Re: [PATCH 1/2] ASoC: Intel: maxim-common: get codec number from ACPI

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 7/20/23 11:26, Brent Lu wrote:
> Implement a helper function to get number of codecs from ACPI
> subsystem to remove the need of quirk flag in machine driver.
> 
> Signed-off-by: Brent Lu <brent.lu@intel.com>
> ---
>  sound/soc/intel/boards/sof_maxim_common.c | 174 +++++++++++++---------
>  sound/soc/intel/boards/sof_maxim_common.h |  21 ++-
>  2 files changed, 113 insertions(+), 82 deletions(-)
> 
> diff --git a/sound/soc/intel/boards/sof_maxim_common.c b/sound/soc/intel/boards/sof_maxim_common.c
> index 112e89951da0..f8b44a81fec1 100644
> --- a/sound/soc/intel/boards/sof_maxim_common.c
> +++ b/sound/soc/intel/boards/sof_maxim_common.c
> @@ -4,6 +4,7 @@
>  #include <linux/module.h>
>  #include <linux/string.h>
>  #include <sound/pcm.h>
> +#include <sound/pcm_params.h>
>  #include <sound/soc.h>
>  #include <sound/soc-acpi.h>
>  #include <sound/soc-dai.h>
> @@ -11,6 +12,21 @@
>  #include <uapi/sound/asound.h>
>  #include "sof_maxim_common.h"
>  
> +/* helper function to get the number of specific codec */
> +static int get_num_codecs(const char *hid)
> +{
> +	struct acpi_device *adev = NULL;
> +	int dev_num = 0;
> +
> +	do {
> +		adev = acpi_dev_get_next_match_dev(adev, hid, NULL, -1);

Humm, I am a bit worried about reference counts.

See
https://elixir.bootlin.com/linux/latest/source/drivers/acpi/utils.c#L916,
it's not clear to me where the get() is done.

Adding Andy to make sure this is done right.

> +		if (adev)
> +			dev_num++;
> +	} while (adev != NULL);
> +
> +	return dev_num;
> +}