net: pse-pd: Use named initializers for arrays of i2c_device_data

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.

---
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(-)

index 4a3c852780f5..49b1527829ad 100644
@@ -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);

index aa07ffbce54d..1845b9c51cf7 100644
@@ -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);
 

index d40cb35a2547..49d6389da067 100644
@@ -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

Thank you!

Best Regards,
Oleksij

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