[PATCH v2 08/24] gpio: Add ZTE ZX279128S GPIO driver

[Bartosz Golaszewski]

On Wed, 14 Oct 2026 09:20:48 +0200, Navid Ghahremani
<ghahramani.navid at gmail.com> said:
> Expose the six banks using the generic GPIO implementation and enable
> the register clock before accessing the bank.
>
> Signed-off-by: Navid Ghahremani <ghahramani.navid at gmail.com>
> ---
>  drivers/gpio/Kconfig          | 12 ++++++
>  drivers/gpio/Makefile         |  1 +
>  drivers/gpio/gpio-zx279128s.c | 79 +++++++++++++++++++++++++++++++++++
>  3 files changed, 92 insertions(+)
>  create mode 100644 drivers/gpio/gpio-zx279128s.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index a48586bb8e..3ae51a3c10 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -902,6 +902,18 @@ config GPIO_ZEVIO
>  	help
>  	  Say yes here to support the GPIO controller in LSI ZEVIO SoCs.
>
> +config GPIO_ZX279128S
> +	tristate "ZTE zx279128s GPIO support"
> +	depends on ARCH_ZTE || COMPILE_TEST
> +	select GPIO_GENERIC
> +	help
> +	  Say yes here to support the GPIO controller of the ZTE zx279128s
> +	  SoC. It has several banks of 16 lines each, which boards such as
> +	  the ZTE ZXHN H3600 use for LEDs, buttons and reset lines.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called gpio-zx279128s.
> +
>  config GPIO_ZYNQ
>  	tristate "Xilinx Zynq GPIO support"
>  	depends on ARCH_ZYNQ || ARCH_ZYNQMP || COMPILE_TEST
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index dc9e6d643b..a57ed7ec71 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -223,5 +223,6 @@ obj-$(CONFIG_GPIO_XLP)			+= gpio-xlp.o
>  obj-$(CONFIG_GPIO_XRA1403)		+= gpio-xra1403.o
>  obj-$(CONFIG_GPIO_XTENSA)		+= gpio-xtensa.o
>  obj-$(CONFIG_GPIO_ZEVIO)		+= gpio-zevio.o
> +obj-$(CONFIG_GPIO_ZX279128S)		+= gpio-zx279128s.o
>  obj-$(CONFIG_GPIO_ZYNQ)			+= gpio-zynq.o
>  obj-$(CONFIG_GPIO_ZYNQMP_MODEPIN)	+= gpio-zynqmp-modepin.o
> diff --git a/drivers/gpio/gpio-zx279128s.c b/drivers/gpio/gpio-zx279128s.c
> new file mode 100644
> index 0000000000..71eb6b5d82
> --- /dev/null
> +++ b/drivers/gpio/gpio-zx279128s.c
> @@ -0,0 +1,79 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ZTE zx279128s GPIO controller
> + *
> + * Copyright (C) 2026 Navid Ghahremani <ghahramani.navid at gmail.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/gpio/generic.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +/*
> + * Each bank has 16 lines, one bit per line in each register. The registers
> + * at 0x04-0x10 and 0x28-0x34 control the interrupts, which are not supported
> + * yet.
> + */
> +#define ZX279128S_GPIO_DIR	0x00	/* 1: output */
> +#define ZX279128S_GPIO_DATA	0x14	/* line level */
> +#define ZX279128S_GPIO_SET	0x18	/* write 1: drive high */
> +#define ZX279128S_GPIO_CLEAR	0x1c	/* write 1: drive low */
> +
> +static int zx279128s_gpio_probe(struct platform_device *pdev)
> +{
> +	struct gpio_generic_chip_config config = { };

Don't initialize it here, instead...

> +	struct device *dev = &pdev->dev;
> +	struct gpio_generic_chip *chip;
> +	void __iomem *base;
> +	struct clk *clk;
> +	int ret;
> +
> +	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
> +	if (!chip)
> +		return -ENOMEM;
> +
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(clk))
> +		return dev_err_probe(dev, PTR_ERR(clk), "failed to get the clock\n");
> +
> +	config.dev = dev;
> +	config.sz = 4;
> +	config.dat = base + ZX279128S_GPIO_DATA;
> +	config.set = base + ZX279128S_GPIO_SET;
> +	config.clr = base + ZX279128S_GPIO_CLEAR;
> +	config.dirout = base + ZX279128S_GPIO_DIR;
> +

... do:

	config = (struct gpio_generic_chip){
		.dev = dev,
		...
	};

> +	ret = gpio_generic_chip_init(chip, &config);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to set up the GPIO chip\n");
> +
> +	chip->gc.ngpio = 16;
> +
> +	return devm_gpiochip_add_data(dev, &chip->gc, NULL);
> +}
> +
> +static const struct of_device_id zx279128s_gpio_of_match[] = {
> +	{ .compatible = "zte,zx279128s-gpio" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, zx279128s_gpio_of_match);
> +
> +static struct platform_driver zx279128s_gpio_driver = {
> +	.probe = zx279128s_gpio_probe,
> +	.driver = {
> +		.name = "zx279128s-gpio",
> +		.of_match_table = zx279128s_gpio_of_match,
> +	},
> +};
> +module_platform_driver(zx279128s_gpio_driver);
> +
> +MODULE_AUTHOR("Navid Ghahremani <ghahramani.navid at gmail.com>");
> +MODULE_DESCRIPTION("ZTE zx279128s GPIO controller driver");
> +MODULE_LICENSE("GPL");
> --
> 2.55.0
>
>

Looks pretty good, I love small drivers like this.

Bart