linux-kernel - [PATCH] ASoC: tlv320aic32x4: Fix the divide by zero

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Message-Id: <20230712151158.20378-1-aarongt.shen@gmail.com>
Date:   Wed, 12 Jul 2023 23:11:58 +0800
From:   Guiting Shen <aarongt.shen@...il.com>
To:     lgirdwood@...il.com
Cc:     broonie@...nel.org, perex@...ex.cz, tiwai@...e.com,
        sboyd@...nel.org, mripard@...nel.org, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, Guiting Shen <aarongt.shen@...il.com>
Subject: [PATCH] ASoC: tlv320aic32x4: Fix the divide by zero

The value of register(NDAC,MDAC,NADC,MADC,BCLKN) maybe zero lead to
divide by zero in clk_aic32x4_div_recalc_rate().And the rate should be
divide by 128 if the value was zero in this function according to the
datasheet.
Add the macro AIC32X4_DIV_MAX to present the 128 and return 0 if failing
to read the value of register.

Signed-off-by: Guiting Shen <aarongt.shen@...il.com>
---
 sound/soc/codecs/tlv320aic32x4-clk.c | 16 +++++++++++-----
 sound/soc/codecs/tlv320aic32x4.h     |  5 +++--
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/sound/soc/codecs/tlv320aic32x4-clk.c b/sound/soc/codecs/tlv320aic32x4-clk.c
index c116e82f712d..5c0a76a4a106 100644
--- a/sound/soc/codecs/tlv320aic32x4-clk.c
+++ b/sound/soc/codecs/tlv320aic32x4-clk.c
@@ -321,7 +321,7 @@ static int clk_aic32x4_div_set_rate(struct clk_hw *hw, unsigned long rate,
 	u8 divisor;
 
 	divisor = DIV_ROUND_UP(parent_rate, rate);
-	if (divisor > 128)
+	if (divisor > AIC32X4_DIV_MAX)
 		return -EINVAL;
 
 	return regmap_update_bits(div->regmap, div->reg,
@@ -334,7 +334,7 @@ static int clk_aic32x4_div_determine_rate(struct clk_hw *hw,
 	unsigned long divisor;
 
 	divisor = DIV_ROUND_UP(req->best_parent_rate, req->rate);
-	if (divisor > 128)
+	if (divisor > AIC32X4_DIV_MAX)
 		return -EINVAL;
 
 	req->rate = DIV_ROUND_UP(req->best_parent_rate, divisor);
@@ -345,12 +345,18 @@ static unsigned long clk_aic32x4_div_recalc_rate(struct clk_hw *hw,
 						unsigned long parent_rate)
 {
 	struct clk_aic32x4 *div = to_clk_aic32x4(hw);
-
 	unsigned int val;
+	int err;
+
+	err = regmap_read(div->regmap, div->reg, &val);
+	if (err)
+		return 0;
 
-	regmap_read(div->regmap, div->reg, &val);
+	val &= AIC32X4_DIV_MASK;
+	if (!val)
+		val = AIC32X4_DIV_MAX;
 
-	return DIV_ROUND_UP(parent_rate, val & AIC32X4_DIV_MASK);
+	return DIV_ROUND_UP(parent_rate, val);
 }
 
 static const struct clk_ops aic32x4_div_ops = {
diff --git a/sound/soc/codecs/tlv320aic32x4.h b/sound/soc/codecs/tlv320aic32x4.h
index 4de5bd9e8cc5..d6101ce73f80 100644
--- a/sound/soc/codecs/tlv320aic32x4.h
+++ b/sound/soc/codecs/tlv320aic32x4.h
@@ -223,8 +223,9 @@ int aic32x4_register_clocks(struct device *dev, const char *mclk_name);
 #define AIC32X4_REFPOWERUP_120MS	0x07
 
 /* Common mask and enable for all of the dividers */
-#define AIC32X4_DIVEN           BIT(7)
-#define AIC32X4_DIV_MASK        GENMASK(6, 0)
+#define AIC32X4_DIVEN			BIT(7)
+#define AIC32X4_DIV_MASK		GENMASK(6, 0)
+#define AIC32X4_DIV_MAX			128
 
 /* Clock Limits */
 #define AIC32X4_MAX_DOSR_FREQ		6200000
-- 
2.25.1