Re: [PATCH v5 5/6] can: mcp251xfd: add gpio functionality

[Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>]

On 9/29/2025 7:08 PM, Bartosz Golaszewski wrote:
> On Fri, Sep 26, 2025 at 3:30 PM Viken Dadhaniya
> <viken.dadhaniya@oss.qualcomm.com> wrote:
>>
>> 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.
>>
>> 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    | 172 ++++++++++++++++++
>>  drivers/net/can/spi/mcp251xfd/mcp251xfd.h     |   2 +
>>  3 files changed, 175 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..88035d4404b5 100644
>> --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
>> +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
>> @@ -1797,6 +1797,172 @@ 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;
>> +       int ret;
>> +
>> +       if (value)
>> +               val = val_mask;
>> +       else
>> +               val = 0;
>> +
>> +       ret = regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON, val_mask, val);
>> +       if (ret)
>> +               dev_err(&priv->spi->dev, "Failed to set GPIO %u: %d\n", offset, ret);
> 
> Why do you loudly complain here but not in other callbacks? I assume
> it's because you had a log here in your previous version (the one
> rebased on v6.16) and just didn't remove it when you switched to the
> new API? Maybe just do `return regmap_update...`?

Sure, I’ll update and post v6.

> 
> Otherwise looks good. With that addressed:
> 
> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
>> +
>> +       return ret;
>> +}
>> +
>> +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;
>> +       int ret;
>> +
>> +       val = FIELD_PREP(MCP251XFD_REG_IOCON_LAT_MASK, *bits);
>> +
>> +       ret = regmap_update_bits(priv->map_reg, MCP251XFD_REG_IOCON,
>> +                                MCP251XFD_REG_IOCON_LAT_MASK, val);
>> +       if (ret)
>> +               dev_err(&priv->spi->dev, "Failed to set GPIOs %d\n", ret);
>> +
>> +       return ret;
>> +}
>> +
>> +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 +2096,12 @@ 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
>>