[PATCH v3 0/2] i2c: core: Introduce i2c_client_get_device_id helper

[PATCH v3 0/2] i2c: core: Introduce i2c_client_get_device_id helper

[Angel Iglesias]

Introduces a new i2c helper to query driver match tables and recover the
identity of the bound device. This helper should help with the migration
of existing drivers to use the new i2c_driver .probe_new callback, which
does not provide the device id with the pointer to the driver data as the
previous .probe callback.

As part of the patchset, migrated the bmp280 IIO driver to .new_probe
callback using the new helper.

Changes from v2 --> v3:
* Update helper function doc comment dropping misleading sentence.

Changes from v1 --> v2:
* Add further clarification that the device queried needs to be bound to
  the driver.
* Drops extra newline after function return.
* Discard unrelated style changes.

Previous version:
 https://lore.kernel.org/all/cover.1667750698.git.ang.iglesiasg@gmail.com/

Angel Iglesias (2):
  i2c: core: Introduce i2c_client_get_device_id helper function
  iio: pressure: bmp280: convert to i2c's .probe_new()

 drivers/i2c/i2c-core-base.c       | 14 ++++++++++++++
 drivers/iio/pressure/bmp280-i2c.c |  6 +++---
 include/linux/i2c.h               |  1 +
 3 files changed, 18 insertions(+), 3 deletions(-)


base-commit: 474b4c719c40ded10b0b3450a396c0698e337802
-- 
2.38.1

[PATCH v3 1/2] i2c: core: Introduce i2c_client_get_device_id helper function

[Angel Iglesias]

Introduces new helper function to aid in .probe_new() refactors. In order
to use existing i2c_get_device_id() on the probe callback, the device
match table needs to be accessible in that function, which would require
bigger refactors in some drivers using the deprecated .probe callback.

This issue was discussed in more detail in the IIO mailing list.

Link: https://lore.kernel.org/all/20221023132302.911644-11-u.kleine-koenig@pengutronix.de/
Suggested-by: Nuno Sá <noname.nuno@gmail.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index b4edf10e8fd0..9aa7b9d9a485 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -2236,6 +2236,20 @@ int i2c_get_device_id(const struct i2c_client *client,
 }
 EXPORT_SYMBOL_GPL(i2c_get_device_id);
 
+/**
+ * i2c_client_get_device_id - get the driver match table entry of a device
+ * @client: the device to query. The device must be bound to a driver
+ *
+ * Returns a pointer to the matching entry if found, NULL otherwise.
+ */
+const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
+{
+	const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
+
+	return i2c_match_id(drv->id_table, client);
+}
+EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
+
 /* ----------------------------------------------------
  * the i2c address scanning function
  * Will not work for 10-bit addresses!
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index f7c49bbdb8a1..d84e0e99f084 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -189,6 +189,7 @@ s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
 					      u8 *values);
 int i2c_get_device_id(const struct i2c_client *client,
 		      struct i2c_device_identity *id);
+const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client);
 #endif /* I2C */
 
 /**
-- 
2.38.1

Re: [PATCH v3 1/2] i2c: core: Introduce i2c_client_get_device_id helper function

[Wolfram Sang]

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On Sun, Nov 13, 2022 at 06:46:30PM +0100, Angel Iglesias wrote:
> Introduces new helper function to aid in .probe_new() refactors. In order
> to use existing i2c_get_device_id() on the probe callback, the device
> match table needs to be accessible in that function, which would require
> bigger refactors in some drivers using the deprecated .probe callback.
> 
> This issue was discussed in more detail in the IIO mailing list.
> 
> Link: https://lore.kernel.org/all/20221023132302.911644-11-u.kleine-koenig@pengutronix.de/
> Suggested-by: Nuno Sá <noname.nuno@gmail.com>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Immutable branch here:

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/client_device_id_helper-immutable

I merged this branch also into i2c/for-mergewindow.

Thank you, everyone!


