diff mbox series

[21/25] ASoC: sun8i-codec: Require an exact BCLK divisor match

Message ID 20201001021148.15852-22-samuel@sholland.org (mailing list archive)
State New, archived
Headers show
Series ASoC: sun8i-codec: support for AIF2 and AIF3 | expand

Commit Message

Samuel Holland Oct. 1, 2020, 2:11 a.m. UTC
Now that we guarantee that SYSCLK is running at the optimal rate when
hw_params succeeds, and that it will continue running at that rate,
SYSCLK will always be an integer multiple of BCLK. So we can always
pick the exact divider, not just the closest divider.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---
 sound/soc/sunxi/sun8i-codec.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

Comments

Maxime Ripard Oct. 5, 2020, 12:01 p.m. UTC | #1
On Wed, Sep 30, 2020 at 09:11:44PM -0500, Samuel Holland wrote:
> Now that we guarantee that SYSCLK is running at the optimal rate when
> hw_params succeeds, and that it will continue running at that rate,
> SYSCLK will always be an integer multiple of BCLK. So we can always
> pick the exact divider, not just the closest divider.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>

Acked-by: Maxime Ripard <mripard@kernel.org>

Maxime
diff mbox series

Patch

diff --git a/sound/soc/sunxi/sun8i-codec.c b/sound/soc/sunxi/sun8i-codec.c
index 86065bee7cd3..d8ce84533ddb 100644
--- a/sound/soc/sunxi/sun8i-codec.c
+++ b/sound/soc/sunxi/sun8i-codec.c
@@ -384,35 +384,31 @@  static const struct sun8i_codec_clk_div sun8i_codec_bclk_div[] = {
 	{ .div = 32,	.val = 8 },
 	{ .div = 48,	.val = 9 },
 	{ .div = 64,	.val = 10 },
 	{ .div = 96,	.val = 11 },
 	{ .div = 128,	.val = 12 },
 	{ .div = 192,	.val = 13 },
 };
 
-static u8 sun8i_codec_get_bclk_div(unsigned int sysclk_rate,
-				   unsigned int lrck_div_order,
-				   unsigned int sample_rate)
+static int sun8i_codec_get_bclk_div(unsigned int sysclk_rate,
+				    unsigned int lrck_div_order,
+				    unsigned int sample_rate)
 {
 	unsigned int div = sysclk_rate / sample_rate >> lrck_div_order;
-	unsigned int best_val = 0, best_diff = ~0;
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(sun8i_codec_bclk_div); i++) {
 		const struct sun8i_codec_clk_div *bdiv = &sun8i_codec_bclk_div[i];
-		unsigned int diff = abs(bdiv->div - div);
 
-		if (diff < best_diff) {
-			best_diff = diff;
-			best_val = bdiv->val;
-		}
+		if (bdiv->div == div)
+			return bdiv->val;
 	}
 
-	return best_val;
+	return -EINVAL;
 }
 
 static int sun8i_codec_get_lrck_div_order(unsigned int slots,
 					  unsigned int slot_width)
 {
 	unsigned int div = slots * slot_width;
 
 	if (div < 16 || div > 256)
@@ -431,18 +427,17 @@  static int sun8i_codec_hw_params(struct snd_pcm_substream *substream,
 				 struct snd_soc_dai *dai)
 {
 	struct sun8i_codec *scodec = snd_soc_dai_get_drvdata(dai);
 	struct sun8i_codec_aif *aif = &scodec->aifs[dai->id];
 	unsigned int sample_rate = params_rate(params);
 	unsigned int slots = aif->slots ?: params_channels(params);
 	unsigned int slot_width = aif->slot_width ?: params_width(params);
 	unsigned int sysclk_rate = sun8i_codec_get_sysclk_rate(sample_rate);
-	int lrck_div_order, ret, word_size;
-	u8 bclk_div;
+	int bclk_div, lrck_div_order, ret, word_size;
 
 	/* word size */
 	switch (params_width(params)) {
 	case 8:
 		word_size = 0x0;
 		break;
 	case 16:
 		word_size = 0x1;
@@ -467,16 +462,19 @@  static int sun8i_codec_hw_params(struct snd_pcm_substream *substream,
 		return lrck_div_order;
 
 	regmap_update_bits(scodec->regmap, SUN8I_AIF1CLK_CTRL,
 			   SUN8I_AIF1CLK_CTRL_AIF1_LRCK_DIV_MASK,
 			   (lrck_div_order - 4) << SUN8I_AIF1CLK_CTRL_AIF1_LRCK_DIV);
 
 	/* BCLK divider (SYSCLK/BCLK ratio) */
 	bclk_div = sun8i_codec_get_bclk_div(sysclk_rate, lrck_div_order, sample_rate);
+	if (bclk_div < 0)
+		return bclk_div;
+
 	regmap_update_bits(scodec->regmap, SUN8I_AIF1CLK_CTRL,
 			   SUN8I_AIF1CLK_CTRL_AIF1_BCLK_DIV_MASK,
 			   bclk_div << SUN8I_AIF1CLK_CTRL_AIF1_BCLK_DIV);
 
 	/* SYSCLK rate */
 	if (aif->open_streams) {
 		ret = clk_set_rate(scodec->clk_module, sysclk_rate);
 		if (ret < 0)