[PATCH 00/13] drivers: Introduce generic device lookup helpers

[PATCH 00/13] drivers: Introduce generic device lookup helpers

[Suzuki K Poulose]

We have device iterators to find a particular device matching a criteria
for a given bus/class/driver. i.e, {bus,class,driver}_find_device() APIs.
The matching criteria is a function pointer for the APIs. Often the lookup
is based on a generic property of a device (e.g, name, fwnode, of node pointer
or device type) rather than a driver specific information. However, each driver
writes up its own "match" function, spilling the similar match functions all
over the driver subsystems.

Additionally the prototype for the "match" functions accepted by the above APIs
have a minute difference which prevents us otherwise sharing the match functions.
i.e,
	int (*match)(struct device *dev, void *data) for {bus/driver}_find_device()
	  vs
	int (*match)(struct device *dev, const void *) for class_find_device()

If we promote the former to accept a "const void*" parameter, we could share one
single match function for all the helpers. This series achieves the following:

 1) Unify the prototype for "match" functions accepted by the device lookup APIs.
 2) Introduce generic match functions to match devices by the generic attributes
    of a device (e.g, name, fwnode, of_node and devt).

Also, in order to prevent creation of such match functions in the future,
we introduce wrapper functions for the look up APIs, which automatically
uses the appropriate match functions.

i.e,
	{bus/class/driver}_find_device_by_name
	{bus/class/driver}_find_device_by_of_node
	{bus/class/driver}_find_device_by_fwnode
	{bus/class/driver}_find_device_by_devt

Additionally, this series also adds wrapper for finding a device by matching
a device driver for platform bus devices - platform_find_device_by_driver() to
avoid a few drivers hard coding the platform bus specific details.

This is part 1 of revised version of the series posted here [0], to allow for better
management of the merging. Part 2 of the series, where these new helpers are consumed
by the individual driver subsystems will be posted once this is series is merged.
The entire tree with both the parts in is available at [1]

[0] https://marc.info/?i=1559577023-558-1-git-send-email-suzuki.poulose@arm.com
[1] git://linux-arm.org/linux-skp.git driver-cleanup/v1

Cc: Alan Tull <atull@kernel.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: David Airlie <airlied@linux.ie>
Cc: David Kershner <david.kershner@unisys.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Elie Morisse <syniurge@gmail.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grant Likely <grant.likely@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Len Brown <lenb@kernel.org
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: Nehal Shah <nehal-bakulchandra.shah@amd.com>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Peter Rosin <peda@axentia.se>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Ott <sebott@linux.ibm.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Shyam Sundar S K <shyam-sundar.s-k@amd.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: devicetree@vger.kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-fpga@vger.kernel.org
Cc: linux-i2c@vger.kernel.org
Cc: linux-leds@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org

Suzuki K Poulose (13):
  acpi: utils: Cleanup acpi_dev_match_cb
  bus_find_device: Unify the match callback with class_find_device
  driver_find_device: Unify the match function with class_find_device()
  drivers: Add generic helper to match by of_node
  drivers: Add generic helper to match by fwnode
  drivers: Add generic helper to match by devt
  drivers: Add generic match helper by ACPI_COMPANION device
  drivers: Add generic helper to match by name
  drivers: Add generic helper to match any device
  drivers: Introduce variants of class_find_device()
  drivers: Introduce variants for bus_find_device()
  drivers: Introduce variants of driver_find_device()
  platform: Add platform_find_device_by_driver() helper

