[PATCH 0/3] i2c/of: switch I2C IP cores at runtime via OF_DYNAMIC

[PATCH 0/3] i2c/of: switch I2C IP cores at runtime via OF_DYNAMIC

[Wolfram Sang]

Here is the newest version of this patch series. Since Rob indicated to be OK
with the approach, I am brave and changed the status from RFC to PATCH.

This series allows an I2C bus to switch between multiple masters, i.e. a
n-to-1-demuxer. This is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once the
task is known. Example: Prefer i2c-gpio over another I2C core because of HW
errata affecting your current runtime configuration.

It works by using OF_DYNAMIC and en-/disabling the i2c parent as needed. See
the binding docs for more details. Because this is largely using OF_DYNAMIC, I
decided to post the whole series to the dt list.

Changes since RFC v2:

* updated docs (sysfs file now described in ABI/testing)
* depends now on OF (thanks buildbot)
* removed mutex handling. This creates a dependency on this patch which adds
  what we need to of-core (thanks Rob):
	https://patchwork.ozlabs.org/patch/539938/
* sysfs-store: use uint instead of ulong (thanks Geert)
* removed typos from commit messages (thanks Geert and Rob)

Changes since RFC v1:

* gracefully handle if i2c adapters are not present at runtime
  (driver not loaded yet)
* added more documentation and examples
* properly put the i2c adapters after use
* respect PAGE_SIZE in sysfs_show

This has been tested on a Renesas Lager board switching between i2c-gpio and
two different IP cores (i2c-rcar and i2c-sh_mobile). The rebinding seems to be
working as expected. However, in practice, I couldn't use the HDMI i2c slaves
with another controller yet, because the rcar-du driver OOPSes when unbinding.
This seems unrelated to this series because it can also be triggered via
sysfs-unbind. soc-camera also had problems properly cleaning up on unbind, a
patch for this already has been sent. So, this series is for sure a good test
for the unbind path of drivers.

A branch can be found here:

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/ip-core-switch-on-4.4

Let me know what you think.

Thanks,

   Wolfram

Wolfram Sang (3):
  dt-bindings: i2c: mux: demux-pinctrl: add bindings
  i2c: mux: demux-pinctrl: add driver
  ARM: shmobile: r8a7790: rework dts to use i2c demuxer

 .../ABI/testing/sysfs-platform-i2c-demux-pinctrl   |  23 ++
 .../devicetree/bindings/i2c/i2c-demux-pinctrl.txt  | 136 +++++++++++
 arch/arm/boot/dts/r8a7790-lager.dts                | 141 +++++++----
 drivers/i2c/muxes/Kconfig                          |   9 +
 drivers/i2c/muxes/Makefile                         |   2 +
 drivers/i2c/muxes/i2c-demux-pinctrl.c              | 272 +++++++++++++++++++++
 6 files changed, 530 insertions(+), 53 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
 create mode 100644 drivers/i2c/muxes/i2c-demux-pinctrl.c

-- 
2.1.4

[PATCH 0/3] i2c/of: switch I2C IP cores at runtime via OF_DYNAMIC

[Wolfram Sang]

Here is the newest version of this patch series. Since Rob indicated to be OK
with the approach, I am brave and changed the status from RFC to PATCH.

This series allows an I2C bus to switch between multiple masters, i.e. a
n-to-1-demuxer. This is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once the
task is known. Example: Prefer i2c-gpio over another I2C core because of HW
errata affecting your current runtime configuration.

It works by using OF_DYNAMIC and en-/disabling the i2c parent as needed. See
the binding docs for more details. Because this is largely using OF_DYNAMIC, I
decided to post the whole series to the dt list.

Changes since RFC v2:

* updated docs (sysfs file now described in ABI/testing)
* depends now on OF (thanks buildbot)
* removed mutex handling. This creates a dependency on this patch which adds
  what we need to of-core (thanks Rob):
	https://patchwork.ozlabs.org/patch/539938/
* sysfs-store: use uint instead of ulong (thanks Geert)
* removed typos from commit messages (thanks Geert and Rob)

Changes since RFC v1:

* gracefully handle if i2c adapters are not present at runtime
  (driver not loaded yet)
* added more documentation and examples
* properly put the i2c adapters after use
* respect PAGE_SIZE in sysfs_show

This has been tested on a Renesas Lager board switching between i2c-gpio and
two different IP cores (i2c-rcar and i2c-sh_mobile). The rebinding seems to be
working as expected. However, in practice, I couldn't use the HDMI i2c slaves
with another controller yet, because the rcar-du driver OOPSes when unbinding.
This seems unrelated to this series because it can also be triggered via
sysfs-unbind. soc-camera also had problems properly cleaning up on unbind, a
patch for this already has been sent. So, this series is for sure a good test
for the unbind path of drivers.

A branch can be found here:

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/ip-core-switch-on-4.4

Let me know what you think.

Thanks,

   Wolfram

Wolfram Sang (3):
  dt-bindings: i2c: mux: demux-pinctrl: add bindings
  i2c: mux: demux-pinctrl: add driver
  ARM: shmobile: r8a7790: rework dts to use i2c demuxer

 .../ABI/testing/sysfs-platform-i2c-demux-pinctrl   |  23 ++
 .../devicetree/bindings/i2c/i2c-demux-pinctrl.txt  | 136 +++++++++++
 arch/arm/boot/dts/r8a7790-lager.dts                | 141 +++++++----
 drivers/i2c/muxes/Kconfig                          |   9 +
 drivers/i2c/muxes/Makefile                         |   2 +
 drivers/i2c/muxes/i2c-demux-pinctrl.c              | 272 +++++++++++++++++++++
 6 files changed, 530 insertions(+), 53 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
 create mode 100644 drivers/i2c/muxes/i2c-demux-pinctrl.c

