Re: [PATCH v2 2/7] gpio: Add Nuvoton NCT6694 GPIO support

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On Thu, Nov 21, 2024 at 7:41 AM Ming Yu <a0282524688@xxxxxxxxx> wrote:
>
> This driver supports GPIO and IRQ functionality for NCT6694 MFD
> device based on USB interface.
>
> Signed-off-by: Ming Yu <tmyu0@xxxxxxxxxxx>
> ---
>  MAINTAINERS                 |   1 +
>  drivers/gpio/Kconfig        |  12 +
>  drivers/gpio/Makefile       |   1 +
>  drivers/gpio/gpio-nct6694.c | 441 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 455 insertions(+)
>  create mode 100644 drivers/gpio/gpio-nct6694.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 9c9a94ff8f98..6688c5c470b7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16545,6 +16545,7 @@ NUVOTON NCT6694 MFD DRIVER
>  M:     Ming Yu <tmyu0@xxxxxxxxxxx>
>  L:     linux-kernel@xxxxxxxxxxxxxxx
>  S:     Supported
> +F:     drivers/gpio/gpio-nct6694.c
>  F:     drivers/mfd/nct6694.c
>  F:     include/linux/mfd/nct6694.h
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 56fee58e281e..7773b5326e60 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -1460,6 +1460,18 @@ config GPIO_MAX77650
>           GPIO driver for MAX77650/77651 PMIC from Maxim Semiconductor.
>           These chips have a single pin that can be configured as GPIO.
>
> +config GPIO_NCT6694
> +       tristate "Nuvoton NCT6694 GPIO controller support"
> +       depends on MFD_NCT6694
> +       select GENERIC_IRQ_CHIP
> +       select GPIOLIB_IRQCHIP
> +       help
> +         This driver supports 8 GPIO pins per bank that can all be interrupt
> +         sources.
> +
> +         This driver can also be built as a module. If so, the module will be
> +         called gpio-nct6694.
> +
>  config GPIO_PALMAS
>         bool "TI PALMAS series PMICs GPIO"
>         depends on MFD_PALMAS
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index af3ba4d81b58..ad80a078b27b 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -123,6 +123,7 @@ obj-$(CONFIG_GPIO_MXC)                      += gpio-mxc.o
>  obj-$(CONFIG_GPIO_MXS)                 += gpio-mxs.o
>  obj-$(CONFIG_GPIO_NOMADIK)             += gpio-nomadik.o
>  obj-$(CONFIG_GPIO_NPCM_SGPIO)          += gpio-npcm-sgpio.o
> +obj-$(CONFIG_GPIO_NCT6694)             += gpio-nct6694.o
>  obj-$(CONFIG_GPIO_OCTEON)              += gpio-octeon.o
>  obj-$(CONFIG_GPIO_OMAP)                        += gpio-omap.o
>  obj-$(CONFIG_GPIO_PALMAS)              += gpio-palmas.o
> diff --git a/drivers/gpio/gpio-nct6694.c b/drivers/gpio/gpio-nct6694.c
> new file mode 100644
> index 000000000000..1776200b3a04
> --- /dev/null
> +++ b/drivers/gpio/gpio-nct6694.c
> @@ -0,0 +1,441 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nuvoton NCT6694 GPIO controller driver based on USB interface.
> + *
> + * Copyright (C) 2024 Nuvoton Technology Corp.
> + */
> +
> +#include <linux/gpio/driver.h>
> +#include <linux/interrupt.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/nct6694.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +/* Host interface */
> +#define NCT6694_GPIO_MOD       0xFF
> +#define NCT6694_GPIO_LEN       0x01
> +
> +/* Report Channel */
> +#define NCT6694_GPIO_VER       0x90
> +#define NCT6694_GPIO_VALID     0x110
> +#define NCT6694_GPI_DATA       0x120
> +#define NCT6694_GPO_DIR                0x170
> +#define NCT6694_GPO_TYPE       0x180
> +#define NCT6694_GPO_DATA       0x190
> +
> +#define NCT6694_GPI_STS                0x130
> +#define NCT6694_GPI_CLR                0x140
> +#define NCT6694_GPI_FALLING    0x150
> +#define NCT6694_GPI_RISING     0x160
> +
> +#define NCT6694_NR_GPIO                8
> +
> +struct nct6694_gpio_data {
> +       struct nct6694 *nct6694;
> +       struct gpio_chip gpio;
> +       struct mutex lock;
> +       /* Protect irq operation */
> +       struct mutex irq_lock;
> +
> +       unsigned char xmit_buf;
> +       unsigned char irq_trig_falling;
> +       unsigned char irq_trig_rising;
> +
> +       /* Current gpio group */
> +       unsigned char group;
> +
> +       /* GPIO line names */
> +       char **names;

