[PATCH v3] mfd: twl-core: Allocate modules with twl_private

[PATCH v3] mfd: twl-core: Allocate modules with twl_private

[Rosen Penev]

Use a flexible array member to allocate the twl_client array together
with struct twl_private. This removes a separate devm_kcalloc() and
keeps the module data tied to the main private structure.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 v3: Capitalize Allocate.
 v2: don't use twl_get_num_slaves().
 drivers/mfd/twl-core.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index f86df356d658..0b78fe30e047 100644
--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -159,7 +159,7 @@ struct twl_private {
 	unsigned int twl_id;
 
 	struct twl_mapping *twl_map;
-	struct twl_client *twl_modules;
+	struct twl_client twl_modules[];
 };
 
 static struct twl_private *twl_priv;
@@ -770,7 +770,9 @@ twl_probe(struct i2c_client *client)
 		goto out;
 	}
 
-	twl_priv = devm_kzalloc(&client->dev, sizeof(struct twl_private),
+	num_slaves = (id->driver_data & TWL6030_CLASS) ? 3 : 4;
+	twl_priv = devm_kzalloc(&client->dev,
+				struct_size(twl_priv, twl_modules, num_slaves),
 				GFP_KERNEL);
 	if (!twl_priv) {
 		status = -ENOMEM;
@@ -787,16 +789,6 @@ twl_probe(struct i2c_client *client)
 		twl_regmap_config = twl4030_regmap_config;
 	}
 
-	num_slaves = twl_get_num_slaves();
-	twl_priv->twl_modules = devm_kcalloc(&client->dev,
-					 num_slaves,
-					 sizeof(struct twl_client),
-					 GFP_KERNEL);
-	if (!twl_priv->twl_modules) {
-		status = -ENOMEM;
-		goto out;
-	}
-
 	for (i = 0; i < num_slaves; i++) {
 		struct twl_client *twl = &twl_priv->twl_modules[i];
 
-- 
2.55.0

Re: [PATCH v3] mfd: twl-core: Allocate modules with twl_private

[Lee Jones]

On Fri, 25 Sep 2026, Rosen Penev wrote:

> Use a flexible array member to allocate the twl_client array together
> with struct twl_private. This removes a separate devm_kcalloc() and
> keeps the module data tied to the main private structure.
>
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  v3: Capitalize Allocate.
>  v2: don't use twl_get_num_slaves().
>  drivers/mfd/twl-core.c | 16 ++++------------
>  1 file changed, 4 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
> index f86df356d658..0b78fe30e047 100644
> --- a/drivers/mfd/twl-core.c
> +++ b/drivers/mfd/twl-core.c
> @@ -159,7 +159,7 @@ struct twl_private {
>  	unsigned int twl_id;
>
>  	struct twl_mapping *twl_map;
> -	struct twl_client *twl_modules;
> +	struct twl_client twl_modules[];
>  };
>
>  static struct twl_private *twl_priv;
> @@ -770,7 +770,9 @@ twl_probe(struct i2c_client *client)
>  		goto out;
>  	}
>
> -	twl_priv = devm_kzalloc(&client->dev, sizeof(struct twl_private),
> +	num_slaves = (id->driver_data & TWL6030_CLASS) ? 3 : 4;

What's wrong with twl_get_num_slaves()?

> +	twl_priv = devm_kzalloc(&client->dev,
> +				struct_size(twl_priv, twl_modules, num_slaves),
>  				GFP_KERNEL);
>  	if (!twl_priv) {
>  		status = -ENOMEM;
> @@ -787,16 +789,6 @@ twl_probe(struct i2c_client *client)
>  		twl_regmap_config = twl4030_regmap_config;
>  	}
>
> -	num_slaves = twl_get_num_slaves();
> -	twl_priv->twl_modules = devm_kcalloc(&client->dev,
> -					 num_slaves,
> -					 sizeof(struct twl_client),
> -					 GFP_KERNEL);
> -	if (!twl_priv->twl_modules) {
> -		status = -ENOMEM;
> -		goto out;
> -	}
> -
>  	for (i = 0; i < num_slaves; i++) {
>  		struct twl_client *twl = &twl_priv->twl_modules[i];
>
> -- 
> 2.55.0
>

-- 
Lee Jones