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Diffstat (limited to 'sound/soc/jz4740/jz4740-i2s.c')
-rw-r--r--sound/soc/jz4740/jz4740-i2s.c54
1 files changed, 50 insertions, 4 deletions
diff --git a/sound/soc/jz4740/jz4740-i2s.c b/sound/soc/jz4740/jz4740-i2s.c
index 6d9cfe0a5041..d0f6c945d9ae 100644
--- a/sound/soc/jz4740/jz4740-i2s.c
+++ b/sound/soc/jz4740/jz4740-i2s.c
@@ -218,18 +218,48 @@ static int jz4740_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
return 0;
}
+static int jz4740_i2s_get_i2sdiv(unsigned long mclk, unsigned long rate,
+ unsigned long i2sdiv_max)
+{
+ unsigned long div, rate1, rate2, err1, err2;
+
+ div = mclk / (64 * rate);
+ if (div == 0)
+ div = 1;
+
+ rate1 = mclk / (64 * div);
+ rate2 = mclk / (64 * (div + 1));
+
+ err1 = abs(rate1 - rate);
+ err2 = abs(rate2 - rate);
+
+ /*
+ * Choose the divider that produces the smallest error in the
+ * output rate and reject dividers with a 5% or higher error.
+ * In the event that both dividers are outside the acceptable
+ * error margin, reject the rate to prevent distorted audio.
+ * (The number 5% is arbitrary.)
+ */
+ if (div <= i2sdiv_max && err1 <= err2 && err1 < rate/20)
+ return div;
+ if (div < i2sdiv_max && err2 < rate/20)
+ return div + 1;
+
+ return -EINVAL;
+}
+
static int jz4740_i2s_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params, struct snd_soc_dai *dai)
{
struct jz4740_i2s *i2s = snd_soc_dai_get_drvdata(dai);
struct regmap_field *div_field;
+ unsigned long i2sdiv_max;
unsigned int sample_size;
- uint32_t ctrl;
- int div;
+ uint32_t ctrl, conf;
+ int div = 1;
regmap_read(i2s->regmap, JZ_REG_AIC_CTRL, &ctrl);
-
- div = clk_get_rate(i2s->clk_i2s) / (64 * params_rate(params));
+ regmap_read(i2s->regmap, JZ_REG_AIC_CONF, &conf);
switch (params_format(params)) {
case SNDRV_PCM_FORMAT_S8:
@@ -258,11 +288,27 @@ static int jz4740_i2s_hw_params(struct snd_pcm_substream *substream,
ctrl &= ~JZ_AIC_CTRL_MONO_TO_STEREO;
div_field = i2s->field_i2sdiv_playback;
+ i2sdiv_max = GENMASK(i2s->soc_info->field_i2sdiv_playback.msb,
+ i2s->soc_info->field_i2sdiv_playback.lsb);
} else {
ctrl &= ~JZ_AIC_CTRL_INPUT_SAMPLE_SIZE;
ctrl |= FIELD_PREP(JZ_AIC_CTRL_INPUT_SAMPLE_SIZE, sample_size);
div_field = i2s->field_i2sdiv_capture;
+ i2sdiv_max = GENMASK(i2s->soc_info->field_i2sdiv_capture.msb,
+ i2s->soc_info->field_i2sdiv_capture.lsb);
+ }
+
+ /*
+ * Only calculate I2SDIV if we're supplying the bit or frame clock.
+ * If the codec is supplying both clocks then the divider output is
+ * unused, and we don't want it to limit the allowed sample rates.
+ */
+ if (conf & (JZ_AIC_CONF_BIT_CLK_MASTER | JZ_AIC_CONF_SYNC_CLK_MASTER)) {
+ div = jz4740_i2s_get_i2sdiv(clk_get_rate(i2s->clk_i2s),
+ params_rate(params), i2sdiv_max);
+ if (div < 0)
+ return div;
}
regmap_write(i2s->regmap, JZ_REG_AIC_CTRL, ctrl);