL);
-	if (!mux->adap) {
-		dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
-		return -ENOMEM;
-	}
+	ret = i2c_mux_reserve_adapters(muxc, mux->data.n_values);
+	if (ret)
+		return ret;
 
 	if (mux->data.idle_in_use)
-		deselect = i2c_mux_reg_deselect;
-	else
-		deselect = NULL;
+		muxc->deselect = i2c_mux_reg_deselect;
 
 	for (i = 0; i < mux->data.n_values; i++) {
 		nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
 		class = mux->data.classes ? mux->data.classes[i] : 0;
 
-		mux->adap[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev, mux,
-						   nr, mux->data.values[i],
-						   class, i2c_mux_reg_select,
-						   deselect);
-		if (!mux->adap[i]) {
-			ret = -ENODEV;
+		ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
+		if (ret) {
 			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
 			goto add_adapter_failed;
 		}
 	}
 
 	dev_dbg(&pdev->dev, "%d port mux on %s adapter\n",
-		 mux->data.n_values, mux->parent->name);
+		 mux->data.n_values, muxc->parent->name);
 
 	return 0;
 
 add_adapter_failed:
-	for (; i > 0; i--)
-		i2c_del_mux_adapter(mux->adap[i - 1]);
+	i2c_mux_del_adapters(muxc);
 
 	return ret;
 }
 
 static int i2c_mux_reg_remove(struct platform_device *pdev)
 {
-	struct regmux *mux = platform_get_drvdata(pdev);
-	int i;
-
-	for (i = 0; i < mux->data.n_values; i++)
-		i2c_del_mux_adapter(mux->adap[i]);
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
 
-	i2c_put_adapter(mux->parent);
+	i2c_mux_del_adapters(muxc);
+	i2c_put_adapter(muxc->parent);
 
 	return 0;
 }
-- 
2.1.4

[PATCH v6 08/24] iio: imu: inv_mpu6050: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c |  2 +-
 drivers/iio/imu/inv_mpu6050/inv_mpu_core.c |  1 -
 drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c  | 32 +++++++++++++-----------------
 drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h  |  3 ++-
 4 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
index 2771106fd650..f62b8bd9ad7e 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
@@ -183,7 +183,7 @@ int inv_mpu_acpi_create_mux_client(struct i2c_client *client)
 			} else
 				return 0; /* no secondary addr, which is OK */
 		}
-		st->mux_client = i2c_new_device(st->mux_adapter, &info);
+		st->mux_client = i2c_new_device(st->muxc->adapter[0], &info);
 		if (!st->mux_client)
 			return -ENODEV;
 	}
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index d192953e9a38..0c2bded2b5b7 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -23,7 +23,6 @@
 #include <linux/kfifo.h>
 #include <linux/spinlock.h>
 #include <linux/iio/iio.h>
-#include <linux/i2c-mux.h>
 #include <linux/acpi.h>
 #include "inv_mpu_iio.h"
 
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
index f581256d9d4c..0d429d788106 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
@@ -15,7 +15,6 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
-#include <linux/i2c-mux.h>
 #include <linux/iio/iio.h>
 #include <linux/module.h>
 #include "inv_mpu_iio.h"
@@ -52,10 +51,9 @@ static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
 	return 0;
 }
 
-static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv,
-				     u32 chan_id)
+static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct i2c_client *client = mux_priv;
+	struct i2c_client *client = i2c_mux_priv(muxc);
 	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
 	struct inv_mpu6050_state *st = iio_priv(indio_dev);
 	int ret = 0;
@@ -84,10 +82,9 @@ write_error:
 	return ret;
 }
 
-static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap,
-				       void *mux_priv, u32 chan_id)
+static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct i2c_client *client = mux_priv;
+	struct i2c_client *client = i2c_mux_priv(muxc);
 	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
 	struct inv_mpu6050_state *st = iio_priv(indio_dev);
 
@@ -136,16 +133,15 @@ static int inv_mpu_probe(struct i2c_client *client,
 		return result;
 
 	st = iio_priv(dev_get_drvdata(&client->dev));
-	st->mux_adapter = i2c_add_mux_adapter(client->adapter,
-					      &client->dev,
-					      client,
-					      0, 0, 0,
-					      inv_mpu6050_select_bypass,
-					      inv_mpu6050_deselect_bypass);
-	if (!st->mux_adapter) {
-		result = -ENODEV;
+	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
+				       0, 0, 0,
+				       inv_mpu6050_select_bypass,
+				       inv_mpu6050_deselect_bypass);
+	if (IS_ERR(st->muxc)) {
+		result = PTR_ERR(st->muxc);
 		goto out_unreg_device;
 	}
+	st->muxc->priv = client;
 
 	result = inv_mpu_acpi_create_mux_client(client);
 	if (result)
@@ -154,7 +150,7 @@ static int inv_mpu_probe(struct i2c_client *client,
 	return 0;
 
 out_del_mux:
-	i2c_del_mux_adapter(st->mux_adapter);
+	i2c_mux_del_adapters(st->muxc);
 out_unreg_device:
 	inv_mpu_core_remove(&client->dev);
 	return result;
@@ -162,11 +158,11 @@ out_unreg_device:
 
 static int inv_mpu_remove(struct i2c_client *client)
 {
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
 	struct inv_mpu6050_state *st = iio_priv(indio_dev);
 
 	inv_mpu_acpi_delete_mux_client(client);
-	i2c_del_mux_adapter(st->mux_adapter);
+	i2c_mux_del_adapters(st->muxc);
 
 	return inv_mpu_core_remove(&client->dev);
 }
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index e302a49703bf..bb3cef6d7059 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -11,6 +11,7 @@
 * GNU General Public License for more details.
 */
 #include <linux/i2c.h>
+#include <linux/i2c-mux.h>
 #include <linux/kfifo.h>
 #include <linux/spinlock.h>
 #include <linux/iio/iio.h>
@@ -127,7 +128,7 @@ struct inv_mpu6050_state {
 	const struct inv_mpu6050_hw *hw;
 	enum   inv_devices chip_type;
 	spinlock_t time_stamp_lock;
-	struct i2c_adapter *mux_adapter;
+	struct i2c_mux_core *muxc;
 	struct i2c_client *mux_client;
 	unsigned int powerup_count;
 	struct inv_mpu6050_platform_data plat_data;
-- 
2.1.4

[PATCH v6 09/24] [media] m88ds3103: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/dvb-frontends/m88ds3103.c      | 18 +++++++++---------
 drivers/media/dvb-frontends/m88ds3103_priv.h |  2 +-
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/media/dvb-frontends/m88ds3103.c b/drivers/media/dvb-frontends/m88ds3103.c
index 76883600ec6f..bf5ffcda7797 100644
--- a/drivers/media/dvb-frontends/m88ds3103.c
+++ b/drivers/media/dvb-frontends/m88ds3103.c
@@ -1251,9 +1251,9 @@ static void m88ds3103_release(struct dvb_frontend *fe)
 	i2c_unregister_device(client);
 }
 
-static int m88ds3103_select(struct i2c_adapter *adap, void *mux_priv, u32 chan)
+static int m88ds3103_select(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct m88ds3103_dev *dev = mux_priv;
+	struct m88ds3103_dev *dev = i2c_mux_priv(muxc);
 	struct i2c_client *client = dev->client;
 	int ret;
 	struct i2c_msg msg = {
@@ -1374,7 +1374,7 @@ static struct i2c_adapter *m88ds3103_get_i2c_adapter(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	return dev->i2c_adapter;
+	return dev->muxc->adapter[0];
 }
 
 static int m88ds3103_probe(struct i2c_client *client,
@@ -1467,13 +1467,13 @@ static int m88ds3103_probe(struct i2c_client *client,
 		goto err_kfree;
 
 	/* create mux i2c adapter for tuner */
-	dev->i2c_adapter = i2c_add_mux_adapter(client->adapter, &client->dev,
-					       dev, 0, 0, 0, m88ds3103_select,
-					       NULL);
-	if (dev->i2c_adapter == NULL) {
-		ret = -ENOMEM;
+	dev->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
+					0, 0, 0, m88ds3103_select, NULL);
+	if (IS_ERR(dev->muxc)) {
+		ret = PTR_ERR(dev->muxc);
 		goto err_kfree;
 	}
+	dev->muxc->priv = dev;
 
 	/* create dvb_frontend */
 	memcpy(&dev->fe.ops, &m88ds3103_ops, sizeof(struct dvb_frontend_ops));
@@ -1502,7 +1502,7 @@ static int m88ds3103_remove(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	i2c_del_mux_adapter(dev->i2c_adapter);
+	i2c_mux_del_adapters(dev->muxc);
 
 	kfree(dev);
 	return 0;
diff --git a/drivers/media/dvb-frontends/m88ds3103_priv.h b/drivers/media/dvb-frontends/m88ds3103_priv.h
index eee8c22c51ec..c5b4e177c6ea 100644
--- a/drivers/media/dvb-frontends/m88ds3103_priv.h
+++ b/drivers/media/dvb-frontends/m88ds3103_priv.h
@@ -42,7 +42,7 @@ struct m88ds3103_dev {
 	enum fe_status fe_status;
 	u32 dvbv3_ber; /* for old DVBv3 API read_ber */
 	bool warm; /* FW running */
-	struct i2c_adapter *i2c_adapter;
+	struct i2c_mux_core *muxc;
 	/* auto detect chip id to do different config */
 	u8 chip_id;
 	/* main mclk is calculated for M88RS6000 dynamically */
-- 
2.1.4

[PATCH v6 10/24] [media] rtl2830: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/dvb-frontends/rtl2830.c      | 17 +++++++++--------
 drivers/media/dvb-frontends/rtl2830_priv.h |  2 +-
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2830.c b/drivers/media/dvb-frontends/rtl2830.c
index 3f96429af0e5..ab02c3a07194 100644
--- a/drivers/media/dvb-frontends/rtl2830.c
+++ b/drivers/media/dvb-frontends/rtl2830.c
@@ -677,9 +677,9 @@ err:
  * adapter lock is already taken by tuner driver.
  * Gate is closed automatically after single I2C transfer.
  */
-static int rtl2830_select(struct i2c_adapter *adap, void *mux_priv, u32 chan_id)
+static int rtl2830_select(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct i2c_client *client = mux_priv;
+	struct i2c_client *client = i2c_mux_priv(muxc);
 	struct rtl2830_dev *dev = i2c_get_clientdata(client);
 	int ret;
 
@@ -712,7 +712,7 @@ static struct i2c_adapter *rtl2830_get_i2c_adapter(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	return dev->adapter;
+	return dev->muxc->adapter[0];
 }
 
 /*
@@ -865,12 +865,13 @@ static int rtl2830_probe(struct i2c_client *client,
 		goto err_regmap_exit;
 
 	/* create muxed i2c adapter for tuner */
-	dev->adapter = i2c_add_mux_adapter(client->adapter, &client->dev,
-			client, 0, 0, 0, rtl2830_select, NULL);
-	if (dev->adapter == NULL) {
-		ret = -ENODEV;
+	dev->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
+					0, 0, 0, rtl2830_select, NULL);
+	if (IS_ERR(dev->muxc)) {
+		ret = PTR_ERR(dev->muxc);
 		goto err_regmap_exit;
 	}
+	dev->muxc->priv = client;
 
 	/* create dvb frontend */
 	memcpy(&dev->fe.ops, &rtl2830_ops, sizeof(dev->fe.ops));
@@ -903,7 +904,7 @@ static int rtl2830_remove(struct i2c_client *client)
 	/* stop statistics polling */
 	cancel_delayed_work_sync(&dev->stat_work);
 
-	i2c_del_mux_adapter(dev->adapter);
+	i2c_mux_del_adapters(dev->muxc);
 	regmap_exit(dev->regmap);
 	kfree(dev);
 
diff --git a/drivers/media/dvb-frontends/rtl2830_priv.h b/drivers/media/dvb-frontends/rtl2830_priv.h
index cf793f39a09b..da4909543da2 100644
--- a/drivers/media/dvb-frontends/rtl2830_priv.h
+++ b/drivers/media/dvb-frontends/rtl2830_priv.h
@@ -29,7 +29,7 @@ struct rtl2830_dev {
 	struct rtl2830_platform_data *pdata;
 	struct i2c_client *client;
 	struct regmap *regmap;
-	struct i2c_adapter *adapter;
+	struct i2c_mux_core *muxc;
 	struct dvb_frontend fe;
 	bool sleeping;
 	unsigned long filters;
-- 
2.1.4

[PATCH v6 11/24] [media] rtl2832: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/dvb-frontends/rtl2832.c      | 22 +++++++++++-----------
 drivers/media/dvb-frontends/rtl2832_priv.h |  2 +-
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c
index 7c96f7679669..545c3bbbc668 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -847,9 +847,9 @@ err:
 	dev_dbg(&client->dev, "failed=%d\n", ret);
 }
 
-static int rtl2832_select(struct i2c_adapter *adap, void *mux_priv, u32 chan_id)
+static int rtl2832_select(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct rtl2832_dev *dev = mux_priv;
+	struct rtl2832_dev *dev = i2c_mux_priv(muxc);
 	struct i2c_client *client = dev->client;
 	int ret;
 
@@ -870,10 +870,9 @@ err:
 	return ret;
 }
 
-static int rtl2832_deselect(struct i2c_adapter *adap, void *mux_priv,
-			    u32 chan_id)
+static int rtl2832_deselect(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct rtl2832_dev *dev = mux_priv;
+	struct rtl2832_dev *dev = i2c_mux_priv(muxc);
 
 	schedule_delayed_work(&dev->i2c_gate_work, usecs_to_jiffies(100));
 	return 0;
@@ -1059,7 +1058,7 @@ static struct i2c_adapter *rtl2832_get_i2c_adapter(struct i2c_client *client)
 	struct rtl2832_dev *dev = i2c_get_clientdata(client);
 
 	dev_dbg(&client->dev, "\n");
-	return dev->i2c_adapter_tuner;
+	return dev->muxc->adapter[0];
 }
 
 static int rtl2832_slave_ts_ctrl(struct i2c_client *client, bool enable)
@@ -1242,12 +1241,13 @@ static int rtl2832_probe(struct i2c_client *client,
 		goto err_regmap_exit;
 
 	/* create muxed i2c adapter for demod tuner bus */
-	dev->i2c_adapter_tuner = i2c_add_mux_adapter(i2c, &i2c->dev, dev,
-			0, 0, 0, rtl2832_select, rtl2832_deselect);
-	if (dev->i2c_adapter_tuner == NULL) {
-		ret = -ENODEV;
+	dev->muxc = i2c_mux_one_adapter(i2c, &i2c->dev, 0, 0, 0, 0, 0,
+					rtl2832_select, rtl2832_deselect);
+	if (IS_ERR(dev->muxc)) {
+		ret = PTR_ERR(dev->muxc);
 		goto err_regmap_exit;
 	}
+	dev->muxc->priv = dev;
 
 	/* create dvb_frontend */
 	memcpy(&dev->fe.ops, &rtl2832_ops, sizeof(struct dvb_frontend_ops));
@@ -1282,7 +1282,7 @@ static int rtl2832_remove(struct i2c_client *client)
 
 	cancel_delayed_work_sync(&dev->i2c_gate_work);
 
-	i2c_del_mux_adapter(dev->i2c_adapter_tuner);
+	i2c_mux_del_adapters(dev->muxc);
 
 	regmap_exit(dev->regmap);
 
diff --git a/drivers/media/dvb-frontends/rtl2832_priv.h b/drivers/media/dvb-frontends/rtl2832_priv.h
index 6b875f462f8b..d8f97d14f6fd 100644
--- a/drivers/media/dvb-frontends/rtl2832_priv.h
+++ b/drivers/media/dvb-frontends/rtl2832_priv.h
@@ -36,7 +36,7 @@ struct rtl2832_dev {
 	struct mutex regmap_mutex;
 	struct regmap_config regmap_config;
 	struct regmap *regmap;
-	struct i2c_adapter *i2c_adapter_tuner;
+	struct i2c_mux_core *muxc;
 	struct dvb_frontend fe;
 	enum fe_status fe_status;
 	u64 post_bit_error_prev; /* for old DVBv3 read_ber() calculation */
-- 
2.1.4

[PATCH v6 12/24] [media] si2168: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/dvb-frontends/si2168.c      | 22 ++++++++++++----------
 drivers/media/dvb-frontends/si2168_priv.h |  2 +-
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/media/dvb-frontends/si2168.c b/drivers/media/dvb-frontends/si2168.c
index 821a8f481507..ca455d01c71d 100644
--- a/drivers/media/dvb-frontends/si2168.c
+++ b/drivers/media/dvb-frontends/si2168.c
@@ -615,9 +615,9 @@ static int si2168_get_tune_settings(struct dvb_frontend *fe,
  * We must use unlocked I2C I/O because I2C adapter lock is already taken
  * by the caller (usually tuner driver).
  */
-static int si2168_select(struct i2c_adapter *adap, void *mux_priv, u32 chan)
+static int si2168_select(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct i2c_client *client = mux_priv;
+	struct i2c_client *client = i2c_mux_priv(muxc);
 	int ret;
 	struct si2168_cmd cmd;
 
@@ -635,9 +635,9 @@ err:
 	return ret;
 }
 
-static int si2168_deselect(struct i2c_adapter *adap, void *mux_priv, u32 chan)
+static int si2168_deselect(struct i2c_mux_core *muxc, u32 chan)
 {
-	struct i2c_client *client = mux_priv;
+	struct i2c_client *client = i2c_mux_priv(muxc);
 	int ret;
 	struct si2168_cmd cmd;
 
@@ -709,17 +709,19 @@ static int si2168_probe(struct i2c_client *client,
 	}
 
 	/* create mux i2c adapter for tuner */
-	dev->adapter = i2c_add_mux_adapter(client->adapter, &client->dev,
-			client, 0, 0, 0, si2168_select, si2168_deselect);
-	if (dev->adapter == NULL) {
-		ret = -ENODEV;
+	dev->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
+					0, 0, 0,
+					si2168_select, si2168_deselect);
+	if (IS_ERR(dev->muxc)) {
+		ret = PTR_ERR(dev->muxc);
 		goto err_kfree;
 	}
+	dev->muxc->priv = client;
 
 	/* create dvb_frontend */
 	memcpy(&dev->fe.ops, &si2168_ops, sizeof(struct dvb_frontend_ops));
 	dev->fe.demodulator_priv = client;
-	*config->i2c_adapter = dev->adapter;
+	*config->i2c_adapter = dev->muxc->adapter[0];
 	*config->fe = &dev->fe;
 	dev->ts_mode = config->ts_mode;
 	dev->ts_clock_inv = config->ts_clock_inv;
@@ -743,7 +745,7 @@ static int si2168_remove(struct i2c_client *client)
 
 	dev_dbg(&client->dev, "\n");
 
-	i2c_del_mux_adapter(dev->adapter);
+	i2c_mux_del_adapters(dev->muxc);
 
 	dev->fe.ops.release = NULL;
 	dev->fe.demodulator_priv = NULL;
diff --git a/drivers/media/dvb-frontends/si2168_priv.h b/drivers/media/dvb-frontends/si2168_priv.h
index c07e6fe2cb10..165bf1412063 100644
--- a/drivers/media/dvb-frontends/si2168_priv.h
+++ b/drivers/media/dvb-frontends/si2168_priv.h
@@ -29,7 +29,7 @@
 
 /* state struct */
 struct si2168_dev {
-	struct i2c_adapter *adapter;
+	struct i2c_mux_core *muxc;
 	struct dvb_frontend fe;
 	enum fe_delivery_system delivery_system;
 	enum fe_status fe_status;
-- 
2.1.4

[PATCH v6 13/24] [media] cx231xx: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/usb/cx231xx/cx231xx-core.c |  6 ++--
 drivers/media/usb/cx231xx/cx231xx-i2c.c  | 47 ++++++++++++++++----------------
 drivers/media/usb/cx231xx/cx231xx.h      |  4 ++-
 3 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/drivers/media/usb/cx231xx/cx231xx-core.c b/drivers/media/usb/cx231xx/cx231xx-core.c
index f497888d94bf..f7aac2abd783 100644
--- a/drivers/media/usb/cx231xx/cx231xx-core.c
+++ b/drivers/media/usb/cx231xx/cx231xx-core.c
@@ -1304,6 +1304,9 @@ int cx231xx_dev_init(struct cx231xx *dev)
 	cx231xx_i2c_register(&dev->i2c_bus[1]);
 	cx231xx_i2c_register(&dev->i2c_bus[2]);
 
+	errCode = cx231xx_i2c_mux_create(dev);
+	if (errCode < 0)
+		return errCode;
 	cx231xx_i2c_mux_register(dev, 0);
 	cx231xx_i2c_mux_register(dev, 1);
 
@@ -1426,8 +1429,7 @@ EXPORT_SYMBOL_GPL(cx231xx_dev_init);
 void cx231xx_dev_uninit(struct cx231xx *dev)
 {
 	/* Un Initialize I2C bus */
-	cx231xx_i2c_mux_unregister(dev, 1);
-	cx231xx_i2c_mux_unregister(dev, 0);
+	cx231xx_i2c_mux_unregister(dev);
 	cx231xx_i2c_unregister(&dev->i2c_bus[2]);
 	cx231xx_i2c_unregister(&dev->i2c_bus[1]);
 	cx231xx_i2c_unregister(&dev->i2c_bus[0]);
diff --git a/drivers/media/usb/cx231xx/cx231xx-i2c.c b/drivers/media/usb/cx231xx/cx231xx-i2c.c
index a29c345b027d..eb22e05d4add 100644
--- a/drivers/media/usb/cx231xx/cx231xx-i2c.c
+++ b/drivers/media/usb/cx231xx/cx231xx-i2c.c
@@ -557,40 +557,41 @@ int cx231xx_i2c_unregister(struct cx231xx_i2c *bus)
  * cx231xx_i2c_mux_select()
  * switch i2c master number 1 between port1 and port3
  */
-static int cx231xx_i2c_mux_select(struct i2c_adapter *adap,
-			void *mux_priv, u32 chan_id)
+static int cx231xx_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct cx231xx *dev = mux_priv;
+	struct cx231xx *dev = i2c_mux_priv(muxc);
 
 	return cx231xx_enable_i2c_port_3(dev, chan_id);
 }
 
+int cx231xx_i2c_mux_create(struct cx231xx *dev)
+{
+	dev->muxc = i2c_mux_alloc(&dev->i2c_bus[1].i2c_adap, dev->dev, 0, 0,
+				  cx231xx_i2c_mux_select, NULL);
+	if (!dev->muxc)
+		return -ENOMEM;
+	dev->muxc->priv = dev;
+	return 0;
+}
+
 int cx231xx_i2c_mux_register(struct cx231xx *dev, int mux_no)
 {
-	struct i2c_adapter *i2c_parent = &dev->i2c_bus[1].i2c_adap;
-	/* what is the correct mux_dev? */
-	struct device *mux_dev = dev->dev;
-
-	dev->i2c_mux_adap[mux_no] = i2c_add_mux_adapter(i2c_parent,
-				mux_dev,
-				dev /* mux_priv */,
-				0,
-				mux_no /* chan_id */,
-				0 /* class */,
-				&cx231xx_i2c_mux_select,
-				NULL);
-
-	if (!dev->i2c_mux_adap[mux_no])
+	int rc;
+
+	rc = i2c_mux_add_adapter(dev->muxc,
+				 0,
+				 mux_no /* chan_id */,
+				 0 /* class */);
+	if (rc)
 		dev_warn(dev->dev,
 			 "i2c mux %d register FAILED\n", mux_no);
 
-	return 0;
+	return rc;
 }
 
-void cx231xx_i2c_mux_unregister(struct cx231xx *dev, int mux_no)
+void cx231xx_i2c_mux_unregister(struct cx231xx *dev)
 {
-	i2c_del_mux_adapter(dev->i2c_mux_adap[mux_no]);
-	dev->i2c_mux_adap[mux_no] = NULL;
+	i2c_mux_del_adapters(dev->muxc);
 }
 
 struct i2c_adapter *cx231xx_get_i2c_adap(struct cx231xx *dev, int i2c_port)
@@ -603,9 +604,9 @@ struct i2c_adapter *cx231xx_get_i2c_adap(struct cx231xx *dev, int i2c_port)
 	case I2C_2:
 		return &dev->i2c_bus[2].i2c_adap;
 	case I2C_1_MUX_1:
-		return dev->i2c_mux_adap[0];
+		return dev->muxc->adapter[0];
 	case I2C_1_MUX_3:
-		return dev->i2c_mux_adap[1];
+		return dev->muxc->adapter[1];
 	default:
 		return NULL;
 	}
diff --git a/drivers/media/usb/cx231xx/cx231xx.h b/drivers/media/usb/cx231xx/cx231xx.h
index 69f6d20870f5..90c867683076 100644
--- a/drivers/media/usb/cx231xx/cx231xx.h
+++ b/drivers/media/usb/cx231xx/cx231xx.h
@@ -624,6 +624,7 @@ struct cx231xx {
 
 	/* I2C adapters: Master 1 & 2 (External) & Master 3 (Internal only) */
 	struct cx231xx_i2c i2c_bus[3];
+	struct i2c_mux_core *muxc;
 	struct i2c_adapter *i2c_mux_adap[2];
 
 	unsigned int xc_fw_load_done:1;
@@ -760,8 +761,9 @@ int cx231xx_reset_analog_tuner(struct cx231xx *dev);
 void cx231xx_do_i2c_scan(struct cx231xx *dev, int i2c_port);
 int cx231xx_i2c_register(struct cx231xx_i2c *bus);
 int cx231xx_i2c_unregister(struct cx231xx_i2c *bus);
+int cx231xx_i2c_mux_create(struct cx231xx *dev);
 int cx231xx_i2c_mux_register(struct cx231xx *dev, int mux_no);
-void cx231xx_i2c_mux_unregister(struct cx231xx *dev, int mux_no);
+void cx231xx_i2c_mux_unregister(struct cx231xx *dev);
 struct i2c_adapter *cx231xx_get_i2c_adap(struct cx231xx *dev, int i2c_port);
 
