From: Gregor Herburger <gregor.herburger@ew.tq-group.com>

The mcp251xfd devices allow two pins to be configured as gpio. Add this
functionality to driver.

Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Gregor Herburger <gregor.herburger@ew.tq-group.com>
Tested-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
Signed-off-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
---
 drivers/net/can/spi/mcp251xfd/Kconfig         |   1 +
 .../net/can/spi/mcp251xfd/mcp251xfd-core.c    | 160 ++++++++++++++++++
 drivers/net/can/spi/mcp251xfd/mcp251xfd.h     |   2 +
 3 files changed, 163 insertions(+)

diff --git a/drivers/net/can/spi/mcp251xfd/Kconfig b/drivers/net/can/spi/mcp251xfd/Kconfig
index 877e4356010d..7c29846e6051 100644
--- a/drivers/net/can/spi/mcp251xfd/Kconfig
+++ b/drivers/net/can/spi/mcp251xfd/Kconfig
@@ -5,6 +5,7 @@ config CAN_MCP251XFD
 	select CAN_RX_OFFLOAD
 	select REGMAP
 	select WANT_DEV_COREDUMP
+	select GPIOLIB
 	help
 	  Driver for the Microchip MCP251XFD SPI FD-CAN controller
 	  family.
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index ea41f04ae1a6..586336d9e421 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -1797,6 +1797,160 @@ static int mcp251xfd_register_check_rx_int(struct mcp251xfd_priv *priv)
 	return 0;
 }
 
+static const char * const mcp251xfd_gpio_names[] = { "GPIO0", "GPIO1" };
+
+static int mcp251xfd_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 pin_mask = MCP251XFD_REG_IOCON_PM(offset);
+	int ret;
+
+	if (priv->rx_int && offset == 1) {
+		netdev_err(priv->ndev, "Can't use GPIO 1 with RX-INT!\n");
+		return -EINVAL;
+	}
+
+	ret = pm_runtime_resume_and_get(priv->ndev->dev.parent);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON, pin_mask, pin_mask);
+}
+
+static void mcp251xfd_gpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+
+	pm_runtime_put(priv->ndev->dev.parent);
+}
+
+static int mcp251xfd_gpio_get_direction(struct gpio_chip *chip,
+					unsigned int offset)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 mask = MCP251XFD_REG_IOCON_TRIS(offset);
+	u32 val;
+	int ret;
+
+	ret = regmap_read(priv->map_reg, MCP251XFD_REG_IOCON, &val);
+	if (ret)
+		return ret;
+
+	if (mask & val)
+		return GPIO_LINE_DIRECTION_IN;
+
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int mcp251xfd_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 mask = MCP251XFD_REG_IOCON_GPIO(offset);
+	u32 val;
+	int ret;
+
+	ret = regmap_read(priv->map_reg, MCP251XFD_REG_IOCON, &val);
+	if (ret)
+		return ret;
+
+	return !!(mask & val);
+}
+
+static int mcp251xfd_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+				       unsigned long *bit)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 val;
+	int ret;
+
+	ret = regmap_read(priv->map_reg, MCP251XFD_REG_IOCON, &val);
+	if (ret)
+		return ret;
+
+	*bit = FIELD_GET(MCP251XFD_REG_IOCON_GPIO_MASK, val) & *mask;
+
+	return 0;
+}
+
+static int mcp251xfd_gpio_direction_output(struct gpio_chip *chip,
+					   unsigned int offset, int value)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 dir_mask = MCP251XFD_REG_IOCON_TRIS(offset);
+	u32 val_mask = MCP251XFD_REG_IOCON_LAT(offset);
+	u32 val;
+
+	if (value)
+		val = val_mask;
+	else
+		val = 0;
+
+	return regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON,
+				  dir_mask | val_mask, val);
+}
+
+static int mcp251xfd_gpio_direction_input(struct gpio_chip *chip,
+					  unsigned int offset)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 dir_mask = MCP251XFD_REG_IOCON_TRIS(offset);
+
+	return regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON, dir_mask, dir_mask);
+}
+
+static int mcp251xfd_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 val_mask = MCP251XFD_REG_IOCON_LAT(offset);
+	u32 val;
+
+	if (value)
+		val = val_mask;
+	else
+		val = 0;
+
+	return regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON, val_mask, val);
+}
+
+static int mcp251xfd_gpio_set_multiple(struct gpio_chip *chip, unsigned long *mask,
+				       unsigned long *bits)
+{
+	struct mcp251xfd_priv *priv = gpiochip_get_data(chip);
+	u32 val;
+
+	val = FIELD_PREP(MCP251XFD_REG_IOCON_LAT_MASK, *bits);
+
+	return regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON,
+				  MCP251XFD_REG_IOCON_LAT_MASK, val);
+}
+
+static int mcp251fdx_gpio_setup(struct mcp251xfd_priv *priv)
+{
+	struct gpio_chip *gc = &priv->gc;
+
+	if (!device_property_present(&priv->spi->dev, "gpio-controller"))
+		return 0;
+
+	gc->label = dev_name(&priv->spi->dev);
+	gc->parent = &priv->spi->dev;
+	gc->owner = THIS_MODULE;
+	gc->request = mcp251xfd_gpio_request;
+	gc->free = mcp251xfd_gpio_free;
+	gc->get_direction = mcp251xfd_gpio_get_direction;
+	gc->direction_output = mcp251xfd_gpio_direction_output;
+	gc->direction_input = mcp251xfd_gpio_direction_input;
+	gc->get = mcp251xfd_gpio_get;
+	gc->get_multiple = mcp251xfd_gpio_get_multiple;
+	gc->set = mcp251xfd_gpio_set;
+	gc->set_multiple = mcp251xfd_gpio_set_multiple;
+	gc->base = -1;
+	gc->can_sleep = true;
+	gc->ngpio = ARRAY_SIZE(mcp251xfd_gpio_names);
+	gc->names = mcp251xfd_gpio_names;
+
+	return devm_gpiochip_add_data(&priv->spi->dev, gc, priv);
+}
+
 static int
 mcp251xfd_register_get_dev_id(const struct mcp251xfd_priv *priv, u32 *dev_id,
 			      u32 *effective_speed_hz_slow,
@@ -1930,6 +2084,12 @@ static int mcp251xfd_register(struct mcp251xfd_priv *priv)
 
