linux-kernel - [PATCH v2 3/5] net: can: mcp251x: propagate the return value of mcp251x_spi

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Message-Id: <20250616-gpiochip-set-rv-net-v2-3-cae0b182a552@linaro.org>
Date: Mon, 16 Jun 2025 09:24:06 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: 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>, 
 Bartosz Golaszewski <brgl@...ev.pl>, 
 "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>, 
 Vincent Mailhol <mailhol.vincent@...adoo.fr>, 
 Heiner Kallweit <hkallweit1@...il.com>, 
 Russell King <linux@...linux.org.uk>
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>
Subject: [PATCH v2 3/5] net: can: mcp251x: propagate the return value of
 mcp251x_spi_write()

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Add an integer return value to mcp251x_write_bits() and use it to
propagate the one returned by mcp251x_spi_write(). Return that value on
error in the request() GPIO callback.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/net/can/spi/mcp251x.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index ec5c64006a16f703bc816983765584c5f3ac76e8..60b7fd3040d02f114693cf66d61c8a075a32e278 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -388,8 +388,8 @@ static void mcp251x_write_2regs(struct spi_device *spi, u8 reg, u8 v1, u8 v2)
 	mcp251x_spi_write(spi, 4);
 }

-static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
-			       u8 mask, u8 val)
+static int mcp251x_write_bits(struct spi_device *spi, u8 reg,
+			      u8 mask, u8 val)
 {
 	struct mcp251x_priv *priv = spi_get_drvdata(spi);

@@ -398,7 +398,7 @@ static void mcp251x_write_bits(struct spi_device *spi, u8 reg,
 	priv->spi_tx_buf[2] = mask;
 	priv->spi_tx_buf[3] = val;

-	mcp251x_spi_write(spi, 4);
+	return mcp251x_spi_write(spi, 4);
 }

 static u8 mcp251x_read_stat(struct spi_device *spi)
@@ -441,6 +441,7 @@ static int mcp251x_gpio_request(struct gpio_chip *chip,
 				unsigned int offset)
 {
 	struct mcp251x_priv *priv = gpiochip_get_data(chip);
+	int ret;
 	u8 val;

 	/* nothing to be done for inputs */
@@ -450,8 +451,10 @@ static int mcp251x_gpio_request(struct gpio_chip *chip,
 	val = BFPCTRL_BFE(offset - MCP251X_GPIO_RX0BF);

 	mutex_lock(&priv->mcp_lock);
-	mcp251x_write_bits(priv->spi, BFPCTRL, val, val);
+	ret = mcp251x_write_bits(priv->spi, BFPCTRL, val, val);
 	mutex_unlock(&priv->mcp_lock);
+	if (ret)
+		return ret;

 	priv->reg_bfpctrl |= val;

-- 
2.48.1