 /* Internal block control functions */
-- 
2.1.4

[PATCH v6 14/24] of/unittest: convert to use an explicit i2c mux core

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/of/unittest.c | 40 +++++++++++++++-------------------------
 1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index e986e6ee52e0..84a65b711e8c 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -1692,13 +1692,7 @@ static struct i2c_driver unittest_i2c_dev_driver = {
 
 #if IS_BUILTIN(CONFIG_I2C_MUX)
 
-struct unittest_i2c_mux_data {
-	int nchans;
-	struct i2c_adapter *adap[];
-};
-
-static int unittest_i2c_mux_select_chan(struct i2c_adapter *adap,
-			       void *client, u32 chan)
+static int unittest_i2c_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
 	return 0;
 }
@@ -1706,11 +1700,11 @@ static int unittest_i2c_mux_select_chan(struct i2c_adapter *adap,
 static int unittest_i2c_mux_probe(struct i2c_client *client,
 		const struct i2c_device_id *id)
 {
-	int ret, i, nchans, size;
+	int ret, i, nchans;
 	struct device *dev = &client->dev;
 	struct i2c_adapter *adap = to_i2c_adapter(dev->parent);
 	struct device_node *np = client->dev.of_node, *child;
-	struct unittest_i2c_mux_data *stm;
+	struct i2c_mux_core *muxc;
 	u32 reg, max_reg;
 
 	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
@@ -1734,25 +1728,23 @@ static int unittest_i2c_mux_probe(struct i2c_client *client,
 		return -EINVAL;
 	}
 
-	size = offsetof(struct unittest_i2c_mux_data, adap[nchans]);
-	stm = devm_kzalloc(dev, size, GFP_KERNEL);
-	if (!stm) {
-		dev_err(dev, "Out of memory\n");
+	muxc = i2c_mux_alloc(adap, dev, 0, 0,
+			     unittest_i2c_mux_select_chan, NULL);
+	if (!muxc)
 		return -ENOMEM;
-	}
-	stm->nchans = nchans;
+	ret = i2c_mux_reserve_adapters(muxc, nchans);
+	if (ret)
+		return ret;
 	for (i = 0; i < nchans; i++) {
-		stm->adap[i] = i2c_add_mux_adapter(adap, dev, client,
-				0, i, 0, unittest_i2c_mux_select_chan, NULL);
-		if (!stm->adap[i]) {
+		ret = i2c_mux_add_adapter(muxc, 0, i, 0);
+		if (ret) {
 			dev_err(dev, "Failed to register mux #%d\n", i);
-			for (i--; i >= 0; i--)
-				i2c_del_mux_adapter(stm->adap[i]);
+			i2c_mux_del_adapters(muxc);
 			return -ENODEV;
 		}
 	}
 
-	i2c_set_clientdata(client, stm);
+	i2c_set_clientdata(client, muxc);
 
 	return 0;
 };
@@ -1761,12 +1753,10 @@ static int unittest_i2c_mux_remove(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct device_node *np = client->dev.of_node;
-	struct unittest_i2c_mux_data *stm = i2c_get_clientdata(client);
-	int i;
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 
 	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
-	for (i = stm->nchans - 1; i >= 0; i--)
-		i2c_del_mux_adapter(stm->adap[i]);
+	i2c_mux_del_adapters(muxc);
 	return 0;
 }
 
-- 
2.1.4

[PATCH v6 15/24] i2c-mux: drop old unused i2c-mux api

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

All i2c mux users are using an explicit i2c mux core, drop support
for implicit i2c mux cores.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/i2c-mux.c   | 59 -------------------------------------------------
 include/linux/i2c-mux.h | 15 -------------
 2 files changed, 74 deletions(-)

diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index d95eb66e11bf..08d99e776a69 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -28,12 +28,6 @@
 #include <linux/slab.h>
 
 /* multiplexer per channel data */
-struct i2c_mux_priv_old {
-	void *mux_priv;
-	int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
-	int (*deselect)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
-};
-
 struct i2c_mux_priv {
 	struct i2c_adapter adap;
 	struct i2c_algorithm algo;
@@ -290,48 +284,6 @@ struct i2c_mux_core *i2c_mux_one_adapter(struct i2c_adapter *parent,
 }
 EXPORT_SYMBOL_GPL(i2c_mux_one_adapter);
 
-static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
-{
-	struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc);
-
-	return priv->select(muxc->parent, priv->mux_priv, chan);
-}
-
-static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
-{
-	struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc);
-
-	return priv->deselect(muxc->parent, priv->mux_priv, chan);
-}
-
-struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
-					struct device *mux_dev, void *mux_priv,
-					u32 force_nr, u32 chan_id,
-					unsigned int class,
-					int (*select)(struct i2c_adapter *,
-						      void *, u32),
-					int (*deselect)(struct i2c_adapter *,
-							void *, u32))
-{
-	struct i2c_mux_core *muxc;
-	struct i2c_mux_priv_old *priv;
-
-	muxc = i2c_mux_one_adapter(parent, mux_dev, sizeof(*priv), 0,
-				   force_nr, chan_id, class,
-				   i2c_mux_select,
-				   deselect ? i2c_mux_deselect : NULL);
-	if (IS_ERR(muxc))
-		return NULL;
-
-	priv = i2c_mux_priv(muxc);
-	priv->select = select;
-	priv->deselect = deselect;
-	priv->mux_priv = mux_priv;
-
-	return muxc->adapter[0];
-}
-EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
-
 void i2c_mux_del_adapters(struct i2c_mux_core *muxc)
 {
 	char symlink_name[20];
@@ -353,17 +305,6 @@ void i2c_mux_del_adapters(struct i2c_mux_core *muxc)
 }
 EXPORT_SYMBOL_GPL(i2c_mux_del_adapters);
 
-void i2c_del_mux_adapter(struct i2c_adapter *adap)
-{
-	struct i2c_mux_priv *priv = adap->algo_data;
-	struct i2c_mux_core *muxc = priv->muxc;
-
-	i2c_mux_del_adapters(muxc);
-	devm_kfree(muxc->dev, muxc->adapter);
-	devm_kfree(muxc->dev, muxc);
-}
-EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
-
 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses");
 MODULE_LICENSE("GPL v2");
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index 0d97d7a3f03c..25c88ccf9c38 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -55,20 +55,6 @@ int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters);
 
 /*
  * Called to create a i2c bus on a multiplexed bus segment.
- * The mux_dev and chan_id parameters are passed to the select
- * and deselect callback functions to perform hardware-specific
- * mux control.
- */
-struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
-				struct device *mux_dev,
-				void *mux_priv, u32 force_nr, u32 chan_id,
-				unsigned int class,
-				int (*select) (struct i2c_adapter *,
-					       void *mux_dev, u32 chan_id),
-				int (*deselect) (struct i2c_adapter *,
-						 void *mux_dev, u32 chan_id));
-/*
- * Called to create a i2c bus on a multiplexed bus segment.
  * The chan_id parameter is passed to the select and deselect
  * callback functions to perform hardware-specific mux control.
  */
@@ -88,7 +74,6 @@ struct i2c_mux_core *i2c_mux_one_adapter(struct i2c_adapter *parent,
 					 int (*deselect)(struct i2c_mux_core *,
 							 u32));
 
-void i2c_del_mux_adapter(struct i2c_adapter *adap);
 void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
 
 #endif /* __KERNEL__ */
-- 
2.1.4

[PATCH v6 16/24] i2c: allow adapter drivers to override the adapter locking

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Add i2c_lock_bus() and i2c_unlock_bus(), which call the new lock_bus and
unlock_bus ops in the adapter. These funcs/ops take an additional flags
argument that indicates for what purpose the adapter is locked.

There are two flags, I2C_LOCK_ADAPTER and I2C_LOCK_SEGMENT, but they are
both implemented the same. For now. Locking the adapter means that the
whole bus is locked, locking the segment means that only the current bus
segment is locked (i.e. i2c traffic on the parent side of mux is still
allowed even if the child side of the mux is locked.

Also support a trylock_bus op (but no function to call it, as it is not
expected to be needed outside of the i2c core).

Implement i2c_lock_adapter/i2c_unlock_adapter in terms of the new locking
scheme (i.e. lock with the I2C_LOCK_ADAPTER flag).

Annotate some of the locking with explicit I2C_LOCK_SEGMENT flags.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/i2c-core.c | 46 ++++++++++++++++++++++++++++------------------
 include/linux/i2c.h    | 28 ++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 20 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 0f2f8484e8ec..21f46d011c33 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -960,10 +960,12 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 }
 
 /**
- * i2c_lock_adapter - Get exclusive access to an I2C bus segment
+ * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
  * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
+ *	locks only this branch in the adapter tree
  */
-void i2c_lock_adapter(struct i2c_adapter *adapter)
+static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, int flags)
 {
 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 
@@ -972,27 +974,30 @@ void i2c_lock_adapter(struct i2c_adapter *adapter)
 	else
 		rt_mutex_lock(&adapter->bus_lock);
 }
-EXPORT_SYMBOL_GPL(i2c_lock_adapter);
 
 /**
- * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
+ * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
  * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
+ *	trylocks only this branch in the adapter tree
  */
-static int i2c_trylock_adapter(struct i2c_adapter *adapter)
+static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, int flags)
 {
 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 
 	if (parent)
-		return i2c_trylock_adapter(parent);
+		return parent->trylock_bus(parent, flags);
 	else
 		return rt_mutex_trylock(&adapter->bus_lock);
 }
 
 /**
- * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
+ * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
  * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
+ *	unlocks only this branch in the adapter tree
  */
-void i2c_unlock_adapter(struct i2c_adapter *adapter)
+static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, int flags)
 {
 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 
@@ -1001,7 +1006,6 @@ void i2c_unlock_adapter(struct i2c_adapter *adapter)
 	else
 		rt_mutex_unlock(&adapter->bus_lock);
 }
-EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
 
 static void i2c_dev_set_name(struct i2c_adapter *adap,
 			     struct i2c_client *client)
@@ -1547,6 +1551,12 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 		return -EINVAL;
 	}
 
+	if (!adap->lock_bus) {
+		adap->lock_bus = i2c_adapter_lock_bus;
+		adap->trylock_bus = i2c_adapter_trylock_bus;
+		adap->unlock_bus = i2c_adapter_unlock_bus;
+	}
+
 	rt_mutex_init(&adap->bus_lock);
 	mutex_init(&adap->userspace_clients_lock);
 	INIT_LIST_HEAD(&adap->userspace_clients);
@@ -2315,16 +2325,16 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 #endif
 
 		if (in_atomic() || irqs_disabled()) {
-			ret = i2c_trylock_adapter(adap);
+			ret = adap->trylock_bus(adap, I2C_LOCK_SEGMENT);
 			if (!ret)
 				/* I2C activity is ongoing. */
 				return -EAGAIN;
 		} else {
-			i2c_lock_adapter(adap);
+			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
 		}
 
 		ret = __i2c_transfer(adap, msgs, num);
-		i2c_unlock_adapter(adap);
+		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
 
 		return ret;
 	} else {
@@ -3099,7 +3109,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
 	flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
 
 	if (adapter->algo->smbus_xfer) {
-		i2c_lock_adapter(adapter);
+		i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
 
 		/* Retry automatically on arbitration loss */
 		orig_jiffies = jiffies;
@@ -3113,7 +3123,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
 				       orig_jiffies + adapter->timeout))
 				break;
 		}
-		i2c_unlock_adapter(adapter);
+		i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
 
 		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
 			goto trace;
@@ -3224,9 +3234,9 @@ int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
 
 	client->slave_cb = slave_cb;
 
-	i2c_lock_adapter(client->adapter);
+	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	ret = client->adapter->algo->reg_slave(client);
-	i2c_unlock_adapter(client->adapter);
+	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
 
 	if (ret) {
 		client->slave_cb = NULL;
@@ -3246,9 +3256,9 @@ int i2c_slave_unregister(struct i2c_client *client)
 		return -EOPNOTSUPP;
 	}
 
-	i2c_lock_adapter(client->adapter);
+	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	ret = client->adapter->algo->unreg_slave(client);
-	i2c_unlock_adapter(client->adapter);
+	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
 
 	if (ret == 0)
 		client->slave_cb = NULL;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 200cf13b00f6..c5f79fec1bfb 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -538,6 +538,10 @@ struct i2c_adapter {
 
 	struct i2c_bus_recovery_info *bus_recovery_info;
 	const struct i2c_adapter_quirks *quirks;
+
+	void (*lock_bus)(struct i2c_adapter *, int flags);
+	int (*trylock_bus)(struct i2c_adapter *, int flags);
+	void (*unlock_bus)(struct i2c_adapter *, int flags);
 };
 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 
@@ -567,8 +571,28 @@ i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 
 /* Adapter locking functions, exported for shared pin cases */
-void i2c_lock_adapter(struct i2c_adapter *);
-void i2c_unlock_adapter(struct i2c_adapter *);
+#define I2C_LOCK_ADAPTER 0x01
+#define I2C_LOCK_SEGMENT 0x02
+static inline void
+i2c_lock_bus(struct i2c_adapter *adapter, int flags)
+{
+	adapter->lock_bus(adapter, flags);
+}
+static inline void
+i2c_unlock_bus(struct i2c_adapter *adapter, int flags)
+{
+	adapter->unlock_bus(adapter, flags);
+}
+static inline void
+i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+	i2c_lock_bus(adapter, I2C_LOCK_ADAPTER);
+}
+static inline void
+i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+	i2c_unlock_bus(adapter, I2C_LOCK_ADAPTER);
+}
 
 /*flags for the client struct: */
 #define I2C_CLIENT_PEC		0x04	/* Use Packet Error Checking */
-- 
2.1.4

[PATCH v6 17/24] i2c: muxes always lock the parent adapter

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Instead of checking for i2c parent adapters for every lock/unlock, simply
override the locking for muxes to always lock/unlock the parent adapter
directly.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/i2c-core.c | 21 +++------------------
 drivers/i2c/i2c-mux.c  | 27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 21f46d011c33..5314434c2b5d 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -967,12 +967,7 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
  */
 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, int flags)
 {
-	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
-
-	if (parent)
-		i2c_lock_adapter(parent);
-	else
-		rt_mutex_lock(&adapter->bus_lock);
+	rt_mutex_lock(&adapter->bus_lock);
 }
 
 /**
@@ -983,12 +978,7 @@ static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, int flags)
  */
 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, int flags)
 {
-	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
-
-	if (parent)
-		return parent->trylock_bus(parent, flags);
-	else
-		return rt_mutex_trylock(&adapter->bus_lock);
+	return rt_mutex_trylock(&adapter->bus_lock);
 }
 
 /**
@@ -999,12 +989,7 @@ static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter, int flags)
  */
 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter, int flags)
 {
-	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
-
-	if (parent)
-		i2c_unlock_adapter(parent);
-	else
-		rt_mutex_unlock(&adapter->bus_lock);
+	rt_mutex_unlock(&adapter->bus_lock);
 }
 
 static void i2c_dev_set_name(struct i2c_adapter *adap,
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 08d99e776a69..e1b2bb112efd 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -98,6 +98,30 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)
 	return class;
 }
 
+static void i2c_parent_lock_bus(struct i2c_adapter *adapter, int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	parent->lock_bus(parent, flags);
+}
+
+static int i2c_parent_trylock_bus(struct i2c_adapter *adapter, int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	return parent->trylock_bus(parent, flags);
+}
+
+static void i2c_parent_unlock_bus(struct i2c_adapter *adapter, int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	parent->unlock_bus(parent, flags);
+}
+
 int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters)
 {
 	struct i2c_adapter **adapter;
@@ -192,6 +216,9 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
 	priv->adap.retries = parent->retries;
 	priv->adap.timeout = parent->timeout;
 	priv->adap.quirks = parent->quirks;
+	priv->adap.lock_bus = i2c_parent_lock_bus;
+	priv->adap.trylock_bus = i2c_parent_trylock_bus;
+	priv->adap.unlock_bus = i2c_parent_unlock_bus;
 
 	/* Sanity check on class */
 	if (i2c_mux_parent_classes(parent) & class)
-- 
2.1.4

[PATCH v6 18/24] i2c-mux: relax locking of the top i2c adapter during mux-locked muxing

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

With a i2c topology like the following

                       GPIO ---|  ------ BAT1
                        |      v /
   I2C  -----+----------+---- MUX
             |                   \
           EEPROM                 ------ BAT2

there is a locking problem with the GPIO controller since it is a client
on the same i2c bus that it muxes. Transfers to the mux clients (e.g. BAT1)
will lock the whole i2c bus prior to attempting to switch the mux to the
correct i2c segment. In the above case, the GPIO device is an I/O expander
with an i2c interface, and since the GPIO subsystem knows nothing (and
rightfully so) about the lockless needs of the i2c mux code, this results
in a deadlock when the GPIO driver issues i2c transfers to modify the
mux.

So, observing that while it is needed to have the i2c bus locked during the
actual MUX update in order to avoid random garbage on the slave side, it
is not strictly a must to have it locked over the whole sequence of a full
select-transfer-deselect mux client operation. The mux itself needs to be
locked, so transfers to clients behind the mux are serialized, and the mux
needs to be stable during all i2c traffic (otherwise individual mux slave
segments might see garbage, or worse).

Introduce this new locking concept as "mux-locked" muxes, and call the
pre-existing mux locking scheme "parent-locked".

Modify the i2c mux locking so that muxes that are "mux-locked" locks only
the muxes on the parent adapter instead of the whole i2c bus when there is
a transfer to the slave side of the mux. This lock serializes transfers to
the slave side of the muxes on the parent adapter.

Add code to i2c-mux-gpio and i2c-mux-pinctrl that checks if all involved
gpio/pinctrl devices have a parent that is an i2c adapter in the same
adapter tree that is muxed, and request a "mux-locked mux" if that is the
case.

Modify the select-transfer-deselect code for "mux-locked" muxes so
that each of the select-transfer-deselect ops locks the mux parent
adapter individually.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/i2c/i2c-core.c              |   1 +
 drivers/i2c/i2c-mux.c               | 152 +++++++++++++++++++++++++++++++++---
 drivers/i2c/muxes/i2c-mux-gpio.c    |  18 +++++
 drivers/i2c/muxes/i2c-mux-pinctrl.c |  38 +++++++++
 include/linux/i2c-mux.h             |   6 ++
 include/linux/i2c.h                 |   1 +
 6 files changed, 203 insertions(+), 13 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 5314434c2b5d..53514ea314cd 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1543,6 +1543,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	}
 
 	rt_mutex_init(&adap->bus_lock);
+	rt_mutex_init(&adap->mux_lock);
 	mutex_init(&adap->userspace_clients_lock);
 	INIT_LIST_HEAD(&adap->userspace_clients);
 
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index e1b2bb112efd..698b25816b65 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -35,6 +35,25 @@ struct i2c_mux_priv {
 	u32 chan_id;
 };
 
+static int __i2c_mux_master_xfer(struct i2c_adapter *adap,
+				 struct i2c_msg msgs[], int num)
+{
+	struct i2c_mux_priv *priv = adap->algo_data;
+	struct i2c_mux_core *muxc = priv->muxc;
+	struct i2c_adapter *parent = muxc->parent;
+	int ret;
+
+	/* Switch to the right mux port and perform the transfer. */
+
+	ret = muxc->select(muxc, priv->chan_id);
+	if (ret >= 0)
+		ret = __i2c_transfer(parent, msgs, num);
+	if (muxc->deselect)
+		muxc->deselect(muxc, priv->chan_id);
+
+	return ret;
+}
+
 static int i2c_mux_master_xfer(struct i2c_adapter *adap,
 			       struct i2c_msg msgs[], int num)
 {
@@ -47,7 +66,29 @@ static int i2c_mux_master_xfer(struct i2c_adapter *adap,
 
 	ret = muxc->select(muxc, priv->chan_id);
 	if (ret >= 0)
-		ret = __i2c_transfer(parent, msgs, num);
+		ret = i2c_transfer(parent, msgs, num);
+	if (muxc->deselect)
+		muxc->deselect(muxc, priv->chan_id);
+
+	return ret;
+}
+
+static int __i2c_mux_smbus_xfer(struct i2c_adapter *adap,
+				u16 addr, unsigned short flags,
+				char read_write, u8 command,
+				int size, union i2c_smbus_data *data)
+{
+	struct i2c_mux_priv *priv = adap->algo_data;
+	struct i2c_mux_core *muxc = priv->muxc;
+	struct i2c_adapter *parent = muxc->parent;
+	int ret;
+
+	/* Select the right mux port and perform the transfer. */
+
+	ret = muxc->select(muxc, priv->chan_id);
+	if (ret >= 0)
+		ret = parent->algo->smbus_xfer(parent, addr, flags,
+					read_write, command, size, data);
 	if (muxc->deselect)
 		muxc->deselect(muxc, priv->chan_id);
 
@@ -68,8 +109,8 @@ static int i2c_mux_smbus_xfer(struct i2c_adapter *adap,
 
 	ret = muxc->select(muxc, priv->chan_id);
 	if (ret >= 0)
-		ret = parent->algo->smbus_xfer(parent, addr, flags,
-					read_write, command, size, data);
+		ret = i2c_smbus_xfer(parent, addr, flags,
+				     read_write, command, size, data);
 	if (muxc->deselect)
 		muxc->deselect(muxc, priv->chan_id);
 
@@ -98,12 +139,49 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)
 	return class;
 }
 
+static void i2c_mux_lock_bus(struct i2c_adapter *adapter, int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	rt_mutex_lock(&parent->mux_lock);
+	if (!(flags & I2C_LOCK_ADAPTER))
+		return;
+	i2c_lock_bus(parent, flags);
+}
+
+static int i2c_mux_trylock_bus(struct i2c_adapter *adapter, int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	if (!rt_mutex_trylock(&parent->mux_lock))
+		return 0;
+	if (!(flags & I2C_LOCK_ADAPTER))
+		return 1;
+	if (parent->trylock_bus(parent, flags))
+		return 1;
+	rt_mutex_unlock(&parent->mux_lock);
+	return 0;
+}
+
+static void i2c_mux_unlock_bus(struct i2c_adapter *adapter, int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	if (flags & I2C_LOCK_ADAPTER)
+		i2c_unlock_bus(parent, flags);
+	rt_mutex_unlock(&parent->mux_lock);
+}
+
 static void i2c_parent_lock_bus(struct i2c_adapter *adapter, int flags)
 {
 	struct i2c_mux_priv *priv = adapter->algo_data;
 	struct i2c_adapter *parent = priv->muxc->parent;
 
-	parent->lock_bus(parent, flags);
+	rt_mutex_lock(&parent->mux_lock);
+	i2c_lock_bus(parent, flags);
 }
 
 static int i2c_parent_trylock_bus(struct i2c_adapter *adapter, int flags)
@@ -111,7 +189,12 @@ static int i2c_parent_trylock_bus(struct i2c_adapter *adapter, int flags)
 	struct i2c_mux_priv *priv = adapter->algo_data;
 	struct i2c_adapter *parent = priv->muxc->parent;
 
-	return parent->trylock_bus(parent, flags);
+	if (!rt_mutex_trylock(&parent->mux_lock))
+		return 0;
+	if (parent->trylock_bus(parent, flags))
+		return 1;
+	rt_mutex_unlock(&parent->mux_lock);
+	return 0;
 }
 
 static void i2c_parent_unlock_bus(struct i2c_adapter *adapter, int flags)
@@ -119,8 +202,35 @@ static void i2c_parent_unlock_bus(struct i2c_adapter *adapter, int flags)
 	struct i2c_mux_priv *priv = adapter->algo_data;
 	struct i2c_adapter *parent = priv->muxc->parent;
 
-	parent->unlock_bus(parent, flags);
+	i2c_unlock_bus(parent, flags);
+	rt_mutex_unlock(&parent->mux_lock);
+}
+
+struct i2c_adapter *i2c_root_adapter(struct device *dev)
+{
+	struct device *i2c;
+	struct i2c_adapter *i2c_root;
+
+	/*
+	 * Walk up the device tree to find an i2c adapter, indicating
+	 * that this is an i2c client device. Check all ancestors to
+	 * handle mfd devices etc.
+	 */
+	for (i2c = dev; i2c; i2c = i2c->parent) {
+		if (i2c->type == &i2c_adapter_type)
+			break;
+	}
+	if (!i2c)
+		return NULL;
+
+	/* Continue up the tree to find the root i2c adapter */
+	i2c_root = to_i2c_adapter(i2c);
+	while (i2c_parent_is_i2c_adapter(i2c_root))
+		i2c_root = i2c_parent_is_i2c_adapter(i2c_root);
+
+	return i2c_root;
 }
+EXPORT_SYMBOL_GPL(i2c_root_adapter);
 
 int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters)
 {
@@ -163,6 +273,8 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
 
 	muxc->parent = parent;
 	muxc->dev = dev;
+	if (flags & I2C_MUX_LOCKED)
+		muxc->mux_locked = 1;
 	muxc->select = select;
 	muxc->deselect = deselect;
 
@@ -200,10 +312,18 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
 	/* Need to do algo dynamically because we don't know ahead
 	 * of time what sort of physical adapter we'll be dealing with.
 	 */
-	if (parent->algo->master_xfer)
-		priv->algo.master_xfer = i2c_mux_master_xfer;
-	if (parent->algo->smbus_xfer)
-		priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
+	if (parent->algo->master_xfer) {
+		if (muxc->mux_locked)
+			priv->algo.master_xfer = i2c_mux_master_xfer;
+		else
+			priv->algo.master_xfer = __i2c_mux_master_xfer;
+	}
+	if (parent->algo->smbus_xfer) {
+		if (muxc->mux_locked)
+			priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
+		else
+			priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
+	}
 	priv->algo.functionality = i2c_mux_functionality;
 
 	/* Now fill out new adapter structure */
@@ -216,9 +336,15 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
 	priv->adap.retries = parent->retries;
 	priv->adap.timeout = parent->timeout;
 	priv->adap.quirks = parent->quirks;
-	priv->adap.lock_bus = i2c_parent_lock_bus;
-	priv->adap.trylock_bus = i2c_parent_trylock_bus;
-	priv->adap.unlock_bus = i2c_parent_unlock_bus;
+	if (muxc->mux_locked) {
+		priv->adap.lock_bus = i2c_mux_lock_bus;
+		priv->adap.trylock_bus = i2c_mux_trylock_bus;
+		priv->adap.unlock_bus = i2c_mux_unlock_bus;
+	} else {
+		priv->adap.lock_bus = i2c_parent_lock_bus;
+		priv->adap.trylock_bus = i2c_parent_trylock_bus;
+		priv->adap.unlock_bus = i2c_parent_unlock_bus;
+	}
 
