[PATCH net-next v1] net: pse-pd: Use named initializers for arrays of i2c_device_data

[PATCH net-next v1] net: pse-pd: Use named initializers for arrays of i2c_device_data

[Uwe Kleine-König (The Capable Hub)]

While being less compact, using named initializers allows to more easily
see which members of the structs are assigned which value without having
to lookup the declaration of the struct. And it's also more robust
against changes to the struct definition.

The mentioned robustness is relevant for a planned change to struct
i2c_device_id that replaces .driver_data by an anonymous union.

While touching all these arrays, unify usage of whitespace in the list
terminator.

This patch doesn't modify the compiled arrays, only their representation
in source form benefits. The former was confirmed with x86 and arm64
builds.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
---
Hello,

the mentioned change to i2c_device_id is the following:

	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;
	+	};
	 };

	 /* pci_epf */

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.

The union added to struct i2c_device_id enables further cleanups like:

	diff --git a/drivers/regulator/ad5398.c b/drivers/regulator/ad5398.c
	index 0123ca8157a8..dfb0b07500a7 100644
	--- a/drivers/regulator/ad5398.c
	+++ b/drivers/regulator/ad5398.c
	@@ -207,8 +207,8 @@ struct ad5398_current_data_format {
	 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};

	 static const struct i2c_device_id ad5398_id[] = {
	-	{ .name = "ad5398", .driver_data = (kernel_ulong_t)&df_10_4_120 },
	-	{ .name = "ad5821", .driver_data = (kernel_ulong_t)&df_10_4_120 },
	+	{ .name = "ad5398", .driver_data_ptr = &df_10_4_120 },
	+	{ .name = "ad5821", .driver_data_ptr = &df_10_4_120 },
	 	{ }
	 };
	 MODULE_DEVICE_TABLE(i2c, ad5398_id);
	@@ -219,8 +219,7 @@ static int ad5398_probe(struct i2c_client *client)
	 	struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
	 	struct regulator_config config = { };
	 	struct ad5398_chip_info *chip;
	-	const struct ad5398_current_data_format *df =
	-	                (struct ad5398_current_data_format *)id->driver_data;
	+	const struct ad5398_current_data_format *df = id->driver_data;

	 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
	 	if (!chip)

that are 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 find a pse-pd driver that benefits, so
this is "only" a regulator driver example.)

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.

Best regards
Uwe

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

 drivers/net/pse-pd/pd692x0.c  | 2 +-
 drivers/net/pse-pd/si3474.c   | 4 ++--
 drivers/net/pse-pd/tps23881.c | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/pse-pd/pd692x0.c b/drivers/net/pse-pd/pd692x0.c
index 4a3c852780f5..49b1527829ad 100644
--- a/drivers/net/pse-pd/pd692x0.c
+++ b/drivers/net/pse-pd/pd692x0.c
@@ -1853,7 +1853,7 @@ static void pd692x0_i2c_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id pd692x0_id[] = {
-	{ PD692X0_PSE_NAME },
+	{ .name = PD692X0_PSE_NAME },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pd692x0_id);
diff --git a/drivers/net/pse-pd/si3474.c b/drivers/net/pse-pd/si3474.c
index aa07ffbce54d..1845b9c51cf7 100644
--- a/drivers/net/pse-pd/si3474.c
+++ b/drivers/net/pse-pd/si3474.c
@@ -550,8 +550,8 @@ static int si3474_i2c_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id si3474_id[] = {
-	{ "si3474" },
-	{}
+	{ .name = "si3474" },
+	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si3474_id);
 
diff --git a/drivers/net/pse-pd/tps23881.c b/drivers/net/pse-pd/tps23881.c
index d40cb35a2547..49d6389da067 100644
--- a/drivers/net/pse-pd/tps23881.c
+++ b/drivers/net/pse-pd/tps23881.c
@@ -1528,8 +1528,8 @@ static int tps23881_i2c_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id tps23881_id[] = {
-	{ "tps23881", .driver_data = (kernel_ulong_t)&tps23881_info[TPS23881] },
-	{ "tps23881b", .driver_data = (kernel_ulong_t)&tps23881_info[TPS23881B] },
+	{ .name = "tps23881", .driver_data = (kernel_ulong_t)&tps23881_info[TPS23881] },
+	{ .name = "tps23881b", .driver_data = (kernel_ulong_t)&tps23881_info[TPS23881B] },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, tps23881_id);

base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
-- 
2.47.3

Re: [PATCH net-next v1] net: pse-pd: Use named initializers for arrays of i2c_device_data

[Oleksij Rempel]

On Tue, May 19, 2026 at 04:01:01PM +0200, Uwe Kleine-König (The Capable Hub) wrote:
> While being less compact, using named initializers allows to more easily
> see which members of the structs are assigned which value without having
> to lookup the declaration of the struct. And it's also more robust
> against changes to the struct definition.
> 
> The mentioned robustness is relevant for a planned change to struct
> i2c_device_id that replaces .driver_data by an anonymous union.
> 
> While touching all these arrays, unify usage of whitespace in the list
> terminator.
> 
> This patch doesn't modify the compiled arrays, only their representation
> in source form benefits. The former was confirmed with x86 and arm64
> builds.
> 
> Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>

Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>

Thank you!

Best Regards,
Oleksij
-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH net-next v1] net: pse-pd: Use named initializers for arrays of i2c_device_data

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 19 May 2026 16:01:01 +0200 you wrote:
> While being less compact, using named initializers allows to more easily
> see which members of the structs are assigned which value without having
> to lookup the declaration of the struct. And it's also more robust
> against changes to the struct definition.
> 
> The mentioned robustness is relevant for a planned change to struct
> i2c_device_id that replaces .driver_data by an anonymous union.
> 
> [...]

Here is the summary with links:
  - [net-next,v1] net: pse-pd: Use named initializers for arrays of i2c_device_data
    https://git.kernel.org/netdev/net-next/c/f186a3ae9061

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html