ASoC: ti: davinci-mcasp: Support for auxclk-fs-ratio

When McASP is bus master and it's AUXCLK clock is not static, but it is
a multiple of the frame sync the constraint rules should take it account
when validating possible stream formats.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/ti/davinci-mcasp.c

@@ -100,6 +100,7 @@ struct davinci_mcasp {
 
 	int	sysclk_freq;
 	bool	bclk_master;
+	u32	auxclk_fs_ratio;
 
 	unsigned long pdir; /* Pin direction bitfield */
 
@@ -1064,13 +1065,13 @@ static int mcasp_dit_hw_param(struct davinci_mcasp *mcasp,
 }
 
 static int davinci_mcasp_calc_clk_div(struct davinci_mcasp *mcasp,
+				      unsigned int sysclk_freq,
 				      unsigned int bclk_freq, bool set)
 {
-	int error_ppm;
-	unsigned int sysclk_freq = mcasp->sysclk_freq;
 	u32 reg = mcasp_get_reg(mcasp, DAVINCI_MCASP_AHCLKXCTL_REG);
 	int div = sysclk_freq / bclk_freq;
 	int rem = sysclk_freq % bclk_freq;
+	int error_ppm;
 	int aux_div = 1;
 
 	if (div > (ACLKXDIV_MASK + 1)) {
@@ -1175,7 +1176,8 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
 		if (mcasp->slot_width)
 			sbits = mcasp->slot_width;
 
-		davinci_mcasp_calc_clk_div(mcasp, rate * sbits * slots, true);
+		davinci_mcasp_calc_clk_div(mcasp, mcasp->sysclk_freq,
+					   rate * sbits * slots, true);
 	}
 
 	ret = mcasp_common_hw_param(mcasp, substream->stream,
@@ -1282,12 +1284,19 @@ static int davinci_mcasp_hw_rule_rate(struct snd_pcm_hw_params *params,
 
 	for (i = 0; i < ARRAY_SIZE(davinci_mcasp_dai_rates); i++) {
 		if (snd_interval_test(ri, davinci_mcasp_dai_rates[i])) {
-			uint bclk_freq = sbits*slots*
+			uint bclk_freq = sbits * slots *
 					 davinci_mcasp_dai_rates[i];
+			unsigned int sysclk_freq;
 			int ppm;
 
-			ppm = davinci_mcasp_calc_clk_div(rd->mcasp, bclk_freq,
-							 false);
+			if (rd->mcasp->auxclk_fs_ratio)
+				sysclk_freq =  davinci_mcasp_dai_rates[i] *
+					       rd->mcasp->auxclk_fs_ratio;
+			else
+				sysclk_freq = rd->mcasp->sysclk_freq;
+
+			ppm = davinci_mcasp_calc_clk_div(rd->mcasp, sysclk_freq,
+							 bclk_freq, false);
 			if (abs(ppm) < DAVINCI_MAX_RATE_ERROR_PPM) {
 				if (range.empty) {
 					range.min = davinci_mcasp_dai_rates[i];
@@ -1321,12 +1330,19 @@ static int davinci_mcasp_hw_rule_format(struct snd_pcm_hw_params *params,
 	for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
 		if (snd_mask_test(fmt, i)) {
 			uint sbits = snd_pcm_format_width(i);
+			unsigned int sysclk_freq;
 			int ppm;
 
+			if (rd->mcasp->auxclk_fs_ratio)
+				sysclk_freq =  rate *
+					       rd->mcasp->auxclk_fs_ratio;
+			else
+				sysclk_freq = rd->mcasp->sysclk_freq;
+
 			if (rd->mcasp->slot_width)
 				sbits = rd->mcasp->slot_width;
 
-			ppm = davinci_mcasp_calc_clk_div(rd->mcasp,
+			ppm = davinci_mcasp_calc_clk_div(rd->mcasp, sysclk_freq,
 							 sbits * slots * rate,
 							 false);
 			if (abs(ppm) < DAVINCI_MAX_RATE_ERROR_PPM) {
@@ -1991,6 +2007,22 @@ static inline int davinci_mcasp_init_gpiochip(struct davinci_mcasp *mcasp)
 }
 #endif /* CONFIG_GPIOLIB */
 
+static int davinci_mcasp_get_dt_params(struct davinci_mcasp *mcasp)
+{
+	struct device_node *np = mcasp->dev->of_node;
+	int ret;
+	u32 val;
+
+	if (!np)
+		return 0;
+
+	ret = of_property_read_u32(np, "auxclk-fs-ratio", &val);
+	if (ret >= 0)
+		mcasp->auxclk_fs_ratio = val;
+
+	return 0;
+}
+
 static int davinci_mcasp_probe(struct platform_device *pdev)
 {
 	struct snd_dmaengine_dai_dma_data *dma_data;
@@ -2224,6 +2256,10 @@ static int davinci_mcasp_probe(struct platform_device *pdev)
 	if (ret)
 		goto err;
 
+	ret = davinci_mcasp_get_dt_params(mcasp);
+	if (ret)
+		return -EINVAL;
+
 	ret = devm_snd_soc_register_component(&pdev->dev,
 					&davinci_mcasp_component,
 					&davinci_mcasp_dai[pdata->op_mode], 1);