 	/* Sanity check on class */
 	if (i2c_mux_parent_classes(parent) & class)
diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
index 1bcc26737359..e382c03e3020 100644
--- a/drivers/i2c/muxes/i2c-mux-gpio.c
+++ b/drivers/i2c/muxes/i2c-mux-gpio.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/gpio.h>
+#include "../../gpio/gpiolib.h"
 #include <linux/of_gpio.h>
 
 struct gpiomux {
@@ -137,6 +138,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	struct i2c_mux_core *muxc;
 	struct gpiomux *mux;
 	struct i2c_adapter *parent;
+	struct i2c_adapter *root;
 	unsigned initial_state, gpio_base;
 	int i, ret;
 
@@ -178,6 +180,9 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	if (!parent)
 		return -EPROBE_DEFER;
 
+	root = i2c_root_adapter(&parent->dev);
+
+	muxc->mux_locked = true;
 	muxc->parent = parent;
 	mux->gpio_base = gpio_base;
 
@@ -193,6 +198,9 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	}
 
 	for (i = 0; i < mux->data.n_gpios; i++) {
+		struct device *gpio_dev;
+		struct gpio_desc *gpio_desc;
+
 		ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
 		if (ret) {
 			dev_err(&pdev->dev, "Failed to request GPIO %d\n",
@@ -209,8 +217,18 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 			i++;	/* gpio_request above succeeded, so must free */
 			goto err_request_gpio;
 		}
+
+		if (!muxc->mux_locked)
+			continue;
+
+		gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]);
+		gpio_dev = &gpio_desc->gdev->dev;
+		muxc->mux_locked = i2c_root_adapter(gpio_dev) == root;
 	}
 
+	if (muxc->mux_locked)
+		dev_info(&pdev->dev, "mux-locked i2c mux\n");
+
 	for (i = 0; i < mux->data.n_values; i++) {
 		u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
 		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index bbfabf4f52be..017c3af7d401 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -24,6 +24,7 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include "../../pinctrl/core.h"
 
 struct i2c_mux_pinctrl {
 	struct i2c_mux_pinctrl_platform_data *pdata;
@@ -120,10 +121,31 @@ static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
 }
 #endif
 
+static struct i2c_adapter *i2c_mux_pinctrl_root_adapter(
+	struct pinctrl_state *state)
+{
+	struct i2c_adapter *root = NULL;
+	struct pinctrl_setting *setting;
+	struct i2c_adapter *pin_root;
+
+	list_for_each_entry(setting, &state->settings, node) {
+		pin_root = i2c_root_adapter(setting->pctldev->dev);
+		if (!pin_root)
+			return NULL;
+		if (!root)
+			root = pin_root;
+		else if (root != pin_root)
+			return NULL;
+	}
+
+	return root;
+}
+
 static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 {
 	struct i2c_mux_core *muxc;
 	struct i2c_mux_pinctrl *mux;
+	struct i2c_adapter *root;
 	int i, ret;
 
 	muxc = i2c_mux_alloc(NULL, &pdev->dev, sizeof(*mux), 0,
@@ -199,6 +221,22 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev)
 		goto err;
 	}
 
+	root = i2c_root_adapter(&muxc->parent->dev);
+
+	muxc->mux_locked = true;
+	for (i = 0; i < mux->pdata->bus_count; i++) {
+		if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) {
+			muxc->mux_locked = false;
+			break;
+		}
+	}
+	if (muxc->mux_locked && mux->pdata->pinctrl_state_idle
+	    && root != i2c_mux_pinctrl_root_adapter(mux->state_idle))
+		muxc->mux_locked = false;
+
+	if (muxc->mux_locked)
+		dev_info(&pdev->dev, "mux-locked i2c mux\n");
+
 	for (i = 0; i < mux->pdata->bus_count; i++) {
 		u32 bus = mux->pdata->base_bus_num ?
 				(mux->pdata->base_bus_num + i) : 0;
diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
index 25c88ccf9c38..d7a16bbe6c4a 100644
--- a/include/linux/i2c-mux.h
+++ b/include/linux/i2c-mux.h
@@ -33,6 +33,7 @@ struct i2c_mux_core {
 	int adapters;
 	int max_adapters;
 	struct device *dev;
+	bool mux_locked;
 
 	void *priv;
 
@@ -46,11 +47,16 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
 				   int (*select)(struct i2c_mux_core *, u32),
 				   int (*deselect)(struct i2c_mux_core *, u32));
 
+/* flags for i2c_mux_alloc */
+#define I2C_MUX_LOCKED (1<<0)
+
 static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
 {
 	return muxc->priv;
 }
 
+struct i2c_adapter *i2c_root_adapter(struct device *dev);
+
 int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters);
 
 /*
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index c5f79fec1bfb..e682d41fa4a6 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -524,6 +524,7 @@ struct i2c_adapter {
 
 	/* data fields that are valid for all devices	*/
 	struct rt_mutex bus_lock;
+	struct rt_mutex mux_lock;
 
 	int timeout;			/* in jiffies */
 	int retries;
-- 
2.1.4

[PATCH v6 19/24] i2c-mux: document i2c muxes and elaborate on parent-/mux-locked muxes

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/i2c/i2c-topology | 370 +++++++++++++++++++++++++++++++++++++++++
 MAINTAINERS                    |   1 +
 2 files changed, 371 insertions(+)
 create mode 100644 Documentation/i2c/i2c-topology

diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
new file mode 100644
index 000000000000..7a10edd0874f
--- /dev/null
+++ b/Documentation/i2c/i2c-topology
@@ -0,0 +1,370 @@
+I2C topology
+============
+
+There are a couple of reasons for building more complex i2c topologies
+than a straight-forward i2c bus with one adapter and one or more devices.
+
+1. A mux may be needed on the bus to prevent address collisions.
+
+2. The bus may be accessible from some external bus master, and arbitration
+   may be needed to determine if it is ok to access the bus.
+
+3. A device (particularly RF tuners) may want to avoid the digital noise
+   from the i2c bus, at least most of the time, and sits behind a gate
+   that has to be operated before the device can be accessed.
+
+Etc
+
+These constructs are represented as i2c adapter trees by Linux, where
+each adapter has a parent adapter (except the root adapter) and zero or
+more child adapters. The root adapter is the actual adapter that issues
+i2c transfers, and all adapters with a parent are part of an "i2c-mux"
+object (quoted, since it can also be an arbitrator or a gate).
+
+Depending of the particular mux driver, something happens when there is
+an i2c transfer on one of its child adapters. The mux driver can
+obviously operate a mux, but it can also do arbitration with an external
+bus master or open a gate. The mux driver has two operations for this,
+select and deselect. select is called before the transfer and (the
+optional) deselect is called after the transfer.
+
+
+Locking
+=======
+
+There are two variants of locking available to i2c muxes, they can be
+mux-locked or parent-locked muxes. As is evident from below, it can be
+useful to know if a mux is mux-locked or if it is parent-locked. The
+following list was correct at the time of writing:
+
+In drivers/i2c/muxes/
+i2c-arb-gpio-challenge    Parent-locked
+i2c-mux-gpio              Normally parent-locked, mux-locked iff
+                          all involved gpio pins are controlled by the
+                          same i2c root adapter that they mux.
+i2c-mux-pca9541           Parent-locked
+i2c-mux-pca954x           Parent-locked
+i2c-mux-pinctrl           Normally parent-locked, mux-locked iff
+                          all involved pinctrl devices are controlled
+                          by the same i2c root adapter that they mux.
+i2c-mux-reg               Parent-locked
+
+In drivers/iio/
+imu/inv_mpu6050/          Parent-locked
+
+In drivers/media/
+dvb-frontends/m88ds3103   Parent-locked
+dvb-frontends/rtl2830     Parent-locked
+dvb-frontends/rtl2832     Parent-locked
+dvb-frontends/si2168      Parent-locked
+usb/cx231xx/              Parent-locked
+
+
+Mux-locked muxes
+----------------
+
+Mux-locked muxes does not lock the entire parent adapter during the
+full select-transfer-deselect transaction, only the muxes on the parent
+adapter are locked. Mux-locked muxes are mostly interesting if the
+select and/or deselect operations must use i2c transfers to complete
+their tasks. Since the parent adapter is not fully locked during the
+full transaction, unrelated i2c transfers may interleave the different
+stages of the transaction. This has the benefit that the mux driver
+may be easier and cleaner to implement, but it has some caveats.
+
+ML1. If you build a topology with a mux-locked mux being the parent
+     of a parent-locked mux, this might break the expectation from the
+     parent-locked mux that the root adapter is locked during the
+     transaction.
+
+ML2. It is not safe to build arbitrary topologies with two (or more)
+     mux-locked muxes that are not siblings, when there are address
+     collisions between the devices on the child adapters of these
+     non-sibling muxes.
+
+     I.e. the select-transfer-deselect transaction targeting e.g. device
+     address 0x42 behind mux-one may be interleaved with a similar
+     operation targeting device address 0x42 behind mux-two. The
+     intension with such a topology would in this hypothetical example
+     be that mux-one and mux-two should not be selected simultaneously,
+     but mux-locked muxes do not guarantee that in all topologies.
+
+ML3. A mux-locked mux cannot be used by a driver for auto-closing
+     gates/muxes, i.e. something that closes automatically after a given
+     number (one, in most cases) of i2c transfers. Unrelated i2c transfers
+     may creep in and close prematurely.
+
+ML4. If any non-i2c operation in the mux driver changes the i2c mux state,
+     the driver has to lock the root adapter during that operation.
+     Otherwise garbage may appear on the bus as seen from devices
+     behind the mux, when an unrelated i2c transfer is in flight during
+     the non-i2c mux-changing operation.
+
+
+Mux-locked Example
+------------------
+
+                   .----------.     .--------.
+    .--------.     |   mux-   |-----| dev D1 |
+    |  root  |--+--|  locked  |     '--------'
+    '--------'  |  |  mux M1  |--.  .--------.
+                |  '----------'  '--| dev D2 |
+                |  .--------.       '--------'
+                '--| dev D3 |
+                   '--------'
+
+When there is an access to D1, this happens:
+
+ 1. Someone issues an i2c-transfer to D1.
+ 2. M1 locks muxes on its parent (the root adapter in this case).
+ 3. M1 calls ->select to ready the mux.
+ 4. M1 (presumably) does some i2c-transfers as part of its select.
+    These transfers are normal i2c-transfers that locks the parent
+    adapter.
+ 5. M1 feeds the i2c-transfer from step 1 to its parent adapter as a
+    normal i2c-transfer that locks the parent adapter.
+ 6. M1 calls ->deselect, if it has one.
+ 7. Same rules as in step 4, but for ->deselect.
+ 8. M1 unlocks muxes on its parent.
+
+This means that accesses to D2 are lockout out for the full duration
+of the entire operation. But accesses to D3 are possibly interleaved
+at any point.
+
+
+Parent-locked muxes
+-------------------
+
+Parent-locked muxes lock the parent adapter during the full select-
+transfer-deselect transaction. The implication is that the mux driver
+has to ensure that any and all i2c transfers through that parent
+adapter during the transaction are unlocked i2c transfers (using e.g.
+__i2c_transfer), or a deadlock will follow. There are a couple of
+caveats.
+
+PL1. If you build a topology with a parent-locked mux being the child
+     of another mux, this might break a possible assumption from the
+     child mux that the root adapter is unused between its select op
+     and the actual transfer (e.g. if the child mux is auto-closing
+     and the parent mux issus i2c-transfers as part of its select).
+     This is especailly the case if the parent mux is mux-locked, but
+     it may also happen if the parent mux is parent-locked.
+
+PL2. If select/deselect calls out to other subsystems such as gpio,
+     pinctrl, regmap or iio, it is essential that any i2c transfers
+     caused by these subsystems are unlocked. This can be convoluted to
+     accomplish, maybe even impossible if an acceptably clean solution
+     is sought.
+
+
+Parent-locked Example
+---------------------
+
+                   .----------.     .--------.
+    .--------.     |  parent- |-----| dev D1 |
+    |  root  |--+--|  locked  |     '--------'
+    '--------'  |  |  mux M1  |--.  .--------.
+                |  '----------'  '--| dev D2 |
+                |  .--------.       '--------'
+                '--| dev D3 |
+                   '--------'
+
+When there is an access to D1, this happens:
+
+ 1. Someone issues an i2c-transfer to D1.
+ 2. M1 locks muxes on its parent (the root adapter in this case).
+ 3. M1 locks its parent adapter.
+ 4. M1 calls ->select to ready the mux.
+ 5. If M1 does any i2c-transfers (on this root adapter) as part of
+    its select, those transfers must be unlocked i2c-transfers so
+    that they do not deadlock the root adapter.
+ 6. M1 feeds the i2c-transfer from step 1 to the root adapter as an
+    unlocked i2c-transfer, so that it does not deadlock the parent
+    adapter.
+ 7. M1 calls ->deselect, if it has one.
+ 8. Same rules as in step 5, but for ->deselect.
+ 9. M1 unlocks its parent adapter.
+10. M1 unlocks muxes on its parent.
+
+
+This means that accesses to both D2 and D3 are locked out for the full
+duration of the entire operation.
+
+
+Complex Examples
+================
+
+Parent-locked mux as parent of parent-locked mux
+------------------------------------------------
+
+This is a useful topology, but it can be bad.
+
+                   .----------.     .----------.     .--------.
+    .--------.     |  parent- |-----|  parent- |-----| dev D1 |
+    |  root  |--+--|  locked  |     |  locked  |     '--------'
+    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
+                |  '----------'  |  '----------'  '--| dev D2 |
+                |  .--------.    |  .--------.       '--------'
+                '--| dev D4 |    '--| dev D3 |
+                   '--------'       '--------'
+
+When any device is accessed, all other devices are locked out for
+the full duration of the operation (both muxes lock their parent,
+and specifically when M2 requests its parent to lock, M1 passes
+the buck to the root adapter).
+
+This topology is bad if M2 is an auto-closing mux and M1->select
+issues any unlocked i2c transfers on the root adapter that may leak
+through and be seen by the M2 adapter, thus closing M2 prematurely.
+
+
+Mux-locked mux as parent of mux-locked mux
+------------------------------------------
+
+This is a good topology.
+
+                   .----------.     .----------.     .--------.
+    .--------.     |   mux-   |-----|   mux-   |-----| dev D1 |
+    |  root  |--+--|  locked  |     |  locked  |     '--------'
+    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
+                |  '----------'  |  '----------'  '--| dev D2 |
+                |  .--------.    |  .--------.       '--------'
+                '--| dev D4 |    '--| dev D3 |
+                   '--------'       '--------'
+
+When device D1 is accessed, accesses to D2 are locked out for the
+full duration of the operation (muxes on the top child adapter of M1
+are locked). But accesses to D3 and D4 are possibly interleaved at
+any point. Accesses to D3 locks out D1 and D2, but accesses to D4
+are still possibly interleaved.
+
+
+Mux-locked mux as parent of parent-locked mux
+---------------------------------------------
+
+This is probably a bad topology.
+
+                   .----------.     .----------.     .--------.
+    .--------.     |   mux-   |-----|  parent- |-----| dev D1 |
+    |  root  |--+--|  locked  |     |  locked  |     '--------'
+    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
+                |  '----------'  |  '----------'  '--| dev D2 |
+                |  .--------.    |  .--------.       '--------'
+                '--| dev D4 |    '--| dev D3 |
+                   '--------'       '--------'
+
+When device D1 is accessed, accesses to D2 and D3 are locked out
+for the full duration of the operation (M1 locks child muxes on the
+root adapter). But accesses to D4 are possibly interleaved at any
+point.
+
+This kind of topology is generally not suitable and should probably
+be avoided. The reason is that M2 probably assumes that there will
+be no i2c transfers during its calls to ->select and ->deselect, and
+if there are, any such transfers might appear on the slave side of M2
+as partial i2c transfers, i.e. garbage or worse. This might cause
+device lockups and/or other problems.
+
+The topology is especially troublesome if M2 is an auto-closing
+mux. In that case, any interleaved accesses to D4 might close M2
+prematurely, as might any i2c-transfers part of M1->select.
+
+But if M2 is not making the above stated assumption, and if M2 is not
+auto-closing, the topology is fine.
+
+
+Parent-locked mux as parent of mux-locked mux
+---------------------------------------------
+
+This is a good topology.
+
+                   .----------.     .----------.     .--------.
+    .--------.     |  parent- |-----|   mux-   |-----| dev D1 |
+    |  root  |--+--|  locked  |     |  locked  |     '--------'
+    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
+                |  '----------'  |  '----------'  '--| dev D2 |
+                |  .--------.    |  .--------.       '--------'
+                '--| dev D4 |    '--| dev D3 |
+                   '--------'       '--------'
+
+When D1 is accessed, accesses to D2 are locked out for the full
+duration of the operation (muxes on the top child adapter of M1
+are locked). Accesses to D3 and D4 are possibly interleaved at
+any point, just as is expected for mux-locked muxes.
+
+When D3 or D4 are accessed, everything else is locked out. For D3
+accesses, M1 locks the root adapter. For D4 accesses, the root
+adapter is locked directly.
+
+
+Two mux-locked sibling muxes
+----------------------------
+
+This is a good topology.
+
+                                    .--------.
+                   .----------.  .--| dev D1 |
+                   |   mux-   |--'  '--------'
+                .--|  locked  |     .--------.
+                |  |  mux M1  |-----| dev D2 |
+                |  '----------'     '--------'
+                |  .----------.     .--------.
+    .--------.  |  |   mux-   |-----| dev D3 |
+    |  root  |--+--|  locked  |     '--------'
+    '--------'  |  |  mux M2  |--.  .--------.
+                |  '----------'  '--| dev D4 |
+                |  .--------.       '--------'
+                '--| dev D5 |
+                   '--------'
+
+When D1 is accessed, accesses to D2, D3 and D4 are locked out. But
+accesses to D5 may be interleaved at any time.
+
+
+Two parent-locked sibling muxes
+-------------------------------
+
+This is a good topology.
+
+                                   .--------.
+                   .----------.  .--| dev D1 |
+                   |  parent- |--'  '--------'
+                .--|  locked  |     .--------.
+                |  |  mux M1  |-----| dev D2 |
+                |  '----------'     '--------'
+                |  .----------.     .--------.
+    .--------.  |  |  parent- |-----| dev D3 |
+    |  root  |--+--|  locked  |     '--------'
+    '--------'  |  |  mux M2  |--.  .--------.
+                |  '----------'  '--| dev D4 |
+                |  .--------.       '--------'
+                '--| dev D5 |
+                   '--------'
+
+When any device is accessed, accesses to all other devices are locked
+out.
+
+
+Mux-locked and parent-locked sibling muxes
+------------------------------------------
+
+This is a good topology.
+
+                                   .--------.
+                   .----------.  .--| dev D1 |
+                   |   mux-   |--'  '--------'
+                .--|  locked  |     .--------.
+                |  |  mux M1  |-----| dev D2 |
+                |  '----------'     '--------'
+                |  .----------.     .--------.
+    .--------.  |  |  parent- |-----| dev D3 |
+    |  root  |--+--|  locked  |     '--------'
+    '--------'  |  |  mux M2  |--.  .--------.
+                |  '----------'  '--| dev D4 |
+                |  .--------.       '--------'
+                '--| dev D5 |
+                   '--------'
+
+When D1 or D2 are accessed, accesses to D3 and D4 are locked out while
+accesses to D5 may interleave. When D3 or D4 are accessed, accesses to
+all other devices are locked out.
diff --git a/MAINTAINERS b/MAINTAINERS
index 03e00c7c88eb..d17afeb81246 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5274,6 +5274,7 @@ I2C MUXES
 M:	Peter Rosin <peda@axentia.se>
 L:	linux-i2c@vger.kernel.org
 S:	Maintained
+F:	Documentation/i2c/i2c-topology
 F:	Documentation/i2c/muxes/
 F:	Documentation/devicetree/bindings/i2c/i2c-mux*
 F:	drivers/i2c/i2c-mux.c
-- 
2.1.4

[PATCH v6 20/24] iio: imu: inv_mpu6050: change the i2c gate to be mux-locked

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

The root i2c adapter lock is then no longer held by the i2c mux during
accesses behind the i2c gate, and such accesses need to take that lock
just like any other ordinary i2c accesses do.

So, declare the i2c gate mux-locked, and zap the code that makes the
unlocked i2c accesses and just use ordinary regmap_write accesses.

This also happens to fix the deadlock described in
http://patchwork.ozlabs.org/patch/584776/ authored by
Adriana Reus <adriana.reus@intel.com> and submitted by
Daniel Baluta <daniel.baluta@intel.com>

----------8<----------
iio: imu: inv_mpu6050: Fix deadlock between i2c adapter lock and mpu lock

This deadlock occurs if the accel/gyro and the sensor on the auxiliary
I2C (in my setup it's an ak8975) are working at the same time.

Scenario:

      T1					T2
     ====				       ====
inv_mpu6050_read_fifo                  aux sensor op (eg. ak8975_read_raw)
        |                                     |
mutex_lock(&indio_dev->mlock)           i2c_transfer
        |                                     |
i2c transaction                         i2c adapter lock
        |                                     |
i2c adapter lock                        i2c_mux_master_xfer
                                              |
                                        inv_mpu6050_select_bypass
                                              |
                                        mutex_lock(&indio_dev->mlock)

When we operate on an mpu sensor the order of locking is mpu lock
followed by the i2c adapter lock. However, when we operate the auxiliary
sensor the order of locking is the other way around.

...
----------8<----------

The reason this patch fixes the deadlock is that T2 does not grab the
i2c adapter lock until the very end (and grabs the newfangled i2c mux
lock where it previously grabbed the i2c adapter lock).

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/i2c/i2c-topology            |  2 +-
 drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c | 56 +++++++------------------------
 2 files changed, 13 insertions(+), 45 deletions(-)

diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
index 7a10edd0874f..346623a80bd1 100644
--- a/Documentation/i2c/i2c-topology
+++ b/Documentation/i2c/i2c-topology
@@ -50,7 +50,7 @@ i2c-mux-pinctrl           Normally parent-locked, mux-locked iff
 i2c-mux-reg               Parent-locked
 
 In drivers/iio/
-imu/inv_mpu6050/          Parent-locked
+imu/inv_mpu6050/          Mux-locked
 
 In drivers/media/
 dvb-frontends/m88ds3103   Parent-locked
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
index 0d429d788106..71ad31a275c9 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
@@ -24,45 +24,16 @@ static const struct regmap_config inv_mpu_regmap_config = {
 	.val_bits = 8,
 };
 
-/*
- * The i2c read/write needs to happen in unlocked mode. As the parent
- * adapter is common. If we use locked versions, it will fail as
- * the mux adapter will lock the parent i2c adapter, while calling
- * select/deselect functions.
- */
-static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
-					  u8 reg, u8 d)
-{
-	int ret;
-	u8 buf[2] = {reg, d};
-	struct i2c_msg msg[1] = {
-		{
-			.addr = client->addr,
-			.flags = 0,
-			.len = sizeof(buf),
-			.buf = buf,
-		}
-	};
-
-	ret = __i2c_transfer(client->adapter, msg, 1);
-	if (ret != 1)
-		return ret;
-
-	return 0;
-}
-
 static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct i2c_client *client = i2c_mux_priv(muxc);
-	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
+	struct iio_dev *indio_dev = i2c_mux_priv(muxc);
 	struct inv_mpu6050_state *st = iio_priv(indio_dev);
 	int ret = 0;
 
 	/* Use the same mutex which was used everywhere to protect power-op */
 	mutex_lock(&indio_dev->mlock);
 	if (!st->powerup_count) {
-		ret = inv_mpu6050_write_reg_unlocked(client,
-						     st->reg->pwr_mgmt_1, 0);
+		ret = regmap_write(st->map, st->reg->pwr_mgmt_1, 0);
 		if (ret)
 			goto write_error;
 
@@ -71,10 +42,9 @@ static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
 	}
 	if (!ret) {
 		st->powerup_count++;
-		ret = inv_mpu6050_write_reg_unlocked(client,
-						     st->reg->int_pin_cfg,
-						     INV_MPU6050_INT_PIN_CFG |
-						     INV_MPU6050_BIT_BYPASS_EN);
+		ret = regmap_write(st->map, st->reg->int_pin_cfg,
+				   INV_MPU6050_INT_PIN_CFG |
+				   INV_MPU6050_BIT_BYPASS_EN);
 	}
 write_error:
 	mutex_unlock(&indio_dev->mlock);
@@ -84,18 +54,16 @@ write_error:
 
 static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
 {
-	struct i2c_client *client = i2c_mux_priv(muxc);
-	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
+	struct iio_dev *indio_dev = i2c_mux_priv(muxc);
 	struct inv_mpu6050_state *st = iio_priv(indio_dev);
 
 	mutex_lock(&indio_dev->mlock);
 	/* It doesn't really mattter, if any of the calls fails */
-	inv_mpu6050_write_reg_unlocked(client, st->reg->int_pin_cfg,
-				       INV_MPU6050_INT_PIN_CFG);
+	regmap_write(st->map, st->reg->int_pin_cfg, INV_MPU6050_INT_PIN_CFG);
 	st->powerup_count--;
 	if (!st->powerup_count)
-		inv_mpu6050_write_reg_unlocked(client, st->reg->pwr_mgmt_1,
-					       INV_MPU6050_BIT_SLEEP);
+		regmap_write(st->map, st->reg->pwr_mgmt_1,
+			     INV_MPU6050_BIT_SLEEP);
 	mutex_unlock(&indio_dev->mlock);
 
 	return 0;
@@ -133,15 +101,15 @@ static int inv_mpu_probe(struct i2c_client *client,
 		return result;
 
 	st = iio_priv(dev_get_drvdata(&client->dev));
-	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
-				       0, 0, 0,
+	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0,
+				       I2C_MUX_LOCKED, 0, 0, 0,
 				       inv_mpu6050_select_bypass,
 				       inv_mpu6050_deselect_bypass);
 	if (IS_ERR(st->muxc)) {
 		result = PTR_ERR(st->muxc);
 		goto out_unreg_device;
 	}
-	st->muxc->priv = client;
+	st->muxc->priv = dev_get_drvdata(&client->dev);
 
 	result = inv_mpu_acpi_create_mux_client(client);
 	if (result)
-- 
2.1.4

[PATCH v6 21/24] [media] si2168: change the i2c gate to be mux-locked

[Peter Rosin]

From: Antti Palosaari <crope@iki.fi>

The root i2c adapter lock is then no longer held by the i2c mux during
accesses behind the i2c gate, and such accesses need to take that lock
just like any other ordinary i2c accesses do.

