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* [PATCH v1 0/2] iio: Rework i2c_device_id initialisation
@ 2026-05-12 12:50 Uwe Kleine-König (The Capable Hub)
  2026-05-12 12:50 ` [PATCH v1 1/2] iio: Drop unused driver_data in four i2c drivers Uwe Kleine-König (The Capable Hub)
  2026-05-12 12:50 ` [PATCH v1 2/2] iio: Initialize i2c_device_id arrays using member names Uwe Kleine-König (The Capable Hub)
  0 siblings, 2 replies; 6+ messages in thread
From: Uwe Kleine-König (The Capable Hub) @ 2026-05-12 12:50 UTC (permalink / raw)
  To: Jonathan Cameron
  Cc: Matteo Martelli, David Lechner, Nuno Sá, Andy Shevchenko,
	Mikael Gonella-Bolduc, Linus Walleij, Sakari Ailus, linux-iio,
	linux-i2c, linux-kernel, Lars-Peter Clausen, Michael Hennerich,
	Puranjay Mohan, Marcelo Schmitt, Antoniu Miclaus,
	Ramona Gradinariu, Ariana Lazar, Alex Lanzano,
	Jean-Baptiste Maneyrol, Remi Buisson, Lorenzo Bianconi,
	Christian Eggers, Tomasz Duszynski, Javier Carrasco,
	Andreas Klinger, Waqar Hameed, Sebastian Andrzej Siewior,
	Gustavo Vaz, Dixit Parmar, Bartosz Golaszewski, Guenter Roeck,
	Chuang Zhu, Kyle Hsieh, Oleksij Rempel, Sander Vanheule,
	Romain Gantois, David Jander, Kurt Borja, Tomas Borquez,
	Matti Vaittinen, chuguangqing, Shi Hao, Erikas Bitovtas,
	Marcus Folkesson

Hello,

this series is a preparation for 

	diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
	index 23ff24080dfd..aebd3a5e90af 100644
	--- a/include/linux/mod_devicetable.h
	+++ b/include/linux/mod_devicetable.h
	@@ -477,7 +477,11 @@ struct rpmsg_device_id {
	 
	 struct i2c_device_id {
		char name[I2C_NAME_SIZE];
	-	kernel_ulong_t driver_data;	/* Data private to the driver */
	+	union {
	+		/* Data private to the driver */
	+		kernel_ulong_t driver_data;
	+		const void *driver_data_ptr;
	+	};
	 };

and this requires that .driver_data is assigned via a named initializer
for static data. This requirement isn't a bad one because named
initializers are also much better readable than list initializers.

Once the union is in place, this allows changes like:
 
	diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
	index 8a082ff034dd..b2aac7348d22 100644
	--- a/drivers/iio/accel/kxcjk-1013.c
	+++ b/drivers/iio/accel/kxcjk-1013.c
	@@ -1429,7 +1429,7 @@ static int kxcjk1013_probe(struct i2c_client *client)
	 
		if (id) {
			name = id->name;
	-		data->info = (const struct kx_chipset_info *)(id->driver_data);
	+		data->info = id->driver_data_ptr;
		} else {
			name = iio_get_acpi_device_name_and_data(&client->dev, &ddata);
			data->info = ddata;
	@@ -1630,11 +1630,11 @@ static const struct dev_pm_ops kxcjk1013_pm_ops = {
	 };
	 