-- 
2.1.4

[PATCH 1/3] dt-bindings: i2c: mux: demux-pinctrl: add bindings

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

These bindings allow an I2C bus to switch between multiple masters. This
is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once
the task is known. Example: Prefer i2c-gpio over another I2C core
because of HW errata affecting your use case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 .../ABI/testing/sysfs-platform-i2c-demux-pinctrl   |  23 ++++
 .../devicetree/bindings/i2c/i2c-demux-pinctrl.txt  | 136 +++++++++++++++++++++
 2 files changed, 159 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt

diff --git a/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl b/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
new file mode 100644
index 00000000000000..7ac7d7262bb718
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
@@ -0,0 +1,23 @@
+What:		/sys/devices/platform/<i2c-demux-name>/cur_master
+Date:		January 2016
+KernelVersion:	4.6
+Contact:	Wolfram Sang <wsa@the-dreams.de>
+Description:
+
+This file selects the active I2C master for a demultiplexed bus.
+
+Write 0 there for the first master, 1 for the second etc. Reading the file will
+give you a list with the active master marked. Example from a Renesas Lager
+board:
+
+root@Lager:~# cat /sys/devices/platform/i2c@8/cur_master
+* 0 - /i2c@9
+  1 - /i2c@e6520000
+  2 - /i2c@e6530000
+
+root@Lager:~# echo 2 > /sys/devices/platform/i2c@8/cur_master
+
+root@Lager:~# cat /sys/devices/platform/i2c@8/cur_master
+  0 - /i2c@9
+  1 - /i2c@e6520000
+* 2 - /i2c@e6530000
diff --git a/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
new file mode 100644
index 00000000000000..6c8aace7d78e64
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
@@ -0,0 +1,136 @@
+Pinctrl-based I2C Bus DeMux
+
+This binding describes an I2C bus demultiplexer that uses pin multiplexing to
+route the I2C signals, and represents the pin multiplexing configuration using
+the pinctrl device tree bindings. This may be used to select one I2C IP core at
+runtime which may have a better feature set for a given task than another I2C
+IP core on the SoC. The most simple example is to fall back to GPIO bitbanging
+if your current runtime configuration hits an errata of the internal IP core.
+
+    +-------------------------------+
+    | SoC                           |
+    |                               |   +-----+  +-----+
+    |   +------------+              |   | dev |  | dev |
+    |   |I2C IP Core1|--\           |   +-----+  +-----+
+    |   +------------+   \-------+  |      |        |
+    |                    |Pinctrl|--|------+--------+
+    |   +------------+   +-------+  |
+    |   |I2C IP Core2|--/           |
+    |   +------------+              |
+    |                               |
+    +-------------------------------+
+
+Required properties:
+- compatible: "i2c-demux-pinctrl"
+- i2c-parent: List of phandles of I2C masters available for selection. The first
+	      one will be used as default.
+- i2c-bus-name: The name of this bus. Also needed as pinctrl-name for the I2C
+		parents.
+
+Furthermore, I2C mux properties and child nodes. See mux.txt in this directory.
+
+Example:
+
+Here is a snipplet for a bus to be demuxed. It contains various i2c clients for
+HDMI, so the bus is named "i2c-hdmi":
+
+	i2chdmi: i2c@8 {
+
+		compatible = "i2c-demux-pinctrl";
+		i2c-parent = <&gpioi2c>, <&iic2>, <&i2c2>;
+		i2c-bus-name = "i2c-hdmi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		ak4643: sound-codec@12 {
+			compatible = "asahi-kasei,ak4643";
+
+			#sound-dai-cells = <0>;
+			reg = <0x12>;
+		};
+
+		composite-in@20 {
+			compatible = "adi,adv7180";
+			reg = <0x20>;
+			remote = <&vin1>;
+
+			port {
+				adv7180: endpoint {
+					bus-width = <8>;
+					remote-endpoint = <&vin1ep0>;
+				};
+			};
+		};
+
+		hdmi@39 {
+			compatible = "adi,adv7511w";
+			reg = <0x39>;
+			interrupt-parent = <&gpio1>;
+			interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
+
+			adi,input-depth = <8>;
+			adi,input-colorspace = "rgb";
+			adi,input-clock = "1x";
+			adi,input-style = <1>;
+			adi,input-justification = "evenly";
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				port@0 {
+					reg = <0>;
+					adv7511_in: endpoint {
+						remote-endpoint = <&du_out_lvds0>;
+					};
+				};
+
+				port@1 {
+					reg = <1>;
+					adv7511_out: endpoint {
+						remote-endpoint = <&hdmi_con>;
+					};
+				};
+			};
+		};
+	};
+
+And for clarification, here are the snipplets for the i2c-parents:
+
+	gpioi2c: i2c@9 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "i2c-gpio";
+		status = "disabled";
+		gpios = <&gpio5 6 GPIO_ACTIVE_HIGH /* sda */
+			 &gpio5 5 GPIO_ACTIVE_HIGH /* scl */
+			>;
+		i2c-gpio,delay-us = <5>;
+	};
+
+...
+
+&i2c2	{
+	pinctrl-0 = <&i2c2_pins>;
+	pinctrl-names = "i2c-hdmi";
+
+	clock-frequency = <100000>;
+};
+
+...
+
+&iic2	{
+	pinctrl-0 = <&iic2_pins>;
+	pinctrl-names = "i2c-hdmi";
+
+	clock-frequency = <100000>;
+};
+
+Please note:
+
+- pinctrl properties for the parent I2C controllers need a pinctrl state
+  with the same name as i2c-bus-name, not "default"!
+
+- the i2c masters must have their status "disabled". This driver will
+  enable them at runtime when needed.
+
-- 
2.1.4

[PATCH 1/3] dt-bindings: i2c: mux: demux-pinctrl: add bindings

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

These bindings allow an I2C bus to switch between multiple masters. This
is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once
the task is known. Example: Prefer i2c-gpio over another I2C core
because of HW errata affecting your use case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 .../ABI/testing/sysfs-platform-i2c-demux-pinctrl   |  23 ++++
 .../devicetree/bindings/i2c/i2c-demux-pinctrl.txt  | 136 +++++++++++++++++++++
 2 files changed, 159 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt

diff --git a/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl b/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
new file mode 100644
index 00000000000000..7ac7d7262bb718
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
@@ -0,0 +1,23 @@
+What:		/sys/devices/platform/<i2c-demux-name>/cur_master
+Date:		January 2016
+KernelVersion:	4.6
+Contact:	Wolfram Sang <wsa@the-dreams.de>
+Description:
+
+This file selects the active I2C master for a demultiplexed bus.
+
+Write 0 there for the first master, 1 for the second etc. Reading the file will
+give you a list with the active master marked. Example from a Renesas Lager
+board:
+
+root@Lager:~# cat /sys/devices/platform/i2c@8/cur_master
+* 0 - /i2c@9
+  1 - /i2c@e6520000
+  2 - /i2c@e6530000
+
+root@Lager:~# echo 2 > /sys/devices/platform/i2c@8/cur_master
+
+root@Lager:~# cat /sys/devices/platform/i2c@8/cur_master
+  0 - /i2c@9
+  1 - /i2c@e6520000
+* 2 - /i2c@e6530000
diff --git a/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
new file mode 100644
index 00000000000000..6c8aace7d78e64
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt
@@ -0,0 +1,136 @@
+Pinctrl-based I2C Bus DeMux
+
+This binding describes an I2C bus demultiplexer that uses pin multiplexing to
+route the I2C signals, and represents the pin multiplexing configuration using
+the pinctrl device tree bindings. This may be used to select one I2C IP core at
+runtime which may have a better feature set for a given task than another I2C
+IP core on the SoC. The most simple example is to fall back to GPIO bitbanging
+if your current runtime configuration hits an errata of the internal IP core.
+
+    +-------------------------------+
+    | SoC                           |
+    |                               |   +-----+  +-----+
+    |   +------------+              |   | dev |  | dev |
+    |   |I2C IP Core1|--\           |   +-----+  +-----+
+    |   +------------+   \-------+  |      |        |
+    |                    |Pinctrl|--|------+--------+
+    |   +------------+   +-------+  |
+    |   |I2C IP Core2|--/           |
+    |   +------------+              |
+    |                               |
+    +-------------------------------+
+
+Required properties:
+- compatible: "i2c-demux-pinctrl"
+- i2c-parent: List of phandles of I2C masters available for selection. The first
+	      one will be used as default.
+- i2c-bus-name: The name of this bus. Also needed as pinctrl-name for the I2C
+		parents.
+
+Furthermore, I2C mux properties and child nodes. See mux.txt in this directory.
+
+Example:
+
+Here is a snipplet for a bus to be demuxed. It contains various i2c clients for
+HDMI, so the bus is named "i2c-hdmi":
+
+	i2chdmi: i2c@8 {
+
+		compatible = "i2c-demux-pinctrl";
+		i2c-parent = <&gpioi2c>, <&iic2>, <&i2c2>;
+		i2c-bus-name = "i2c-hdmi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		ak4643: sound-codec@12 {
+			compatible = "asahi-kasei,ak4643";
+
+			#sound-dai-cells = <0>;
+			reg = <0x12>;
+		};
+
+		composite-in@20 {
+			compatible = "adi,adv7180";
+			reg = <0x20>;
+			remote = <&vin1>;
+
+			port {
+				adv7180: endpoint {
+					bus-width = <8>;
+					remote-endpoint = <&vin1ep0>;
+				};
+			};
+		};
+
+		hdmi@39 {
+			compatible = "adi,adv7511w";
+			reg = <0x39>;
+			interrupt-parent = <&gpio1>;
+			interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
+
+			adi,input-depth = <8>;
+			adi,input-colorspace = "rgb";
+			adi,input-clock = "1x";
+			adi,input-style = <1>;
+			adi,input-justification = "evenly";
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				port@0 {
+					reg = <0>;
+					adv7511_in: endpoint {
+						remote-endpoint = <&du_out_lvds0>;
+					};
+				};
+
+				port@1 {
+					reg = <1>;
+					adv7511_out: endpoint {
+						remote-endpoint = <&hdmi_con>;
+					};
+				};
+			};
+		};
+	};
+
+And for clarification, here are the snipplets for the i2c-parents:
+
+	gpioi2c: i2c@9 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "i2c-gpio";
+		status = "disabled";
+		gpios = <&gpio5 6 GPIO_ACTIVE_HIGH /* sda */
+			 &gpio5 5 GPIO_ACTIVE_HIGH /* scl */
+			>;
+		i2c-gpio,delay-us = <5>;
+	};
+
+...
+
+&i2c2	{
+	pinctrl-0 = <&i2c2_pins>;
+	pinctrl-names = "i2c-hdmi";
+
+	clock-frequency = <100000>;
+};
+
+...
+
+&iic2	{
+	pinctrl-0 = <&iic2_pins>;
+	pinctrl-names = "i2c-hdmi";
+
+	clock-frequency = <100000>;
+};
+
+Please note:
+
+- pinctrl properties for the parent I2C controllers need a pinctrl state
+  with the same name as i2c-bus-name, not "default"!
+
+- the i2c masters must have their status "disabled". This driver will
+  enable them at runtime when needed.
+
-- 
2.1.4

[PATCH 2/3] i2c: mux: demux-pinctrl: add driver

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

This driver allows an I2C bus to switch between multiple masters. This
is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once
the task is known. Example: Prefer i2c-gpio over another I2C core
because of HW errata affecting your use case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/muxes/Kconfig             |   9 ++
 drivers/i2c/muxes/Makefile            |   2 +
 drivers/i2c/muxes/i2c-demux-pinctrl.c | 272 ++++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 drivers/i2c/muxes/i2c-demux-pinctrl.c

diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index f06b0e24673b87..e280c8ecc0b59b 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -72,4 +72,13 @@ config I2C_MUX_REG
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-mux-reg.
 
+config I2C_DEMUX_PINCTRL
+	tristate "pinctrl-based I2C demultiplexer"
+	depends on PINCTRL && OF
+	select OF_DYNAMIC
+	help
+	  If you say yes to this option, support will be included for an I2C
+	  demultiplexer that uses the pinctrl subsystem. This is useful if you
+	  want to change the I2C master at run-time depending on features.
+
 endmenu
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index e89799b76a9280..7c267c29b19196 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -3,6 +3,8 @@
 
 obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE)	+= i2c-arb-gpio-challenge.o
 