So, declare the i2c gate mux-locked, and zap the code that makes the
i2c accesses unlocked. But add a mutex so that firmware commands are
still serialized.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/i2c/i2c-topology            |  2 +-
 drivers/media/dvb-frontends/si2168.c      | 85 ++++++++-----------------------
 drivers/media/dvb-frontends/si2168_priv.h |  1 +
 3 files changed, 23 insertions(+), 65 deletions(-)

diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
index 346623a80bd1..a9ca97df7661 100644
--- a/Documentation/i2c/i2c-topology
+++ b/Documentation/i2c/i2c-topology
@@ -56,7 +56,7 @@ In drivers/media/
 dvb-frontends/m88ds3103   Parent-locked
 dvb-frontends/rtl2830     Parent-locked
 dvb-frontends/rtl2832     Parent-locked
-dvb-frontends/si2168      Parent-locked
+dvb-frontends/si2168      Mux-locked
 usb/cx231xx/              Parent-locked
 
 
diff --git a/drivers/media/dvb-frontends/si2168.c b/drivers/media/dvb-frontends/si2168.c
index ca455d01c71d..2eecbb2ef48e 100644
--- a/drivers/media/dvb-frontends/si2168.c
+++ b/drivers/media/dvb-frontends/si2168.c
@@ -18,53 +18,23 @@
 
 static const struct dvb_frontend_ops si2168_ops;
 
-/* Own I2C adapter locking is needed because of I2C gate logic. */
-static int si2168_i2c_master_send_unlocked(const struct i2c_client *client,
-					   const char *buf, int count)
-{
-	int ret;
-	struct i2c_msg msg = {
-		.addr = client->addr,
-		.flags = 0,
-		.len = count,
-		.buf = (char *)buf,
-	};
-
-	ret = __i2c_transfer(client->adapter, &msg, 1);
-	return (ret == 1) ? count : ret;
-}
-
-static int si2168_i2c_master_recv_unlocked(const struct i2c_client *client,
-					   char *buf, int count)
-{
-	int ret;
-	struct i2c_msg msg = {
-		.addr = client->addr,
-		.flags = I2C_M_RD,
-		.len = count,
-		.buf = buf,
-	};
-
-	ret = __i2c_transfer(client->adapter, &msg, 1);
-	return (ret == 1) ? count : ret;
-}
-
 /* execute firmware command */
-static int si2168_cmd_execute_unlocked(struct i2c_client *client,
-				       struct si2168_cmd *cmd)
+static int si2168_cmd_execute(struct i2c_client *client, struct si2168_cmd *cmd)
 {
+	struct si2168_dev *dev = i2c_get_clientdata(client);
 	int ret;
 	unsigned long timeout;
 
+	mutex_lock(&dev->i2c_mutex);
+
 	if (cmd->wlen) {
 		/* write cmd and args for firmware */
-		ret = si2168_i2c_master_send_unlocked(client, cmd->args,
-						      cmd->wlen);
+		ret = i2c_master_send(client, cmd->args, cmd->wlen);
 		if (ret < 0) {
-			goto err;
+			goto err_mutex_unlock;
 		} else if (ret != cmd->wlen) {
 			ret = -EREMOTEIO;
-			goto err;
+			goto err_mutex_unlock;
 		}
 	}
 
@@ -73,13 +43,12 @@ static int si2168_cmd_execute_unlocked(struct i2c_client *client,
 		#define TIMEOUT 70
 		timeout = jiffies + msecs_to_jiffies(TIMEOUT);
 		while (!time_after(jiffies, timeout)) {
-			ret = si2168_i2c_master_recv_unlocked(client, cmd->args,
-							      cmd->rlen);
+			ret = i2c_master_recv(client, cmd->args, cmd->rlen);
 			if (ret < 0) {
-				goto err;
+				goto err_mutex_unlock;
 			} else if (ret != cmd->rlen) {
 				ret = -EREMOTEIO;
-				goto err;
+				goto err_mutex_unlock;
 			}
 
 			/* firmware ready? */
@@ -94,32 +63,23 @@ static int si2168_cmd_execute_unlocked(struct i2c_client *client,
 		/* error bit set? */
 		if ((cmd->args[0] >> 6) & 0x01) {
 			ret = -EREMOTEIO;
-			goto err;
+			goto err_mutex_unlock;
 		}
 
 		if (!((cmd->args[0] >> 7) & 0x01)) {
 			ret = -ETIMEDOUT;
-			goto err;
+			goto err_mutex_unlock;
 		}
 	}
 
+	mutex_unlock(&dev->i2c_mutex);
 	return 0;
-err:
+err_mutex_unlock:
+	mutex_unlock(&dev->i2c_mutex);
 	dev_dbg(&client->dev, "failed=%d\n", ret);
 	return ret;
 }
 
-static int si2168_cmd_execute(struct i2c_client *client, struct si2168_cmd *cmd)
-{
-	int ret;
-
-	i2c_lock_adapter(client->adapter);
-	ret = si2168_cmd_execute_unlocked(client, cmd);
-	i2c_unlock_adapter(client->adapter);
-
-	return ret;
-}
-
 static int si2168_read_status(struct dvb_frontend *fe, enum fe_status *status)
 {
 	struct i2c_client *client = fe->demodulator_priv;
@@ -610,11 +570,6 @@ static int si2168_get_tune_settings(struct dvb_frontend *fe,
 	return 0;
 }
 
-/*
- * I2C gate logic
- * We must use unlocked I2C I/O because I2C adapter lock is already taken
- * by the caller (usually tuner driver).
- */
 static int si2168_select(struct i2c_mux_core *muxc, u32 chan)
 {
 	struct i2c_client *client = i2c_mux_priv(muxc);
@@ -625,7 +580,7 @@ static int si2168_select(struct i2c_mux_core *muxc, u32 chan)
 	memcpy(cmd.args, "\xc0\x0d\x01", 3);
 	cmd.wlen = 3;
 	cmd.rlen = 0;
-	ret = si2168_cmd_execute_unlocked(client, &cmd);
+	ret = si2168_cmd_execute(client, &cmd);
 	if (ret)
 		goto err;
 
@@ -645,7 +600,7 @@ static int si2168_deselect(struct i2c_mux_core *muxc, u32 chan)
 	memcpy(cmd.args, "\xc0\x0d\x00", 3);
 	cmd.wlen = 3;
 	cmd.rlen = 0;
-	ret = si2168_cmd_execute_unlocked(client, &cmd);
+	ret = si2168_cmd_execute(client, &cmd);
 	if (ret)
 		goto err;
 
@@ -708,9 +663,11 @@ static int si2168_probe(struct i2c_client *client,
 		goto err;
 	}
 
+	mutex_init(&dev->i2c_mutex);
+
 	/* create mux i2c adapter for tuner */
-	dev->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
-					0, 0, 0,
+	dev->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0,
+					I2C_MUX_LOCKED, 0, 0, 0,
 					si2168_select, si2168_deselect);
 	if (IS_ERR(dev->muxc)) {
 		ret = PTR_ERR(dev->muxc);
diff --git a/drivers/media/dvb-frontends/si2168_priv.h b/drivers/media/dvb-frontends/si2168_priv.h
index 165bf1412063..8a1f36d2014d 100644
--- a/drivers/media/dvb-frontends/si2168_priv.h
+++ b/drivers/media/dvb-frontends/si2168_priv.h
@@ -29,6 +29,7 @@
 
 /* state struct */
 struct si2168_dev {
+	struct mutex i2c_mutex;
 	struct i2c_mux_core *muxc;
 	struct dvb_frontend fe;
 	enum fe_delivery_system delivery_system;
-- 
2.1.4

[PATCH v6 22/24] [media] rtl2832: change the i2c gate to be mux-locked

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

The root i2c adapter lock is then no longer held by the i2c mux during
accesses behind the i2c gate, and such accesses need to take that lock
just like any other ordinary i2c accesses do.

So, declare the i2c gate mux-locked, and zap the regmap overrides
that makes the i2c accesses unlocked and use plain old regmap
accesses. This also removes the need for the regmap wrappers used by
rtl2832_sdr, so deconvolute the code further and provide the regmap
handle directly instead of the wrapper functions.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/i2c/i2c-topology            |   2 +-
 drivers/media/dvb-frontends/rtl2832.c     | 191 +++++-------------------------
 drivers/media/dvb-frontends/rtl2832.h     |   4 +-
 drivers/media/dvb-frontends/rtl2832_sdr.c |  13 +-
 drivers/media/dvb-frontends/rtl2832_sdr.h |   5 +-
 drivers/media/usb/dvb-usb-v2/rtl28xxu.c   |   5 +-
 6 files changed, 38 insertions(+), 182 deletions(-)

diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
index a9ca97df7661..3f359bd93591 100644
--- a/Documentation/i2c/i2c-topology
+++ b/Documentation/i2c/i2c-topology
@@ -55,7 +55,7 @@ imu/inv_mpu6050/          Mux-locked
 In drivers/media/
 dvb-frontends/m88ds3103   Parent-locked
 dvb-frontends/rtl2830     Parent-locked
-dvb-frontends/rtl2832     Parent-locked
+dvb-frontends/rtl2832     Mux-locked
 dvb-frontends/si2168      Mux-locked
 usb/cx231xx/              Parent-locked
 
diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c
index 545c3bbbc668..ac5ac5f7a335 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -153,43 +153,6 @@ static const struct rtl2832_reg_entry registers[] = {
 	[DVBT_REG_4MSEL]	= {0x013,  0, 0},
 };
 
-/* Our regmap is bypassing I2C adapter lock, thus we do it! */
-static int rtl2832_bulk_write(struct i2c_client *client, unsigned int reg,
-			      const void *val, size_t val_count)
-{
-	struct rtl2832_dev *dev = i2c_get_clientdata(client);
-	int ret;
-
-	i2c_lock_adapter(client->adapter);
-	ret = regmap_bulk_write(dev->regmap, reg, val, val_count);
-	i2c_unlock_adapter(client->adapter);
-	return ret;
-}
-
-static int rtl2832_update_bits(struct i2c_client *client, unsigned int reg,
-			       unsigned int mask, unsigned int val)
-{
-	struct rtl2832_dev *dev = i2c_get_clientdata(client);
-	int ret;
-
-	i2c_lock_adapter(client->adapter);
-	ret = regmap_update_bits(dev->regmap, reg, mask, val);
-	i2c_unlock_adapter(client->adapter);
-	return ret;
-}
-
-static int rtl2832_bulk_read(struct i2c_client *client, unsigned int reg,
-			     void *val, size_t val_count)
-{
-	struct rtl2832_dev *dev = i2c_get_clientdata(client);
-	int ret;
-
-	i2c_lock_adapter(client->adapter);
-	ret = regmap_bulk_read(dev->regmap, reg, val, val_count);
-	i2c_unlock_adapter(client->adapter);
-	return ret;
-}
-
 static int rtl2832_rd_demod_reg(struct rtl2832_dev *dev, int reg, u32 *val)
 {
 	struct i2c_client *client = dev->client;
@@ -204,7 +167,7 @@ static int rtl2832_rd_demod_reg(struct rtl2832_dev *dev, int reg, u32 *val)
 	len = (msb >> 3) + 1;
 	mask = REG_MASK(msb - lsb);
 
-	ret = rtl2832_bulk_read(client, reg_start_addr, reading, len);
+	ret = regmap_bulk_read(dev->regmap, reg_start_addr, reading, len);
 	if (ret)
 		goto err;
 
@@ -234,7 +197,7 @@ static int rtl2832_wr_demod_reg(struct rtl2832_dev *dev, int reg, u32 val)
 	len = (msb >> 3) + 1;
 	mask = REG_MASK(msb - lsb);
 
-	ret = rtl2832_bulk_read(client, reg_start_addr, reading, len);
+	ret = regmap_bulk_read(dev->regmap, reg_start_addr, reading, len);
 	if (ret)
 		goto err;
 
@@ -248,7 +211,7 @@ static int rtl2832_wr_demod_reg(struct rtl2832_dev *dev, int reg, u32 val)
 	for (i = 0; i < len; i++)
 		writing[i] = (writing_tmp >> ((len - 1 - i) * 8)) & 0xff;
 
-	ret = rtl2832_bulk_write(client, reg_start_addr, writing, len);
+	ret = regmap_bulk_write(dev->regmap, reg_start_addr, writing, len);
 	if (ret)
 		goto err;
 
@@ -525,7 +488,8 @@ static int rtl2832_set_frontend(struct dvb_frontend *fe)
 	}
 
 	for (j = 0; j < sizeof(bw_params[0]); j++) {
-		ret = rtl2832_bulk_write(client, 0x11c + j, &bw_params[i][j], 1);
+		ret = regmap_bulk_write(dev->regmap,
+					0x11c + j, &bw_params[i][j], 1);
 		if (ret)
 			goto err;
 	}
@@ -581,11 +545,11 @@ static int rtl2832_get_frontend(struct dvb_frontend *fe,
 	if (dev->sleeping)
 		return 0;
 
-	ret = rtl2832_bulk_read(client, 0x33c, buf, 2);
+	ret = regmap_bulk_read(dev->regmap, 0x33c, buf, 2);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_bulk_read(client, 0x351, &buf[2], 1);
+	ret = regmap_bulk_read(dev->regmap, 0x351, &buf[2], 1);
 	if (ret)
 		goto err;
 
@@ -716,7 +680,7 @@ static int rtl2832_read_status(struct dvb_frontend *fe, enum fe_status *status)
 	/* signal strength */
 	if (dev->fe_status & FE_HAS_SIGNAL) {
 		/* read digital AGC */
-		ret = rtl2832_bulk_read(client, 0x305, &u8tmp, 1);
+		ret = regmap_bulk_read(dev->regmap, 0x305, &u8tmp, 1);
 		if (ret)
 			goto err;
 
@@ -742,7 +706,7 @@ static int rtl2832_read_status(struct dvb_frontend *fe, enum fe_status *status)
 			{87659938, 87659938, 87885178, 88241743},
 		};
 
-		ret = rtl2832_bulk_read(client, 0x33c, &u8tmp, 1);
+		ret = regmap_bulk_read(dev->regmap, 0x33c, &u8tmp, 1);
 		if (ret)
 			goto err;
 
@@ -754,7 +718,7 @@ static int rtl2832_read_status(struct dvb_frontend *fe, enum fe_status *status)
 		if (hierarchy > HIERARCHY_NUM - 1)
 			goto err;
 
-		ret = rtl2832_bulk_read(client, 0x40c, buf, 2);
+		ret = regmap_bulk_read(dev->regmap, 0x40c, buf, 2);
 		if (ret)
 			goto err;
 
@@ -775,7 +739,7 @@ static int rtl2832_read_status(struct dvb_frontend *fe, enum fe_status *status)
 
 	/* BER */
 	if (dev->fe_status & FE_HAS_LOCK) {
-		ret = rtl2832_bulk_read(client, 0x34e, buf, 2);
+		ret = regmap_bulk_read(dev->regmap, 0x34e, buf, 2);
 		if (ret)
 			goto err;
 
@@ -825,8 +789,6 @@ static int rtl2832_read_ber(struct dvb_frontend *fe, u32 *ber)
 
 /*
  * I2C gate/mux/repeater logic
- * We must use unlocked __i2c_transfer() here (through regmap) because of I2C
- * adapter lock is already taken by tuner driver.
  * There is delay mechanism to avoid unneeded I2C gate open / close. Gate close
  * is delayed here a little bit in order to see if there is sequence of I2C
  * messages sent to same I2C bus.
@@ -838,7 +800,7 @@ static void rtl2832_i2c_gate_work(struct work_struct *work)
 	int ret;
 
 	/* close gate */
-	ret = rtl2832_update_bits(dev->client, 0x101, 0x08, 0x00);
+	ret = regmap_update_bits(dev->regmap, 0x101, 0x08, 0x00);
 	if (ret)
 		goto err;
 
@@ -856,10 +818,7 @@ static int rtl2832_select(struct i2c_mux_core *muxc, u32 chan_id)
 	/* terminate possible gate closing */
 	cancel_delayed_work(&dev->i2c_gate_work);
 
-	/*
-	 * I2C adapter lock is already taken and due to that we will use
-	 * regmap_update_bits() which does not lock again I2C adapter.
-	 */
+	/* open gate */
 	ret = regmap_update_bits(dev->regmap, 0x101, 0x08, 0x08);
 	if (ret)
 		goto err;
@@ -932,94 +891,6 @@ static bool rtl2832_volatile_reg(struct device *dev, unsigned int reg)
 }
 
 /*
- * We implement own I2C access routines for regmap in order to get manual access
- * to I2C adapter lock, which is needed for I2C mux adapter.
- */
-static int rtl2832_regmap_read(void *context, const void *reg_buf,
-			       size_t reg_size, void *val_buf, size_t val_size)
-{
-	struct i2c_client *client = context;
-	int ret;
-	struct i2c_msg msg[2] = {
-		{
-			.addr = client->addr,
-			.flags = 0,
-			.len = reg_size,
-			.buf = (u8 *)reg_buf,
-		}, {
-			.addr = client->addr,
-			.flags = I2C_M_RD,
-			.len = val_size,
-			.buf = val_buf,
-		}
-	};
-
-	ret = __i2c_transfer(client->adapter, msg, 2);
-	if (ret != 2) {
-		dev_warn(&client->dev, "i2c reg read failed %d reg %02x\n",
-			 ret, *(u8 *)reg_buf);
-		if (ret >= 0)
-			ret = -EREMOTEIO;
-		return ret;
-	}
-	return 0;
-}
-
-static int rtl2832_regmap_write(void *context, const void *data, size_t count)
-{
-	struct i2c_client *client = context;
-	int ret;
-	struct i2c_msg msg[1] = {
-		{
-			.addr = client->addr,
-			.flags = 0,
-			.len = count,
-			.buf = (u8 *)data,
-		}
-	};
-
-	ret = __i2c_transfer(client->adapter, msg, 1);
-	if (ret != 1) {
-		dev_warn(&client->dev, "i2c reg write failed %d reg %02x\n",
-			 ret, *(u8 *)data);
-		if (ret >= 0)
-			ret = -EREMOTEIO;
-		return ret;
-	}
-	return 0;
-}
-
-static int rtl2832_regmap_gather_write(void *context, const void *reg,
-				       size_t reg_len, const void *val,
-				       size_t val_len)
-{
-	struct i2c_client *client = context;
-	int ret;
-	u8 buf[256];
-	struct i2c_msg msg[1] = {
-		{
-			.addr = client->addr,
-			.flags = 0,
-			.len = 1 + val_len,
-			.buf = buf,
-		}
-	};
-
-	buf[0] = *(u8 const *)reg;
-	memcpy(&buf[1], val, val_len);
-
-	ret = __i2c_transfer(client->adapter, msg, 1);
-	if (ret != 1) {
-		dev_warn(&client->dev, "i2c reg write failed %d reg %02x\n",
-			 ret, *(u8 const *)reg);
-		if (ret >= 0)
-			ret = -EREMOTEIO;
-		return ret;
-	}
-	return 0;
-}
-
-/*
  * FIXME: Hack. Implement own regmap locking in order to silence lockdep
  * recursive lock warning. That happens when regmap I2C client calls I2C mux
  * adapter, which leads demod I2C repeater enable via demod regmap. Operation
@@ -1072,29 +943,29 @@ static int rtl2832_slave_ts_ctrl(struct i2c_client *client, bool enable)
 		ret = rtl2832_wr_demod_reg(dev, DVBT_SOFT_RST, 0x0);
 		if (ret)
 			goto err;
-		ret = rtl2832_bulk_write(client, 0x10c, "\x5f\xff", 2);
+		ret = regmap_bulk_write(dev->regmap, 0x10c, "\x5f\xff", 2);
 		if (ret)
 			goto err;
 		ret = rtl2832_wr_demod_reg(dev, DVBT_PIP_ON, 0x1);
 		if (ret)
 			goto err;
-		ret = rtl2832_bulk_write(client, 0x0bc, "\x18", 1);
+		ret = regmap_bulk_write(dev->regmap, 0x0bc, "\x18", 1);
 		if (ret)
 			goto err;
-		ret = rtl2832_bulk_write(client, 0x192, "\x7f\xf7\xff", 3);
+		ret = regmap_bulk_write(dev->regmap, 0x192, "\x7f\xf7\xff", 3);
 		if (ret)
 			goto err;
 	} else {
-		ret = rtl2832_bulk_write(client, 0x192, "\x00\x0f\xff", 3);
+		ret = regmap_bulk_write(dev->regmap, 0x192, "\x00\x0f\xff", 3);
 		if (ret)
 			goto err;
-		ret = rtl2832_bulk_write(client, 0x0bc, "\x08", 1);
+		ret = regmap_bulk_write(dev->regmap, 0x0bc, "\x08", 1);
 		if (ret)
 			goto err;
 		ret = rtl2832_wr_demod_reg(dev, DVBT_PIP_ON, 0x0);
 		if (ret)
 			goto err;
-		ret = rtl2832_bulk_write(client, 0x10c, "\x00\x00", 2);
+		ret = regmap_bulk_write(dev->regmap, 0x10c, "\x00\x00", 2);
 		if (ret)
 			goto err;
 		ret = rtl2832_wr_demod_reg(dev, DVBT_SOFT_RST, 0x1);
@@ -1123,7 +994,7 @@ static int rtl2832_pid_filter_ctrl(struct dvb_frontend *fe, int onoff)
 	else
 		u8tmp = 0x00;
 
-	ret = rtl2832_update_bits(client, 0x061, 0xc0, u8tmp);
+	ret = regmap_update_bits(dev->regmap, 0x061, 0xc0, u8tmp);
 	if (ret)
 		goto err;
 
@@ -1158,14 +1029,14 @@ static int rtl2832_pid_filter(struct dvb_frontend *fe, u8 index, u16 pid,
 	buf[1] = (dev->filters >>  8) & 0xff;
 	buf[2] = (dev->filters >> 16) & 0xff;
 	buf[3] = (dev->filters >> 24) & 0xff;
-	ret = rtl2832_bulk_write(client, 0x062, buf, 4);
+	ret = regmap_bulk_write(dev->regmap, 0x062, buf, 4);
 	if (ret)
 		goto err;
 
 	/* add PID */
 	buf[0] = (pid >> 8) & 0xff;
 	buf[1] = (pid >> 0) & 0xff;
-	ret = rtl2832_bulk_write(client, 0x066 + 2 * index, buf, 2);
+	ret = regmap_bulk_write(dev->regmap, 0x066 + 2 * index, buf, 2);
 	if (ret)
 		goto err;
 
@@ -1183,12 +1054,6 @@ static int rtl2832_probe(struct i2c_client *client,
 	struct rtl2832_dev *dev;
 	int ret;
 	u8 tmp;
-	static const struct regmap_bus regmap_bus = {
-		.read = rtl2832_regmap_read,
-		.write = rtl2832_regmap_write,
-		.gather_write = rtl2832_regmap_gather_write,
-		.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
-	};
 	static const struct regmap_range_cfg regmap_range_cfg[] = {
 		{
 			.selector_reg     = 0x00,
@@ -1228,20 +1093,20 @@ static int rtl2832_probe(struct i2c_client *client,
 	dev->regmap_config.ranges = regmap_range_cfg,
 	dev->regmap_config.num_ranges = ARRAY_SIZE(regmap_range_cfg),
 	dev->regmap_config.cache_type = REGCACHE_NONE,
-	dev->regmap = regmap_init(&client->dev, &regmap_bus, client,
-				  &dev->regmap_config);
+	dev->regmap = regmap_init_i2c(client, &dev->regmap_config);
 	if (IS_ERR(dev->regmap)) {
 		ret = PTR_ERR(dev->regmap);
 		goto err_kfree;
 	}
 
 	/* check if the demod is there */
-	ret = rtl2832_bulk_read(client, 0x000, &tmp, 1);
+	ret = regmap_bulk_read(dev->regmap, 0x000, &tmp, 1);
 	if (ret)
 		goto err_regmap_exit;
 
 	/* create muxed i2c adapter for demod tuner bus */
-	dev->muxc = i2c_mux_one_adapter(i2c, &i2c->dev, 0, 0, 0, 0, 0,
+	dev->muxc = i2c_mux_one_adapter(i2c, &i2c->dev, 0,
+					I2C_MUX_LOCKED, 0, 0, 0,
 					rtl2832_select, rtl2832_deselect);
 	if (IS_ERR(dev->muxc)) {
 		ret = PTR_ERR(dev->muxc);
@@ -1259,9 +1124,7 @@ static int rtl2832_probe(struct i2c_client *client,
 	pdata->slave_ts_ctrl = rtl2832_slave_ts_ctrl;
 	pdata->pid_filter = rtl2832_pid_filter;
 	pdata->pid_filter_ctrl = rtl2832_pid_filter_ctrl;
-	pdata->bulk_read = rtl2832_bulk_read;
-	pdata->bulk_write = rtl2832_bulk_write;
-	pdata->update_bits = rtl2832_update_bits;
+	pdata->regmap = dev->regmap;
 
 	dev_info(&client->dev, "Realtek RTL2832 successfully attached\n");
 	return 0;
diff --git a/drivers/media/dvb-frontends/rtl2832.h b/drivers/media/dvb-frontends/rtl2832.h
index 6390af64cf45..03c0de039fa9 100644
--- a/drivers/media/dvb-frontends/rtl2832.h
+++ b/drivers/media/dvb-frontends/rtl2832.h
@@ -57,9 +57,7 @@ struct rtl2832_platform_data {
 	int (*pid_filter)(struct dvb_frontend *, u8, u16, int);
 	int (*pid_filter_ctrl)(struct dvb_frontend *, int);
 /* private: Register access for SDR module use only */
-	int (*bulk_read)(struct i2c_client *, unsigned int, void *, size_t);
-	int (*bulk_write)(struct i2c_client *, unsigned int, const void *, size_t);
-	int (*update_bits)(struct i2c_client *, unsigned int, unsigned int, unsigned int);
+	struct regmap *regmap;
 };
 
