linux-kernel - [PATCH v2 05/17] ASoC: sun8i-codec: Round up the LRCK divisor

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Message-Id: <20201014061941.4306-6-samuel@sholland.org>
Date:   Wed, 14 Oct 2020 01:19:29 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>, Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>
Cc:     Ondrej Jirman <megous@...ous.com>, alsa-devel@...a-project.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Samuel Holland <samuel@...lland.org>
Subject: [PATCH v2 05/17] ASoC: sun8i-codec: Round up the LRCK divisor

The codec supports only power-of-two BCLK/LRCK divisors. If either the
slot width or the number of slots is not a power of two, the LRCK
divisor must be rounded up to provide enough space. To do that, use
order_base_2 (instead of ilog2, which rounds down).

Since the rounded divisor is also needed for setting the SYSCLK/BCLK
divisor, return the order base 2 instead of fully calculating the
hardware register encoding.

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

diff --git a/sound/soc/sunxi/sun8i-codec.c b/sound/soc/sunxi/sun8i-codec.c
index 82576066c249..92fcef45097d 100644
--- a/sound/soc/sunxi/sun8i-codec.c
+++ b/sound/soc/sunxi/sun8i-codec.c
@@ -300,33 +300,35 @@ static u8 sun8i_codec_get_bclk_div(struct sun8i_codec *scodec,
 			best_diff = diff;
 			best_val = bdiv->val;
 		}
 	}
 
 	return best_val;
 }
 
-static int sun8i_codec_get_lrck_div(unsigned int channels,
-				    unsigned int word_size)
+static int sun8i_codec_get_lrck_div_order(unsigned int slots,
+					  unsigned int slot_width)
 {
-	unsigned int div = word_size * channels;
+	unsigned int div = slots * slot_width;
 
 	if (div < 16 || div > 256)
 		return -EINVAL;
 
-	return ilog2(div) - 4;
+	return order_base_2(div);
 }
 
 static int sun8i_codec_hw_params(struct snd_pcm_substream *substream,
 				 struct snd_pcm_hw_params *params,
 				 struct snd_soc_dai *dai)
 {
 	struct sun8i_codec *scodec = snd_soc_dai_get_drvdata(dai);
-	int lrck_div, sample_rate, word_size;
+	unsigned int slots = params_channels(params);
+	unsigned int slot_width = params_width(params);
+	int lrck_div_order, sample_rate, word_size;
 	u8 bclk_div;
 
 	/* word size */
 	switch (params_width(params)) {
 	case 8:
 		word_size = 0x0;
 		break;
 	case 16:
@@ -346,24 +348,24 @@ static int sun8i_codec_hw_params(struct snd_pcm_substream *substream,
 			   SUN8I_AIF1CLK_CTRL_AIF1_WORD_SIZ_MASK,
 			   word_size << SUN8I_AIF1CLK_CTRL_AIF1_WORD_SIZ);
 
 	bclk_div = sun8i_codec_get_bclk_div(scodec, params_rate(params), 16);
 	regmap_update_bits(scodec->regmap, SUN8I_AIF1CLK_CTRL,
 			   SUN8I_AIF1CLK_CTRL_AIF1_BCLK_DIV_MASK,
 			   bclk_div << SUN8I_AIF1CLK_CTRL_AIF1_BCLK_DIV);
 
-	lrck_div = sun8i_codec_get_lrck_div(params_channels(params),
-					    params_physical_width(params));
-	if (lrck_div < 0)
-		return lrck_div;
+	/* LRCK divider (BCLK/LRCK ratio) */
+	lrck_div_order = sun8i_codec_get_lrck_div_order(slots, slot_width);
+	if (lrck_div_order < 0)
+		return lrck_div_order;
 
 	regmap_update_bits(scodec->regmap, SUN8I_AIF1CLK_CTRL,
 			   SUN8I_AIF1CLK_CTRL_AIF1_LRCK_DIV_MASK,
-			   lrck_div << SUN8I_AIF1CLK_CTRL_AIF1_LRCK_DIV);
+			   (lrck_div_order - 4) << SUN8I_AIF1CLK_CTRL_AIF1_LRCK_DIV);
 
 	sample_rate = sun8i_codec_get_hw_rate(params);
 	if (sample_rate < 0)
 		return sample_rate;
 
 	regmap_update_bits(scodec->regmap, SUN8I_SYS_SR_CTRL,
 			   SUN8I_SYS_SR_CTRL_AIF1_FS_MASK,
 			   sample_rate << SUN8I_SYS_SR_CTRL_AIF1_FS);
-- 
2.26.2