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ASoC: mxs-saif: fix setting master base rate

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The SAIF base oversample rates are either 512*fs or 384*fs. An additional
divider exists within the SAIF to generate sub-multiples of these two base
rates if MCLK is required by the codec.

 * The sub-rates for the 512x base rate are: 256x, 128x, 64x, and 32x.
 * The sub-rates for the 384x base rate are: 192x, 96x, and 48x.

Setting the base rate depending on the modulo operation with 32 and 48
give wrong results for some mclk.

If mclk=18.432MHz both modulo operations results in 0. As testing the
result with 32 is done first, a wrong base rate of 512*fs is set instead
of the correct 384*fs.

Fix this by setting the base rate depending on the calculated sub-rate.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Jörg Krause 2017-01-13 21:44:27 +01:00 committed by Mark Brown
parent b25658ed7d
commit bcb8c27082
1 changed files with 17 additions and 7 deletions
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24
sound/soc/mxs/mxs-saif.c
View File

@ -119,23 +119,33 @@ static int mxs_saif_set_clk(struct mxs_saif *saif,
* Set SAIF clock
*
* The SAIF clock should be either 384*fs or 512*fs.
* If MCLK is used, the SAIF clk ratio need to match mclk ratio.
* For 32x mclk, set saif clk as 512*fs.
* For 48x mclk, set saif clk as 384*fs.
* If MCLK is used, the SAIF clk ratio needs to match mclk ratio.
* For 256x, 128x, 64x, and 32x sub-rates, set saif clk as 512*fs.
* For 192x, 96x, and 48x sub-rates, set saif clk as 384*fs.
*
* If MCLK is not used, we just set saif clk to 512*fs.
*/
clk_prepare_enable(master_saif->clk);
if (master_saif->mclk_in_use) {
if (mclk % 32 == 0) {
switch (mclk / rate) {
case 32:
case 64:
case 128:
case 256:
case 512:
scr &= ~BM_SAIF_CTRL_BITCLK_BASE_RATE;
ret = clk_set_rate(master_saif->clk, 512 * rate);
} else if (mclk % 48 == 0) {
break;
case 48:
case 96:
case 192:
case 384:
scr |= BM_SAIF_CTRL_BITCLK_BASE_RATE;
ret = clk_set_rate(master_saif->clk, 384 * rate);
} else {
/* SAIF MCLK should be either 32x or 48x */
break;
default:
/* SAIF MCLK should be a sub-rate of 512x or 384x */
clk_disable_unprepare(master_saif->clk);
return -EINVAL;
}