ASoC: stm32: sai: fix oversampling mode

Set OSR bit if mclk/fs ratio is 512.
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_sai_sub.c

@@ -913,7 +913,7 @@ static int stm32_sai_configure_clock(struct snd_soc_dai *cpu_dai,
 				     struct snd_pcm_hw_params *params)
 {
 	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
-	int div = 0;
+	int div = 0, cr1 = 0;
 	int sai_clk_rate, mclk_ratio, den;
 	unsigned int rate = params_rate(params);
 
@@ -958,13 +958,19 @@ static int stm32_sai_configure_clock(struct snd_soc_dai *cpu_dai,
 		} else {
 			if (sai->mclk_rate) {
 				mclk_ratio = sai->mclk_rate / rate;
-				if ((mclk_ratio != 512) &&
-				    (mclk_ratio != 256)) {
+				if (mclk_ratio == 512) {
+					cr1 = SAI_XCR1_OSR;
+				} else if (mclk_ratio != 256) {
 					dev_err(cpu_dai->dev,
 						"Wrong mclk ratio %d\n",
 						mclk_ratio);
 					return -EINVAL;
 				}
+
+				regmap_update_bits(sai->regmap,
+						   STM_SAI_CR1_REGX,
+						   SAI_XCR1_OSR, cr1);
+
 				div = stm32_sai_get_clk_div(sai, sai_clk_rate,
 							    sai->mclk_rate);
 				if (div < 0)