[PATCH 5.15.y 2/3] ASoC: tlv320aic32x4: Fix the divide by zero

[Sasha Levin <sashal@kernel.org>]

From: Guiting Shen <aarongt.shen@gmail.com>

[ Upstream commit 11e756cc85fac43e2025306ad6aea80114cc7e98 ]

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@gmail.com>
Link: https://lore.kernel.org/r/20230813125520.11067-1-aarongt.shen@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Stable-dep-of: 8cf9607d2d85 ("ASoC: tlv320aic32x4: Prevent division by zero in divider callbacks")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 96979243d3a6a..4ade06e5f5cd3 100644
--- a/sound/soc/codecs/tlv320aic32x4-clk.c
+++ b/sound/soc/codecs/tlv320aic32x4-clk.c
@@ -319,7 +319,7 @@ 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,
@@ -332,7 +332,7 @@ 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);
@@ -343,12 +343,18 @@ 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 e9fd2e55d6c3b..7a89ac4d5f574 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
-- 
2.53.0