	 static const struct i2c_device_id kxcjk1013_id[] = {
	-	{ .name = "kxcjk1013", .driver_data = (kernel_ulong_t)&kxcjk1013_info },
	-	{ .name = "kxcj91008", .driver_data = (kernel_ulong_t)&kxcj91008_info },
	-	{ .name = "kxtj21009", .driver_data = (kernel_ulong_t)&kxtj21009_info },
	-	{ .name = "kxtf9", .driver_data = (kernel_ulong_t)&kxtf9_info },
	-	{ .name = "kx023-1025", .driver_data = (kernel_ulong_t)&kx0231025_info },
	+	{ .name = "kxcjk1013", .driver_data_ptr = &kxcjk1013_info },
	+	{ .name = "kxcj91008", .driver_data_ptr = &kxcj91008_info },
	+	{ .name = "kxtj21009", .driver_data_ptr = &kxtj21009_info },
	+	{ .name = "kxtf9", .driver_data_ptr = &kxtf9_info },
	+	{ .name = "kx023-1025", .driver_data_ptr = &kx0231025_info },
		{ }
	 };
	 MODULE_DEVICE_TABLE(i2c, kxcjk1013_id);

that is an improvement for readability (again!) and it keeps some
properties of the pointers (here: being const) without having to pay
attention for that. (I didn't spot a driver that doesn't have that const
on casting back in drivers/iio, but other subsystems will benefit here,
too.)

My additional motivation for this effort is CHERI[1]. This is a hardware
extension that uses 128 bit pointers but unsigned long is still 64 bit.
So with CHERI you cannot store pointers in unsigned long variables.

The first patch drops a few unused assignments to .driver_data (which is
still better than assigning the values by name) and the second converts
all iio drivers with driver_data to use named initializers.

Best regards
Uwe

[1] https://cheri-alliance.org/discover-cheri/
    https://lwn.net/Articles/1037974/

Uwe Kleine-König (The Capable Hub) (2):
  iio: Drop unused driver_data in four i2c drivers
  iio: Initialize i2c_device_id arrays using member names

