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  3. [PATCH v5 0/4] media: i2c: ds90ub953: Add back channel GPIO support
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[PATCH v5 4/4] media: i2c: ds90ub953: use guard() to simplify code

Guoniu Zhou posted 4 patches 1 month ago
[PATCH v5 4/4] media: i2c: ds90ub953: use guard() to simplify code
Posted by Guoniu Zhou 1 month ago 
From: Guoniu Zhou <guoniu.zhou@nxp.com>

Use guard() to simplify mutex locking. No functional change.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Guoniu Zhou <guoniu.zhou@nxp.com>
---
 drivers/media/i2c/ds90ub953.c | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/drivers/media/i2c/ds90ub953.c b/drivers/media/i2c/ds90ub953.c
index a85c6a9b64070491db161ca1586179dba9c69cb0..3a459687aefce05ac025a517c8d4cc6d76cd7293 100644
--- a/drivers/media/i2c/ds90ub953.c
+++ b/drivers/media/i2c/ds90ub953.c
@@ -113,20 +113,18 @@ static int ub953_read(struct ub953_data *priv, u8 reg, u8 *val, int *err)
 	if (err && *err)
 		return *err;
 
-	mutex_lock(&priv->reg_lock);
+	guard(mutex)(&priv->reg_lock);
 
 	ret = regmap_read(priv->regmap, reg, &v);
 	if (ret) {
 		dev_err(&priv->client->dev, "Cannot read register 0x%02x: %d\n",
 			reg, ret);
-		goto out_unlock;
+		goto err;
 	}
 
 	*val = v;
 
-out_unlock:
-	mutex_unlock(&priv->reg_lock);
-
+err:
 	if (ret && err)
 		*err = ret;
 
@@ -140,15 +138,13 @@ static int ub953_write(struct ub953_data *priv, u8 reg, u8 val, int *err)
 	if (err && *err)
 		return *err;
 
-	mutex_lock(&priv->reg_lock);
+	guard(mutex)(&priv->reg_lock);
 
 	ret = regmap_write(priv->regmap, reg, val);
 	if (ret)
 		dev_err(&priv->client->dev,
 			"Cannot write register 0x%02x: %d\n", reg, ret);
 
-	mutex_unlock(&priv->reg_lock);
-
 	if (ret && err)
 		*err = ret;
 
@@ -185,18 +181,18 @@ static int ub953_read_ind(struct ub953_data *priv, u8 block, u8 reg, u8 *val,
 	if (err && *err)
 		return *err;
 
-	mutex_lock(&priv->reg_lock);
+	guard(mutex)(&priv->reg_lock);
 
 	ret = ub953_select_ind_reg_block(priv, block);
 	if (ret)
-		goto out_unlock;
+		goto err;
 
 	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
 	if (ret) {
 		dev_err(&priv->client->dev,
 			"Write to IND_ACC_ADDR failed when reading %u:0x%02x: %d\n",
 			block, reg, ret);
-		goto out_unlock;
+		goto err;
 	}
 
 	ret = regmap_read(priv->regmap, UB953_REG_IND_ACC_DATA, &v);
@@ -204,14 +200,12 @@ static int ub953_read_ind(struct ub953_data *priv, u8 block, u8 reg, u8 *val,
 		dev_err(&priv->client->dev,
 			"Write to IND_ACC_DATA failed when reading %u:0x%02x: %d\n",
 			block, reg, ret);
-		goto out_unlock;
+		goto err;
 	}
 
 	*val = v;
 
-out_unlock:
-	mutex_unlock(&priv->reg_lock);
-
+err:
 	if (ret && err)
 		*err = ret;
 
@@ -227,18 +221,18 @@ static int ub953_write_ind(struct ub953_data *priv, u8 block, u8 reg, u8 val,
 	if (err && *err)
 		return *err;
 
-	mutex_lock(&priv->reg_lock);
+	guard(mutex)(&priv->reg_lock);
 
 	ret = ub953_select_ind_reg_block(priv, block);
 	if (ret)
-		goto out_unlock;
+		goto err;
 
 	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
 	if (ret) {
 		dev_err(&priv->client->dev,
 			"Write to IND_ACC_ADDR failed when writing %u:0x%02x: %d\n",
 			block, reg, ret);
-		goto out_unlock;
+		goto err;
 	}
 
 	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_DATA, val);
@@ -248,9 +242,7 @@ static int ub953_write_ind(struct ub953_data *priv, u8 block, u8 reg, u8 val,
 			block, reg, ret);
 	}
 
-out_unlock:
-	mutex_unlock(&priv->reg_lock);
-
+err:
 	if (ret && err)
 		*err = ret;
 

-- 
2.34.1
Re: [PATCH v5 4/4] media: i2c: ds90ub953: use guard() to simplify code
Posted by Tomi Valkeinen 3 weeks ago 
Hi,

On 28/02/2026 08:18, Guoniu Zhou wrote:
> From: Guoniu Zhou <guoniu.zhou@nxp.com>
> 
> Use guard() to simplify mutex locking. No functional change.