 #endif /* RTL2832_H */
diff --git a/drivers/media/dvb-frontends/rtl2832_sdr.c b/drivers/media/dvb-frontends/rtl2832_sdr.c
index b860f02a4e55..6a6b1debe277 100644
--- a/drivers/media/dvb-frontends/rtl2832_sdr.c
+++ b/drivers/media/dvb-frontends/rtl2832_sdr.c
@@ -35,6 +35,7 @@
 #include <linux/platform_device.h>
 #include <linux/jiffies.h>
 #include <linux/math64.h>
+#include <linux/regmap.h>
 
 static bool rtl2832_sdr_emulated_fmt;
 module_param_named(emulated_formats, rtl2832_sdr_emulated_fmt, bool, 0644);
@@ -169,9 +170,9 @@ static int rtl2832_sdr_wr_regs(struct rtl2832_sdr_dev *dev, u16 reg,
 {
 	struct platform_device *pdev = dev->pdev;
 	struct rtl2832_sdr_platform_data *pdata = pdev->dev.platform_data;
-	struct i2c_client *client = pdata->i2c_client;
+	struct regmap *regmap = pdata->regmap;
 
-	return pdata->bulk_write(client, reg, val, len);
+	return regmap_bulk_write(regmap, reg, val, len);
 }
 
 #if 0
@@ -181,9 +182,9 @@ static int rtl2832_sdr_rd_regs(struct rtl2832_sdr_dev *dev, u16 reg, u8 *val,
 {
 	struct platform_device *pdev = dev->pdev;
 	struct rtl2832_sdr_platform_data *pdata = pdev->dev.platform_data;
-	struct i2c_client *client = pdata->i2c_client;
+	struct regmap *regmap = pdata->regmap;
 
-	return pdata->bulk_read(client, reg, val, len);
+	return regmap_bulk_read(regmap, reg, val, len);
 }
 #endif
 
@@ -199,9 +200,9 @@ static int rtl2832_sdr_wr_reg_mask(struct rtl2832_sdr_dev *dev, u16 reg,
 {
 	struct platform_device *pdev = dev->pdev;
 	struct rtl2832_sdr_platform_data *pdata = pdev->dev.platform_data;
-	struct i2c_client *client = pdata->i2c_client;
+	struct regmap *regmap = pdata->regmap;
 
-	return pdata->update_bits(client, reg, mask, val);
+	return regmap_update_bits(regmap, reg, mask, val);
 }
 
 /* Private functions */
diff --git a/drivers/media/dvb-frontends/rtl2832_sdr.h b/drivers/media/dvb-frontends/rtl2832_sdr.h
index 342ea84860df..d8fc7e7212e3 100644
--- a/drivers/media/dvb-frontends/rtl2832_sdr.h
+++ b/drivers/media/dvb-frontends/rtl2832_sdr.h
@@ -56,10 +56,7 @@ struct rtl2832_sdr_platform_data {
 #define RTL2832_SDR_TUNER_R828D     0x2b
 	u8 tuner;
 
-	struct i2c_client *i2c_client;
-	int (*bulk_read)(struct i2c_client *, unsigned int, void *, size_t);
-	int (*bulk_write)(struct i2c_client *, unsigned int, const void *, size_t);
-	int (*update_bits)(struct i2c_client *, unsigned int, unsigned int, unsigned int);
+	struct regmap *regmap;
 	struct dvb_frontend *dvb_frontend;
 	struct v4l2_subdev *v4l2_subdev;
 	struct dvb_usb_device *dvb_usb_device;
diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
index fa72642d41f3..eb7af8cb8aca 100644
--- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
+++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
@@ -1333,10 +1333,7 @@ static int rtl2832u_tuner_attach(struct dvb_usb_adapter *adap)
 	case TUNER_RTL2832_R828D:
 		pdata.clk = dev->rtl2832_platform_data.clk;
 		pdata.tuner = dev->tuner;
-		pdata.i2c_client = dev->i2c_client_demod;
-		pdata.bulk_read = dev->rtl2832_platform_data.bulk_read;
-		pdata.bulk_write = dev->rtl2832_platform_data.bulk_write;
-		pdata.update_bits = dev->rtl2832_platform_data.update_bits;
+		pdata.regmap = dev->rtl2832_platform_data.regmap;
 		pdata.dvb_frontend = adap->fe[0];
 		pdata.dvb_usb_device = d;
 		pdata.v4l2_subdev = subdev;
-- 
2.1.4

[PATCH v6 23/24] [media] rtl2832_sdr: get rid of empty regmap wrappers

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/dvb-frontends/rtl2832_sdr.c | 302 +++++++++++++-----------------
 1 file changed, 132 insertions(+), 170 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2832_sdr.c b/drivers/media/dvb-frontends/rtl2832_sdr.c
index 6a6b1debe277..47a480a7d46c 100644
--- a/drivers/media/dvb-frontends/rtl2832_sdr.c
+++ b/drivers/media/dvb-frontends/rtl2832_sdr.c
@@ -120,6 +120,7 @@ struct rtl2832_sdr_dev {
 	unsigned long flags;
 
 	struct platform_device *pdev;
+	struct regmap *regmap;
 
 	struct video_device vdev;
 	struct v4l2_device v4l2_dev;
@@ -164,47 +165,6 @@ struct rtl2832_sdr_dev {
 	unsigned long jiffies_next;
 };
 
-/* write multiple registers */
-static int rtl2832_sdr_wr_regs(struct rtl2832_sdr_dev *dev, u16 reg,
-		const u8 *val, int len)
-{
-	struct platform_device *pdev = dev->pdev;
-	struct rtl2832_sdr_platform_data *pdata = pdev->dev.platform_data;
-	struct regmap *regmap = pdata->regmap;
-
-	return regmap_bulk_write(regmap, reg, val, len);
-}
-
-#if 0
-/* read multiple registers */
-static int rtl2832_sdr_rd_regs(struct rtl2832_sdr_dev *dev, u16 reg, u8 *val,
-		int len)
-{
-	struct platform_device *pdev = dev->pdev;
-	struct rtl2832_sdr_platform_data *pdata = pdev->dev.platform_data;
-	struct regmap *regmap = pdata->regmap;
-
-	return regmap_bulk_read(regmap, reg, val, len);
-}
-#endif
-
-/* write single register */
-static int rtl2832_sdr_wr_reg(struct rtl2832_sdr_dev *dev, u16 reg, u8 val)
-{
-	return rtl2832_sdr_wr_regs(dev, reg, &val, 1);
-}
-
-/* write single register with mask */
-static int rtl2832_sdr_wr_reg_mask(struct rtl2832_sdr_dev *dev, u16 reg,
-		u8 val, u8 mask)
-{
-	struct platform_device *pdev = dev->pdev;
-	struct rtl2832_sdr_platform_data *pdata = pdev->dev.platform_data;
-	struct regmap *regmap = pdata->regmap;
-
-	return regmap_update_bits(regmap, reg, mask, val);
-}
-
 /* Private functions */
 static struct rtl2832_sdr_frame_buf *rtl2832_sdr_get_next_fill_buf(
 		struct rtl2832_sdr_dev *dev)
@@ -559,11 +519,11 @@ static int rtl2832_sdr_set_adc(struct rtl2832_sdr_dev *dev)
 
 	f_sr = dev->f_adc;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x13e, "\x00\x00", 2);
+	ret = regmap_bulk_write(dev->regmap, 0x13e, "\x00\x00", 2);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x115, "\x00\x00\x00\x00", 4);
+	ret = regmap_bulk_write(dev->regmap, 0x115, "\x00\x00\x00\x00", 4);
 	if (ret)
 		goto err;
 
@@ -589,7 +549,7 @@ static int rtl2832_sdr_set_adc(struct rtl2832_sdr_dev *dev)
 	buf[1] = (u32tmp >>  8) & 0xff;
 	buf[2] = (u32tmp >>  0) & 0xff;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x119, buf, 3);
+	ret = regmap_bulk_write(dev->regmap, 0x119, buf, 3);
 	if (ret)
 		goto err;
 
@@ -603,15 +563,15 @@ static int rtl2832_sdr_set_adc(struct rtl2832_sdr_dev *dev)
 		u8tmp2 = 0xcd; /* enable ADC I, ADC Q */
 	}
 
-	ret = rtl2832_sdr_wr_reg(dev, 0x1b1, u8tmp1);
+	ret = regmap_write(dev->regmap, 0x1b1, u8tmp1);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_reg(dev, 0x008, u8tmp2);
+	ret = regmap_write(dev->regmap, 0x008, u8tmp2);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_reg(dev, 0x006, 0x80);
+	ret = regmap_write(dev->regmap, 0x006, 0x80);
 	if (ret)
 		goto err;
 
@@ -622,168 +582,169 @@ static int rtl2832_sdr_set_adc(struct rtl2832_sdr_dev *dev)
 	buf[1] = (u32tmp >> 16) & 0xff;
 	buf[2] = (u32tmp >>  8) & 0xff;
 	buf[3] = (u32tmp >>  0) & 0xff;
-	ret = rtl2832_sdr_wr_regs(dev, 0x19f, buf, 4);
+	ret = regmap_bulk_write(dev->regmap, 0x19f, buf, 4);
 	if (ret)
 		goto err;
 
 	/* low-pass filter */
-	ret = rtl2832_sdr_wr_regs(dev, 0x11c,
-			"\xca\xdc\xd7\xd8\xe0\xf2\x0e\x35\x06\x50\x9c\x0d\x71\x11\x14\x71\x74\x19\x41\xa5",
-			20);
+	ret = regmap_bulk_write(dev->regmap, 0x11c,
+				"\xca\xdc\xd7\xd8\xe0\xf2\x0e\x35\x06\x50\x9c\x0d\x71\x11\x14\x71\x74\x19\x41\xa5",
+				20);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x017, "\x11\x10", 2);
+	ret = regmap_bulk_write(dev->regmap, 0x017, "\x11\x10", 2);
 	if (ret)
 		goto err;
 
 	/* mode */
-	ret = rtl2832_sdr_wr_regs(dev, 0x019, "\x05", 1);
+	ret = regmap_write(dev->regmap, 0x019, 0x05);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x01a, "\x1b\x16\x0d\x06\x01\xff", 6);
+	ret = regmap_bulk_write(dev->regmap, 0x01a,
+				"\x1b\x16\x0d\x06\x01\xff", 6);
 	if (ret)
 		goto err;
 
 	/* FSM */
-	ret = rtl2832_sdr_wr_regs(dev, 0x192, "\x00\xf0\x0f", 3);
+	ret = regmap_bulk_write(dev->regmap, 0x192, "\x00\xf0\x0f", 3);
 	if (ret)
 		goto err;
 
 	/* PID filter */
-	ret = rtl2832_sdr_wr_regs(dev, 0x061, "\x60", 1);
+	ret = regmap_write(dev->regmap, 0x061, 0x60);
 	if (ret)
 		goto err;
 
 	/* used RF tuner based settings */
 	switch (pdata->tuner) {
 	case RTL2832_SDR_TUNER_E4000:
-		ret = rtl2832_sdr_wr_regs(dev, 0x112, "\x5a", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x102, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x103, "\x5a", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c7, "\x30", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x104, "\xd0", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x105, "\xbe", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c8, "\x18", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x106, "\x35", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c9, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ca, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cb, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x107, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cd, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ce, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x108, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x109, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10a, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10b, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x011, "\xd4", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1e5, "\xf0", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1d9, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1db, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1dd, "\x14", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1de, "\xec", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1d8, "\x0c", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1e6, "\x02", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1d7, "\x09", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00d, "\x83", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x010, "\x49", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00d, "\x87", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00d, "\x85", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x013, "\x02", 1);
+		ret = regmap_write(dev->regmap, 0x112, 0x5a);
+		ret = regmap_write(dev->regmap, 0x102, 0x40);
+		ret = regmap_write(dev->regmap, 0x103, 0x5a);
+		ret = regmap_write(dev->regmap, 0x1c7, 0x30);
+		ret = regmap_write(dev->regmap, 0x104, 0xd0);
+		ret = regmap_write(dev->regmap, 0x105, 0xbe);
+		ret = regmap_write(dev->regmap, 0x1c8, 0x18);
+		ret = regmap_write(dev->regmap, 0x106, 0x35);
+		ret = regmap_write(dev->regmap, 0x1c9, 0x21);
+		ret = regmap_write(dev->regmap, 0x1ca, 0x21);
+		ret = regmap_write(dev->regmap, 0x1cb, 0x00);
+		ret = regmap_write(dev->regmap, 0x107, 0x40);
+		ret = regmap_write(dev->regmap, 0x1cd, 0x10);
+		ret = regmap_write(dev->regmap, 0x1ce, 0x10);
+		ret = regmap_write(dev->regmap, 0x108, 0x80);
+		ret = regmap_write(dev->regmap, 0x109, 0x7f);
+		ret = regmap_write(dev->regmap, 0x10a, 0x80);
+		ret = regmap_write(dev->regmap, 0x10b, 0x7f);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_write(dev->regmap, 0x011, 0xd4);
+		ret = regmap_write(dev->regmap, 0x1e5, 0xf0);
+		ret = regmap_write(dev->regmap, 0x1d9, 0x00);
+		ret = regmap_write(dev->regmap, 0x1db, 0x00);
+		ret = regmap_write(dev->regmap, 0x1dd, 0x14);
+		ret = regmap_write(dev->regmap, 0x1de, 0xec);
+		ret = regmap_write(dev->regmap, 0x1d8, 0x0c);
+		ret = regmap_write(dev->regmap, 0x1e6, 0x02);
+		ret = regmap_write(dev->regmap, 0x1d7, 0x09);
+		ret = regmap_write(dev->regmap, 0x00d, 0x83);
+		ret = regmap_write(dev->regmap, 0x010, 0x49);
+		ret = regmap_write(dev->regmap, 0x00d, 0x87);
+		ret = regmap_write(dev->regmap, 0x00d, 0x85);
+		ret = regmap_write(dev->regmap, 0x013, 0x02);
 		break;
 	case RTL2832_SDR_TUNER_FC0012:
 	case RTL2832_SDR_TUNER_FC0013:
-		ret = rtl2832_sdr_wr_regs(dev, 0x112, "\x5a", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x102, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x103, "\x5a", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c7, "\x2c", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x104, "\xcc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x105, "\xbe", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c8, "\x16", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x106, "\x35", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c9, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ca, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cb, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x107, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cd, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ce, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x108, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x109, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10a, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10b, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x011, "\xe9\xbf", 2);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1e5, "\xf0", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1d9, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1db, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1dd, "\x11", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1de, "\xef", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1d8, "\x0c", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1e6, "\x02", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1d7, "\x09", 1);
+		ret = regmap_write(dev->regmap, 0x112, 0x5a);
+		ret = regmap_write(dev->regmap, 0x102, 0x40);
+		ret = regmap_write(dev->regmap, 0x103, 0x5a);
+		ret = regmap_write(dev->regmap, 0x1c7, 0x2c);
+		ret = regmap_write(dev->regmap, 0x104, 0xcc);
+		ret = regmap_write(dev->regmap, 0x105, 0xbe);
+		ret = regmap_write(dev->regmap, 0x1c8, 0x16);
+		ret = regmap_write(dev->regmap, 0x106, 0x35);
+		ret = regmap_write(dev->regmap, 0x1c9, 0x21);
+		ret = regmap_write(dev->regmap, 0x1ca, 0x21);
+		ret = regmap_write(dev->regmap, 0x1cb, 0x00);
+		ret = regmap_write(dev->regmap, 0x107, 0x40);
+		ret = regmap_write(dev->regmap, 0x1cd, 0x10);
+		ret = regmap_write(dev->regmap, 0x1ce, 0x10);
+		ret = regmap_write(dev->regmap, 0x108, 0x80);
+		ret = regmap_write(dev->regmap, 0x109, 0x7f);
+		ret = regmap_write(dev->regmap, 0x10a, 0x80);
+		ret = regmap_write(dev->regmap, 0x10b, 0x7f);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_bulk_write(dev->regmap, 0x011, "\xe9\xbf", 2);
+		ret = regmap_write(dev->regmap, 0x1e5, 0xf0);
+		ret = regmap_write(dev->regmap, 0x1d9, 0x00);
+		ret = regmap_write(dev->regmap, 0x1db, 0x00);
+		ret = regmap_write(dev->regmap, 0x1dd, 0x11);
+		ret = regmap_write(dev->regmap, 0x1de, 0xef);
+		ret = regmap_write(dev->regmap, 0x1d8, 0x0c);
+		ret = regmap_write(dev->regmap, 0x1e6, 0x02);
+		ret = regmap_write(dev->regmap, 0x1d7, 0x09);
 		break;
 	case RTL2832_SDR_TUNER_R820T:
 	case RTL2832_SDR_TUNER_R828D:
-		ret = rtl2832_sdr_wr_regs(dev, 0x112, "\x5a", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x102, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x115, "\x01", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x103, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c7, "\x24", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x104, "\xcc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x105, "\xbe", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c8, "\x14", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x106, "\x35", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c9, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ca, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cb, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x107, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cd, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ce, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x108, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x109, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10a, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10b, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x011, "\xf4", 1);
+		ret = regmap_write(dev->regmap, 0x112, 0x5a);
+		ret = regmap_write(dev->regmap, 0x102, 0x40);
+		ret = regmap_write(dev->regmap, 0x115, 0x01);
+		ret = regmap_write(dev->regmap, 0x103, 0x80);
+		ret = regmap_write(dev->regmap, 0x1c7, 0x24);
+		ret = regmap_write(dev->regmap, 0x104, 0xcc);
+		ret = regmap_write(dev->regmap, 0x105, 0xbe);
+		ret = regmap_write(dev->regmap, 0x1c8, 0x14);
+		ret = regmap_write(dev->regmap, 0x106, 0x35);
+		ret = regmap_write(dev->regmap, 0x1c9, 0x21);
+		ret = regmap_write(dev->regmap, 0x1ca, 0x21);
+		ret = regmap_write(dev->regmap, 0x1cb, 0x00);
+		ret = regmap_write(dev->regmap, 0x107, 0x40);
+		ret = regmap_write(dev->regmap, 0x1cd, 0x10);
+		ret = regmap_write(dev->regmap, 0x1ce, 0x10);
+		ret = regmap_write(dev->regmap, 0x108, 0x80);
+		ret = regmap_write(dev->regmap, 0x109, 0x7f);
+		ret = regmap_write(dev->regmap, 0x10a, 0x80);
+		ret = regmap_write(dev->regmap, 0x10b, 0x7f);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_write(dev->regmap, 0x011, 0xf4);
 		break;
 	case RTL2832_SDR_TUNER_FC2580:
-		ret = rtl2832_sdr_wr_regs(dev, 0x112, "\x39", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x102, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x103, "\x5a", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c7, "\x2c", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x104, "\xcc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x105, "\xbe", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c8, "\x16", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x106, "\x35", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1c9, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ca, "\x21", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cb, "\x00", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x107, "\x40", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1cd, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x1ce, "\x10", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x108, "\x80", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x109, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10a, "\x9c", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x10b, "\x7f", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x00e, "\xfc", 1);
-		ret = rtl2832_sdr_wr_regs(dev, 0x011, "\xe9\xf4", 2);
+		ret = regmap_write(dev->regmap, 0x112, 0x39);
+		ret = regmap_write(dev->regmap, 0x102, 0x40);
+		ret = regmap_write(dev->regmap, 0x103, 0x5a);
+		ret = regmap_write(dev->regmap, 0x1c7, 0x2c);
+		ret = regmap_write(dev->regmap, 0x104, 0xcc);
+		ret = regmap_write(dev->regmap, 0x105, 0xbe);
+		ret = regmap_write(dev->regmap, 0x1c8, 0x16);
+		ret = regmap_write(dev->regmap, 0x106, 0x35);
+		ret = regmap_write(dev->regmap, 0x1c9, 0x21);
+		ret = regmap_write(dev->regmap, 0x1ca, 0x21);
+		ret = regmap_write(dev->regmap, 0x1cb, 0x00);
+		ret = regmap_write(dev->regmap, 0x107, 0x40);
+		ret = regmap_write(dev->regmap, 0x1cd, 0x10);
+		ret = regmap_write(dev->regmap, 0x1ce, 0x10);
+		ret = regmap_write(dev->regmap, 0x108, 0x80);
+		ret = regmap_write(dev->regmap, 0x109, 0x7f);
+		ret = regmap_write(dev->regmap, 0x10a, 0x9c);
+		ret = regmap_write(dev->regmap, 0x10b, 0x7f);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_write(dev->regmap, 0x00e, 0xfc);
+		ret = regmap_bulk_write(dev->regmap, 0x011, "\xe9\xf4", 2);
 		break;
 	default:
 		dev_notice(&pdev->dev, "Unsupported tuner\n");
 	}
 
 	/* software reset */
-	ret = rtl2832_sdr_wr_reg_mask(dev, 0x101, 0x04, 0x04);
+	ret = regmap_update_bits(dev->regmap, 0x101, 0x04, 0x04);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_reg_mask(dev, 0x101, 0x00, 0x04);
+	ret = regmap_update_bits(dev->regmap, 0x101, 0x04, 0x00);
 	if (ret)
 		goto err;
 err:
@@ -798,29 +759,29 @@ static void rtl2832_sdr_unset_adc(struct rtl2832_sdr_dev *dev)
 	dev_dbg(&pdev->dev, "\n");
 
 	/* PID filter */
-	ret = rtl2832_sdr_wr_regs(dev, 0x061, "\xe0", 1);
+	ret = regmap_write(dev->regmap, 0x061, 0xe0);
 	if (ret)
 		goto err;
 
 	/* mode */
-	ret = rtl2832_sdr_wr_regs(dev, 0x019, "\x20", 1);
+	ret = regmap_write(dev->regmap, 0x019, 0x20);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x017, "\x11\x10", 2);
+	ret = regmap_bulk_write(dev->regmap, 0x017, "\x11\x10", 2);
 	if (ret)
 		goto err;
 
 	/* FSM */
-	ret = rtl2832_sdr_wr_regs(dev, 0x192, "\x00\x0f\xff", 3);
+	ret = regmap_bulk_write(dev->regmap, 0x192, "\x00\x0f\xff", 3);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x13e, "\x40\x00", 2);
+	ret = regmap_bulk_write(dev->regmap, 0x13e, "\x40\x00", 2);
 	if (ret)
 		goto err;
 
-	ret = rtl2832_sdr_wr_regs(dev, 0x115, "\x06\x3f\xce\xcc", 4);
+	ret = regmap_bulk_write(dev->regmap, 0x115, "\x06\x3f\xce\xcc", 4);
 	if (ret)
 		goto err;
 err:
@@ -1400,6 +1361,7 @@ static int rtl2832_sdr_probe(struct platform_device *pdev)
 	subdev = pdata->v4l2_subdev;
 	dev->v4l2_subdev = pdata->v4l2_subdev;
 	dev->pdev = pdev;
+	dev->regmap = pdata->regmap;
 	dev->udev = pdata->dvb_usb_device->udev;
 	dev->f_adc = bands_adc[0].rangelow;
 	dev->f_tuner = bands_fm[0].rangelow;
-- 
2.1.4

[PATCH v6 24/24] [media] rtl2832: regmap is aware of lockdep, drop local locking hack

[Peter Rosin]

From: Peter Rosin <peda@axentia.se>

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/media/dvb-frontends/rtl2832.c      | 30 ------------------------------
 drivers/media/dvb-frontends/rtl2832_priv.h |  1 -
 2 files changed, 31 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c
index ac5ac5f7a335..23459fed2516 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -890,32 +890,6 @@ static bool rtl2832_volatile_reg(struct device *dev, unsigned int reg)
 	return false;
 }
 
-/*
- * FIXME: Hack. Implement own regmap locking in order to silence lockdep
- * recursive lock warning. That happens when regmap I2C client calls I2C mux
- * adapter, which leads demod I2C repeater enable via demod regmap. Operation
- * takes two regmap locks recursively - but those are different regmap instances
- * in a two different I2C drivers, so it is not deadlock. Proper fix is to make
- * regmap aware of lockdep.
- */
-static void rtl2832_regmap_lock(void *__dev)
-{
-	struct rtl2832_dev *dev = __dev;
-	struct i2c_client *client = dev->client;
-
-	dev_dbg(&client->dev, "\n");
-	mutex_lock(&dev->regmap_mutex);
-}
-
-static void rtl2832_regmap_unlock(void *__dev)
-{
-	struct rtl2832_dev *dev = __dev;
-	struct i2c_client *client = dev->client;
-
-	dev_dbg(&client->dev, "\n");
-	mutex_unlock(&dev->regmap_mutex);
-}
-
 static struct dvb_frontend *rtl2832_get_dvb_frontend(struct i2c_client *client)
 {
 	struct rtl2832_dev *dev = i2c_get_clientdata(client);
@@ -1082,12 +1056,8 @@ static int rtl2832_probe(struct i2c_client *client,
 	dev->sleeping = true;
 	INIT_DELAYED_WORK(&dev->i2c_gate_work, rtl2832_i2c_gate_work);
 	/* create regmap */
-	mutex_init(&dev->regmap_mutex);
 	dev->regmap_config.reg_bits =  8,
 	dev->regmap_config.val_bits =  8,
-	dev->regmap_config.lock = rtl2832_regmap_lock,
-	dev->regmap_config.unlock = rtl2832_regmap_unlock,
-	dev->regmap_config.lock_arg = dev,
 	dev->regmap_config.volatile_reg = rtl2832_volatile_reg,
 	dev->regmap_config.max_register = 5 * 0x100,
 	dev->regmap_config.ranges = regmap_range_cfg,
diff --git a/drivers/media/dvb-frontends/rtl2832_priv.h b/drivers/media/dvb-frontends/rtl2832_priv.h
index d8f97d14f6fd..c1a8a69e9015 100644
--- a/drivers/media/dvb-frontends/rtl2832_priv.h
+++ b/drivers/media/dvb-frontends/rtl2832_priv.h
@@ -33,7 +33,6 @@
 struct rtl2832_dev {
 	struct rtl2832_platform_data *pdata;
 	struct i2c_client *client;
-	struct mutex regmap_mutex;
 	struct regmap_config regmap_config;
 	struct regmap *regmap;
 	struct i2c_mux_core *muxc;
-- 
2.1.4

Re: [PATCH v6 08/24] iio: imu: inv_mpu6050: convert to use an explicit i2c mux core

[Jonathan Cameron]

On 03/04/16 09:52, Peter Rosin wrote:
> From: Peter Rosin <peda@axentia.se>
> 
> Allocate an explicit i2c mux core to handle parent and child adapters
> etc. Update the select/deselect ops to be in terms of the i2c mux core
> instead of the child adapter.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
I'm mostly fine with this (though one unrelated change seems to have snuck
in).  However, I'm not set up to test it - hence other than fixing the change
you can have my ack, but ideal would be a tested by from someone with
relevant hardware...  However, it looks to be a fairly mechanical change so
if no one is currently setup to test it, then don't let it hold up the
series too long!