+obj-$(CONFIG_I2C_DEMUX_PINCTRL)		+= i2c-demux-pinctrl.o
+
 obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
 obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
new file mode 100644
index 00000000000000..7748a0a5ddb9f1
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
@@ -0,0 +1,272 @@
+/*
+ * Pinctrl based I2C DeMultiplexer
+ *
+ * Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
+ * Copyright (C) 2015-16 by Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ *
+ * See the bindings doc for DTS setup and the sysfs doc for usage information.
+ * (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+struct i2c_demux_pinctrl_chan {
+	struct device_node *parent_np;
+	struct i2c_adapter *parent_adap;
+	struct of_changeset chgset;
+};
+
+struct i2c_demux_pinctrl_priv {
+	int cur_chan;
+	int num_chan;
+	struct device *dev;
+	const char *bus_name;
+	struct i2c_adapter cur_adap;
+	struct i2c_algorithm algo;
+	struct i2c_demux_pinctrl_chan chan[];
+};
+
+static struct property status_okay = { .name = "status", .length = 3, .value = "ok" };
+
+static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
+	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
+
+	return __i2c_transfer(parent, msgs, num);
+}
+
+static u32 i2c_demux_functionality(struct i2c_adapter *adap)
+{
+	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
+	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
+
+	return parent->algo->functionality(parent);
+}
+
+static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
+{
+	struct i2c_adapter *adap;
+	struct pinctrl *p;
+	int ret;
+
+	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
+	if (ret)
+		goto err;
+
+	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
+	if (!adap) {
+		ret = -ENODEV;
+		goto err;
+	}
+
+	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
+	if (IS_ERR(p)) {
+		ret = PTR_ERR(p);
+		goto err_with_put;
+	}
+
+	priv->chan[new_chan].parent_adap = adap;
+	priv->cur_chan = new_chan;
+
+	/* Now fill out current adapter structure. cur_chan must be up to date */
+	priv->algo.master_xfer = i2c_demux_master_xfer;
+	priv->algo.functionality = i2c_demux_functionality;
+
+	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
+		 "i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
+	priv->cur_adap.owner = THIS_MODULE;
+	priv->cur_adap.algo = &priv->algo;
+	priv->cur_adap.algo_data = priv;
+	priv->cur_adap.dev.parent = priv->dev;
+	priv->cur_adap.class = adap->class;
+	priv->cur_adap.retries = adap->retries;
+	priv->cur_adap.timeout = adap->timeout;
+	priv->cur_adap.quirks = adap->quirks;
+	priv->cur_adap.dev.of_node = priv->dev->of_node;
+	ret = i2c_add_adapter(&priv->cur_adap);
+	if (ret < 0)
+		goto err_with_put;
+
+	return 0;
+
+ err_with_put:
+	i2c_put_adapter(adap);
+ err:
+	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
+	return ret;
+}
+
+static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
+{
+	int ret, cur = priv->cur_chan;
+
+	if (cur < 0)
+		return 0;
+
+	i2c_del_adapter(&priv->cur_adap);
+	i2c_put_adapter(priv->chan[cur].parent_adap);
+
+	ret = of_changeset_revert(&priv->chan[cur].chgset);
+
+	priv->chan[cur].parent_adap = NULL;
+	priv->cur_chan = -EINVAL;
+
+	return ret;
+}
+
+static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
+{
+	int ret;
+
+	if (new_chan = priv->cur_chan)
+		return 0;
+
+	ret = i2c_demux_deactivate_master(priv);
+	if (ret)
+		return ret;
+
+	return i2c_demux_activate_master(priv, new_chan);
+}
+
+static ssize_t cur_master_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+	int count = 0, i;
+
+	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
+		count += scnprintf(buf + count, PAGE_SIZE - count, "%c %d - %s\n",
+				 i = priv->cur_chan ? '*' : ' ', i,
+				 priv->chan[i].parent_np->full_name);
+
+	return count;
+}
+
+static ssize_t cur_master_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val >= priv->num_chan)
+		return -EINVAL;
+
+	ret = i2c_demux_change_master(priv, val);
+
+	return ret < 0 ? ret : count;
+}
+static DEVICE_ATTR_RW(cur_master);
+
+static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct i2c_demux_pinctrl_priv *priv;
+	int num_chan, i, j, err;
+
+	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
+	if (num_chan < 2) {
+		dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
+		return -EINVAL;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
+			   + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
+	if (err)
+		return err;
+
+	for (i = 0; i < num_chan; i++) {
+		struct device_node *adap_np;
+
+		adap_np = of_parse_phandle(np, "i2c-parent", i);
+		if (!adap_np) {
+			dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
+			err = -ENOENT;
+			goto err_rollback;
+		}
+		priv->chan[i].parent_np = adap_np;
+
+		of_changeset_init(&priv->chan[i].chgset);
+		of_changeset_update_property(&priv->chan[i].chgset, adap_np, &status_okay);
+	}
+
+	priv->num_chan = num_chan;
+	priv->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, priv);
+
+	/* switch to first parent as active master */
+	i2c_demux_activate_master(priv, 0);
+
+	err = device_create_file(&pdev->dev, &dev_attr_cur_master);
+	if (err)
+		goto err_rollback;
+
+	return 0;
+
+err_rollback:
+	for (j = 0; j < i; j++) {
+		of_node_put(priv->chan[j].parent_np);
+		of_changeset_destroy(&priv->chan[j].chgset);
+	}
+
+	return err;
+}
+
+static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
+{
+	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
+	int i;
+
+	device_remove_file(&pdev->dev, &dev_attr_cur_master);
+
+	i2c_demux_deactivate_master(priv);
+
+	for (i = 0; i < priv->num_chan; i++) {
+		of_node_put(priv->chan[i].parent_np);
+		of_changeset_destroy(&priv->chan[i].chgset);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
+	{ .compatible = "i2c-demux-pinctrl", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
+
+static struct platform_driver i2c_demux_pinctrl_driver = {
+	.driver	= {
+		.name = "i2c-demux-pinctrl",
+		.of_match_table = i2c_demux_pinctrl_of_match,
+	},
+	.probe	= i2c_demux_pinctrl_probe,
+	.remove	= i2c_demux_pinctrl_remove,
+};
+module_platform_driver(i2c_demux_pinctrl_driver);
+
+MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
+MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-demux-pinctrl");
-- 
2.1.4

[PATCH 2/3] i2c: mux: demux-pinctrl: add driver

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

This driver allows an I2C bus to switch between multiple masters. This
is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once
the task is known. Example: Prefer i2c-gpio over another I2C core
because of HW errata affecting your use case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/muxes/Kconfig             |   9 ++
 drivers/i2c/muxes/Makefile            |   2 +
 drivers/i2c/muxes/i2c-demux-pinctrl.c | 272 ++++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+)
 create mode 100644 drivers/i2c/muxes/i2c-demux-pinctrl.c

diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index f06b0e24673b87..e280c8ecc0b59b 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -72,4 +72,13 @@ config I2C_MUX_REG
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-mux-reg.
 
