linux-kernel - Re: [PATCH 3/4] net: can: mcp251x: use new GPIO line value setter callbacks

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Message-ID: <b2f87cff-3a81-482b-bfdd-389950b7ec8e@wanadoo.fr>
Date: Tue, 10 Jun 2025 22:55:02 +0900
From: Vincent Mailhol <mailhol.vincent@...adoo.fr>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-gpio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-mediatek@...ts.infradead.org, linux-can@...r.kernel.org,
 linux-arm-msm@...r.kernel.org,
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
 Andrew Lunn <andrew@...n.ch>, Vladimir Oltean <olteanv@...il.com>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 Linus Walleij <linus.walleij@...aro.org>,
 "Chester A. Unal" <chester.a.unal@...nc9.com>,
 Daniel Golle <daniel@...rotopia.org>, DENG Qingfang <dqfext@...il.com>,
 Sean Wang <sean.wang@...iatek.com>, Matthias Brugger
 <matthias.bgg@...il.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 Marc Kleine-Budde <mkl@...gutronix.de>,
 Heiner Kallweit <hkallweit1@...il.com>, Russell King <linux@...linux.org.uk>
Subject: Re: [PATCH 3/4] net: can: mcp251x: use new GPIO line value setter
 callbacks

On 10/06/2025 at 21:37, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> struct gpio_chip now has callbacks for setting line values that return
> an integer, allowing to indicate failures. Convert the driver to using
> them.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This does not match the address with which you sent the patch: brgl@...ev.pl

> ---
>  drivers/net/can/spi/mcp251x.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> index ec5c64006a16f703bc816983765584c5f3ac76e8..7545497d14b46c6388f3976c2bf7b9a99e959c1e 100644
> --- a/drivers/net/can/spi/mcp251x.c
> +++ b/drivers/net/can/spi/mcp251x.c
> @@ -530,8 +530,8 @@ static int mcp251x_gpio_get_multiple(struct gpio_chip *chip,
>  	return 0;
>  }
>  
> -static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> -			     int value)
> +static int mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
> +			    int value)
>  {
>  	struct mcp251x_priv *priv = gpiochip_get_data(chip);
>  	u8 mask, val;
> @@ -545,9 +545,11 @@ static void mcp251x_gpio_set(struct gpio_chip *chip, unsigned int offset,
>  
>  	priv->reg_bfpctrl &= ~mask;
>  	priv->reg_bfpctrl |= val;
> +
> +	return 0;

mcp251x_gpio_set() calls mcp251x_write_bits() which calls mcp251x_spi_write()
which can fail.

For this change to really make sense, the return value of mcp251x_spi_write()
should be propagated all the way around.

>  }
>  
> -static void
> +static int
>  mcp251x_gpio_set_multiple(struct gpio_chip *chip,
>  			  unsigned long *maskp, unsigned long *bitsp)
>  {
> @@ -561,7 +563,7 @@ mcp251x_gpio_set_multiple(struct gpio_chip *chip,
>  	val = FIELD_PREP(BFPCTRL_BFS_MASK, val);
>  
>  	if (!mask)
> -		return;
> +		return 0;
>  
>  	mutex_lock(&priv->mcp_lock);
>  	mcp251x_write_bits(priv->spi, BFPCTRL, mask, val);
> @@ -569,6 +571,8 @@ mcp251x_gpio_set_multiple(struct gpio_chip *chip,
>  
>  	priv->reg_bfpctrl &= ~mask;
>  	priv->reg_bfpctrl |= val;
> +
> +	return 0;

Same as above.

>  }
>  
>  static void mcp251x_gpio_restore(struct spi_device *spi)
> @@ -594,8 +598,8 @@ static int mcp251x_gpio_setup(struct mcp251x_priv *priv)
>  	gpio->get_direction = mcp251x_gpio_get_direction;
>  	gpio->get = mcp251x_gpio_get;
>  	gpio->get_multiple = mcp251x_gpio_get_multiple;
> -	gpio->set = mcp251x_gpio_set;
> -	gpio->set_multiple = mcp251x_gpio_set_multiple;
> +	gpio->set_rv = mcp251x_gpio_set;
> +	gpio->set_multiple_rv = mcp251x_gpio_set_multiple;
>  	gpio->base = -1;
>  	gpio->ngpio = ARRAY_SIZE(mcp251x_gpio_names);
>  	gpio->names = mcp251x_gpio_names;
> 

Yours sincerely,
Vincent Mailhol