[PATCH net-next] net: dsa: mt7530: Constify struct regmap_config

[PATCH net-next] net: dsa: mt7530: Constify struct regmap_config

[Christophe JAILLET]

'struct regmap_config' are not modified in these drivers. They be
statically defined instead of allocated and populated at run-time.

The main benefits are:
  - it saves some memory at runtime
  - the structures can be declared as 'const', which is always better for
    structures that hold some function pointers
  - the code is less verbose

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/net/dsa/mt7530-mdio.c | 21 +++++++++------------
 drivers/net/dsa/mt7530-mmio.c | 21 ++++++++++-----------
 2 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/drivers/net/dsa/mt7530-mdio.c b/drivers/net/dsa/mt7530-mdio.c
index 51df42ccdbe6..0286a6cecb6f 100644
--- a/drivers/net/dsa/mt7530-mdio.c
+++ b/drivers/net/dsa/mt7530-mdio.c
@@ -136,10 +136,17 @@ static const struct of_device_id mt7530_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mt7530_of_match);
 
+static const struct regmap_config regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = MT7530_CREV,
+	.disable_locking = true,
+};
+
 static int
 mt7530_probe(struct mdio_device *mdiodev)
 {
-	static struct regmap_config *regmap_config;
 	struct mt7530_priv *priv;
 	struct device_node *dn;
 	int ret;
@@ -193,18 +200,8 @@ mt7530_probe(struct mdio_device *mdiodev)
 			return PTR_ERR(priv->io_pwr);
 	}
 
-	regmap_config = devm_kzalloc(&mdiodev->dev, sizeof(*regmap_config),
-				     GFP_KERNEL);
-	if (!regmap_config)
-		return -ENOMEM;
-
-	regmap_config->reg_bits = 16;
-	regmap_config->val_bits = 32;
-	regmap_config->reg_stride = 4;
-	regmap_config->max_register = MT7530_CREV;
-	regmap_config->disable_locking = true;
 	priv->regmap = devm_regmap_init(priv->dev, &mt7530_regmap_bus, priv,
-					regmap_config);
+					&regmap_config);
 	if (IS_ERR(priv->regmap))
 		return PTR_ERR(priv->regmap);
 
diff --git a/drivers/net/dsa/mt7530-mmio.c b/drivers/net/dsa/mt7530-mmio.c
index 842d74268e77..1dc8b93fb51a 100644
--- a/drivers/net/dsa/mt7530-mmio.c
+++ b/drivers/net/dsa/mt7530-mmio.c
@@ -18,10 +18,17 @@ static const struct of_device_id mt7988_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mt7988_of_match);
 
+static const struct regmap_config sw_regmap_config = {
+	.name = "switch",
+	.reg_bits = 16,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = MT7530_CREV,
+};
+
 static int
 mt7988_probe(struct platform_device *pdev)
 {
-	static struct regmap_config *sw_regmap_config;
 	struct mt7530_priv *priv;
 	void __iomem *base_addr;
 	int ret;
@@ -49,16 +56,8 @@ mt7988_probe(struct platform_device *pdev)
 		return -ENXIO;
 	}
 
-	sw_regmap_config = devm_kzalloc(&pdev->dev, sizeof(*sw_regmap_config), GFP_KERNEL);
-	if (!sw_regmap_config)
-		return -ENOMEM;
-
-	sw_regmap_config->name = "switch";
-	sw_regmap_config->reg_bits = 16;
-	sw_regmap_config->val_bits = 32;
-	sw_regmap_config->reg_stride = 4;
-	sw_regmap_config->max_register = MT7530_CREV;
-	priv->regmap = devm_regmap_init_mmio(&pdev->dev, base_addr, sw_regmap_config);
+	priv->regmap = devm_regmap_init_mmio(&pdev->dev, base_addr,
+					     &sw_regmap_config);
 	if (IS_ERR(priv->regmap))
 		return PTR_ERR(priv->regmap);
 
-- 
2.50.1

Re: [PATCH net-next] net: dsa: mt7530: Constify struct regmap_config

[Daniel Golle]

On Sun, Jul 13, 2025 at 05:09:24PM +0200, Christophe JAILLET wrote:
> 'struct regmap_config' are not modified in these drivers. They be
> statically defined instead of allocated and populated at run-time.
> 
> The main benefits are:
>   - it saves some memory at runtime
>   - the structures can be declared as 'const', which is always better for
>     structures that hold some function pointers
>   - the code is less verbose
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  drivers/net/dsa/mt7530-mdio.c | 21 +++++++++------------
>  drivers/net/dsa/mt7530-mmio.c | 21 ++++++++++-----------
>  2 files changed, 19 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/net/dsa/mt7530-mdio.c b/drivers/net/dsa/mt7530-mdio.c
> index 51df42ccdbe6..0286a6cecb6f 100644
> --- a/drivers/net/dsa/mt7530-mdio.c
> +++ b/drivers/net/dsa/mt7530-mdio.c
> @@ -136,10 +136,17 @@ static const struct of_device_id mt7530_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, mt7530_of_match);
>  
> +static const struct regmap_config regmap_config = {

Maybe calling this one 'regmap_config_mdio'...


> +	.reg_bits = 16,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = MT7530_CREV,
> +	.disable_locking = true,
> +};
> +
> ...

> diff --git a/drivers/net/dsa/mt7530-mmio.c b/drivers/net/dsa/mt7530-mmio.c
> index 842d74268e77..1dc8b93fb51a 100644
> --- a/drivers/net/dsa/mt7530-mmio.c
> +++ b/drivers/net/dsa/mt7530-mmio.c
> @@ -18,10 +18,17 @@ static const struct of_device_id mt7988_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, mt7988_of_match);
>  
> +static const struct regmap_config sw_regmap_config = {

... and this one 'regmap_config_mmio' would be a bit nicer.

> +	.name = "switch",
> +	.reg_bits = 16,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = MT7530_CREV,
> +};
> +

Other than that:

Reviewed-by: Daniel Golle <daniel@makrotopia.org>

Re: [PATCH net-next] net: dsa: mt7530: Constify struct regmap_config

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Sun, 13 Jul 2025 17:09:24 +0200 you wrote:
> 'struct regmap_config' are not modified in these drivers. They be
> statically defined instead of allocated and populated at run-time.
> 
> The main benefits are:
>   - it saves some memory at runtime
>   - the structures can be declared as 'const', which is always better for
>     structures that hold some function pointers
>   - the code is less verbose
> 
> [...]

Here is the summary with links:
  - [net-next] net: dsa: mt7530: Constify struct regmap_config
    https://git.kernel.org/netdev/net-next/c/9eb73f92a0b0

You are awesome, thank you!
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