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Re: [PATCH v3 1/2] i2c: core: Introduce i2c_client_get_device_id helper function

[Jonathan Cameron]

On Mon, 14 Nov 2022 20:53:20 +0100
Wolfram Sang <wsa@kernel.org> wrote:

> On Sun, Nov 13, 2022 at 06:46:30PM +0100, Angel Iglesias wrote:
> > Introduces new helper function to aid in .probe_new() refactors. In order
> > to use existing i2c_get_device_id() on the probe callback, the device
> > match table needs to be accessible in that function, which would require
> > bigger refactors in some drivers using the deprecated .probe callback.
> > 
> > This issue was discussed in more detail in the IIO mailing list.
> > 
> > Link: https://lore.kernel.org/all/20221023132302.911644-11-u.kleine-koenig@pengutronix.de/
> > Suggested-by: Nuno Sá <noname.nuno@gmail.com>
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Suggested-by: Jonathan Cameron <jic23@kernel.org>
> > Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>  
> 
> Immutable branch here:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/client_device_id_helper-immutable
> 
> I merged this branch also into i2c/for-mergewindow.
> 
> Thank you, everyone!
> 

Excellent.  Merged that into iio.git/togreg and applied patch 2.

Thanks,

Jonathan

Re: [PATCH v3 1/2] i2c: core: Introduce i2c_client_get_device_id helper function

[Jonathan Cameron]

On Sun, 13 Nov 2022 18:46:30 +0100
Angel Iglesias <ang.iglesiasg@gmail.com> wrote:

> Introduces new helper function to aid in .probe_new() refactors. In order
> to use existing i2c_get_device_id() on the probe callback, the device
> match table needs to be accessible in that function, which would require
> bigger refactors in some drivers using the deprecated .probe callback.
> 
> This issue was discussed in more detail in the IIO mailing list.
> 
> Link: https://lore.kernel.org/all/20221023132302.911644-11-u.kleine-koenig@pengutronix.de/
> Suggested-by: Nuno Sá <noname.nuno@gmail.com>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> 
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index b4edf10e8fd0..9aa7b9d9a485 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -2236,6 +2236,20 @@ int i2c_get_device_id(const struct i2c_client *client,
>  }
>  EXPORT_SYMBOL_GPL(i2c_get_device_id);
>  
> +/**
> + * i2c_client_get_device_id - get the driver match table entry of a device
> + * @client: the device to query. The device must be bound to a driver
> + *
> + * Returns a pointer to the matching entry if found, NULL otherwise.
> + */
> +const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
> +{
> +	const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
> +
> +	return i2c_match_id(drv->id_table, client);
> +}
> +EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
> +
>  /* ----------------------------------------------------
>   * the i2c address scanning function
>   * Will not work for 10-bit addresses!
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index f7c49bbdb8a1..d84e0e99f084 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -189,6 +189,7 @@ s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
>  					      u8 *values);
>  int i2c_get_device_id(const struct i2c_client *client,
>  		      struct i2c_device_identity *id);
> +const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client);
>  #endif /* I2C */
>  
>  /**

[PATCH v3 2/2] iio: pressure: bmp280: convert to i2c's .probe_new()

[Angel Iglesias]

Use i2c_client_get_device_id() to get the i2c_device_id* parameter in the
.new_probe() callback.

Signed-off-by: Angel Iglesias <ang.iglesiasg@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/pressure/bmp280-i2c.c b/drivers/iio/pressure/bmp280-i2c.c
index 0c27211f3ea0..14eab086d24a 100644
--- a/drivers/iio/pressure/bmp280-i2c.c
+++ b/drivers/iio/pressure/bmp280-i2c.c
@@ -5,11 +5,11 @@
 
 #include "bmp280.h"
 
-static int bmp280_i2c_probe(struct i2c_client *client,
-			    const struct i2c_device_id *id)
+static int bmp280_i2c_probe(struct i2c_client *client)
 {
 	struct regmap *regmap;
 	const struct regmap_config *regmap_config;
+	const struct i2c_device_id *id = i2c_client_get_device_id(client);
 
 	switch (id->driver_data) {
 	case BMP180_CHIP_ID:
@@ -65,7 +65,7 @@ static struct i2c_driver bmp280_i2c_driver = {
 		.of_match_table = bmp280_of_i2c_match,
 		.pm = pm_ptr(&bmp280_dev_pm_ops),
 	},
-	.probe		= bmp280_i2c_probe,
+	.probe_new	= bmp280_i2c_probe,
 	.id_table	= bmp280_i2c_id,
 };
 module_i2c_driver(bmp280_i2c_driver);
-- 
2.38.1