 	mcp251xfd_ethtool_init(priv);
 
+	err = mcp251fdx_gpio_setup(priv);
+	if (err) {
+		dev_err_probe(&priv->spi->dev, err, "Failed to register gpio-controller.\n");
+		goto out_runtime_disable;
+	}
+
 	err = register_candev(ndev);
 	if (err)
 		goto out_runtime_disable;
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
index bd28510a6583..085d7101e595 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h
@@ -15,6 +15,7 @@
 #include <linux/can/dev.h>
 #include <linux/can/rx-offload.h>
 #include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/regmap.h>
@@ -676,6 +677,7 @@ struct mcp251xfd_priv {
 
 	struct mcp251xfd_devtype_data devtype_data;
 	struct can_berr_counter bec;
+	struct gpio_chip gc;
 };
 
 #define MCP251XFD_IS(_model) \
-- 
2.34.1

On Wed, Oct 1, 2025 at 11:10 AM Viken Dadhaniya
<viken.dadhaniya@oss.qualcomm.com> wrote:
> +
> +       if (!device_property_present(&priv->spi->dev, "gpio-controller"))
> +               return 0;
> +

Hi! I didn't notice this before you're returning 0 here, meaning the
device will be attached to the driver even though it doesn't do
anything. It would make more sense to return -ENODEV.

Bart

On 01.10.2025 15:52:56, Bartosz Golaszewski wrote:
> On Wed, Oct 1, 2025 at 11:10 AM Viken Dadhaniya
> <viken.dadhaniya@oss.qualcomm.com> wrote:
> > +
> > +       if (!device_property_present(&priv->spi->dev, "gpio-controller"))
> > +               return 0;
> > +
> 
> Hi! I didn't notice this before you're returning 0 here, meaning the
> device will be attached to the driver even though it doesn't do
> anything. It would make more sense to return -ENODEV.

I consider the GPIO functionality of the mcp251xfd CAN controllers
optional. So if the DT doesn't contain gpio-controller, continue without
GPIO functionality.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

On Wed, Oct 1, 2025 at 3:59 PM Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 01.10.2025 15:52:56, Bartosz Golaszewski wrote:
> > On Wed, Oct 1, 2025 at 11:10 AM Viken Dadhaniya
> > <viken.dadhaniya@oss.qualcomm.com> wrote:
> > > +
> > > +       if (!device_property_present(&priv->spi->dev, "gpio-controller"))
> > > +               return 0;
> > > +
> >
> > Hi! I didn't notice this before you're returning 0 here, meaning the
> > device will be attached to the driver even though it doesn't do
> > anything. It would make more sense to return -ENODEV.
>
> I consider the GPIO functionality of the mcp251xfd CAN controllers
> optional. So if the DT doesn't contain gpio-controller, continue without
> GPIO functionality.
>

Ah, sorry, I thought this was the driver's probe() callback. It's
actually just a function. This could probably be registered as an
auxiliary device for less build-time dependencies but whatever.
Nevermind my last comment.

Bart