Acked-by: Jonathan Cameron <jic23@kernel.org>

Jonathan
> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c |  2 +-
>  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c |  1 -
>  drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c  | 32 +++++++++++++-----------------
>  drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h  |  3 ++-
>  4 files changed, 17 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> index 2771106fd650..f62b8bd9ad7e 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> @@ -183,7 +183,7 @@ int inv_mpu_acpi_create_mux_client(struct i2c_client *client)
>  			} else
>  				return 0; /* no secondary addr, which is OK */
>  		}
> -		st->mux_client = i2c_new_device(st->mux_adapter, &info);
> +		st->mux_client = i2c_new_device(st->muxc->adapter[0], &info);
>  		if (!st->mux_client)
>  			return -ENODEV;
>  	}
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> index d192953e9a38..0c2bded2b5b7 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> @@ -23,7 +23,6 @@
>  #include <linux/kfifo.h>
>  #include <linux/spinlock.h>
>  #include <linux/iio/iio.h>
> -#include <linux/i2c-mux.h>
>  #include <linux/acpi.h>
>  #include "inv_mpu_iio.h"
>  
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
> index f581256d9d4c..0d429d788106 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
> @@ -15,7 +15,6 @@
>  #include <linux/delay.h>
>  #include <linux/err.h>
>  #include <linux/i2c.h>
> -#include <linux/i2c-mux.h>
>  #include <linux/iio/iio.h>
>  #include <linux/module.h>
>  #include "inv_mpu_iio.h"
> @@ -52,10 +51,9 @@ static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
>  	return 0;
>  }
>  
> -static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv,
> -				     u32 chan_id)
> +static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>  {
> -	struct i2c_client *client = mux_priv;
> +	struct i2c_client *client = i2c_mux_priv(muxc);
>  	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>  	int ret = 0;
> @@ -84,10 +82,9 @@ write_error:
>  	return ret;
>  }
>  
> -static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap,
> -				       void *mux_priv, u32 chan_id)
> +static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>  {
> -	struct i2c_client *client = mux_priv;
> +	struct i2c_client *client = i2c_mux_priv(muxc);
>  	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>  
> @@ -136,16 +133,15 @@ static int inv_mpu_probe(struct i2c_client *client,
>  		return result;
>  
>  	st = iio_priv(dev_get_drvdata(&client->dev));
> -	st->mux_adapter = i2c_add_mux_adapter(client->adapter,
> -					      &client->dev,
> -					      client,
> -					      0, 0, 0,
> -					      inv_mpu6050_select_bypass,
> -					      inv_mpu6050_deselect_bypass);
> -	if (!st->mux_adapter) {
> -		result = -ENODEV;
> +	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
> +				       0, 0, 0,
> +				       inv_mpu6050_select_bypass,
> +				       inv_mpu6050_deselect_bypass);
> +	if (IS_ERR(st->muxc)) {
> +		result = PTR_ERR(st->muxc);
>  		goto out_unreg_device;
>  	}
> +	st->muxc->priv = client;
>  
>  	result = inv_mpu_acpi_create_mux_client(client);
>  	if (result)
> @@ -154,7 +150,7 @@ static int inv_mpu_probe(struct i2c_client *client,
>  	return 0;
>  
>  out_del_mux:
> -	i2c_del_mux_adapter(st->mux_adapter);
> +	i2c_mux_del_adapters(st->muxc);
>  out_unreg_device:
>  	inv_mpu_core_remove(&client->dev);
>  	return result;
> @@ -162,11 +158,11 @@ out_unreg_device:
>  
>  static int inv_mpu_remove(struct i2c_client *client)
>  {
> -	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
Why this change?  Seems unrelated.
>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>  
>  	inv_mpu_acpi_delete_mux_client(client);
> -	i2c_del_mux_adapter(st->mux_adapter);
> +	i2c_mux_del_adapters(st->muxc);
>  
>  	return inv_mpu_core_remove(&client->dev);
>  }
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> index e302a49703bf..bb3cef6d7059 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> @@ -11,6 +11,7 @@
>  * GNU General Public License for more details.
>  */
>  #include <linux/i2c.h>
> +#include <linux/i2c-mux.h>
>  #include <linux/kfifo.h>
>  #include <linux/spinlock.h>
>  #include <linux/iio/iio.h>
> @@ -127,7 +128,7 @@ struct inv_mpu6050_state {
>  	const struct inv_mpu6050_hw *hw;
>  	enum   inv_devices chip_type;
>  	spinlock_t time_stamp_lock;
> -	struct i2c_adapter *mux_adapter;
> +	struct i2c_mux_core *muxc;
>  	struct i2c_client *mux_client;
>  	unsigned int powerup_count;
>  	struct inv_mpu6050_platform_data plat_data;
> 

Re: [PATCH v6 20/24] iio: imu: inv_mpu6050: change the i2c gate to be mux-locked

[Jonathan Cameron]

On 03/04/16 09:52, Peter Rosin wrote:
> From: Peter Rosin <peda@axentia.se>
> 
> The root i2c adapter lock is then no longer held by the i2c mux during
> accesses behind the i2c gate, and such accesses need to take that lock
> just like any other ordinary i2c accesses do.
> 
> So, declare the i2c gate mux-locked, and zap the code that makes the
> unlocked i2c accesses and just use ordinary regmap_write accesses.
> 
> This also happens to fix the deadlock described in
> http://patchwork.ozlabs.org/patch/584776/ authored by
> Adriana Reus <adriana.reus@intel.com> and submitted by
> Daniel Baluta <daniel.baluta@intel.com>
> 
> ----------8<----------
> iio: imu: inv_mpu6050: Fix deadlock between i2c adapter lock and mpu lock
> 
> This deadlock occurs if the accel/gyro and the sensor on the auxiliary
> I2C (in my setup it's an ak8975) are working at the same time.
> 
> Scenario:
> 
>       T1					T2
>      ====				       ====
> inv_mpu6050_read_fifo                  aux sensor op (eg. ak8975_read_raw)
>         |                                     |
> mutex_lock(&indio_dev->mlock)           i2c_transfer
>         |                                     |
> i2c transaction                         i2c adapter lock
>         |                                     |
> i2c adapter lock                        i2c_mux_master_xfer
>                                               |
>                                         inv_mpu6050_select_bypass
>                                               |
>                                         mutex_lock(&indio_dev->mlock)
> 
> When we operate on an mpu sensor the order of locking is mpu lock
> followed by the i2c adapter lock. However, when we operate the auxiliary
> sensor the order of locking is the other way around.
> 
> ...
> ----------8<----------
> 
> The reason this patch fixes the deadlock is that T2 does not grab the
> i2c adapter lock until the very end (and grabs the newfangled i2c mux
> lock where it previously grabbed the i2c adapter lock).
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
This one obviously wants a ack from Adriana or Daniel in addition to mine.
I'm more than happy for these to go through the i2c tree btw.

Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
>  Documentation/i2c/i2c-topology            |  2 +-
>  drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c | 56 +++++++------------------------
>  2 files changed, 13 insertions(+), 45 deletions(-)
> 
> diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
> index 7a10edd0874f..346623a80bd1 100644
> --- a/Documentation/i2c/i2c-topology
> +++ b/Documentation/i2c/i2c-topology
> @@ -50,7 +50,7 @@ i2c-mux-pinctrl           Normally parent-locked, mux-locked iff
>  i2c-mux-reg               Parent-locked
>  
>  In drivers/iio/
> -imu/inv_mpu6050/          Parent-locked
> +imu/inv_mpu6050/          Mux-locked
>  
>  In drivers/media/
>  dvb-frontends/m88ds3103   Parent-locked
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
> index 0d429d788106..71ad31a275c9 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
> @@ -24,45 +24,16 @@ static const struct regmap_config inv_mpu_regmap_config = {
>  	.val_bits = 8,
>  };
>  
> -/*
> - * The i2c read/write needs to happen in unlocked mode. As the parent
> - * adapter is common. If we use locked versions, it will fail as
> - * the mux adapter will lock the parent i2c adapter, while calling
> - * select/deselect functions.
> - */
> -static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
> -					  u8 reg, u8 d)
> -{
> -	int ret;
> -	u8 buf[2] = {reg, d};
> -	struct i2c_msg msg[1] = {
> -		{
> -			.addr = client->addr,
> -			.flags = 0,
> -			.len = sizeof(buf),
> -			.buf = buf,
> -		}
> -	};
> -
> -	ret = __i2c_transfer(client->adapter, msg, 1);
> -	if (ret != 1)
> -		return ret;
> -
> -	return 0;
> -}
> -
>  static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>  {
> -	struct i2c_client *client = i2c_mux_priv(muxc);
> -	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
> +	struct iio_dev *indio_dev = i2c_mux_priv(muxc);
>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>  	int ret = 0;
>  
>  	/* Use the same mutex which was used everywhere to protect power-op */
>  	mutex_lock(&indio_dev->mlock);
>  	if (!st->powerup_count) {
> -		ret = inv_mpu6050_write_reg_unlocked(client,
> -						     st->reg->pwr_mgmt_1, 0);
> +		ret = regmap_write(st->map, st->reg->pwr_mgmt_1, 0);
>  		if (ret)
>  			goto write_error;
>  
> @@ -71,10 +42,9 @@ static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>  	}
>  	if (!ret) {
>  		st->powerup_count++;
> -		ret = inv_mpu6050_write_reg_unlocked(client,
> -						     st->reg->int_pin_cfg,
> -						     INV_MPU6050_INT_PIN_CFG |
> -						     INV_MPU6050_BIT_BYPASS_EN);
> +		ret = regmap_write(st->map, st->reg->int_pin_cfg,
> +				   INV_MPU6050_INT_PIN_CFG |
> +				   INV_MPU6050_BIT_BYPASS_EN);
>  	}
>  write_error:
>  	mutex_unlock(&indio_dev->mlock);
> @@ -84,18 +54,16 @@ write_error:
>  
>  static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>  {
> -	struct i2c_client *client = i2c_mux_priv(muxc);
> -	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
> +	struct iio_dev *indio_dev = i2c_mux_priv(muxc);
>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>  
>  	mutex_lock(&indio_dev->mlock);
>  	/* It doesn't really mattter, if any of the calls fails */
> -	inv_mpu6050_write_reg_unlocked(client, st->reg->int_pin_cfg,
> -				       INV_MPU6050_INT_PIN_CFG);
> +	regmap_write(st->map, st->reg->int_pin_cfg, INV_MPU6050_INT_PIN_CFG);
>  	st->powerup_count--;
>  	if (!st->powerup_count)
> -		inv_mpu6050_write_reg_unlocked(client, st->reg->pwr_mgmt_1,
> -					       INV_MPU6050_BIT_SLEEP);
> +		regmap_write(st->map, st->reg->pwr_mgmt_1,
> +			     INV_MPU6050_BIT_SLEEP);
>  	mutex_unlock(&indio_dev->mlock);
>  
>  	return 0;
> @@ -133,15 +101,15 @@ static int inv_mpu_probe(struct i2c_client *client,
>  		return result;
>  
>  	st = iio_priv(dev_get_drvdata(&client->dev));
> -	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
> -				       0, 0, 0,
> +	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0,
> +				       I2C_MUX_LOCKED, 0, 0, 0,
>  				       inv_mpu6050_select_bypass,
>  				       inv_mpu6050_deselect_bypass);
>  	if (IS_ERR(st->muxc)) {
>  		result = PTR_ERR(st->muxc);
>  		goto out_unreg_device;
>  	}
> -	st->muxc->priv = client;
> +	st->muxc->priv = dev_get_drvdata(&client->dev);
>  
>  	result = inv_mpu_acpi_create_mux_client(client);
>  	if (result)
> 

Re: [PATCH v6 19/24] i2c-mux: document i2c muxes and elaborate on parent-/mux-locked muxes

[Jonathan Cameron]

On 03/04/16 09:52, Peter Rosin wrote:
> From: Peter Rosin <peda@axentia.se>
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
Very nice, one typo that I could see.

> ---
>  Documentation/i2c/i2c-topology | 370 +++++++++++++++++++++++++++++++++++++++++
>  MAINTAINERS                    |   1 +
>  2 files changed, 371 insertions(+)
>  create mode 100644 Documentation/i2c/i2c-topology
> 
> diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
> new file mode 100644
> index 000000000000..7a10edd0874f
> --- /dev/null
> +++ b/Documentation/i2c/i2c-topology
> @@ -0,0 +1,370 @@
> +I2C topology
> +============
> +
> +There are a couple of reasons for building more complex i2c topologies
> +than a straight-forward i2c bus with one adapter and one or more devices.
> +
> +1. A mux may be needed on the bus to prevent address collisions.
> +
> +2. The bus may be accessible from some external bus master, and arbitration
> +   may be needed to determine if it is ok to access the bus.
> +
> +3. A device (particularly RF tuners) may want to avoid the digital noise
> +   from the i2c bus, at least most of the time, and sits behind a gate
> +   that has to be operated before the device can be accessed.
> +
> +Etc
> +
> +These constructs are represented as i2c adapter trees by Linux, where
> +each adapter has a parent adapter (except the root adapter) and zero or
> +more child adapters. The root adapter is the actual adapter that issues
> +i2c transfers, and all adapters with a parent are part of an "i2c-mux"
> +object (quoted, since it can also be an arbitrator or a gate).
> +
> +Depending of the particular mux driver, something happens when there is
> +an i2c transfer on one of its child adapters. The mux driver can
> +obviously operate a mux, but it can also do arbitration with an external
> +bus master or open a gate. The mux driver has two operations for this,
> +select and deselect. select is called before the transfer and (the
> +optional) deselect is called after the transfer.
> +
> +
> +Locking
> +=======
> +
> +There are two variants of locking available to i2c muxes, they can be
> +mux-locked or parent-locked muxes. As is evident from below, it can be
> +useful to know if a mux is mux-locked or if it is parent-locked. The
> +following list was correct at the time of writing:
> +
> +In drivers/i2c/muxes/
> +i2c-arb-gpio-challenge    Parent-locked
> +i2c-mux-gpio              Normally parent-locked, mux-locked iff
> +                          all involved gpio pins are controlled by the
> +                          same i2c root adapter that they mux.
> +i2c-mux-pca9541           Parent-locked
> +i2c-mux-pca954x           Parent-locked
> +i2c-mux-pinctrl           Normally parent-locked, mux-locked iff
> +                          all involved pinctrl devices are controlled
> +                          by the same i2c root adapter that they mux.
> +i2c-mux-reg               Parent-locked
> +
> +In drivers/iio/
> +imu/inv_mpu6050/          Parent-locked
> +
> +In drivers/media/
> +dvb-frontends/m88ds3103   Parent-locked
> +dvb-frontends/rtl2830     Parent-locked
> +dvb-frontends/rtl2832     Parent-locked
> +dvb-frontends/si2168      Parent-locked
> +usb/cx231xx/              Parent-locked
> +
> +
> +Mux-locked muxes
> +----------------
> +
> +Mux-locked muxes does not lock the entire parent adapter during the
> +full select-transfer-deselect transaction, only the muxes on the parent
> +adapter are locked. Mux-locked muxes are mostly interesting if the
> +select and/or deselect operations must use i2c transfers to complete
> +their tasks. Since the parent adapter is not fully locked during the
> +full transaction, unrelated i2c transfers may interleave the different
> +stages of the transaction. This has the benefit that the mux driver
> +may be easier and cleaner to implement, but it has some caveats.
> +
> +ML1. If you build a topology with a mux-locked mux being the parent
> +     of a parent-locked mux, this might break the expectation from the
> +     parent-locked mux that the root adapter is locked during the
> +     transaction.
> +
> +ML2. It is not safe to build arbitrary topologies with two (or more)
> +     mux-locked muxes that are not siblings, when there are address
> +     collisions between the devices on the child adapters of these
> +     non-sibling muxes.
> +
> +     I.e. the select-transfer-deselect transaction targeting e.g. device
> +     address 0x42 behind mux-one may be interleaved with a similar
> +     operation targeting device address 0x42 behind mux-two. The
> +     intension with such a topology would in this hypothetical example
> +     be that mux-one and mux-two should not be selected simultaneously,
> +     but mux-locked muxes do not guarantee that in all topologies.
> +
> +ML3. A mux-locked mux cannot be used by a driver for auto-closing
> +     gates/muxes, i.e. something that closes automatically after a given
> +     number (one, in most cases) of i2c transfers. Unrelated i2c transfers
> +     may creep in and close prematurely.
> +
> +ML4. If any non-i2c operation in the mux driver changes the i2c mux state,
> +     the driver has to lock the root adapter during that operation.
> +     Otherwise garbage may appear on the bus as seen from devices
> +     behind the mux, when an unrelated i2c transfer is in flight during
> +     the non-i2c mux-changing operation.
> +
> +
> +Mux-locked Example
> +------------------
> +
> +                   .----------.     .--------.
> +    .--------.     |   mux-   |-----| dev D1 |
> +    |  root  |--+--|  locked  |     '--------'
> +    '--------'  |  |  mux M1  |--.  .--------.
> +                |  '----------'  '--| dev D2 |
> +                |  .--------.       '--------'
> +                '--| dev D3 |
> +                   '--------'
> +
> +When there is an access to D1, this happens:
> +
> + 1. Someone issues an i2c-transfer to D1.
> + 2. M1 locks muxes on its parent (the root adapter in this case).
> + 3. M1 calls ->select to ready the mux.
> + 4. M1 (presumably) does some i2c-transfers as part of its select.
> +    These transfers are normal i2c-transfers that locks the parent
> +    adapter.
> + 5. M1 feeds the i2c-transfer from step 1 to its parent adapter as a
> +    normal i2c-transfer that locks the parent adapter.
> + 6. M1 calls ->deselect, if it has one.
> + 7. Same rules as in step 4, but for ->deselect.
> + 8. M1 unlocks muxes on its parent.
> +
> +This means that accesses to D2 are lockout out for the full duration
> +of the entire operation. But accesses to D3 are possibly interleaved
> +at any point.
> +
> +
> +Parent-locked muxes
> +-------------------
> +
> +Parent-locked muxes lock the parent adapter during the full select-
> +transfer-deselect transaction. The implication is that the mux driver
> +has to ensure that any and all i2c transfers through that parent
> +adapter during the transaction are unlocked i2c transfers (using e.g.
> +__i2c_transfer), or a deadlock will follow. There are a couple of
> +caveats.
> +
> +PL1. If you build a topology with a parent-locked mux being the child
> +     of another mux, this might break a possible assumption from the
> +     child mux that the root adapter is unused between its select op
> +     and the actual transfer (e.g. if the child mux is auto-closing
> +     and the parent mux issus i2c-transfers as part of its select).
> +     This is especailly the case if the parent mux is mux-locked, but
especially
> +     it may also happen if the parent mux is parent-locked.
> +
> +PL2. If select/deselect calls out to other subsystems such as gpio,
> +     pinctrl, regmap or iio, it is essential that any i2c transfers
> +     caused by these subsystems are unlocked. This can be convoluted to
> +     accomplish, maybe even impossible if an acceptably clean solution
> +     is sought.
> +
> +
> +Parent-locked Example
> +---------------------
> +
> +                   .----------.     .--------.
> +    .--------.     |  parent- |-----| dev D1 |
> +    |  root  |--+--|  locked  |     '--------'
> +    '--------'  |  |  mux M1  |--.  .--------.
> +                |  '----------'  '--| dev D2 |
> +                |  .--------.       '--------'
> +                '--| dev D3 |
> +                   '--------'
> +
> +When there is an access to D1, this happens:
> +
> + 1. Someone issues an i2c-transfer to D1.
> + 2. M1 locks muxes on its parent (the root adapter in this case).
> + 3. M1 locks its parent adapter.
> + 4. M1 calls ->select to ready the mux.
> + 5. If M1 does any i2c-transfers (on this root adapter) as part of
> +    its select, those transfers must be unlocked i2c-transfers so
> +    that they do not deadlock the root adapter.
> + 6. M1 feeds the i2c-transfer from step 1 to the root adapter as an
> +    unlocked i2c-transfer, so that it does not deadlock the parent
> +    adapter.
> + 7. M1 calls ->deselect, if it has one.
> + 8. Same rules as in step 5, but for ->deselect.
> + 9. M1 unlocks its parent adapter.
> +10. M1 unlocks muxes on its parent.
> +
> +
> +This means that accesses to both D2 and D3 are locked out for the full
> +duration of the entire operation.
> +
> +
> +Complex Examples
> +================
> +
> +Parent-locked mux as parent of parent-locked mux
> +------------------------------------------------
> +
> +This is a useful topology, but it can be bad.
> +
> +                   .----------.     .----------.     .--------.
> +    .--------.     |  parent- |-----|  parent- |-----| dev D1 |
> +    |  root  |--+--|  locked  |     |  locked  |     '--------'
> +    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
> +                |  '----------'  |  '----------'  '--| dev D2 |
> +                |  .--------.    |  .--------.       '--------'
> +                '--| dev D4 |    '--| dev D3 |
> +                   '--------'       '--------'
> +
> +When any device is accessed, all other devices are locked out for
> +the full duration of the operation (both muxes lock their parent,
> +and specifically when M2 requests its parent to lock, M1 passes
> +the buck to the root adapter).
> +
> +This topology is bad if M2 is an auto-closing mux and M1->select
> +issues any unlocked i2c transfers on the root adapter that may leak
> +through and be seen by the M2 adapter, thus closing M2 prematurely.
> +
> +
> +Mux-locked mux as parent of mux-locked mux
> +------------------------------------------
> +
> +This is a good topology.
> +
> +                   .----------.     .----------.     .--------.
> +    .--------.     |   mux-   |-----|   mux-   |-----| dev D1 |
> +    |  root  |--+--|  locked  |     |  locked  |     '--------'
> +    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
> +                |  '----------'  |  '----------'  '--| dev D2 |
> +                |  .--------.    |  .--------.       '--------'
> +                '--| dev D4 |    '--| dev D3 |
> +                   '--------'       '--------'
> +
> +When device D1 is accessed, accesses to D2 are locked out for the
> +full duration of the operation (muxes on the top child adapter of M1
> +are locked). But accesses to D3 and D4 are possibly interleaved at
> +any point. Accesses to D3 locks out D1 and D2, but accesses to D4
> +are still possibly interleaved.
> +
> +
> +Mux-locked mux as parent of parent-locked mux
> +---------------------------------------------
> +
> +This is probably a bad topology.
> +
> +                   .----------.     .----------.     .--------.
> +    .--------.     |   mux-   |-----|  parent- |-----| dev D1 |
> +    |  root  |--+--|  locked  |     |  locked  |     '--------'
> +    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
> +                |  '----------'  |  '----------'  '--| dev D2 |
> +                |  .--------.    |  .--------.       '--------'
> +                '--| dev D4 |    '--| dev D3 |
> +                   '--------'       '--------'
> +
> +When device D1 is accessed, accesses to D2 and D3 are locked out
> +for the full duration of the operation (M1 locks child muxes on the
> +root adapter). But accesses to D4 are possibly interleaved at any
> +point.
> +
> +This kind of topology is generally not suitable and should probably
> +be avoided. The reason is that M2 probably assumes that there will
> +be no i2c transfers during its calls to ->select and ->deselect, and
> +if there are, any such transfers might appear on the slave side of M2
> +as partial i2c transfers, i.e. garbage or worse. This might cause
> +device lockups and/or other problems.
> +
> +The topology is especially troublesome if M2 is an auto-closing
> +mux. In that case, any interleaved accesses to D4 might close M2
> +prematurely, as might any i2c-transfers part of M1->select.
> +
> +But if M2 is not making the above stated assumption, and if M2 is not
> +auto-closing, the topology is fine.
> +
> +
> +Parent-locked mux as parent of mux-locked mux
> +---------------------------------------------
> +
> +This is a good topology.
> +
> +                   .----------.     .----------.     .--------.
> +    .--------.     |  parent- |-----|   mux-   |-----| dev D1 |
> +    |  root  |--+--|  locked  |     |  locked  |     '--------'
> +    '--------'  |  |  mux M1  |--.  |  mux M2  |--.  .--------.
> +                |  '----------'  |  '----------'  '--| dev D2 |
> +                |  .--------.    |  .--------.       '--------'
> +                '--| dev D4 |    '--| dev D3 |
> +                   '--------'       '--------'
> +
> +When D1 is accessed, accesses to D2 are locked out for the full
> +duration of the operation (muxes on the top child adapter of M1
> +are locked). Accesses to D3 and D4 are possibly interleaved at
> +any point, just as is expected for mux-locked muxes.
> +
> +When D3 or D4 are accessed, everything else is locked out. For D3
> +accesses, M1 locks the root adapter. For D4 accesses, the root
> +adapter is locked directly.
> +
> +
> +Two mux-locked sibling muxes
> +----------------------------
> +
> +This is a good topology.
> +
> +                                    .--------.
> +                   .----------.  .--| dev D1 |
> +                   |   mux-   |--'  '--------'
> +                .--|  locked  |     .--------.
> +                |  |  mux M1  |-----| dev D2 |
> +                |  '----------'     '--------'
> +                |  .----------.     .--------.
> +    .--------.  |  |   mux-   |-----| dev D3 |
> +    |  root  |--+--|  locked  |     '--------'
> +    '--------'  |  |  mux M2  |--.  .--------.
> +                |  '----------'  '--| dev D4 |
> +                |  .--------.       '--------'
> +                '--| dev D5 |
> +                   '--------'
> +
> +When D1 is accessed, accesses to D2, D3 and D4 are locked out. But
> +accesses to D5 may be interleaved at any time.
> +
> +
> +Two parent-locked sibling muxes
> +-------------------------------
> +
> +This is a good topology.
> +
> +                                   .--------.
> +                   .----------.  .--| dev D1 |
> +                   |  parent- |--'  '--------'
> +                .--|  locked  |     .--------.
> +                |  |  mux M1  |-----| dev D2 |
> +                |  '----------'     '--------'
> +                |  .----------.     .--------.
> +    .--------.  |  |  parent- |-----| dev D3 |
> +    |  root  |--+--|  locked  |     '--------'
> +    '--------'  |  |  mux M2  |--.  .--------.
> +                |  '----------'  '--| dev D4 |
> +                |  .--------.       '--------'
> +                '--| dev D5 |
> +                   '--------'
> +
> +When any device is accessed, accesses to all other devices are locked
> +out.
> +
> +
> +Mux-locked and parent-locked sibling muxes
> +------------------------------------------
> +
> +This is a good topology.
> +
> +                                   .--------.
> +                   .----------.  .--| dev D1 |
> +                   |   mux-   |--'  '--------'
> +                .--|  locked  |     .--------.
> +                |  |  mux M1  |-----| dev D2 |
> +                |  '----------'     '--------'
> +                |  .----------.     .--------.
> +    .--------.  |  |  parent- |-----| dev D3 |
> +    |  root  |--+--|  locked  |     '--------'
> +    '--------'  |  |  mux M2  |--.  .--------.
> +                |  '----------'  '--| dev D4 |
> +                |  .--------.       '--------'
> +                '--| dev D5 |
> +                   '--------'
> +
> +When D1 or D2 are accessed, accesses to D3 and D4 are locked out while
> +accesses to D5 may interleave. When D3 or D4 are accessed, accesses to
> +all other devices are locked out.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 03e00c7c88eb..d17afeb81246 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5274,6 +5274,7 @@ I2C MUXES
>  M:	Peter Rosin <peda@axentia.se>
>  L:	linux-i2c@vger.kernel.org
>  S:	Maintained
> +F:	Documentation/i2c/i2c-topology
>  F:	Documentation/i2c/muxes/
>  F:	Documentation/devicetree/bindings/i2c/i2c-mux*
>  F:	drivers/i2c/i2c-mux.c
> 

Re: [PATCH v6 08/24] iio: imu: inv_mpu6050: convert to use an explicit i2c mux core

[Peter Rosin]

On 2016-04-03 12:51, Jonathan Cameron wrote:
> On 03/04/16 09:52, Peter Rosin wrote:
>> From: Peter Rosin <peda@axentia.se>
>>
>> Allocate an explicit i2c mux core to handle parent and child adapters
>> etc. Update the select/deselect ops to be in terms of the i2c mux core
>> instead of the child adapter.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
> I'm mostly fine with this (though one unrelated change seems to have snuck
> in).  However, I'm not set up to test it - hence other than fixing the change
> you can have my ack, but ideal would be a tested by from someone with
> relevant hardware...  However, it looks to be a fairly mechanical change so
> if no one is currently setup to test it, then don't let it hold up the
> series too long!
> 
> Acked-by: Jonathan Cameron <jic23@kernel.org>

Thanks for your acks!

