[alsa-devel] [PATCH v3] ASoC: bytcr_rt5640: Allow quirk set via module option

[Pierre-Louis Bossart]

On 4/23/17 2:22 AM, Takashi Iwai wrote:
> The bytcr-rt5640 driver has a few quirk setups depending on the board,
> where the quirk value is set by DMI matching.  When you have a new
> device to add the support, you often experience to try the different
> quirk by trial-and-error.  Or, you may have a development model that
> still has no proper DMI string.  In either case, you'd need to compile
> the driver at each time.
>
> This patch introduces a module option to override the quirk value on
> the fly.  User can boot like snd-soc-sst-bytcr-rt5640.quirk=0x4004 to
> override the default value without recompilation.  It's a raw value,
> so user needs to check the source code for the meaning of each bit.
>
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
> v1->v2: override the quirk value completely
> v2->v3: print the override information
>
>  sound/soc/intel/boards/bytcr_rt5640.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/sound/soc/intel/boards/bytcr_rt5640.c b/sound/soc/intel/boards/bytcr_rt5640.c
> index 5c7219fb3aa8..0ac32788f216 100644
> --- a/sound/soc/intel/boards/bytcr_rt5640.c
> +++ b/sound/soc/intel/boards/bytcr_rt5640.c
> @@ -19,6 +19,7 @@
>
>  #include <linux/init.h>
>  #include <linux/module.h>
> +#include <linux/moduleparam.h>
>  #include <linux/platform_device.h>
>  #include <linux/acpi.h>
>  #include <linux/device.h>
> @@ -58,6 +59,9 @@ struct byt_rt5640_private {
>  };
>
>  static unsigned long byt_rt5640_quirk = BYT_RT5640_MCLK_EN;
> +static unsigned int quirk_override;
> +module_param_named(quirk, quirk_override, int, 0444);
> +MODULE_PARM_DESC(quirk, "Board-specific quirk override");
>
>  static void log_quirks(struct device *dev)
>  {
> @@ -806,6 +810,11 @@ static int snd_byt_rt5640_mc_probe(struct platform_device *pdev)
>
>  	/* check quirks before creating card */
>  	dmi_check_system(byt_rt5640_quirk_table);
> +	if (quirk_override) {
> +		dev_info(&pdev->dev, "Overriding quirk %0x => 0x%x\n",
> +			 (unsigned int)byt_rt5640_quirk, quirk_override);

I was talking about a more complete message that would e.g check if 
MCLK_EN is set when MCLK_25MHZ is set, etc.
I'll add a follow-up patch, for now

Acked-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>

> +		byt_rt5640_quirk = quirk_override;
> +	}
>  	log_quirks(&pdev->dev);
>
>  	if ((byt_rt5640_quirk & BYT_RT5640_SSP2_AIF2) ||
>