Re: [PATCH] hwmon: acpi_power_meter: use named initializers for acpi_device_id

[Guenter Roeck]

On 9/15/26 06:40, Pawel Zalewski wrote:
> Use a designated initializer for the acpi_device_id fields which makes the
> code more readable and consistent with how lists are initialized in the
> rest of the kernel code base. Also drop explicitly setting fields to 0
> where it is redundant.
>
> Unify the list terminator to have a single space between the brackets and
> no trailing comma.
>
> Signed-off-by: Pawel Zalewski <pzalewski@xxxxxxxxxxxxxxxxxxxx>
> ---
> This series is converting lists that contain the acpi_device_id struct,
> which is defined in the include/linux/device-id/acpi.h to make use of named
> initializers (which they do not use currently). This work is part of the on
> going effort in the kernel associated with device-ids [1]
>
> The plan is to convert acpi_device_id::driver_data to have an anonymous
> union, similarly to what was introduced for PCI and I2C device ID tables.
> The goal is to increase type-safety (most of the existing casts are gone),
> to improve readability and to make use intent a bit more clear:
>
> ```
> union {
> 	kernel_ulong_t driver_data;
> 	const void *driver_data_ptr;
> }
> ```
>
> But for that to work all lists containing the structs need to use named
> initializers first to avoid triggering -Wmissing-braces. I already have
> patches that implement this and touching a lot of kernel subsystmes that
> use the acpi_device_id struct and that list keeps on growing. Therefore,
> I have decided to split the series per every subsystem into:
> - pre-clean-ups that convert the lists to use named initializers
>    (which is this series)
> - actual implementations that make some of the modules use the new
>    driver_data_ptr member
>
> That way the task can be fragmented into manageable and independent chunks
> of work and makes this effort easier to review.
>
> Tested builds on x86-64 in Yocto using 7.3-rc3.
>
> [1] https://lore.kernel.org/all/cover.1780048925.git.u.kleine-koenig@xxxxxxxxxxxx/
> ---
>   drivers/hwmon/acpi_power_meter.c | 4 ++--
>   drivers/hwmon/asus_atk0110.c     | 4 ++--
>   drivers/hwmon/pt5161l.c          | 4 ++--
>   drivers/hwmon/xgene-hwmon.c      | 6 +++---

The subject and patch description fail to mention that it touches four
drivers and not just acpi_power_meter. Do not sneak in undocumented changes,
please.

>   4 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c
> index 8a539e8d1334..d8e871509405 100644
> --- a/drivers/hwmon/acpi_power_meter.c
> +++ b/drivers/hwmon/acpi_power_meter.c
> @@ -54,8 +54,8 @@ static int can_cap_in_hardware(void)
>   }
>   
>   static const struct acpi_device_id power_meter_ids[] = {
> -	{"ACPI000D", 0},
> -	{"", 0},
> +	{ .id = "ACPI000D" },
> +	{ }

This is a functional change. It replaces a pointer to an empty string
with a NULL pointer. I don't know ACPI expectations (drivers use both),
but the change needs to be explained.

>   };
>   MODULE_DEVICE_TABLE(acpi, power_meter_ids);
>   
> diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c
> index 92afb64c09df..868c4e14d26a 100644
> --- a/drivers/hwmon/asus_atk0110.c
> +++ b/drivers/hwmon/asus_atk0110.c
> @@ -141,8 +141,8 @@ typedef ssize_t (*sysfs_show_func)(struct device *dev,
>   			struct device_attribute *attr, char *buf);
>   
>   static const struct acpi_device_id atk_ids[] = {
> -	{ATK_HID, 0},
> -	{"", 0},
> +	{ .id = ATK_HID },
> +	{ }
>   };
>   MODULE_DEVICE_TABLE(acpi, atk_ids);
>   
> diff --git a/drivers/hwmon/pt5161l.c b/drivers/hwmon/pt5161l.c
> index 2b408a69b085..1638f54f8eae 100644
> --- a/drivers/hwmon/pt5161l.c
> +++ b/drivers/hwmon/pt5161l.c
> @@ -611,8 +611,8 @@ static const struct of_device_id __maybe_unused pt5161l_of_match[] = {
>   MODULE_DEVICE_TABLE(of, pt5161l_of_match);
>   
>   static const struct acpi_device_id __maybe_unused pt5161l_acpi_match[] = {
> -	{ "PT5161L", 0 },
> -	{},
> +	{ .id = "PT5161L" },
> +	{ }
>   };
>   MODULE_DEVICE_TABLE(acpi, pt5161l_acpi_match);
>   
> diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
> index 38b140c23c88..eebbb741deac 100644
> --- a/drivers/hwmon/xgene-hwmon.c
> +++ b/drivers/hwmon/xgene-hwmon.c
> @@ -595,9 +595,9 @@ static void xgene_hwmon_tx_done(struct mbox_client *cl, void *msg, int ret)
>   
>   #ifdef CONFIG_ACPI
>   static const struct acpi_device_id xgene_hwmon_acpi_match[] = {
> -	{"APMC0D29", XGENE_HWMON_V 1},
> -	{"APMC0D8A", XGENE_HWMON_V2},
> -	{},
> +	{ .id = "APMC0D29", .driver_data = XGENE_HWMON_V1 },
> +	{ .id = "APMC0D8A", .driver_data = XGENE_HWMON_V2 },
> +	{ }
>   };
>   MODULE_DEVICE_TABLE(acpi, xgene_hwmon_acpi_match);
>   #endif
>
> ---
> base-commit: 587858367581b9c55c3690f4e63382ad622719d4
> change-id: 20260915-acpi-hwmon-12061c767bc7
>
> Best regards,
> --
> Pawel Zalewski <pzalewski@xxxxxxxxxxxxxxxxxxxx>