+config I2C_DEMUX_PINCTRL
+	tristate "pinctrl-based I2C demultiplexer"
+	depends on PINCTRL && OF
+	select OF_DYNAMIC
+	help
+	  If you say yes to this option, support will be included for an I2C
+	  demultiplexer that uses the pinctrl subsystem. This is useful if you
+	  want to change the I2C master at run-time depending on features.
+
 endmenu
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index e89799b76a9280..7c267c29b19196 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -3,6 +3,8 @@
 
 obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE)	+= i2c-arb-gpio-challenge.o
 
+obj-$(CONFIG_I2C_DEMUX_PINCTRL)		+= i2c-demux-pinctrl.o
+
 obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
 obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
new file mode 100644
index 00000000000000..7748a0a5ddb9f1
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
@@ -0,0 +1,272 @@
+/*
+ * Pinctrl based I2C DeMultiplexer
+ *
+ * Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
+ * Copyright (C) 2015-16 by Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ *
+ * See the bindings doc for DTS setup and the sysfs doc for usage information.
+ * (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+struct i2c_demux_pinctrl_chan {
+	struct device_node *parent_np;
+	struct i2c_adapter *parent_adap;
+	struct of_changeset chgset;
+};
+
+struct i2c_demux_pinctrl_priv {
+	int cur_chan;
+	int num_chan;
+	struct device *dev;
+	const char *bus_name;
+	struct i2c_adapter cur_adap;
+	struct i2c_algorithm algo;
+	struct i2c_demux_pinctrl_chan chan[];
+};
+
+static struct property status_okay = { .name = "status", .length = 3, .value = "ok" };
+
+static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
+	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
+
+	return __i2c_transfer(parent, msgs, num);
+}
+
+static u32 i2c_demux_functionality(struct i2c_adapter *adap)
+{
+	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
+	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
+
+	return parent->algo->functionality(parent);
+}
+
+static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
+{
+	struct i2c_adapter *adap;
+	struct pinctrl *p;
+	int ret;
+
+	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
+	if (ret)
+		goto err;
+
+	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
+	if (!adap) {
+		ret = -ENODEV;
+		goto err;
+	}
+
+	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
+	if (IS_ERR(p)) {
+		ret = PTR_ERR(p);
+		goto err_with_put;
+	}
+
+	priv->chan[new_chan].parent_adap = adap;
+	priv->cur_chan = new_chan;
+
+	/* Now fill out current adapter structure. cur_chan must be up to date */
+	priv->algo.master_xfer = i2c_demux_master_xfer;
+	priv->algo.functionality = i2c_demux_functionality;
+
+	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
+		 "i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
+	priv->cur_adap.owner = THIS_MODULE;
+	priv->cur_adap.algo = &priv->algo;
+	priv->cur_adap.algo_data = priv;
+	priv->cur_adap.dev.parent = priv->dev;
+	priv->cur_adap.class = adap->class;
+	priv->cur_adap.retries = adap->retries;
+	priv->cur_adap.timeout = adap->timeout;
+	priv->cur_adap.quirks = adap->quirks;
+	priv->cur_adap.dev.of_node = priv->dev->of_node;
+	ret = i2c_add_adapter(&priv->cur_adap);
+	if (ret < 0)
+		goto err_with_put;
+
+	return 0;
+
+ err_with_put:
+	i2c_put_adapter(adap);
+ err:
+	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
+	return ret;
+}
+
+static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
+{
+	int ret, cur = priv->cur_chan;
+
+	if (cur < 0)
+		return 0;
+
+	i2c_del_adapter(&priv->cur_adap);
+	i2c_put_adapter(priv->chan[cur].parent_adap);
+
+	ret = of_changeset_revert(&priv->chan[cur].chgset);
+
+	priv->chan[cur].parent_adap = NULL;
+	priv->cur_chan = -EINVAL;
+
+	return ret;
+}
+
+static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
+{
+	int ret;
+
+	if (new_chan == priv->cur_chan)
+		return 0;
+
+	ret = i2c_demux_deactivate_master(priv);
+	if (ret)
+		return ret;
+
+	return i2c_demux_activate_master(priv, new_chan);
+}
+
+static ssize_t cur_master_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+	int count = 0, i;
+
+	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
+		count += scnprintf(buf + count, PAGE_SIZE - count, "%c %d - %s\n",
+				 i == priv->cur_chan ? '*' : ' ', i,
+				 priv->chan[i].parent_np->full_name);
+
+	return count;
+}
+
+static ssize_t cur_master_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val >= priv->num_chan)
+		return -EINVAL;
+
+	ret = i2c_demux_change_master(priv, val);
+
+	return ret < 0 ? ret : count;
+}
+static DEVICE_ATTR_RW(cur_master);
+
+static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct i2c_demux_pinctrl_priv *priv;
+	int num_chan, i, j, err;
+
+	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
+	if (num_chan < 2) {
+		dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
+		return -EINVAL;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
+			   + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
+	if (err)
+		return err;
+
+	for (i = 0; i < num_chan; i++) {
+		struct device_node *adap_np;
+
+		adap_np = of_parse_phandle(np, "i2c-parent", i);
+		if (!adap_np) {
+			dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
+			err = -ENOENT;
+			goto err_rollback;
+		}
+		priv->chan[i].parent_np = adap_np;
+
+		of_changeset_init(&priv->chan[i].chgset);
+		of_changeset_update_property(&priv->chan[i].chgset, adap_np, &status_okay);
+	}
+
+	priv->num_chan = num_chan;
+	priv->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, priv);
+
+	/* switch to first parent as active master */
+	i2c_demux_activate_master(priv, 0);
+
+	err = device_create_file(&pdev->dev, &dev_attr_cur_master);
+	if (err)
+		goto err_rollback;
+
+	return 0;
+
+err_rollback:
+	for (j = 0; j < i; j++) {
+		of_node_put(priv->chan[j].parent_np);
+		of_changeset_destroy(&priv->chan[j].chgset);
+	}
+
+	return err;
+}
+
+static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
+{
+	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
+	int i;
+
+	device_remove_file(&pdev->dev, &dev_attr_cur_master);
+
+	i2c_demux_deactivate_master(priv);
+
+	for (i = 0; i < priv->num_chan; i++) {
+		of_node_put(priv->chan[i].parent_np);
+		of_changeset_destroy(&priv->chan[i].chgset);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
+	{ .compatible = "i2c-demux-pinctrl", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
+
+static struct platform_driver i2c_demux_pinctrl_driver = {
+	.driver	= {
+		.name = "i2c-demux-pinctrl",
+		.of_match_table = i2c_demux_pinctrl_of_match,
+	},
+	.probe	= i2c_demux_pinctrl_probe,
+	.remove	= i2c_demux_pinctrl_remove,
+};
+module_platform_driver(i2c_demux_pinctrl_driver);
+
+MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
+MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-demux-pinctrl");
-- 
2.1.4

[PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

Create a seperate bus for HDMI related I2C slaves and assign it
to a i2c-gpio master. It can be switched to the i2c-rcar or
i2c-sh_mobile core at runtime.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

After the technical details of the underlying driver seem to be more or less
sorted out, I would appreciate some discussion here about changing the Lager
DTS e.g. if we really want GPIO to be the default?

 arch/arm/boot/dts/r8a7790-lager.dts | 141 ++++++++++++++++++++++--------------
 1 file changed, 88 insertions(+), 53 deletions(-)

diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
index c553abd711eeb3..d8f0ca8e094dad 100644
--- a/arch/arm/boot/dts/r8a7790-lager.dts
+++ b/arch/arm/boot/dts/r8a7790-lager.dts
@@ -49,6 +49,8 @@
 	aliases {
 		serial0 = &scifa0;
 		serial1 = &scifa1;
+		i2c8 = &i2chdmi;
+		i2c9 = &gpioi2c;
 	};
 
 	chosen {
@@ -252,6 +254,79 @@
 		#clock-cells = <0>;
 		clock-frequency = <148500000>;
 	};
+
+
+	gpioi2c: i2c@9 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "i2c-gpio";
+		status = "disabled";
+		gpios = <&gpio5 6 GPIO_ACTIVE_HIGH /* sda */
+			 &gpio5 5 GPIO_ACTIVE_HIGH /* scl */
+			>;
+		i2c-gpio,delay-us = <5>;
+	};
+
+	i2chdmi: i2c@8 {
+
+		compatible = "i2c-demux-pinctrl";
+		i2c-parent = <&gpioi2c>, <&iic2>, <&i2c2>;
+		i2c-bus-name = "i2c-hdmi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		ak4643: sound-codec@12 {
+			compatible = "asahi-kasei,ak4643";
+
+			#sound-dai-cells = <0>;
+			reg = <0x12>;
+		};
+
+		composite-in@20 {
+			compatible = "adi,adv7180";
+			reg = <0x20>;
+			remote = <&vin1>;
+
+			port {
+				adv7180: endpoint {
+					bus-width = <8>;
+					remote-endpoint = <&vin1ep0>;
+				};
+			};
+		};
+
+		hdmi@39 {
+			compatible = "adi,adv7511w";
+			reg = <0x39>;
+			interrupt-parent = <&gpio1>;
+			interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
+
+			adi,input-depth = <8>;
+			adi,input-colorspace = "rgb";
+			adi,input-clock = "1x";
+			adi,input-style = <1>;
+			adi,input-justification = "evenly";
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				port@0 {
+					reg = <0>;
+					adv7511_in: endpoint {
+						remote-endpoint = <&du_out_lvds0>;
+					};
+				};
+
+				port@1 {
+					reg = <1>;
+					adv7511_out: endpoint {
+						remote-endpoint = <&hdmi_con>;
+					};
+				};
+			};
+		};
+	};
 };
 
 &du {
@@ -352,6 +427,11 @@
 		renesas,function = "iic1";
 	};
 
+	i2c2_pins: i2c2 {
+		renesas,groups = "i2c2";
+		renesas,function = "i2c2";
+	};
+
 	iic2_pins: iic2 {
 		renesas,groups = "iic2";
 		renesas,function = "iic2";
@@ -532,63 +612,18 @@
 	pinctrl-names = "default";
 };
 
-&iic2	{
-	status = "okay";
-	pinctrl-0 = <&iic2_pins>;
-	pinctrl-names = "default";
+&i2c2	{
+	pinctrl-0 = <&i2c2_pins>;
+	pinctrl-names = "i2c-hdmi";
 
 	clock-frequency = <100000>;
+};
 
-	ak4643: codec@12 {
-		compatible = "asahi-kasei,ak4643";
-		#sound-dai-cells = <0>;
-		reg = <0x12>;
-	};
-
-	composite-in@20 {
-		compatible = "adi,adv7180";
-		reg = <0x20>;
-		remote = <&vin1>;
-
-		port {
-			adv7180: endpoint {
-				bus-width = <8>;
-				remote-endpoint = <&vin1ep0>;
-			};
-		};
-	};
-
-	hdmi@39 {
-		compatible = "adi,adv7511w";
-		reg = <0x39>;
-		interrupt-parent = <&gpio1>;
-		interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
-
-		adi,input-depth = <8>;
-		adi,input-colorspace = "rgb";
-		adi,input-clock = "1x";
-		adi,input-style = <1>;
-		adi,input-justification = "evenly";
-
-		ports {
-			#address-cells = <1>;
-			#size-cells = <0>;
-
-			port@0 {
-				reg = <0>;
-				adv7511_in: endpoint {
-					remote-endpoint = <&du_out_lvds0>;
-				};
-			};
+&iic2	{
+	pinctrl-0 = <&iic2_pins>;
+	pinctrl-names = "i2c-hdmi";
 
-			port@1 {
-				reg = <1>;
-				adv7511_out: endpoint {
-					remote-endpoint = <&hdmi_con>;
-				};
-			};
-		};
-	};
+	clock-frequency = <100000>;
 };
 
 &iic3 {
-- 
2.1.4

[PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

Create a seperate bus for HDMI related I2C slaves and assign it
to a i2c-gpio master. It can be switched to the i2c-rcar or
i2c-sh_mobile core at runtime.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

