linux-kernel - Re: [PATCH 06/10] ASoC: wm8940: Convert to snd_soc_cache

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Message-ID: <4E8D90E9.5060208@cam.ac.uk>
Date:	Thu, 06 Oct 2011 12:28:41 +0100
From:	Jonathan Cameron <jic23@....ac.uk>
To:	Axel Lin <axel.lin@...il.com>
CC:	linux-kernel@...r.kernel.org,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Ian Lartey <ian@...nsource.wolfsonmicro.com>,
	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lrg@...com>, alsa-devel@...a-project.org
Subject: Re: [PATCH 06/10] ASoC: wm8940: Convert to snd_soc_cache_sync

On 10/06/11 07:17, Axel Lin wrote:
> Convert to snd_soc_cache_sync for sync reg_cache with the hardware.
Looks sane, but I'm not that familiar with the cache side of things, so you'll want
an ack from someone who is.  One comment inline.
> 
> Signed-off-by: Axel Lin <axel.lin@...il.com>
> ---
>  sound/soc/codecs/wm8940.c |   46 +++++++++++++++++++++-----------------------
>  1 files changed, 22 insertions(+), 24 deletions(-)
> 
> diff --git a/sound/soc/codecs/wm8940.c b/sound/soc/codecs/wm8940.c
> index 7e0f54c..a4abfdf 100644
> --- a/sound/soc/codecs/wm8940.c
> +++ b/sound/soc/codecs/wm8940.c
> @@ -45,6 +45,17 @@ struct wm8940_priv {
>  	enum snd_soc_control_type control_type;
>  };
>  
> +static int wm8940_volatile_register(struct snd_soc_codec *codec,
> +				    unsigned int reg)
> +{
> +	switch (reg) {
> +	case WM8940_SOFTRESET:
> +		return 1;
> +	default:
> +		return 0;
> +	}
> +}
I guess this makes sense from point of view of keeping things inline with
more complex drivers.  Otherwise I'd expect to see something like:
{
	return !!(reg == WM894_SOFTRESET);
}
> +
>  static u16 wm8940_reg_defaults[] = {
>  	0x8940, /* Soft Reset */
>  	0x0000, /* Power 1 */
> @@ -459,6 +470,14 @@ static int wm8940_set_bias_level(struct snd_soc_codec *codec,
>  		ret = snd_soc_write(codec, WM8940_POWER1, pwr_reg | 0x1);
>  		break;
>  	case SND_SOC_BIAS_STANDBY:
> +		if (codec->dapm.bias_level == SND_SOC_BIAS_OFF) {
> +			ret = snd_soc_cache_sync(codec);
> +			if (ret < 0) {
> +				dev_err(codec->dev, "Failed to sync cache: %d\n", ret);
> +				return ret;
> +			}
> +		}
> +
>  		/* ensure bufioen and biasen */
>  		pwr_reg |= (1 << 2) | (1 << 3);
>  		/* set vmid to 300k for standby */
> @@ -659,30 +678,8 @@ static int wm8940_suspend(struct snd_soc_codec *codec, pm_message_t state)
>  
>  static int wm8940_resume(struct snd_soc_codec *codec)
>  {
> -	int i;
> -	int ret;
> -	u8 data[3];
> -	u16 *cache = codec->reg_cache;
> -
> -	/* Sync reg_cache with the hardware
> -	 * Could use auto incremented writes to speed this up
> -	 */
> -	for (i = 0; i < ARRAY_SIZE(wm8940_reg_defaults); i++) {
> -		data[0] = i;
> -		data[1] = (cache[i] & 0xFF00) >> 8;
> -		data[2] = cache[i] & 0x00FF;
> -		ret = codec->hw_write(codec->control_data, data, 3);
> -		if (ret < 0)
> -			goto error_ret;
> -		else if (ret != 3) {
> -			ret = -EIO;
> -			goto error_ret;
> -		}
> -	}
> -	ret = wm8940_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
> -
> -error_ret:
> -	return ret;
> +	wm8940_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
> +	return 0;
>  }
>  
>  static int wm8940_probe(struct snd_soc_codec *codec)
> @@ -742,6 +739,7 @@ static struct snd_soc_codec_driver soc_codec_dev_wm8940 = {
>  	.reg_cache_size = ARRAY_SIZE(wm8940_reg_defaults),
>  	.reg_word_size = sizeof(u16),
>  	.reg_cache_default = wm8940_reg_defaults,
> +	.volatile_register = wm8940_volatile_register,
>  };
>  
>  #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)

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