You only use this in probe() and after assigning it to gc->names, you
never reference it again. You don't need this field here, it can be a
local variable in probe().

> +};
> +
> +static int nct6694_get_direction(struct gpio_chip *gpio, unsigned int offset)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPO_DIR + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       return !(BIT(offset) & data->xmit_buf);
> +}
> +
> +static int nct6694_direction_input(struct gpio_chip *gpio, unsigned int offset)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPO_DIR + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       data->xmit_buf &= ~(1 << offset);
> +
> +       return nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                NCT6694_GPO_DIR + data->group,
> +                                NCT6694_GPIO_LEN, &data->xmit_buf);
> +}
> +
> +static int nct6694_direction_output(struct gpio_chip *gpio,
> +                                   unsigned int offset, int val)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       /* Set direction to output */
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPO_DIR + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       data->xmit_buf |= (1 << offset);
> +       ret = nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                               NCT6694_GPO_DIR + data->group,
> +                               NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       /* Then set output level */
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPO_DATA + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (val)
> +               data->xmit_buf |= (1 << offset);
> +       else
> +               data->xmit_buf &= ~(1 << offset);
> +
> +       return nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                NCT6694_GPO_DATA + data->group,
> +                                NCT6694_GPIO_LEN, &data->xmit_buf);
> +}
> +
> +static int nct6694_get_value(struct gpio_chip *gpio, unsigned int offset)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPO_DIR + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (BIT(offset) & data->xmit_buf) {
> +               ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                      NCT6694_GPO_DATA + data->group,
> +                                      NCT6694_GPIO_LEN, &data->xmit_buf);
> +               if (ret < 0)
> +                       return ret;
> +
> +               return !!(BIT(offset) & data->xmit_buf);
> +       }
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPI_DATA + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       return !!(BIT(offset) & data->xmit_buf);
> +}
> +
> +static void nct6694_set_value(struct gpio_chip *gpio, unsigned int offset,
> +                             int val)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +
> +       guard(mutex)(&data->lock);
> +
> +       nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                        NCT6694_GPO_DATA + data->group,
> +                        NCT6694_GPIO_LEN, &data->xmit_buf);
> +
> +       if (val)
> +               data->xmit_buf |= (1 << offset);
> +       else
> +               data->xmit_buf &= ~(1 << offset);
> +
> +       nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                         NCT6694_GPO_DATA + data->group,
> +                         NCT6694_GPIO_LEN, &data->xmit_buf);
> +}
> +
> +static int nct6694_set_config(struct gpio_chip *gpio, unsigned int offset,
> +                             unsigned long config)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPO_TYPE + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       switch (pinconf_to_config_param(config)) {
> +       case PIN_CONFIG_DRIVE_OPEN_DRAIN:
> +               data->xmit_buf |= (1 << offset);
> +               break;
> +       case PIN_CONFIG_DRIVE_PUSH_PULL:
> +               data->xmit_buf &= ~(1 << offset);
> +               break;
> +       default:
> +               return -ENOTSUPP;
> +       }
> +
> +       return nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                NCT6694_GPO_TYPE + data->group,
> +                                NCT6694_GPIO_LEN, &data->xmit_buf);
> +}
> +
> +static int nct6694_init_valid_mask(struct gpio_chip *gpio,
> +                                  unsigned long *valid_mask,
> +                                  unsigned int ngpios)
> +{
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPIO_VALID + data->group,
> +                              NCT6694_GPIO_LEN, &data->xmit_buf);
> +       if (ret < 0)
> +               return ret;
> +
> +       *valid_mask = data->xmit_buf;
> +
> +       return ret;
> +}
> +
> +static irqreturn_t nct6694_irq_handler(int irq, void *priv)
> +{
> +       struct nct6694_gpio_data *data = priv;
> +       unsigned char status;
