[alsa-devel] [PATCH 5/7] ASoC: max9867: Calculate LRCLK divider

[Ladislav Michl]

Do not limit sample rate to a few precalculated frequencies
based on "Common NI Values Table" and put the same equation
used to create that table directly in code.

Signed-off-by: Ladislav Michl <ladis at linux-mips.org>
---
 sound/soc/codecs/max9867.c | 64 +++-------------------------------------------
 1 file changed, 4 insertions(+), 60 deletions(-)

diff --git a/sound/soc/codecs/max9867.c b/sound/soc/codecs/max9867.c
index 2f60924fe919..026b7cf94910 100644
--- a/sound/soc/codecs/max9867.c
+++ b/sound/soc/codecs/max9867.c
@@ -126,75 +126,19 @@ static const struct snd_soc_dapm_route max9867_audio_map[] = {
 	{"LINE_IN", NULL, "Right Line"},
 };
 
-enum rates {
-	pcm_rate_8, pcm_rate_16, pcm_rate_24,
-	pcm_rate_32, pcm_rate_44,
-	pcm_rate_48, max_pcm_rate,
-};
-
-static const struct ni_div_rates {
-	u32 mclk;
-	u16 ni[max_pcm_rate];
-} ni_div[] = {
-	{11289600, {0x116A, 0x22D4, 0x343F, 0x45A9, 0x6000, 0x687D} },
-	{12000000, {0x1062, 0x20C5, 0x3127, 0x4189, 0x5A51, 0x624E} },
-	{12288000, {0x1000, 0x2000, 0x3000, 0x4000, 0x5833, 0x6000} },
-	{13000000, {0x0F20, 0x1E3F, 0x2D5F, 0x3C7F, 0x535F, 0x5ABE} },
-	{19200000, {0x0A3D, 0x147B, 0x1EB8, 0x28F6, 0x3873, 0x3D71} },
-	{24000000, {0x1062, 0x20C5, 0x1893, 0x4189, 0x5A51, 0x624E} },
-	{26000000, {0x0F20, 0x1E3F, 0x16AF, 0x3C7F, 0x535F, 0x5ABE} },
-	{27000000, {0x0E90, 0x1D21, 0x15D8, 0x3A41, 0x5048, 0x5762} },
-};
-
-static inline int get_ni_value(int mclk, int rate)
-{
-	int i, ret = 0;
-
-	/* find the closest rate index*/
-	for (i = 0; i < ARRAY_SIZE(ni_div); i++) {
-		if (ni_div[i].mclk >= mclk)
-			break;
-	}
-	if (i == ARRAY_SIZE(ni_div))
-		return -EINVAL;
-
-	switch (rate) {
-	case 8000:
-		return ni_div[i].ni[pcm_rate_8];
-	case 16000:
-		return ni_div[i].ni[pcm_rate_16];
-	case 32000:
-		return ni_div[i].ni[pcm_rate_32];
-	case 44100:
-		return ni_div[i].ni[pcm_rate_44];
-	case 48000:
-		return ni_div[i].ni[pcm_rate_48];
-	default:
-		pr_err("%s wrong rate %d\n", __func__, rate);
-		ret = -EINVAL;
-	}
-	return ret;
-}
-
 static int max9867_dai_hw_params(struct snd_pcm_substream *substream,
 		struct snd_pcm_hw_params *params, struct snd_soc_dai *dai)
 {
 	struct snd_soc_codec *codec = dai->codec;
 	struct max9867_priv *max9867 = snd_soc_codec_get_drvdata(codec);
-	unsigned int ni_h, ni_l;
-	int value;
-
-	value = get_ni_value(max9867->sysclk, params_rate(params));
-	if (value < 0)
-		return value;
+	unsigned int ni = DIV_ROUND_CLOSEST_ULL(96 * 0x10000 *
+		(unsigned long long)params_rate(params), max9867->sysclk);
 
-	ni_h = (0xFF00 & value) >> 8;
-	ni_l = 0x00FF & value;
 	/* set up the ni value */
 	regmap_update_bits(max9867->regmap, MAX9867_AUDIOCLKHIGH,
-		MAX9867_NI_HIGH_MASK, ni_h);
+		MAX9867_NI_HIGH_MASK, (0xFF00 & ni) >> 8);
 	regmap_update_bits(max9867->regmap, MAX9867_AUDIOCLKLOW,
-		MAX9867_NI_LOW_MASK, ni_l);
+		MAX9867_NI_LOW_MASK, 0x00FF & ni);
 	if (!max9867->master) {
 		/*
 		 * digital pll locks on to any externally supplied LRCLK signal
-- 
2.15.1