[alsa-devel] [PATCH 10/10] ASoC: SMDKV310: Add I2S support

[Mark Brown]

On Mon, Dec 20, 2010 at 11:05:57AM +0900, Jassi at opensource.wolfsonmicro.com wrote:

> +	ret = snd_soc_dai_set_pll(codec_dai, WM8994_FLL1, WM8994_FLL_SRC_MCLK1,
> +					SMDK_WM8994_FREQ, pll_out);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = snd_soc_dai_set_sysclk(codec_dai, WM8994_SYSCLK_FLL1,
> +					pll_out, SND_SOC_CLOCK_IN);
> +	if (ret < 0)
> +		return ret;

...

> +static struct snd_soc_ops smdk_ops = {
> +	.hw_params = smdk_hw_params,
> +};

This means that the FLL won't ever get powered off when it goes idle.
While it's not going to be such an issue on a board like this as it is a
reference design it's likely people will lift the code into places where
it does matter so it'd be good to get such support into the driver.

> +	/* HeadPhone */
> +	snd_soc_dapm_enable_pin(dapm, "HPOUT1R");
> +	snd_soc_dapm_enable_pin(dapm, "HPOUT1L");

There's no need to explicitly enable pins that aren't being actively
managed - the default is for all pins to be enabled.

> +	snd_soc_dapm_sync(dapm);
> +

Core should be doing this automatically for you these days, on the other
hand this does no harm.