Re: [PATCH 1/2] ASoC: max98090: Add master clock handling

From: Stephen Warren
Date: Thu May 22 2014 - 11:51:47 EST


On 05/22/2014 03:17 AM, Tushar Behera wrote:
> If master clock is provided through device tree, then update
> the master clock frequency during set_sysclk.
>
> Documentation has been updated to reflect the change.

> diff --git a/sound/soc/codecs/max98090.c b/sound/soc/codecs/max98090.c

> @@ -1929,6 +1930,11 @@ static int max98090_dai_set_sysclk(struct snd_soc_dai *dai,
> if (freq == max98090->sysclk)
> return 0;
>
> + if (!IS_ERR(max98090->mclk)) {
> + freq = clk_round_rate(max98090->mclk, freq);
> + clk_set_rate(max98090->mclk, freq);
> + }

What are the intended semantics of set_sysclk()?
sound/soc/tegra/tegra_wm98090.c assumes that set_sysclk() is a
notification to the CODEC driver to tell it what rate the MCLK input is
set to (the rate is set before calling set_sysclk), whereas the code
above assumes that this function is to tell the CODEC to somehow
configure its input clock to be a particular rate. I have a feeling the
code above might fail on Tegra.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/