> +
> +       guard(mutex)(&data->lock);
> +
> +       nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                        NCT6694_GPI_STS + data->group,
> +                        NCT6694_GPIO_LEN, &data->xmit_buf);
> +
> +       status = data->xmit_buf;
> +
> +       while (status) {
> +               int bit = __ffs(status);
> +
> +               data->xmit_buf = BIT(bit);
> +               handle_nested_irq(irq_find_mapping(data->gpio.irq.domain, bit));
> +               status &= ~(1 << bit);
> +               nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                 NCT6694_GPI_CLR + data->group,
> +                                 NCT6694_GPIO_LEN, &data->xmit_buf);
> +       }
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static int nct6694_get_irq_trig(struct nct6694_gpio_data *data)
> +{
> +       int ret;
> +
> +       guard(mutex)(&data->lock);
> +
> +       ret = nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                              NCT6694_GPI_FALLING + data->group,
> +                              NCT6694_GPIO_LEN, &data->irq_trig_falling);
> +       if (ret)
> +               return ret;
> +
> +       return nct6694_read_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                               NCT6694_GPI_RISING + data->group,
> +                               NCT6694_GPIO_LEN, &data->irq_trig_rising);
> +}
> +
> +static void nct6694_irq_mask(struct irq_data *d)
> +{
> +       struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
> +       irq_hw_number_t hwirq = irqd_to_hwirq(d);
> +
> +       gpiochip_disable_irq(gpio, hwirq);
> +}
> +
> +static void nct6694_irq_unmask(struct irq_data *d)
> +{
> +       struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
> +       irq_hw_number_t hwirq = irqd_to_hwirq(d);
> +
> +       gpiochip_enable_irq(gpio, hwirq);
> +}
> +
> +static int nct6694_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> +       struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +       irq_hw_number_t hwirq = irqd_to_hwirq(d);
> +
> +       guard(mutex)(&data->lock);
> +
> +       switch (type) {
> +       case IRQ_TYPE_EDGE_RISING:
> +               data->irq_trig_rising |= BIT(hwirq);
> +               break;
> +
> +       case IRQ_TYPE_EDGE_FALLING:
> +               data->irq_trig_falling |= BIT(hwirq);
> +               break;
> +
> +       case IRQ_TYPE_EDGE_BOTH:
> +               data->irq_trig_rising |= BIT(hwirq);
> +               data->irq_trig_falling |= BIT(hwirq);
> +               break;
> +
> +       default:
> +               return -ENOTSUPP;
> +       }
> +
> +       return 0;
> +}
> +
> +static void nct6694_irq_bus_lock(struct irq_data *d)
> +{
> +       struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +
> +       mutex_lock(&data->irq_lock);
> +}
> +
> +static void nct6694_irq_bus_sync_unlock(struct irq_data *d)
> +{
> +       struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
> +       struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
> +
> +       scoped_guard(mutex, &data->lock) {
> +               nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                 NCT6694_GPI_FALLING + data->group,
> +                                 NCT6694_GPIO_LEN, &data->irq_trig_falling);
> +
> +               nct6694_write_msg(data->nct6694, NCT6694_GPIO_MOD,
> +                                 NCT6694_GPI_RISING + data->group,
> +                                 NCT6694_GPIO_LEN, &data->irq_trig_rising);
> +       }
> +
> +       mutex_unlock(&data->irq_lock);
> +}
> +
> +static const struct irq_chip nct6694_irq_chip = {
> +       .name                   = "nct6694-gpio",
> +       .irq_mask               = nct6694_irq_mask,
> +       .irq_unmask             = nct6694_irq_unmask,
> +       .irq_set_type           = nct6694_irq_set_type,
> +       .irq_bus_lock           = nct6694_irq_bus_lock,
> +       .irq_bus_sync_unlock    = nct6694_irq_bus_sync_unlock,
> +       .flags                  = IRQCHIP_IMMUTABLE,
> +       GPIOCHIP_IRQ_RESOURCE_HELPERS,
> +};
> +
> +static int nct6694_gpio_probe(struct platform_device *pdev)
> +{
> +       const struct mfd_cell *cell = mfd_get_cell(pdev);
> +       struct device *dev = &pdev->dev;
> +       struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
> +       struct nct6694_gpio_data *data;
> +       struct gpio_irq_chip *girq;
> +       int ret, irq, i;
> +
> +       irq = irq_create_mapping(nct6694->domain,
> +                                NCT6694_IRQ_GPIO0 + cell->id);
> +       if (!irq)
> +               return -EINVAL;
> +
> +       data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +       if (!data)
> +               return -ENOMEM;
> +
> +       data->names = devm_kzalloc(dev, sizeof(char *) * NCT6694_NR_GPIO,