> Jonathan
>> ---
>>  drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c |  2 +-
>>  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c |  1 -
>>  drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c  | 32 +++++++++++++-----------------
>>  drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h  |  3 ++-
>>  4 files changed, 17 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
>> index 2771106fd650..f62b8bd9ad7e 100644
>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
>> @@ -183,7 +183,7 @@ int inv_mpu_acpi_create_mux_client(struct i2c_client *client)
>>  			} else
>>  				return 0; /* no secondary addr, which is OK */
>>  		}
>> -		st->mux_client = i2c_new_device(st->mux_adapter, &info);
>> +		st->mux_client = i2c_new_device(st->muxc->adapter[0], &info);
>>  		if (!st->mux_client)
>>  			return -ENODEV;
>>  	}
>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
>> index d192953e9a38..0c2bded2b5b7 100644
>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
>> @@ -23,7 +23,6 @@
>>  #include <linux/kfifo.h>
>>  #include <linux/spinlock.h>
>>  #include <linux/iio/iio.h>
>> -#include <linux/i2c-mux.h>
>>  #include <linux/acpi.h>
>>  #include "inv_mpu_iio.h"
>>  
>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>> index f581256d9d4c..0d429d788106 100644
>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>> @@ -15,7 +15,6 @@
>>  #include <linux/delay.h>
>>  #include <linux/err.h>
>>  #include <linux/i2c.h>
>> -#include <linux/i2c-mux.h>
>>  #include <linux/iio/iio.h>
>>  #include <linux/module.h>
>>  #include "inv_mpu_iio.h"
>> @@ -52,10 +51,9 @@ static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
>>  	return 0;
>>  }
>>  
>> -static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv,
>> -				     u32 chan_id)
>> +static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>  {
>> -	struct i2c_client *client = mux_priv;
>> +	struct i2c_client *client = i2c_mux_priv(muxc);
>>  	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);

Here, the existing code uses drv_get_drvdata to get from i2c_client to iio_dev...

>>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>  	int ret = 0;
>> @@ -84,10 +82,9 @@ write_error:
>>  	return ret;
>>  }
>>  
>> -static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap,
>> -				       void *mux_priv, u32 chan_id)
>> +static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>  {
>> -	struct i2c_client *client = mux_priv;
>> +	struct i2c_client *client = i2c_mux_priv(muxc);
>>  	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);

...and here too...

>>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>  
>> @@ -136,16 +133,15 @@ static int inv_mpu_probe(struct i2c_client *client,
>>  		return result;
>>  
>>  	st = iio_priv(dev_get_drvdata(&client->dev));
>> -	st->mux_adapter = i2c_add_mux_adapter(client->adapter,
>> -					      &client->dev,
>> -					      client,
>> -					      0, 0, 0,
>> -					      inv_mpu6050_select_bypass,
>> -					      inv_mpu6050_deselect_bypass);
>> -	if (!st->mux_adapter) {
>> -		result = -ENODEV;
>> +	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
>> +				       0, 0, 0,
>> +				       inv_mpu6050_select_bypass,
>> +				       inv_mpu6050_deselect_bypass);
>> +	if (IS_ERR(st->muxc)) {
>> +		result = PTR_ERR(st->muxc);
>>  		goto out_unreg_device;
>>  	}
>> +	st->muxc->priv = client;
>>  
>>  	result = inv_mpu_acpi_create_mux_client(client);
>>  	if (result)
>> @@ -154,7 +150,7 @@ static int inv_mpu_probe(struct i2c_client *client,
>>  	return 0;
>>  
>>  out_del_mux:
>> -	i2c_del_mux_adapter(st->mux_adapter);
>> +	i2c_mux_del_adapters(st->muxc);
>>  out_unreg_device:
>>  	inv_mpu_core_remove(&client->dev);
>>  	return result;
>> @@ -162,11 +158,11 @@ out_unreg_device:
>>  
>>  static int inv_mpu_remove(struct i2c_client *client)
>>  {
>> -	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>> +	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
> Why this change?  Seems unrelated.

...which is why I made this change. Maybe a bad call, but the inconsistency
disturbed me and I was changing the function anyway. I could split it out
to its own commit I suppose, or should I just not bother at all?

Cheers,
Peter

>>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>  
>>  	inv_mpu_acpi_delete_mux_client(client);
>> -	i2c_del_mux_adapter(st->mux_adapter);
>> +	i2c_mux_del_adapters(st->muxc);
>>  
>>  	return inv_mpu_core_remove(&client->dev);
>>  }
>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>> index e302a49703bf..bb3cef6d7059 100644
>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>> @@ -11,6 +11,7 @@
>>  * GNU General Public License for more details.
>>  */
>>  #include <linux/i2c.h>
>> +#include <linux/i2c-mux.h>
>>  #include <linux/kfifo.h>
>>  #include <linux/spinlock.h>
>>  #include <linux/iio/iio.h>
>> @@ -127,7 +128,7 @@ struct inv_mpu6050_state {
>>  	const struct inv_mpu6050_hw *hw;
>>  	enum   inv_devices chip_type;
>>  	spinlock_t time_stamp_lock;
>> -	struct i2c_adapter *mux_adapter;
>> +	struct i2c_mux_core *muxc;
>>  	struct i2c_client *mux_client;
>>  	unsigned int powerup_count;
>>  	struct inv_mpu6050_platform_data plat_data;
>>
> 

Re: [PATCH v6 14/24] of/unittest: convert to use an explicit i2c mux core

[Rob Herring]

On Sun, Apr 03, 2016 at 10:52:44AM +0200, Peter Rosin wrote:
> From: Peter Rosin <peda@axentia.se>
> 
> Allocate an explicit i2c mux core to handle parent and child adapters
> etc. Update the select op to be in terms of the i2c mux core instead
> of the child adapter.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  drivers/of/unittest.c | 40 +++++++++++++++-------------------------
>  1 file changed, 15 insertions(+), 25 deletions(-)

I assume you ran the unittest...

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v6 14/24] of/unittest: convert to use an explicit i2c mux core

[Peter Rosin]

On 2016-04-04 07:16, Rob Herring wrote:
> On Sun, Apr 03, 2016 at 10:52:44AM +0200, Peter Rosin wrote:
>> From: Peter Rosin <peda@axentia.se>
>>
>> Allocate an explicit i2c mux core to handle parent and child adapters
>> etc. Update the select op to be in terms of the i2c mux core instead
>> of the child adapter.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> ---
>>  drivers/of/unittest.c | 40 +++++++++++++++-------------------------
>>  1 file changed, 15 insertions(+), 25 deletions(-)
> 
> I assume you ran the unittest...

It's one of the few drivers I do have hardware for, so yes, I did
indeed test it!

> Acked-by: Rob Herring <robh@kernel.org>

Thanks!

Cheers,
Peter

Re: [PATCH v6 19/24] i2c-mux: document i2c muxes and elaborate on parent-/mux-locked muxes

[Peter Rosin]

On 2016-04-03 13:09, Jonathan Cameron wrote:
> On 03/04/16 09:52, Peter Rosin wrote:
>> From: Peter Rosin <peda@axentia.se>
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
> Very nice, one typo that I could see.

Thanks!

*snip*

>> +     and the actual transfer (e.g. if the child mux is auto-closing
>> +     and the parent mux issus i2c-transfers as part of its select).
>> +     This is especailly the case if the parent mux is mux-locked, but
> especially

Fixed now in my local repo.

Cheers,
Peter

Re: [PATCH v6 08/24] iio: imu: inv_mpu6050: convert to use an explicit i2c mux core

[Jonathan Cameron]

On 03/04/16 12:51, Peter Rosin wrote:
> On 2016-04-03 12:51, Jonathan Cameron wrote:
>> On 03/04/16 09:52, Peter Rosin wrote:
>>> From: Peter Rosin <peda@axentia.se>
>>>
>>> Allocate an explicit i2c mux core to handle parent and child adapters
>>> etc. Update the select/deselect ops to be in terms of the i2c mux core
>>> instead of the child adapter.
>>>
>>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> I'm mostly fine with this (though one unrelated change seems to have snuck
>> in).  However, I'm not set up to test it - hence other than fixing the change
>> you can have my ack, but ideal would be a tested by from someone with
>> relevant hardware...  However, it looks to be a fairly mechanical change so
>> if no one is currently setup to test it, then don't let it hold up the
>> series too long!
>>
>> Acked-by: Jonathan Cameron <jic23@kernel.org>
> 
> Thanks for your acks!
> 
>> Jonathan
>>> ---
>>>  drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c |  2 +-
>>>  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c |  1 -
>>>  drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c  | 32 +++++++++++++-----------------
>>>  drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h  |  3 ++-
>>>  4 files changed, 17 insertions(+), 21 deletions(-)
>>>
>>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
>>> index 2771106fd650..f62b8bd9ad7e 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
>>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
>>> @@ -183,7 +183,7 @@ int inv_mpu_acpi_create_mux_client(struct i2c_client *client)
>>>  			} else
>>>  				return 0; /* no secondary addr, which is OK */
>>>  		}
>>> -		st->mux_client = i2c_new_device(st->mux_adapter, &info);
>>> +		st->mux_client = i2c_new_device(st->muxc->adapter[0], &info);
>>>  		if (!st->mux_client)
>>>  			return -ENODEV;
>>>  	}
>>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
>>> index d192953e9a38..0c2bded2b5b7 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
>>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
>>> @@ -23,7 +23,6 @@
>>>  #include <linux/kfifo.h>
>>>  #include <linux/spinlock.h>
>>>  #include <linux/iio/iio.h>
>>> -#include <linux/i2c-mux.h>
>>>  #include <linux/acpi.h>
>>>  #include "inv_mpu_iio.h"
>>>  
>>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>>> index f581256d9d4c..0d429d788106 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>>> @@ -15,7 +15,6 @@
>>>  #include <linux/delay.h>
>>>  #include <linux/err.h>
>>>  #include <linux/i2c.h>
>>> -#include <linux/i2c-mux.h>
>>>  #include <linux/iio/iio.h>
>>>  #include <linux/module.h>
>>>  #include "inv_mpu_iio.h"
>>> @@ -52,10 +51,9 @@ static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
>>>  	return 0;
>>>  }
>>>  
>>> -static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv,
>>> -				     u32 chan_id)
>>> +static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>>  {
>>> -	struct i2c_client *client = mux_priv;
>>> +	struct i2c_client *client = i2c_mux_priv(muxc);
>>>  	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
> 
> Here, the existing code uses drv_get_drvdata to get from i2c_client to iio_dev...
> 
>>>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>>  	int ret = 0;
>>> @@ -84,10 +82,9 @@ write_error:
>>>  	return ret;
>>>  }
>>>  
>>> -static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap,
>>> -				       void *mux_priv, u32 chan_id)
>>> +static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>>  {
>>> -	struct i2c_client *client = mux_priv;
>>> +	struct i2c_client *client = i2c_mux_priv(muxc);
>>>  	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
> 
> ...and here too...
> 
>>>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>>  
>>> @@ -136,16 +133,15 @@ static int inv_mpu_probe(struct i2c_client *client,
>>>  		return result;
>>>  
>>>  	st = iio_priv(dev_get_drvdata(&client->dev));
>>> -	st->mux_adapter = i2c_add_mux_adapter(client->adapter,
>>> -					      &client->dev,
>>> -					      client,
>>> -					      0, 0, 0,
>>> -					      inv_mpu6050_select_bypass,
>>> -					      inv_mpu6050_deselect_bypass);
>>> -	if (!st->mux_adapter) {
>>> -		result = -ENODEV;
>>> +	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
>>> +				       0, 0, 0,
>>> +				       inv_mpu6050_select_bypass,
>>> +				       inv_mpu6050_deselect_bypass);
>>> +	if (IS_ERR(st->muxc)) {
>>> +		result = PTR_ERR(st->muxc);
>>>  		goto out_unreg_device;
>>>  	}
>>> +	st->muxc->priv = client;
>>>  
>>>  	result = inv_mpu_acpi_create_mux_client(client);
>>>  	if (result)
>>> @@ -154,7 +150,7 @@ static int inv_mpu_probe(struct i2c_client *client,
>>>  	return 0;
>>>  
>>>  out_del_mux:
>>> -	i2c_del_mux_adapter(st->mux_adapter);
>>> +	i2c_mux_del_adapters(st->muxc);
>>>  out_unreg_device:
>>>  	inv_mpu_core_remove(&client->dev);
>>>  	return result;
>>> @@ -162,11 +158,11 @@ out_unreg_device:
>>>  
>>>  static int inv_mpu_remove(struct i2c_client *client)
>>>  {
>>> -	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>>> +	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
>> Why this change?  Seems unrelated.
> 
> ...which is why I made this change. Maybe a bad call, but the inconsistency
> disturbed me and I was changing the function anyway. I could split it out
> to its own commit I suppose, or should I just not bother at all?
Funny thing is I'd say the i2c_get_clientdata option is the better of the two!

I don't really care though either way.

J
> 
> Cheers,
> Peter
> 
>>>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>>  
>>>  	inv_mpu_acpi_delete_mux_client(client);
>>> -	i2c_del_mux_adapter(st->mux_adapter);
>>> +	i2c_mux_del_adapters(st->muxc);
>>>  
>>>  	return inv_mpu_core_remove(&client->dev);
>>>  }
>>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>>> index e302a49703bf..bb3cef6d7059 100644
>>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
>>> @@ -11,6 +11,7 @@
>>>  * GNU General Public License for more details.
>>>  */
>>>  #include <linux/i2c.h>
>>> +#include <linux/i2c-mux.h>
>>>  #include <linux/kfifo.h>
>>>  #include <linux/spinlock.h>
>>>  #include <linux/iio/iio.h>
>>> @@ -127,7 +128,7 @@ struct inv_mpu6050_state {
>>>  	const struct inv_mpu6050_hw *hw;
>>>  	enum   inv_devices chip_type;
>>>  	spinlock_t time_stamp_lock;
>>> -	struct i2c_adapter *mux_adapter;
>>> +	struct i2c_mux_core *muxc;
>>>  	struct i2c_client *mux_client;
>>>  	unsigned int powerup_count;
>>>  	struct inv_mpu6050_platform_data plat_data;
>>>
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH v6 00/24] i2c mux cleanup and locking update

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 588 bytes --]

Hi Peter,

> To summarize the series, there's some i2c-mux infrastructure cleanup work
> first (I think that part stands by itself as desireable regardless), the
> locking changes are in 16/24 and after with the real meat in 18/24. There
> is some documentation added in 19/24 while 20/24 and after are cleanups to
> existing drivers utilizing the new stuff.

My idea is to review and pull in the infrastructure work for 4.7 and the
locking changes to 4.8. This gives us one cycle to fix regressions (if
any) in the infrastructure work first. Is that okay with you?

Thanks,

   Wolfram


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH v6 00/24] i2c mux cleanup and locking update

[Peter Rosin]

Hi!

On 2016-04-11 14:39, Wolfram Sang wrote:
> Hi Peter,
>
>> To summarize the series, there's some i2c-mux infrastructure cleanup work
>> first (I think that part stands by itself as desireable regardless), the
>> locking changes are in 16/24 and after with the real meat in 18/24. There
>> is some documentation added in 19/24 while 20/24 and after are cleanups to
>> existing drivers utilizing the new stuff.
>
> My idea is to review and pull in the infrastructure work for 4.7 and the
> locking changes to 4.8. This gives us one cycle to fix regressions (if
> any) in the infrastructure work first. Is that okay with you?

I was just thinking about how it appears impossible to get it all of it
merged in one go and what to do about it...

The untra-defensive approach is only merge stuff that has actually been
tested on real hw, and to hold off the rest until someone has tested. That
can obviously take forever. At the same time, many of the patches are kind
of mechanical, and feels rather safe.

  1 i2c-mux: add common data for every i2c-mux instance
  2 i2c: i2c-mux-gpio: convert to use an explicit i2c mux core
  3 i2c: i2c-mux-pinctrl: convert to use an explicit i2c mux core
  4 i2c: i2c-arb-gpio-challenge: convert to use an explicit i2c mux core
  5 i2c: i2c-mux-pca9541: convert to use an explicit i2c mux core
  6 i2c: i2c-mux-pca954x: convert to use an explicit i2c mux core
  7 i2c: i2c-mux-reg: convert to use an explicit i2c mux core
  8 iio: imu: inv_mpu6050: convert to use an explicit i2c mux core
  9 [media] m88ds3103: convert to use an explicit i2c mux core
10 [media] rtl2830: convert to use an explicit i2c mux core
11 [media] rtl2832: convert to use an explicit i2c mux core
12 [media] si2168: convert to use an explicit i2c mux core
13 [media] cx231xx: convert to use an explicit i2c mux core
14 of/unittest: convert to use an explicit i2c mux core
15 i2c-mux: drop old unused i2c-mux api
16 i2c: allow adapter drivers to override the adapter locking
17 i2c: muxes always lock the parent adapter
18 i2c-mux: relax locking of the top i2c adapter during mux-locked muxing
19 i2c-mux: document i2c muxes and elaborate on parent-/mux-locked muxes
20 iio: imu: inv_mpu6050: change the i2c gate to be mux-locked
21 [media] si2168: change the i2c gate to be mux-locked
22 [media] rtl2832: change the i2c gate to be mux-locked
23 [media] rtl2832_sdr: get rid of empty regmap wrappers
24 [media] rtl2832: regmap is aware of lockdep, drop local locking hack

I have tested 1, 2, 14, 16, 17 and 18 on real hw.
Antti has tested 9, 10, 11, 12, 16, 17, 21, 22, 23 and 24, but they
have been rebased since and 22 in particular is not a pure rebase since
the driver moved underneath me. And the locking was not 100% the same
either, not that I expect things to have gone south, but...
15 is a functional no-op once 2-14 are merged.
19 is docs only.
Jonathan acked 8 and 20, but 20 needs a tested-by from Daniel Baluta
and/or Adriana Reus.

That leaves 3, 4, 5, 6, 7, 13, but all those fall in the mechanical
category, with the possible exception of 13 which is more complex
than the other patches in the 2-14 range. But 13 builds, and besides,
what can possibly go wrong with a patch with that number? :-)

IIUC, your suggestion is to push 1-15 for 4.7, i.e. hope for the best
with 3, 4, 5, 6, 7 and 13. And then hopefully get testing for 20, and
retesting for 21, 22, 23 and 24 and merge 16-24 for 4.8.

That seems like a good plan to me.

Maybe we should give Antti some more time to re-add his tested-by tags
on 9-12 before they are merged into non-rewritable branches?

Cheers,
Peter

Re: [PATCH v6 00/24] i2c mux cleanup and locking update

[Wolfram Sang]

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> can obviously take forever. At the same time, many of the patches are kind
> of mechanical, and feels rather safe.

I agree about the mechanical stuff, thus my suggestion. We do what we
can about testing and reviewing. And once it reaches linux-next
(hopefully next week latest), test coverage will increase significantly
and we can fix issues incrementally from there on. Same goes when it
finally hits Linus' tree, coverage will increase more, but we should be
really at a very sane level then ;)

I will  also pick up patch 15 (the removal) for 4.8. So we have the full
4.7 cycle to revert if something goes very wrong.

> Maybe we should give Antti some more time to re-add his tested-by tags
> on 9-12 before they are merged into non-rewritable branches?

Yes. That would be great. I need to sync with the media maintainers
anyhow. I'd like to push all the patches via my tree.

Thanks,

   Wolfram


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Re: [PATCH v6 01/24] i2c-mux: add common data for every i2c-mux instance

[Wolfram Sang]

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Hi Peter,

first high-level review:

> +int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters)

I'd suggest to rename 'adapters' into 'num_adapters' throughout this
patch. I think it makes the code a lot easier to understand.

> +{
> +	struct i2c_adapter **adapter;
> +
> +	if (adapters <= muxc->max_adapters)
> +		return 0;
> +
> +	adapter = devm_kmalloc_array(muxc->dev,
> +				     adapters, sizeof(*adapter),
> +				     GFP_KERNEL);
> +	if (!adapter)
> +		return -ENOMEM;
> +
> +	if (muxc->adapter) {
> +		memcpy(adapter, muxc->adapter,
> +		       muxc->max_adapters * sizeof(*adapter));
> +		devm_kfree(muxc->dev, muxc->adapter);
> +	}
> +
> +	muxc->adapter = adapter;
> +	muxc->max_adapters = adapters;
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(i2c_mux_reserve_adapters);

Despite that I wonder why not using some of the realloc functions, I
wonder even more if we couldn't supply num_adapters to i2c_mux_alloc()
and reserve the memory statically. i2c busses are not
dynamic/hot-pluggable so that should be good enough?

> -	WARN(sysfs_create_link(&priv->adap.dev.kobj, &mux_dev->kobj, "mux_device"),
> -			       "can't create symlink to mux device\n");
> +	WARN(sysfs_create_link(&priv->adap.dev.kobj, &muxc->dev->kobj,
> +			       "mux_device"),

Ignoring the 80 char limit here makes the code more readable.

> +	     "can't create symlink to mux device\n");
>  
>  	snprintf(symlink_name, sizeof(symlink_name), "channel-%u", chan_id);
> -	WARN(sysfs_create_link(&mux_dev->kobj, &priv->adap.dev.kobj, symlink_name),
> -			       "can't create symlink for channel %u\n", chan_id);
> +	WARN(sysfs_create_link(&muxc->dev->kobj, &priv->adap.dev.kobj,
> +			       symlink_name),

ditto.

> +	     "can't create symlink for channel %u\n", chan_id);
>  	dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
>  		 i2c_adapter_id(&priv->adap));
>  
> -	return &priv->adap;
> +	muxc->adapter[muxc->adapters++] = &priv->adap;
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(i2c_mux_add_adapter);
> +
> +struct i2c_mux_core *i2c_mux_one_adapter(struct i2c_adapter *parent,
> +					 struct device *dev, int sizeof_priv,
> +					 u32 flags, u32 force_nr,
> +					 u32 chan_id, unsigned int class,
> +					 int (*select)(struct i2c_mux_core *,
> +						       u32),

ditto

> +					 int (*deselect)(struct i2c_mux_core *,
> +							 u32))

ditto

> +{
> +	struct i2c_mux_core *muxc;
> +	int ret;
> +
> +	muxc = i2c_mux_alloc(parent, dev, sizeof_priv, flags, select, deselect);
> +	if (!muxc)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = i2c_mux_add_adapter(muxc, force_nr, chan_id, class);
> +	if (ret) {
> +		devm_kfree(dev, muxc);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return muxc;
> +}
> +EXPORT_SYMBOL_GPL(i2c_mux_one_adapter);

Are you sure the above function pays off? Its argument list is very
complex and it doesn't save a lot of code. Having seperate calls is
probably more understandable in drivers? Then again, I assume it makes
the conversion of existing drivers easier.

So much for now. Thanks!

