ASoC: EDB93xx: Manage I2S rates according to datasheet for CS4271 CODEC.

Manage I2S rates according to datasheet for CS4271 CODEC in EDB93xx
machine driver.

Signed-off-by: Alexander Sverdlin <subaparts@yandex.ru>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/sound/soc/ep93xx/edb93xx.c b/sound/soc/ep93xx/edb93xx.c
index b270085..d3aa151 100644 (file)
--- a/sound/soc/ep93xx/edb93xx.c
+++ b/sound/soc/ep93xx/edb93xx.c
@@ -41,17 +41,17 @@ static int edb93xx_hw_params(struct snd_pcm_substream *substream,
        struct snd_soc_dai *codec_dai = rtd->codec_dai;
        struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
        int err;
+       unsigned int mclk_rate;
        unsigned int rate = params_rate(params);
+
        /*
-        * We set LRCLK equal to `rate' and SCLK = LRCLK * 64,
-        * because our sample size is 32 bit * 2 channels.
-        * I2S standard permits us to transmit more bits than
-        * the codec uses.
-        * MCLK = SCLK * 4 is the best recommended value,
-        * but we have to fall back to ratio 2 for higher
-        * sample rates.
+        * According to CS4271 datasheet we use MCLK/LRCK=256 for
+        * rates below 50kHz and 128 for higher sample rates
         */
-       unsigned int mclk_rate = rate * 64 * ((rate <= 48000) ? 4 : 2);
+       if (rate < 50000)
+               mclk_rate = rate * 64 * 4;
+       else
+               mclk_rate = rate * 64 * 2;
 
        err = snd_soc_dai_set_fmt(codec_dai, SND_SOC_DAIFMT_I2S |
                                  SND_SOC_DAIFMT_NB_IF |