 drivers/iio/accel/adxl345_i2c.c               |  4 +-
 drivers/iio/accel/adxl355_i2c.c               |  4 +-
 drivers/iio/accel/adxl372_i2c.c               |  4 +-
 drivers/iio/accel/adxl380_i2c.c               |  8 +-
 drivers/iio/accel/bma180.c                    | 10 +-
 drivers/iio/accel/bmc150-accel-i2c.c          | 20 ++--
 drivers/iio/accel/bmi088-accel-i2c.c          |  6 +-
 drivers/iio/accel/da280.c                     |  6 +-
 drivers/iio/accel/fxls8962af-i2c.c            |  8 +-
 drivers/iio/accel/kxcjk-1013.c                | 10 +-
 drivers/iio/accel/mc3230.c                    |  4 +-
 drivers/iio/accel/mma8452.c                   | 12 +--
 drivers/iio/adc/ad7091r5.c                    |  2 +-
 drivers/iio/adc/ad799x.c                      | 16 ++--
 drivers/iio/adc/ina2xx-adc.c                  | 12 +--
 drivers/iio/adc/ltc2309.c                     |  4 +-
 drivers/iio/adc/ltc2471.c                     |  4 +-
 drivers/iio/adc/ltc2497.c                     |  4 +-
 drivers/iio/adc/max34408.c                    |  4 +-
 drivers/iio/adc/mcp3422.c                     | 16 ++--
 drivers/iio/adc/pac1921.c                     |  2 +-
 drivers/iio/adc/ti-adc081c.c                  |  6 +-
 drivers/iio/adc/ti-ads1015.c                  |  6 +-
 drivers/iio/adc/ti-ads7138.c                  |  4 +-
 drivers/iio/cdc/ad7150.c                      |  6 +-
 drivers/iio/cdc/ad7746.c                      |  6 +-
 drivers/iio/chemical/atlas-ezo-sensor.c       |  6 +-
 drivers/iio/chemical/atlas-sensor.c           | 10 +-
 drivers/iio/chemical/sgp30.c                  |  4 +-
 drivers/iio/chemical/vz89x.c                  |  4 +-
 drivers/iio/dac/ad5064.c                      | 94 +++++++++----------
 drivers/iio/dac/ad5380.c                      | 32 +++----
 drivers/iio/dac/ad5446-i2c.c                  | 12 +--
 drivers/iio/dac/ad5696-i2c.c                  | 32 +++----
 drivers/iio/dac/ds4424.c                      |  8 +-
 drivers/iio/dac/max517.c                      | 10 +-
 drivers/iio/dac/max5821.c                     |  2 +-
 drivers/iio/dac/mcp4725.c                     |  4 +-
 drivers/iio/dac/mcp47feb02.c                  | 48 +++++-----
 drivers/iio/dac/ti-dac5571.c                  | 22 ++---
 drivers/iio/health/max30102.c                 |  6 +-
 drivers/iio/humidity/ens210.c                 | 12 +--
 drivers/iio/humidity/htu21.c                  |  4 +-
 drivers/iio/imu/bmi270/bmi270_i2c.c           |  4 +-
 .../iio/imu/inv_icm42600/inv_icm42600_i2c.c   | 14 +--
 .../iio/imu/inv_icm45600/inv_icm45600_i2c.c   | 16 ++--
 drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c     | 36 +++----
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c   | 48 +++++-----
 drivers/iio/light/apds9160.c                  |  2 +-
 drivers/iio/light/as73211.c                   |  4 +-
 drivers/iio/light/bh1750.c                    | 10 +-
 drivers/iio/light/isl29018.c                  |  6 +-
 drivers/iio/light/ltr501.c                    |  8 +-
 drivers/iio/light/opt3001.c                   |  4 +-
 drivers/iio/light/opt4001.c                   |  4 +-
 drivers/iio/light/si1145.c                    | 14 +--
 drivers/iio/light/tsl2563.c                   |  8 +-
 drivers/iio/light/tsl2583.c                   |  6 +-
 drivers/iio/light/tsl2772.c                   | 22 ++---
 drivers/iio/light/vcnl4000.c                  | 14 +--
 drivers/iio/light/veml6030.c                  |  6 +-
 drivers/iio/magnetometer/ak8975.c             | 14 +--
 drivers/iio/magnetometer/hmc5843_i2c.c        |  8 +-
 drivers/iio/magnetometer/yamaha-yas530.c      |  8 +-
 drivers/iio/potentiometer/ad5272.c            | 10 +-
 drivers/iio/potentiometer/ds1803.c            |  8 +-
 drivers/iio/potentiometer/tpl0102.c           |  8 +-
 drivers/iio/pressure/abp060mg.c               | 90 +++++++++++-------
 drivers/iio/pressure/bmp280-i2c.c             | 12 +--
 drivers/iio/pressure/dlhl60d.c                |  4 +-
 drivers/iio/pressure/ms5611_i2c.c             |  4 +-
 drivers/iio/pressure/ms5637.c                 |  8 +-
 drivers/iio/pressure/st_pressure_i2c.c        | 16 ++--
 drivers/iio/proximity/aw96103.c               |  4 +-
 drivers/iio/proximity/srf08.c                 |  6 +-
 drivers/iio/proximity/sx9310.c                |  4 +-
 drivers/iio/proximity/sx9324.c                |  2 +-
 drivers/iio/proximity/sx9360.c                |  2 +-
 drivers/iio/temperature/tmp117.c              |  4 +-
 79 files changed, 479 insertions(+), 457 deletions(-)


base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
-- 
2.47.3


^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-05-12 14:01 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-12 12:50 [PATCH v1 0/2] iio: Rework i2c_device_id initialisation Uwe Kleine-König (The Capable Hub)
2026-05-12 12:50 ` [PATCH v1 1/2] iio: Drop unused driver_data in four i2c drivers Uwe Kleine-König (The Capable Hub)
2026-05-12 14:01   ` Jonathan Cameron
2026-05-12 12:50 ` [PATCH v1 2/2] iio: Initialize i2c_device_id arrays using member names Uwe Kleine-König (The Capable Hub)
2026-05-12 13:16   ` Linus Walleij
2026-05-12 14:00   ` Jonathan Cameron

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