This patch adds support for the PCA9570 I2C GPO expander. Signed-off-by: Sungbo Eo <man...@gorani.run> --- Tested in kernel 5.4 on an ipq40xx platform.
This is my first time submitting a whole driver patch, and I'm not really familiar with this PCA expander series. Please let me know how I can improve this patch further. (Do I also need to document the DT compatible string?) FYI there's an unmerged patch for this chip. http://driverdev.linuxdriverproject.org/pipermail/driverdev-devel/2017-May/105602.html I don't have PCA9571 either so I didn't add support for it. --- drivers/gpio/Kconfig | 8 ++ drivers/gpio/Makefile | 1 + drivers/gpio/gpio-pca9570.c | 159 ++++++++++++++++++++++++++++++++++++ 3 files changed, 168 insertions(+) create mode 100644 drivers/gpio/gpio-pca9570.c diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index c6b5c65c8405..d10dcb81b841 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -962,6 +962,14 @@ config GPIO_PCA953X_IRQ Say yes here to enable the pca953x to be used as an interrupt controller. It requires the driver to be built in the kernel. +config GPIO_PCA9570 + tristate "PCA9570 4-Bit I2C GPO expander" + help + Say yes here to enable the GPO driver for the NXP PCA9570 chip. + + To compile this driver as a module, choose M here: the module will + be called gpio-pca9570. + config GPIO_PCF857X tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders" select GPIOLIB_IRQCHIP diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 1e4894e0bf0f..33cb40c28a61 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -110,6 +110,7 @@ obj-$(CONFIG_GPIO_OCTEON) += gpio-octeon.o obj-$(CONFIG_GPIO_OMAP) += gpio-omap.o obj-$(CONFIG_GPIO_PALMAS) += gpio-palmas.o obj-$(CONFIG_GPIO_PCA953X) += gpio-pca953x.o +obj-$(CONFIG_GPIO_PCA9570) += gpio-pca9570.o obj-$(CONFIG_GPIO_PCF857X) += gpio-pcf857x.o obj-$(CONFIG_GPIO_PCH) += gpio-pch.o obj-$(CONFIG_GPIO_PCIE_IDIO_24) += gpio-pcie-idio-24.o diff --git a/drivers/gpio/gpio-pca9570.c b/drivers/gpio/gpio-pca9570.c new file mode 100644 index 000000000000..9ed01554f5df --- /dev/null +++ b/drivers/gpio/gpio-pca9570.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for PCA9570 I2C GPO expander + * + * Copyright (C) 2020 Sungbo Eo <man...@gorani.run> + * + * Based on gpio-tpic2810.c + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/ + * Andrew F. Davis <a...@ti.com> + */ + +#include <linux/gpio/driver.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mutex.h> + +/** + * struct pca9570 - GPIO driver data + * @chip: GPIO controller chip + * @client: I2C device pointer + * @buffer: Buffer for device register + * @lock: Protects write sequences + */ +struct pca9570 { + struct gpio_chip chip; + struct i2c_client *client; + u8 buffer; + struct mutex lock; +}; + +static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value); + +static int pca9570_get_direction(struct gpio_chip *chip, + unsigned offset) +{ + /* This device always output */ + return GPIO_LINE_DIRECTION_OUT; +} + +static int pca9570_direction_input(struct gpio_chip *chip, + unsigned offset) +{ + /* This device is output only */ + return -EINVAL; +} + +static int pca9570_direction_output(struct gpio_chip *chip, + unsigned offset, int value) +{ + /* This device always output */ + pca9570_set(chip, offset, value); + return 0; +} + +static void pca9570_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits) +{ + struct pca9570 *gpio = gpiochip_get_data(chip); + u8 buffer; + int err; + + mutex_lock(&gpio->lock); + + buffer = gpio->buffer & ~mask; + buffer |= (mask & bits); + + err = i2c_smbus_write_byte(gpio->client, buffer); + if (!err) + gpio->buffer = buffer; + + mutex_unlock(&gpio->lock); +} + +static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value) +{ + pca9570_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0); +} + +static void pca9570_set_multiple(struct gpio_chip *chip, unsigned long *mask, + unsigned long *bits) +{ + pca9570_set_mask_bits(chip, *mask, *bits); +} + +static const struct gpio_chip template_chip = { + .label = "pca9570", + .owner = THIS_MODULE, + .get_direction = pca9570_get_direction, + .direction_input = pca9570_direction_input, + .direction_output = pca9570_direction_output, + .set = pca9570_set, + .set_multiple = pca9570_set_multiple, + .base = -1, + .ngpio = 4, + .can_sleep = true, +}; + +static const struct of_device_id pca9570_of_match_table[] = { + { .compatible = "nxp,pca9570" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, pca9570_of_match_table); + +static int pca9570_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct pca9570 *gpio; + int ret; + + gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL); + if (!gpio) + return -ENOMEM; + + i2c_set_clientdata(client, gpio); + + gpio->chip = template_chip; + gpio->chip.parent = &client->dev; + + gpio->client = client; + + mutex_init(&gpio->lock); + + ret = gpiochip_add_data(&gpio->chip, gpio); + if (ret < 0) { + dev_err(&client->dev, "Unable to register gpiochip\n"); + return ret; + } + + return 0; +} + +static int pca9570_remove(struct i2c_client *client) +{ + struct pca9570 *gpio = i2c_get_clientdata(client); + + gpiochip_remove(&gpio->chip); + + return 0; +} + +static const struct i2c_device_id pca9570_id_table[] = { + { "pca9570", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(i2c, pca9570_id_table); + +static struct i2c_driver pca9570_driver = { + .driver = { + .name = "pca9570", + .of_match_table = pca9570_of_match_table, + }, + .probe = pca9570_probe, + .remove = pca9570_remove, + .id_table = pca9570_id_table, +}; +module_i2c_driver(pca9570_driver); + +MODULE_AUTHOR("Sungbo Eo <man...@gorani.run>"); +MODULE_DESCRIPTION("GPIO expander driver for PCA9570"); +MODULE_LICENSE("GPL v2"); -- 2.27.0