After the technical details of the underlying driver seem to be more or less
sorted out, I would appreciate some discussion here about changing the Lager
DTS e.g. if we really want GPIO to be the default?

 arch/arm/boot/dts/r8a7790-lager.dts | 141 ++++++++++++++++++++++--------------
 1 file changed, 88 insertions(+), 53 deletions(-)

diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
index c553abd711eeb3..d8f0ca8e094dad 100644
--- a/arch/arm/boot/dts/r8a7790-lager.dts
+++ b/arch/arm/boot/dts/r8a7790-lager.dts
@@ -49,6 +49,8 @@
 	aliases {
 		serial0 = &scifa0;
 		serial1 = &scifa1;
+		i2c8 = &i2chdmi;
+		i2c9 = &gpioi2c;
 	};
 
 	chosen {
@@ -252,6 +254,79 @@
 		#clock-cells = <0>;
 		clock-frequency = <148500000>;
 	};
+
+
+	gpioi2c: i2c@9 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "i2c-gpio";
+		status = "disabled";
+		gpios = <&gpio5 6 GPIO_ACTIVE_HIGH /* sda */
+			 &gpio5 5 GPIO_ACTIVE_HIGH /* scl */
+			>;
+		i2c-gpio,delay-us = <5>;
+	};
+
+	i2chdmi: i2c@8 {
+
+		compatible = "i2c-demux-pinctrl";
+		i2c-parent = <&gpioi2c>, <&iic2>, <&i2c2>;
+		i2c-bus-name = "i2c-hdmi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		ak4643: sound-codec@12 {
+			compatible = "asahi-kasei,ak4643";
+
+			#sound-dai-cells = <0>;
+			reg = <0x12>;
+		};
+
+		composite-in@20 {
+			compatible = "adi,adv7180";
+			reg = <0x20>;
+			remote = <&vin1>;
+
+			port {
+				adv7180: endpoint {
+					bus-width = <8>;
+					remote-endpoint = <&vin1ep0>;
+				};
+			};
+		};
+
+		hdmi@39 {
+			compatible = "adi,adv7511w";
+			reg = <0x39>;
+			interrupt-parent = <&gpio1>;
+			interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
+
+			adi,input-depth = <8>;
+			adi,input-colorspace = "rgb";
+			adi,input-clock = "1x";
+			adi,input-style = <1>;
+			adi,input-justification = "evenly";
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				port@0 {
+					reg = <0>;
+					adv7511_in: endpoint {
+						remote-endpoint = <&du_out_lvds0>;
+					};
+				};
+
+				port@1 {
+					reg = <1>;
+					adv7511_out: endpoint {
+						remote-endpoint = <&hdmi_con>;
+					};
+				};
+			};
+		};
+	};
 };
 
 &du {
@@ -352,6 +427,11 @@
 		renesas,function = "iic1";
 	};
 
+	i2c2_pins: i2c2 {
+		renesas,groups = "i2c2";
+		renesas,function = "i2c2";
+	};
+
 	iic2_pins: iic2 {
 		renesas,groups = "iic2";
 		renesas,function = "iic2";
@@ -532,63 +612,18 @@
 	pinctrl-names = "default";
 };
 
-&iic2	{
-	status = "okay";
-	pinctrl-0 = <&iic2_pins>;
-	pinctrl-names = "default";
+&i2c2	{
+	pinctrl-0 = <&i2c2_pins>;
+	pinctrl-names = "i2c-hdmi";
 
 	clock-frequency = <100000>;
+};
 
-	ak4643: codec@12 {
-		compatible = "asahi-kasei,ak4643";
-		#sound-dai-cells = <0>;
-		reg = <0x12>;
-	};
-
-	composite-in@20 {
-		compatible = "adi,adv7180";
-		reg = <0x20>;
-		remote = <&vin1>;
-
-		port {
-			adv7180: endpoint {
-				bus-width = <8>;
-				remote-endpoint = <&vin1ep0>;
-			};
-		};
-	};
-
-	hdmi@39 {
-		compatible = "adi,adv7511w";
-		reg = <0x39>;
-		interrupt-parent = <&gpio1>;
-		interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
-
-		adi,input-depth = <8>;
-		adi,input-colorspace = "rgb";
-		adi,input-clock = "1x";
-		adi,input-style = <1>;
-		adi,input-justification = "evenly";
-
-		ports {
-			#address-cells = <1>;
-			#size-cells = <0>;
-
-			port@0 {
-				reg = <0>;
-				adv7511_in: endpoint {
-					remote-endpoint = <&du_out_lvds0>;
-				};
-			};
+&iic2	{
+	pinctrl-0 = <&iic2_pins>;
+	pinctrl-names = "i2c-hdmi";
 
-			port@1 {
-				reg = <1>;
-				adv7511_out: endpoint {
-					remote-endpoint = <&hdmi_con>;
-				};
-			};
-		};
-	};
+	clock-frequency = <100000>;
 };
 
 &iic3 {
-- 
2.1.4

Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Sergei Shtylyov]

On 01/13/2016 05:29 PM, Wolfram Sang wrote:

> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> Create a seperate bus for HDMI related I2C slaves and assign it

    Separate.

> to a i2c-gpio master. It can be switched to the i2c-rcar or
> i2c-sh_mobile core at runtime.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>
> After the technical details of the underlying driver seem to be more or less
> sorted out, I would appreciate some discussion here about changing the Lager
> DTS e.g. if we really want GPIO to be the default?
>
>   arch/arm/boot/dts/r8a7790-lager.dts | 141 ++++++++++++++++++++++--------------
>   1 file changed, 88 insertions(+), 53 deletions(-)
>
> diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
> index c553abd711eeb3..d8f0ca8e094dad 100644
> --- a/arch/arm/boot/dts/r8a7790-lager.dts
> +++ b/arch/arm/boot/dts/r8a7790-lager.dts
[...]
> @@ -252,6 +254,79 @@
>   		#clock-cells = <0>;
>   		clock-frequency = <148500000>;
>   	};
> +
> +
> +	gpioi2c: i2c@9 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		compatible = "i2c-gpio";

    I think this prop should go first.

> +		status = "disabled";

    In a board file? When do you intend to enable it?