That's not strictly true, as the unlock will happen later with this
patch. Still, this cleanup makes sense.

> 
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Guoniu Zhou <guoniu.zhou@nxp.com>
> ---
>  drivers/media/i2c/ds90ub953.c | 34 +++++++++++++---------------------
>  1 file changed, 13 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/media/i2c/ds90ub953.c b/drivers/media/i2c/ds90ub953.c
> index a85c6a9b64070491db161ca1586179dba9c69cb0..3a459687aefce05ac025a517c8d4cc6d76cd7293 100644
> --- a/drivers/media/i2c/ds90ub953.c
> +++ b/drivers/media/i2c/ds90ub953.c
> @@ -113,20 +113,18 @@ static int ub953_read(struct ub953_data *priv, u8 reg, u8 *val, int *err)
>  	if (err && *err)
>  		return *err;
>  
> -	mutex_lock(&priv->reg_lock);
> +	guard(mutex)(&priv->reg_lock);
>  
>  	ret = regmap_read(priv->regmap, reg, &v);
>  	if (ret) {
>  		dev_err(&priv->client->dev, "Cannot read register 0x%02x: %d\n",
>  			reg, ret);
> -		goto out_unlock;
> +		goto err;
>  	}
>  
>  	*val = v;
>  
> -out_unlock:
> -	mutex_unlock(&priv->reg_lock);
> -
> +err:

I think the label should be just "out", as this is not an error path
(even if we jump to the label when handling an error). Similar comment
to the below cases.

>  	if (ret && err)
>  		*err = ret;
>  
> @@ -140,15 +138,13 @@ static int ub953_write(struct ub953_data *priv, u8 reg, u8 val, int *err)
>  	if (err && *err)
>  		return *err;
>  
> -	mutex_lock(&priv->reg_lock);
> +	guard(mutex)(&priv->reg_lock);
>  
>  	ret = regmap_write(priv->regmap, reg, val);
>  	if (ret)
>  		dev_err(&priv->client->dev,
>  			"Cannot write register 0x%02x: %d\n", reg, ret);
>  
> -	mutex_unlock(&priv->reg_lock);
> -
>  	if (ret && err)
>  		*err = ret;
>  
> @@ -185,18 +181,18 @@ static int ub953_read_ind(struct ub953_data *priv, u8 block, u8 reg, u8 *val,
>  	if (err && *err)
>  		return *err;
>  
> -	mutex_lock(&priv->reg_lock);
> +	guard(mutex)(&priv->reg_lock);
>  
>  	ret = ub953_select_ind_reg_block(priv, block);
>  	if (ret)
> -		goto out_unlock;
> +		goto err;
>  
>  	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
>  	if (ret) {
>  		dev_err(&priv->client->dev,
>  			"Write to IND_ACC_ADDR failed when reading %u:0x%02x: %d\n",
>  			block, reg, ret);
> -		goto out_unlock;
> +		goto err;
>  	}
>  
>  	ret = regmap_read(priv->regmap, UB953_REG_IND_ACC_DATA, &v);
> @@ -204,14 +200,12 @@ static int ub953_read_ind(struct ub953_data *priv, u8 block, u8 reg, u8 *val,
>  		dev_err(&priv->client->dev,
>  			"Write to IND_ACC_DATA failed when reading %u:0x%02x: %d\n",
>  			block, reg, ret);
> -		goto out_unlock;
> +		goto err;
>  	}
>  
>  	*val = v;
>  
> -out_unlock:
> -	mutex_unlock(&priv->reg_lock);
> -
> +err:
>  	if (ret && err)
>  		*err = ret;
>  
> @@ -227,18 +221,18 @@ static int ub953_write_ind(struct ub953_data *priv, u8 block, u8 reg, u8 val,
>  	if (err && *err)
>  		return *err;
>  
> -	mutex_lock(&priv->reg_lock);
> +	guard(mutex)(&priv->reg_lock);
>  
>  	ret = ub953_select_ind_reg_block(priv, block);
>  	if (ret)
> -		goto out_unlock;
> +		goto err;
>  
>  	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_ADDR, reg);
>  	if (ret) {
>  		dev_err(&priv->client->dev,
>  			"Write to IND_ACC_ADDR failed when writing %u:0x%02x: %d\n",
>  			block, reg, ret);
> -		goto out_unlock;
> +		goto err;
>  	}
>  
>  	ret = regmap_write(priv->regmap, UB953_REG_IND_ACC_DATA, val);
> @@ -248,9 +242,7 @@ static int ub953_write_ind(struct ub953_data *priv, u8 block, u8 reg, u8 val,
>  			block, reg, ret);
>  	}
>  
> -out_unlock:
> -	mutex_unlock(&priv->reg_lock);
> -
> +err:
>  	if (ret && err)
>  		*err = ret;
>  
>

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