[v6,0/4] Extend device_get_match_data() to struct bus_type

This patch series extend device_get_match_data() to struct bus_type,
so that buses like I2C can get matched data.

There is a plan to replace i2c_get_match_data()->device_get_match_data()
later, once this patch hits mainline as it is redundant.

v5->v6:
 * Cced linux-rtc and linux-iio as these subsytems uses i2c_get_match_
   data() and this function become redundant once this patch series hits
   mainline.
 * Added Rb tag from Sakari for patch#1.
 * Moved patch#3 from v5 to patch#2 and patch#2 from v5 to patch#4.
 * Added Rb tag from Andy for patch#2
 * Separate patch#3 to prepare for better difference for
   i2c_match_id() changes.
 * Merged patch#4 from v5 with patch#4.
v4->v5:
 * Added const struct device_driver variable 'drv' in i2c_device_get_match
   _data().
 * For code readability and maintenance perspective, added separate NULL
   check for drv and client variable and added comment for NULL check for
   drv variable.
 * Created separate patch for converting i2c_of_match_device_sysfs() to
   non-static.
 * Removed export symbol for i2c_of_match_device_sysfs().
 * Replaced 'dev->driver'->'drv'.
 * Replaced return value data->NULL to avoid (potentially) stale pointers,
   if there is no match.

v3->v4:
 * Documented corner case for device_get_match_data()
 * Dropped struct i2c_driver parameter from i2c_get_match_data_helper()
 * Split I2C sysfs handling in separate patch(patch#3)
 * Added space after of_device_id for i2c_of_match_device_sysfs()
 * Added const parameter for struct i2c_client, to prevent overriding it's
   pointer.
 * Moved declaration from public i2c.h->i2c-core.h
v2->v3:
 * Added Rb tag from Andy for patch#1.
 * Extended to support i2c_of_match_device() as suggested by Andy.
 * Changed i2c_of_match_device_sysfs() as non-static function as it is
   needed for i2c_device_get_match_data().
 * Added a TODO comment to use i2c_verify_client() when it accepts const
   pointer.
 * Added multiple returns to make code path for device_get_match_data()
   faster in i2c_get_match_data().
RFC v1->v2:
 * Replaced "Signed-off-by"->"Suggested-by" tag for Dmitry.
 * Documented device_get_match_data().
 * Added multiple returns to make code path for generic fwnode-based
   lookup faster.
 * Fixed build warnings reported by kernel test robot <lkp@intel.com>
 * Added const qualifier to return type and parameter struct i2c_driver
   in i2c_get_match_data_helper().
 * Added const qualifier to struct i2c_driver in i2c_get_match_data()
 * Dropped driver variable from i2c_device_get_match_data()
 * Replaced to_i2c_client with logic for assigning verify_client as it
   returns non const pointer.

Biju Das (4):
  drivers: fwnode: Extend device_get_match_data() to struct bus_type
  i2c: i2c-core-of: Convert i2c_of_match_device_sysfs() to non-static
  i2c: Enhance i2c_get_match_data()
  i2c: Add i2c_device_get_match_data() callback

 drivers/base/property.c     | 27 ++++++++++++++++-
 drivers/i2c/i2c-core-base.c | 58 +++++++++++++++++++++++++++++++------
 drivers/i2c/i2c-core-of.c   |  4 +--
 drivers/i2c/i2c-core.h      |  9 ++++++
 include/linux/device/bus.h  |  3 ++
 5 files changed, 89 insertions(+), 12 deletions(-)