   Wolfram


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Re: [PATCH v6 01/24] i2c-mux: add common data for every i2c-mux instance

[Peter Rosin]

Hi!

On 2016-04-11 22:46, Wolfram Sang wrote:
> Hi Peter,
> 
> first high-level review:
> 
>> +int i2c_mux_reserve_adapters(struct i2c_mux_core *muxc, int adapters)
> 
> I'd suggest to rename 'adapters' into 'num_adapters' throughout this
> patch. I think it makes the code a lot easier to understand.

Hmm, you mean just the variable names, right? And not function names
such as i2c_mux_reserve_(num_)adapters?

>> +{
>> +	struct i2c_adapter **adapter;
>> +
>> +	if (adapters <= muxc->max_adapters)
>> +		return 0;
>> +
>> +	adapter = devm_kmalloc_array(muxc->dev,
>> +				     adapters, sizeof(*adapter),
>> +				     GFP_KERNEL);
>> +	if (!adapter)
>> +		return -ENOMEM;
>> +
>> +	if (muxc->adapter) {
>> +		memcpy(adapter, muxc->adapter,
>> +		       muxc->max_adapters * sizeof(*adapter));
>> +		devm_kfree(muxc->dev, muxc->adapter);
>> +	}
>> +
>> +	muxc->adapter = adapter;
>> +	muxc->max_adapters = adapters;
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(i2c_mux_reserve_adapters);
> 
> Despite that I wonder why not using some of the realloc functions, I

When I wrote it, I found no devm_ version of realloc. I'm not finding
anything now either...

> wonder even more if we couldn't supply num_adapters to i2c_mux_alloc()
> and reserve the memory statically. i2c busses are not
> dynamic/hot-pluggable so that should be good enough?

Yes, that would work, but it would take some restructuring in some of
the drivers that currently don't know how many child adapters they
are going to need when they call i2c_mux_alloc.

Because you thought about removing i2c_mux_reserve_adapters completely,
and not provide any means of adding more adapters than specified in
the i2c_mux_alloc call, right?

>> -	WARN(sysfs_create_link(&priv->adap.dev.kobj, &mux_dev->kobj, "mux_device"),
>> -			       "can't create symlink to mux device\n");
>> +	WARN(sysfs_create_link(&priv->adap.dev.kobj, &muxc->dev->kobj,
>> +			       "mux_device"),
> 
> Ignoring the 80 char limit here makes the code more readable.

That is only true if you actually have more than 80 characters, so I don't
agree. Are you adamant about it? (I'm not)

>> +	     "can't create symlink to mux device\n");
>>  
>>  	snprintf(symlink_name, sizeof(symlink_name), "channel-%u", chan_id);
>> -	WARN(sysfs_create_link(&mux_dev->kobj, &priv->adap.dev.kobj, symlink_name),
>> -			       "can't create symlink for channel %u\n", chan_id);
>> +	WARN(sysfs_create_link(&muxc->dev->kobj, &priv->adap.dev.kobj,
>> +			       symlink_name),
> 
> ditto.
> 
>> +	     "can't create symlink for channel %u\n", chan_id);
>>  	dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
>>  		 i2c_adapter_id(&priv->adap));
>>  
>> -	return &priv->adap;
>> +	muxc->adapter[muxc->adapters++] = &priv->adap;
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(i2c_mux_add_adapter);
>> +
>> +struct i2c_mux_core *i2c_mux_one_adapter(struct i2c_adapter *parent,
>> +					 struct device *dev, int sizeof_priv,
>> +					 u32 flags, u32 force_nr,
>> +					 u32 chan_id, unsigned int class,
>> +					 int (*select)(struct i2c_mux_core *,
>> +						       u32),
> 
> ditto
> 
>> +					 int (*deselect)(struct i2c_mux_core *,
>> +							 u32))
> 
> ditto
> 
>> +{
>> +	struct i2c_mux_core *muxc;
>> +	int ret;
>> +
>> +	muxc = i2c_mux_alloc(parent, dev, sizeof_priv, flags, select, deselect);
>> +	if (!muxc)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	ret = i2c_mux_add_adapter(muxc, force_nr, chan_id, class);
>> +	if (ret) {
>> +		devm_kfree(dev, muxc);
>> +		return ERR_PTR(ret);
>> +	}
>> +
>> +	return muxc;
>> +}
>> +EXPORT_SYMBOL_GPL(i2c_mux_one_adapter);
> 
> Are you sure the above function pays off? Its argument list is very
> complex and it doesn't save a lot of code. Having seperate calls is
> probably more understandable in drivers? Then again, I assume it makes
> the conversion of existing drivers easier.

I added it in v4, you can check earlier versions if you like. Without
it most gate-muxes (i.e. typically the muxes in drivers/media) grew
since the i2c_add_mux_adapter call got replaced by two calls, i.e.
i2c_mux_alloc followed by i2c_max_add_adapter, and coupled with
error checks made it look more complex than before. So, this wasn't
much of a cleanup from the point of those drivers.

> So much for now. Thanks!

Yeah, thanks!

Cheers,
Peter

Re: [PATCH v6 01/24] i2c-mux: add common data for every i2c-mux instance

[Wolfram Sang]

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> > I'd suggest to rename 'adapters' into 'num_adapters' throughout this
> > patch. I think it makes the code a lot easier to understand.
> 
> Hmm, you mean just the variable names, right? And not function names
> such as i2c_mux_reserve_(num_)adapters?

Yes, only variable names.

> > Despite that I wonder why not using some of the realloc functions, I
> 
> When I wrote it, I found no devm_ version of realloc. I'm not finding
> anything now either...

Right, there is no devm_ version of it :(

> > wonder even more if we couldn't supply num_adapters to i2c_mux_alloc()
> > and reserve the memory statically. i2c busses are not
> > dynamic/hot-pluggable so that should be good enough?
> 
> Yes, that would work, but it would take some restructuring in some of
> the drivers that currently don't know how many child adapters they
> are going to need when they call i2c_mux_alloc.

Which ones?

> Because you thought about removing i2c_mux_reserve_adapters completely,
> and not provide any means of adding more adapters than specified in
> the i2c_mux_alloc call, right?

Yes. I assumed I2C to be static enough that such information is known in
advance.

> > Ignoring the 80 char limit here makes the code more readable.
> 
> That is only true if you actually have more than 80 characters, so I don't
> agree. Are you adamant about it? (I'm not)

No. Keep it if you prefer it.

> >> +EXPORT_SYMBOL_GPL(i2c_mux_one_adapter);
> > 
> > Are you sure the above function pays off? Its argument list is very
> > complex and it doesn't save a lot of code. Having seperate calls is
> > probably more understandable in drivers? Then again, I assume it makes
> > the conversion of existing drivers easier.
> 
> I added it in v4, you can check earlier versions if you like. Without
> it most gate-muxes (i.e. typically the muxes in drivers/media) grew
> since the i2c_add_mux_adapter call got replaced by two calls, i.e.
> i2c_mux_alloc followed by i2c_max_add_adapter, and coupled with
> error checks made it look more complex than before. So, this wasn't
> much of a cleanup from the point of those drivers.

Hmm, v3 didn't have the driver patches posted with it. Can you push it
to your branch? I am also not too strong with this one, but having a
look how it looks without would be nice.


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Re: [PATCH v6 20/24] iio: imu: inv_mpu6050: change the i2c gate to be mux-locked

[Daniel Baluta]

On Sun, Apr 3, 2016 at 1:54 PM, Jonathan Cameron <jic23@kernel.org> wrote:
> On 03/04/16 09:52, Peter Rosin wrote:
>> From: Peter Rosin <peda@axentia.se>
>>
>> The root i2c adapter lock is then no longer held by the i2c mux during
>> accesses behind the i2c gate, and such accesses need to take that lock
>> just like any other ordinary i2c accesses do.
>>
>> So, declare the i2c gate mux-locked, and zap the code that makes the
>> unlocked i2c accesses and just use ordinary regmap_write accesses.
>>
>> This also happens to fix the deadlock described in
>> http://patchwork.ozlabs.org/patch/584776/ authored by
>> Adriana Reus <adriana.reus@intel.com> and submitted by
>> Daniel Baluta <daniel.baluta@intel.com>
>>
>> ----------8<----------
>> iio: imu: inv_mpu6050: Fix deadlock between i2c adapter lock and mpu lock
>>
>> This deadlock occurs if the accel/gyro and the sensor on the auxiliary
>> I2C (in my setup it's an ak8975) are working at the same time.
>>
>> Scenario:
>>
>>       T1                                      T2
>>      ====                                    ====
>> inv_mpu6050_read_fifo                  aux sensor op (eg. ak8975_read_raw)
>>         |                                     |
>> mutex_lock(&indio_dev->mlock)           i2c_transfer
>>         |                                     |
>> i2c transaction                         i2c adapter lock
>>         |                                     |
>> i2c adapter lock                        i2c_mux_master_xfer
>>                                               |
>>                                         inv_mpu6050_select_bypass
>>                                               |
>>                                         mutex_lock(&indio_dev->mlock)
>>
>> When we operate on an mpu sensor the order of locking is mpu lock
>> followed by the i2c adapter lock. However, when we operate the auxiliary
>> sensor the order of locking is the other way around.
>>
>> ...
>> ----------8<----------
>>
>> The reason this patch fixes the deadlock is that T2 does not grab the
>> i2c adapter lock until the very end (and grabs the newfangled i2c mux
>> lock where it previously grabbed the i2c adapter lock).
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
> This one obviously wants a ack from Adriana or Daniel in addition to mine.
> I'm more than happy for these to go through the i2c tree btw.
>
> Acked-by: Jonathan Cameron <jic23@kernel.org>

Acked-by: Daniel Baluta <daniel.baluta@intel.com>


>> ---
>>  Documentation/i2c/i2c-topology            |  2 +-
>>  drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c | 56 +++++++------------------------
>>  2 files changed, 13 insertions(+), 45 deletions(-)
>>
>> diff --git a/Documentation/i2c/i2c-topology b/Documentation/i2c/i2c-topology
>> index 7a10edd0874f..346623a80bd1 100644
>> --- a/Documentation/i2c/i2c-topology
>> +++ b/Documentation/i2c/i2c-topology
>> @@ -50,7 +50,7 @@ i2c-mux-pinctrl           Normally parent-locked, mux-locked iff
>>  i2c-mux-reg               Parent-locked
>>
>>  In drivers/iio/
>> -imu/inv_mpu6050/          Parent-locked
>> +imu/inv_mpu6050/          Mux-locked
>>
>>  In drivers/media/
>>  dvb-frontends/m88ds3103   Parent-locked
>> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>> index 0d429d788106..71ad31a275c9 100644
>> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>> @@ -24,45 +24,16 @@ static const struct regmap_config inv_mpu_regmap_config = {
>>       .val_bits = 8,
>>  };
>>
>> -/*
>> - * The i2c read/write needs to happen in unlocked mode. As the parent
>> - * adapter is common. If we use locked versions, it will fail as
>> - * the mux adapter will lock the parent i2c adapter, while calling
>> - * select/deselect functions.
>> - */
>> -static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
>> -                                       u8 reg, u8 d)
>> -{
>> -     int ret;
>> -     u8 buf[2] = {reg, d};
>> -     struct i2c_msg msg[1] = {
>> -             {
>> -                     .addr = client->addr,
>> -                     .flags = 0,
>> -                     .len = sizeof(buf),
>> -                     .buf = buf,
>> -             }
>> -     };
>> -
>> -     ret = __i2c_transfer(client->adapter, msg, 1);
>> -     if (ret != 1)
>> -             return ret;
>> -
>> -     return 0;
>> -}
>> -
>>  static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>  {
>> -     struct i2c_client *client = i2c_mux_priv(muxc);
>> -     struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
>> +     struct iio_dev *indio_dev = i2c_mux_priv(muxc);
>>       struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>       int ret = 0;
>>
>>       /* Use the same mutex which was used everywhere to protect power-op */
>>       mutex_lock(&indio_dev->mlock);
>>       if (!st->powerup_count) {
>> -             ret = inv_mpu6050_write_reg_unlocked(client,
>> -                                                  st->reg->pwr_mgmt_1, 0);
>> +             ret = regmap_write(st->map, st->reg->pwr_mgmt_1, 0);
>>               if (ret)
>>                       goto write_error;
>>
>> @@ -71,10 +42,9 @@ static int inv_mpu6050_select_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>       }
>>       if (!ret) {
>>               st->powerup_count++;
>> -             ret = inv_mpu6050_write_reg_unlocked(client,
>> -                                                  st->reg->int_pin_cfg,
>> -                                                  INV_MPU6050_INT_PIN_CFG |
>> -                                                  INV_MPU6050_BIT_BYPASS_EN);
>> +             ret = regmap_write(st->map, st->reg->int_pin_cfg,
>> +                                INV_MPU6050_INT_PIN_CFG |
>> +                                INV_MPU6050_BIT_BYPASS_EN);
>>       }
>>  write_error:
>>       mutex_unlock(&indio_dev->mlock);
>> @@ -84,18 +54,16 @@ write_error:
>>
>>  static int inv_mpu6050_deselect_bypass(struct i2c_mux_core *muxc, u32 chan_id)
>>  {
>> -     struct i2c_client *client = i2c_mux_priv(muxc);
>> -     struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
>> +     struct iio_dev *indio_dev = i2c_mux_priv(muxc);
>>       struct inv_mpu6050_state *st = iio_priv(indio_dev);
>>
>>       mutex_lock(&indio_dev->mlock);
>>       /* It doesn't really mattter, if any of the calls fails */
>> -     inv_mpu6050_write_reg_unlocked(client, st->reg->int_pin_cfg,
>> -                                    INV_MPU6050_INT_PIN_CFG);
>> +     regmap_write(st->map, st->reg->int_pin_cfg, INV_MPU6050_INT_PIN_CFG);
>>       st->powerup_count--;
>>       if (!st->powerup_count)
>> -             inv_mpu6050_write_reg_unlocked(client, st->reg->pwr_mgmt_1,
>> -                                            INV_MPU6050_BIT_SLEEP);
>> +             regmap_write(st->map, st->reg->pwr_mgmt_1,
>> +                          INV_MPU6050_BIT_SLEEP);
>>       mutex_unlock(&indio_dev->mlock);
>>
>>       return 0;
>> @@ -133,15 +101,15 @@ static int inv_mpu_probe(struct i2c_client *client,
>>               return result;
>>
>>       st = iio_priv(dev_get_drvdata(&client->dev));
>> -     st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
>> -                                    0, 0, 0,
>> +     st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0,
>> +                                    I2C_MUX_LOCKED, 0, 0, 0,
>>                                      inv_mpu6050_select_bypass,
>>                                      inv_mpu6050_deselect_bypass);
>>       if (IS_ERR(st->muxc)) {
>>               result = PTR_ERR(st->muxc);
>>               goto out_unreg_device;
>>       }
>> -     st->muxc->priv = client;
>> +     st->muxc->priv = dev_get_drvdata(&client->dev);
>>
>>       result = inv_mpu_acpi_create_mux_client(client);
>>       if (result)
>>
>
> --
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> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v6 08/24] iio: imu: inv_mpu6050: convert to use an explicit i2c mux core

[Crestez Dan Leonard]

On 04/03/2016 11:52 AM, Peter Rosin wrote:
> From: Peter Rosin <peda@axentia.se>
> 
> Allocate an explicit i2c mux core to handle parent and child adapters
> etc. Update the select/deselect ops to be in terms of the i2c mux core
> instead of the child adapter.
> 
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> @@ -136,16 +133,15 @@ static int inv_mpu_probe(struct i2c_client *client,
>  		return result;
>  
>  	st = iio_priv(dev_get_drvdata(&client->dev));
> -	st->mux_adapter = i2c_add_mux_adapter(client->adapter,
> -					      &client->dev,
> -					      client,
> -					      0, 0, 0,
> -					      inv_mpu6050_select_bypass,
> -					      inv_mpu6050_deselect_bypass);
> -	if (!st->mux_adapter) {
> -		result = -ENODEV;
> +	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0, 0,
> +				       0, 0, 0,
> +				       inv_mpu6050_select_bypass,
> +				       inv_mpu6050_deselect_bypass);
> +	if (IS_ERR(st->muxc)) {
> +		result = PTR_ERR(st->muxc);
>  		goto out_unreg_device;
>  	}
> +	st->muxc->priv = client;

I just tested this patch on mpu9150 (combo mpu6050+ak8975) and I got a
crash on probe which looks sort of like this:

[    5.565374] RIP: 0010:[<ffffffff81481aed>] [<ffffffff81481aed>]
mutex_lock+0xd/0x30
[    5.565374] Call Trace:
[    5.565374]  [<ffffffff813be34c>] inv_mpu6050_select_bypass+0x1c/0xa0
...
[    5.565374]  [<ffffffff81392141>] i2c_transfer+0x51/0x90
...
[    5.565374]  [<ffffffff81392cb5>] i2c_smbus_read_i2c_block_data+0x45/0xd0
[    5.565374]  [<ffffffff813bec5a>] ak8975_probe+0x14a/0x5c0
...
[    5.565374]  [<ffffffff813933d8>] i2c_new_device+0x178/0x1e0
[    5.565374]  [<ffffffff8139362d>] of_i2c_register_device+0xdd/0x1a0
[    5.565374]  [<ffffffff8139372b>] of_i2c_register_devices+0x3b/0x60
[    5.565374]  [<ffffffff81393e88>] i2c_register_adapter+0x178/0x410
[    5.565374]  [<ffffffff81394203>] i2c_add_adapter+0x73/0x90
[    5.565374]  [<ffffffff81395f3d>] i2c_mux_add_adapter+0x2ed/0x400
[    5.565374]  [<ffffffff81396091>] i2c_mux_one_adapter+0x41/0x70
[    5.565374]  [<ffffffff813be48a>] inv_mpu_probe+0xba/0x1a0

This happens because muxc->priv is not initialized when probing devices
behind the mux as described by devicetree. This can be easily fixed by
using muxc->dev instead of muxc->priv, or perhaps by calling
i2c_mux_alloc, initializing priv and later doing i2c_mux_add_adapter.

These fixes are driver-specific and other drivers might experience
similar issues. Perhaps i2c_mux_one_adapter should take void *priv just
like old i2c_add_mux_adapter?

After I fix this locally the deadlock when reading from both devices no
longer happens.

--
Regards,
Leonard

Re: [PATCH v6 08/24] iio: imu: inv_mpu6050: convert to use an explicit i2c mux core

[Peter Rosin]

<hans.verkuil@cisco.com>,Arnd Bergmann <arnd@arndb.de>,Tommi Rantala <tt.rantala@gmail.com>,linux-i2c@vger.kernel.org,linux-doc@vger.kernel.org,linux-iio@vger.kernel.org,linux-media@vger.kernel.org,devicetree@vger.kernel.org
Message-ID: <B09CD200-56D1-4BE0-B567-90CC23507ED5@lysator.liu.se>

On April 19, 2016 5:58:11 PM CEST, Crestez Dan Leonard <leonard.crestez@intel.com> wrote:
> On 04/03/2016 11:52 AM, Peter Rosin wrote:
> > From: Peter Rosin <peda@axentia.se>
> > 
> > Allocate an explicit i2c mux core to handle parent and child
> adapters
> > etc. Update the select/deselect ops to be in terms of the i2c mux
> core
> > instead of the child adapter.
> > 
> > --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> > +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c
> > @@ -136,16 +133,15 @@ static int inv_mpu_probe(struct i2c_client
> *client,
> >  		return result;
> >  
> >  	st = iio_priv(dev_get_drvdata(&client->dev));
> > -	st->mux_adapter = i2c_add_mux_adapter(client->adapter,
> > -					      &client->dev,
> > -					      client,
> > -					      0, 0, 0,
> > -					      inv_mpu6050_select_bypass,
> > -					      inv_mpu6050_deselect_bypass);
> > -	if (!st->mux_adapter) {
> > -		result = -ENODEV;
> > +	st->muxc = i2c_mux_one_adapter(client->adapter, &client->dev, 0,
> 0,
> > +				       0, 0, 0,
> > +				       inv_mpu6050_select_bypass,
> > +				       inv_mpu6050_deselect_bypass);
> > +	if (IS_ERR(st->muxc)) {
> > +		result = PTR_ERR(st->muxc);
> >  		goto out_unreg_device;
> >  	}
> > +	st->muxc->priv = client;
> 
> I just tested this patch on mpu9150 (combo mpu6050+ak8975) and I got a
> crash on probe which looks sort of like this:
> 
> [    5.565374] RIP: 0010:[<ffffffff81481aed>] [<ffffffff81481aed>]
> mutex_lock+0xd/0x30
> [    5.565374] Call Trace:
> [    5.565374]  [<ffffffff813be34c>]
> inv_mpu6050_select_bypass+0x1c/0xa0
> ...
> [    5.565374]  [<ffffffff81392141>] i2c_transfer+0x51/0x90
> ...
> [    5.565374]  [<ffffffff81392cb5>]
> i2c_smbus_read_i2c_block_data+0x45/0xd0
> [    5.565374]  [<ffffffff813bec5a>] ak8975_probe+0x14a/0x5c0
> ...
> [    5.565374]  [<ffffffff813933d8>] i2c_new_device+0x178/0x1e0
> [    5.565374]  [<ffffffff8139362d>] of_i2c_register_device+0xdd/0x1a0
> [    5.565374]  [<ffffffff8139372b>] of_i2c_register_devices+0x3b/0x60
> [    5.565374]  [<ffffffff81393e88>] i2c_register_adapter+0x178/0x410
> [    5.565374]  [<ffffffff81394203>] i2c_add_adapter+0x73/0x90
> [    5.565374]  [<ffffffff81395f3d>] i2c_mux_add_adapter+0x2ed/0x400
> [    5.565374]  [<ffffffff81396091>] i2c_mux_one_adapter+0x41/0x70
> [    5.565374]  [<ffffffff813be48a>] inv_mpu_probe+0xba/0x1a0
> 
> This happens because muxc->priv is not initialized when probing
> devices
> behind the mux as described by devicetree. This can be easily fixed by
> using muxc->dev instead of muxc->priv, or perhaps by calling
> i2c_mux_alloc, initializing priv and later doing i2c_mux_add_adapter.
> 
> These fixes are driver-specific and other drivers might experience
> similar issues. Perhaps i2c_mux_one_adapter should take void *priv
> just
> like old i2c_add_mux_adapter?
> 
> After I fix this locally the deadlock when reading from both devices
> no
> longer happens.
> 
> --
> Regards,
> Leonard

Duh. Obvious now that you point it out. Thanks for catching this!

I will just remove the i2c_mux_one_adapter interface for v7 and
have the affected drivers do i2c_mux_alloc as a separate step
(which was one of your suggested paths forward...)

Thanks again, and sorry for the inconvenience,
Peter

(Written on my phone, sorry for crappy formatting)

Re: [PATCH v6 01/24] i2c-mux: add common data for every i2c-mux instance

[Peter Rosin]

Wolfram Sang wrote:
> > > wonder even more if we couldn't supply num_adapters to i2c_mux_alloc()
> > > and reserve the memory statically. i2c busses are not
> > > dynamic/hot-pluggable so that should be good enough?
> > 
> > Yes, that would work, but it would take some restructuring in some of
> > the drivers that currently don't know how many child adapters they
> > are going to need when they call i2c_mux_alloc.
> 
> Which ones?

If you look at i2c-mux-reg.c, it currently allocates its private
struct regmux, then fills it with various platform things and then
when it knows how many children it needs it allocates them. After
v6 it first allocates a mux core and private struct regmux in one go
using i2c_mux_alloc, then continues in much the same way as before.

If the number of children is needed for the i2c_mux_alloc call, then
this is certainly doable, and it would probably not be all that bad,
but the simplest approach would probably be to allocate the private
struct regmux first, then dig through the platform data, then allocate
the mux core when the number of children is known. Which would still
be two allocations separated by the platform data dig.

So, your suggestion would basically move the mux core allocation
from generally being done early together with other private data to
later when the driver has figured out how many children it's going
to create.

The restructuring I thought about is needed if the intention of this
was to reduce number of allocations, but maybe you just wanted
what I described above? Because what I did in v6 and what you are
suggesting is quite similar in complexity, but your version has the
advantage of not having the need for realloc.

So, I have made this change locally (and the adapters->num_adapters
change) and I like it. I haven't even compile-tested it yet though,
but I'll get back when I have done some testing.

> > Because you thought about removing i2c_mux_reserve_adapters completely,
> > and not provide any means of adding more adapters than specified in
> > the i2c_mux_alloc call, right?
> 
> Yes. I assumed I2C to be static enough that such information is known in
> advance.
> 
> > > Ignoring the 80 char limit here makes the code more readable.
> > 
> > That is only true if you actually have more than 80 characters, so I don't
> > agree. Are you adamant about it? (I'm not)
> 
> No. Keep it if you prefer it.
> 
> > >> +EXPORT_SYMBOL_GPL(i2c_mux_one_adapter);
> > > 
> > > Are you sure the above function pays off? Its argument list is very
> > > complex and it doesn't save a lot of code. Having seperate calls is
> > > probably more understandable in drivers? Then again, I assume it makes
> > > the conversion of existing drivers easier.
> > 
> > I added it in v4, you can check earlier versions if you like. Without
> > it most gate-muxes (i.e. typically the muxes in drivers/media) grew
> > since the i2c_add_mux_adapter call got replaced by two calls, i.e.
> > i2c_mux_alloc followed by i2c_max_add_adapter, and coupled with
> > error checks made it look more complex than before. So, this wasn't
> > much of a cleanup from the point of those drivers.
> 
> Hmm, v3 didn't have the driver patches posted with it. Can you push it
> to your branch? I am also not too strong with this one, but having a
> look how it looks without would be nice.

Although I'm not sure what you meant by "driver patches", I have pushed
mux-core-and-locking-2 and mux-core-and-locking-3 to
https://github.com/peda-r/i2c-mux/ (note that these are the branches as
they where when I posted v2 and v3 to the list, i.e. w/o fixups)

Those early versions updated all drivers with each change, making each
patch big, so if that was what you meant by missing "driver patches" then
there simply were no driver patches.

If you meant the follow-up patches to relax locking in the media drivers
etc, I only compile-tested them using throwaway branches back then (if I
even had branches). So, I don't have anything ready to push, sorry.

Cheers,
Peter