 arch/powerpc/platforms/pseries/ibmebus.c           |   4 +-
 drivers/acpi/acpi_lpss.c                           |   4 +-
 drivers/acpi/sleep.c                               |   2 +-
 drivers/acpi/utils.c                               |  11 +-
 drivers/amba/tegra-ahb.c                           |   4 +-
 drivers/base/bus.c                                 |  28 +--
 drivers/base/core.c                                |  36 ++++
 drivers/base/devcon.c                              |   2 +-
 drivers/base/driver.c                              |   4 +-
 drivers/base/platform.c                            |  14 ++
 drivers/char/ipmi/ipmi_msghandler.c                |   8 +-
 drivers/char/ipmi/ipmi_si_platform.c               |   2 +-
 drivers/firmware/efi/dev-path-parser.c             |   4 +-
 drivers/gpu/drm/drm_mipi_dsi.c                     |   2 +-
 drivers/gpu/drm/tegra/dc.c                         |   4 +-
 drivers/hwtracing/coresight/coresight.c            |   6 +-
 drivers/hwtracing/coresight/of_coresight.c         |   2 +-
 drivers/hwtracing/intel_th/core.c                  |   5 +-
 drivers/i2c/busses/i2c-amd-mp2-pci.c               |   2 +-
 drivers/i2c/i2c-core-acpi.c                        |   4 +-
 drivers/i2c/i2c-core-of.c                          |   4 +-
 drivers/iio/inkern.c                               |   2 +-
 drivers/infiniband/hw/hns/hns_roce_hw_v1.c         |   2 +-
 drivers/iommu/arm-smmu-v3.c                        |   2 +-
 drivers/iommu/arm-smmu.c                           |   2 +-
 drivers/mfd/altera-sysmgr.c                        |   4 +-
 drivers/mfd/syscon.c                               |   2 +-
 drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c |   2 +-
 drivers/net/ethernet/ti/cpsw-phy-sel.c             |   4 +-
 drivers/net/ethernet/ti/davinci_emac.c             |   2 +-
 drivers/net/ethernet/toshiba/tc35815.c             |   4 +-
 drivers/nvmem/core.c                               |   2 +-
 drivers/of/of_mdio.c                               |   2 +-
 drivers/of/platform.c                              |   2 +-
 drivers/pci/probe.c                                |   2 +-
 drivers/pci/search.c                               |   4 +-
 drivers/s390/cio/ccwgroup.c                        |   2 +-
 drivers/s390/cio/chsc_sch.c                        |   2 +-
 drivers/s390/cio/css.c                             |   4 +-
 drivers/s390/cio/device.c                          |   6 +-
 drivers/s390/cio/scm.c                             |   4 +-
 drivers/s390/crypto/ap_bus.c                       |   8 +-
 drivers/scsi/scsi_proc.c                           |   2 +-
 drivers/spi/spi.c                                  |   4 +-
 drivers/staging/most/core.c                        |   4 +-
 drivers/thunderbolt/switch.c                       |   4 +-
 drivers/usb/core/devio.c                           |   4 +-
 drivers/usb/core/usb.c                             |   4 +-
 drivers/usb/phy/phy-am335x-control.c               |   4 +-
 drivers/usb/phy/phy-isp1301.c                      |   4 +-
 drivers/visorbus/visorbus_main.c                   |   4 +-
 include/linux/device.h                             | 188 ++++++++++++++++++++-
 include/linux/platform_device.h                    |   3 +
 sound/soc/rockchip/rk3399_gru_sound.c              |   2 +-
 54 files changed, 320 insertions(+), 123 deletions(-)

-- 
2.7.4

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[PATCH 08/13] drivers: Add generic helper to match by name

[Suzuki K Poulose]

Add a helper to match the device name

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-leds@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/base/core.c    | 6 ++++++
 include/linux/device.h | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 597095b..5724f93 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3352,3 +3352,9 @@ int device_match_acpi_dev(struct device *dev, const void *adev)
 	return ACPI_COMPANION(dev) == adev;
 }
 EXPORT_SYMBOL(device_match_acpi_dev);
+
+int device_match_name(struct device *dev, const void *name)
+{
+	return sysfs_streq(dev_name(dev), name);
+}
+EXPORT_SYMBOL_GPL(device_match_name);
diff --git a/include/linux/device.h b/include/linux/device.h
index a03b50d..74dd9c6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -167,6 +167,7 @@ int device_match_of_node(struct device *dev, const void *np);
 int device_match_fwnode(struct device *dev, const void *fwnode);
 int device_match_devt(struct device *dev, const void *pdevt);
 int device_match_acpi_dev(struct device *dev, const void *adev);
+int device_match_name(struct device *dev, const void *name);
 
 int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
 		     int (*fn)(struct device *dev, void *data));
-- 
2.7.4

[PATCH 10/13] drivers: Introduce variants of class_find_device()

[Suzuki K Poulose]

Now that we have generic helpers to match various generic
device attributes, provide wrappers to the class_find_device()
to lookup devices by individual properties. The new wrappers
except the lookup by devt, drops the "start" device pointer as
none of the existing users need it and the attributes are usually
unique. The idea is to stop the proliferation of custom match
functions to do generic attribute matching.

