Re: [PATCH v4 13/15] acpi: Add acpi_dev_get_next_match_dev() and helper macro

[Andy Shevchenko]

On Sun, Jan 03, 2021 at 11:12:33PM +0000, Daniel Scally wrote:
> To ensure we handle situations in which multiple sensors of the same
> model (and therefore _HID) are present in a system, we need to be able
> to iterate over devices matching a known _HID but unknown _UID and _HRV
>  - add acpi_dev_get_next_match_dev() to accommodate that possibility and
> change acpi_dev_get_first_match_dev() to simply call the new function
> with a NULL starting point. Add an iterator macro for convenience.

I guess we need Rafael's blessing on this.

> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Reviewed-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
> ---
> Changes in v4:
> 
> 	- None
> 
>  drivers/acpi/utils.c    | 30 ++++++++++++++++++++++++++----
>  include/acpi/acpi_bus.h |  7 +++++++
>  2 files changed, 33 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> index d5411a166685..ddca1550cce6 100644
> --- a/drivers/acpi/utils.c
> +++ b/drivers/acpi/utils.c
> @@ -843,12 +843,13 @@ bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
>  EXPORT_SYMBOL(acpi_dev_present);
>  
>  /**
> - * acpi_dev_get_first_match_dev - Return the first match of ACPI device
> + * acpi_dev_get_next_match_dev - Return the next match of ACPI device
> + * @adev: Pointer to the previous acpi_device matching this @hid, @uid and @hrv
>   * @hid: Hardware ID of the device.
>   * @uid: Unique ID of the device, pass NULL to not check _UID
>   * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
>   *
> - * Return the first match of ACPI device if a matching device was present
> + * Return the next match of ACPI device if another matching device was present
>   * at the moment of invocation, or NULL otherwise.
>   *
>   * The caller is responsible to call put_device() on the returned device.
> @@ -856,8 +857,9 @@ EXPORT_SYMBOL(acpi_dev_present);
>   * See additional information in acpi_dev_present() as well.
>   */
>  struct acpi_device *
> -acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
> +acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv)
>  {
> +	struct device *start = adev ? &adev->dev : NULL;
>  	struct acpi_dev_match_info match = {};
>  	struct device *dev;
>  
> @@ -865,9 +867,29 @@ acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
>  	match.uid = uid;
>  	match.hrv = hrv;
>  
> -	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
> +	dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb);
>  	return dev ? to_acpi_device(dev) : NULL;
>  }
> +EXPORT_SYMBOL(acpi_dev_get_next_match_dev);
> +
> +/**
> + * acpi_dev_get_first_match_dev - Return the first match of ACPI device
> + * @hid: Hardware ID of the device.
> + * @uid: Unique ID of the device, pass NULL to not check _UID
> + * @hrv: Hardware Revision of the device, pass -1 to not check _HRV
> + *
> + * Return the first match of ACPI device if a matching device was present
> + * at the moment of invocation, or NULL otherwise.
> + *
> + * The caller is responsible to call put_device() on the returned device.
> + *
> + * See additional information in acpi_dev_present() as well.
> + */
> +struct acpi_device *
> +acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
> +{
> +	return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv);
> +}
>  EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
>  
>  /*
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index a3abcc4b7d9f..0a028ba967d3 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -688,9 +688,16 @@ static inline bool acpi_device_can_poweroff(struct acpi_device *adev)
>  
>  bool acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *uid2);
>  
> +struct acpi_device *
> +acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv);
>  struct acpi_device *
>  acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv);
>  
> +#define for_each_acpi_dev_match(adev, hid, uid, hrv)			\
> +	for (adev = acpi_dev_get_first_match_dev(hid, uid, hrv);	\
> +	     adev;							\
> +	     adev = acpi_dev_get_next_match_dev(adev, hid, uid, hrv))
> +
>  static inline void acpi_dev_put(struct acpi_device *adev)
>  {
>  	put_device(&adev->dev);
> -- 
> 2.25.1
> 

-- 
With Best Regards,
Andy Shevchenko