> +		gpios = <&gpio5 6 GPIO_ACTIVE_HIGH /* sda */
> +			 &gpio5 5 GPIO_ACTIVE_HIGH /* scl */
> +			>;
> +		i2c-gpio,delay-us = <5>;
> +	};
[...]

MBR, Sergei

Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Sergei Shtylyov]

On 01/13/2016 05:29 PM, Wolfram Sang wrote:

> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> Create a seperate bus for HDMI related I2C slaves and assign it

    Separate.

> to a i2c-gpio master. It can be switched to the i2c-rcar or
> i2c-sh_mobile core at runtime.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>
> After the technical details of the underlying driver seem to be more or less
> sorted out, I would appreciate some discussion here about changing the Lager
> DTS e.g. if we really want GPIO to be the default?
>
>   arch/arm/boot/dts/r8a7790-lager.dts | 141 ++++++++++++++++++++++--------------
>   1 file changed, 88 insertions(+), 53 deletions(-)
>
> diff --git a/arch/arm/boot/dts/r8a7790-lager.dts b/arch/arm/boot/dts/r8a7790-lager.dts
> index c553abd711eeb3..d8f0ca8e094dad 100644
> --- a/arch/arm/boot/dts/r8a7790-lager.dts
> +++ b/arch/arm/boot/dts/r8a7790-lager.dts
[...]
> @@ -252,6 +254,79 @@
>   		#clock-cells = <0>;
>   		clock-frequency = <148500000>;
>   	};
> +
> +
> +	gpioi2c: i2c@9 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		compatible = "i2c-gpio";

    I think this prop should go first.

> +		status = "disabled";

    In a board file? When do you intend to enable it?

> +		gpios = <&gpio5 6 GPIO_ACTIVE_HIGH /* sda */
> +			 &gpio5 5 GPIO_ACTIVE_HIGH /* scl */
> +			>;
> +		i2c-gpio,delay-us = <5>;
> +	};
[...]

MBR, Sergei

Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 109 bytes --]


>    In a board file? When do you intend to enable it?

Please read the cover letter of this patch series.


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Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 109 bytes --]


>    In a board file? When do you intend to enable it?

Please read the cover letter of this patch series.


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Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Sergei Shtylyov]

On 01/13/2016 08:57 PM, Wolfram Sang wrote:

>>     In a board file? When do you intend to enable it?
>
> Please read the cover letter of this patch series.

    Sorry, I'd only skimmed thru it.

MBR, Sergei

Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Sergei Shtylyov]

On 01/13/2016 08:57 PM, Wolfram Sang wrote:

>>     In a board file? When do you intend to enable it?
>
> Please read the cover letter of this patch series.

    Sorry, I'd only skimmed thru it.

MBR, Sergei

Re: [PATCH 1/3] dt-bindings: i2c: mux: demux-pinctrl: add bindings

[Rob Herring]

On Wed, Jan 13, 2016 at 03:29:27PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> These bindings allow an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  .../ABI/testing/sysfs-platform-i2c-demux-pinctrl   |  23 ++++
>  .../devicetree/bindings/i2c/i2c-demux-pinctrl.txt  | 136 +++++++++++++++++++++
>  2 files changed, 159 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt

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

Re: [PATCH 1/3] dt-bindings: i2c: mux: demux-pinctrl: add bindings

[Rob Herring]

On Wed, Jan 13, 2016 at 03:29:27PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> These bindings allow an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  .../ABI/testing/sysfs-platform-i2c-demux-pinctrl   |  23 ++++
>  .../devicetree/bindings/i2c/i2c-demux-pinctrl.txt  | 136 +++++++++++++++++++++
>  2 files changed, 159 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.txt

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

Re: [PATCH 1/3] dt-bindings: i2c: mux: demux-pinctrl: add bindings

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 585 bytes --]

On Wed, Jan 13, 2016 at 03:29:27PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> These bindings allow an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Squashed with patch 2 and applied to for-next, thanks!


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Re: [PATCH 1/3] dt-bindings: i2c: mux: demux-pinctrl: add bindings

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 585 bytes --]

On Wed, Jan 13, 2016 at 03:29:27PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> These bindings allow an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Squashed with patch 2 and applied to for-next, thanks!


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Re: [PATCH 2/3] i2c: mux: demux-pinctrl: add driver

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 583 bytes --]

On Wed, Jan 13, 2016 at 03:29:28PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> This driver allows an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Squashed with patch 1 and applied to for-next, thanks!


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Re: [PATCH 2/3] i2c: mux: demux-pinctrl: add driver

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 583 bytes --]

On Wed, Jan 13, 2016 at 03:29:28PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> This driver allows an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Squashed with patch 1 and applied to for-next, thanks!


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Re: [PATCH 2/3] i2c: mux: demux-pinctrl: add driver

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 641 bytes --]

On Wed, Jan 13, 2016 at 03:29:28PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas-jBu1N2QxHDJrcw3mvpCnnVaTQe2KTcn/@public.gmane.org>
> 
> This driver allows an I2C bus to switch between multiple masters. This
> is not hot-switching because connected I2C slaves will be
> re-instantiated. It is meant to select the best I2C core at runtime once
> the task is known. Example: Prefer i2c-gpio over another I2C core
> because of HW errata affecting your use case.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas-jBu1N2QxHDJrcw3mvpCnnVaTQe2KTcn/@public.gmane.org>

Squashed with patch 1 and applied to for-next, thanks!


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Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 505 bytes --]

On Wed, Jan 13, 2016 at 03:29:29PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> Create a seperate bus for HDMI related I2C slaves and assign it
> to a i2c-gpio master. It can be switched to the i2c-rcar or
> i2c-sh_mobile core at runtime.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

After some discussion with Simon (thanks!), I will replace this patch
with one which is not only simpler but also more useful ;) Stay tuned.


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Re: [PATCH 3/3] ARM: shmobile: r8a7790: rework dts to use i2c demuxer

[Wolfram Sang]

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On Wed, Jan 13, 2016 at 03:29:29PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> 
> Create a seperate bus for HDMI related I2C slaves and assign it
> to a i2c-gpio master. It can be switched to the i2c-rcar or
> i2c-sh_mobile core at runtime.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

After some discussion with Simon (thanks!), I will replace this patch
with one which is not only simpler but also more useful ;) Stay tuned.


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