So now we have :

    class_find_device_by_name
    class_find_device_by_of_node
    class_find_device_by_fwnode
    class_find_device_by_devt

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-leds@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: Mark Brown <broonie@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Rosin <peda@axentia.se>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 include/linux/device.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/include/linux/device.h b/include/linux/device.h
index 8c8727b..4396edc 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -474,6 +474,57 @@ extern struct device *class_find_device(struct class *class,
 					struct device *start, const void *data,
 					int (*match)(struct device *, const void *));
 
+/**
+ * class_find_device_by_name - device iterator for locating a particular device
+ * of a specific name.
+ * @class: class type
+ * @name: name of the device to match
+ */
+static inline struct device *class_find_device_by_name(struct class *class,
+						       const char *name)
+{
+	return class_find_device(class, NULL, name, device_match_name);
+}
+
+/**
+ * class_find_device_by_of_node : device iterator for locating a particular device
+ * matching the of_node.
+ * @class: class type
+ * @np: of_node of the device to match.
+ */
+static inline struct device *
+class_find_device_by_of_node(struct class *class, const struct device_node *np)
+{
+	return class_find_device(class, NULL, np, device_match_of_node);
+}
+
+/**
+ * class_find_device_by_fwnode : device iterator for locating a particular device
+ * matching the fwnode.
+ * @class: class type
+ * @fwnode: fwnode of the device to match.
+ */
+static inline struct device *
+class_find_device_by_fwnode(struct class *class,
+			    const struct fwnode_handle *fwnode)
+{
+	return class_find_device(class, NULL, fwnode, device_match_fwnode);
+}
+
+/**
+ * class_find_device_by_devt : device iterator for locating a particular device
+ * matching the device type.
+ * @class: class type
+ * @start: device to start search from
+ * @devt: device type of the device to match.
+ */
+static inline struct device *class_find_device_by_devt(struct class *class,
+						       struct device *start,
+						       dev_t devt)
+{
+	return class_find_device(class, start, &devt, device_match_devt);
+}
+
 struct class_attribute {
 	struct attribute attr;
 	ssize_t (*show)(struct class *class, struct class_attribute *attr,
-- 
2.7.4

Re: [PATCH 10/13] drivers: Introduce variants of class_find_device()

[Greg KH]

On Wed, Jun 05, 2019 at 04:13:47PM +0100, Suzuki K Poulose wrote:
> +/**
> + * class_find_device_by_devt : device iterator for locating a particular device
> + * matching the device type.
> + * @class: class type
> + * @start: device to start search from
> + * @devt: device type of the device to match.
> + */
> +static inline struct device *class_find_device_by_devt(struct class *class,
> +						       struct device *start,
> +						       dev_t devt)
> +{
> +	return class_find_device(class, start, &devt, device_match_devt);
> +}

Still has the start parameter, despite the changelog saying it would not
:(

Re: [PATCH 10/13] drivers: Introduce variants of class_find_device()

[Suzuki K Poulose]

Hi Greg,

On 06/05/2019 05:14 PM, Greg KH wrote:
> On Wed, Jun 05, 2019 at 04:13:47PM +0100, Suzuki K Poulose wrote:
>> +/**
>> + * class_find_device_by_devt : device iterator for locating a particular device
>> + * matching the device type.
>> + * @class: class type
>> + * @start: device to start search from
>> + * @devt: device type of the device to match.
>> + */
>> +static inline struct device *class_find_device_by_devt(struct class *class,
>> +						       struct device *start,
>> +						       dev_t devt)
>> +{
>> +	return class_find_device(class, start, &devt, device_match_devt);
>> +}
> 
> Still has the start parameter, despite the changelog saying it would not
> :(
> 

Well, I kept the start parameter just for the _devt variants, as
mentioned in the changelog:

" The new wrappers except the lookup by devt, drops the "start" device 
pointer as none of the existing users need it and the attributes are 
usually unique. The idea is to stop the proliferation of custom match.."

Somehow I thought the dev_t may be duplicate for devices, which is why
I didn't change that alone. But that was silly of me to ignore the minor
number part. I will respin it fixing that.

Suzuki