devm_kcalloc()?

> +                                  GFP_KERNEL);
> +       if (!data->names)
> +               return -ENOMEM;
> +
> +       for (i = 0; i < NCT6694_NR_GPIO; i++) {
> +               data->names[i] = devm_kasprintf(dev, GFP_KERNEL, "GPIO%X%d",
> +                                               cell->id, i);
> +               if (!data->names[i])
> +                       return -ENOMEM;
> +       }
> +
> +       data->nct6694 = nct6694;
> +       data->group = cell->id;
> +
> +       data->gpio.names                = (const char * const*)data->names;
> +       data->gpio.label                = pdev->name;
> +       data->gpio.direction_input      = nct6694_direction_input;
> +       data->gpio.get                  = nct6694_get_value;
> +       data->gpio.direction_output     = nct6694_direction_output;
> +       data->gpio.set                  = nct6694_set_value;
> +       data->gpio.get_direction        = nct6694_get_direction;
> +       data->gpio.set_config           = nct6694_set_config;
> +       data->gpio.init_valid_mask      = nct6694_init_valid_mask;
> +       data->gpio.base                 = -1;
> +       data->gpio.can_sleep            = false;
> +       data->gpio.owner                = THIS_MODULE;
> +       data->gpio.ngpio                = NCT6694_NR_GPIO;
> +
> +       mutex_init(&data->irq_lock);
> +
> +       platform_set_drvdata(pdev, data);

There is no corresponding platform_get_drvdata() so you don't need this.

> +
> +       ret = nct6694_get_irq_trig(data);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to get irq trigger type\n");
> +
> +       /* Register gpio chip to GPIO framework */
> +       girq = &data->gpio.irq;
> +       gpio_irq_chip_set_chip(girq, &nct6694_irq_chip);
> +       girq->parent_handler = NULL;
> +       girq->num_parents = 0;
> +       girq->parents = NULL;
> +       girq->default_type = IRQ_TYPE_NONE;
> +       girq->handler = handle_level_irq;
> +       girq->threaded = true;
> +
> +       ret = devm_request_threaded_irq(dev, irq, NULL, nct6694_irq_handler,
> +                                       IRQF_ONESHOT | IRQF_SHARED,
> +                                       "nct6694-gpio", data);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to request irq\n");
> +
> +       return devm_gpiochip_add_data(dev, &data->gpio, data);
> +}
> +
> +static struct platform_driver nct6694_gpio_driver = {
> +       .driver = {
> +               .name   = "nct6694-gpio",
> +       },
> +       .probe          = nct6694_gpio_probe,
> +};
> +
> +module_platform_driver(nct6694_gpio_driver);
> +
> +MODULE_DESCRIPTION("USB-GPIO controller driver for NCT6694");
> +MODULE_AUTHOR("Ming Yu <tmyu0@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");

It's an MFD device, don't you need a MODULE_ALIAS() for this module to load?

Bart

> --
> 2.34.1
>
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