gpio: Add support for Airoha EN7523 GPIO controller

Airoha's GPIO controller on their ARM EN7523 SoCs consists of two banks of 32
GPIOs. Each instance in DT is for a single bank.

Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

drivers/gpio/Kconfig

@@ -247,6 +247,16 @@ config GPIO_EM
 	help
 	  Say yes here to support GPIO on Renesas Emma Mobile SoCs.
 
+config GPIO_EN7523
+	tristate "Airoha GPIO support"
+	depends on ARCH_AIROHA
+	default ARCH_AIROHA
+	select GPIO_GENERIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Say Y or M here to support the GPIO controller block on the
+	  Airoha EN7523 SoC. It supports two banks of 32 GPIOs.
+
 config GPIO_EP93XX
 	def_bool y
 	depends on ARCH_EP93XX

drivers/gpio/Makefile

@@ -55,6 +55,7 @@ obj-$(CONFIG_GPIO_DLN2)			+= gpio-dln2.o
 obj-$(CONFIG_GPIO_DWAPB)		+= gpio-dwapb.o
 obj-$(CONFIG_GPIO_EIC_SPRD)		+= gpio-eic-sprd.o
 obj-$(CONFIG_GPIO_EM)			+= gpio-em.o
+obj-$(CONFIG_GPIO_EN7523)		+= gpio-en7523.o
 obj-$(CONFIG_GPIO_EP93XX)		+= gpio-ep93xx.o
 obj-$(CONFIG_GPIO_EXAR)			+= gpio-exar.o
 obj-$(CONFIG_GPIO_F7188X)		+= gpio-f7188x.o

drivers/gpio/gpio-en7523.c

@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/types.h>
+#include <linux/io.h>
+#include <linux/bits.h>
+#include <linux/gpio/driver.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define AIROHA_GPIO_MAX		32
+
+/**
+ * airoha_gpio_ctrl - Airoha GPIO driver data
+ * @gc: Associated gpio_chip instance.
+ * @data: The data register.
+ * @dir0: The direction register for the lower 16 pins.
+ * @dir1: The direction register for the higher 16 pins.
+ * @output: The output enable register.
+ */
+struct airoha_gpio_ctrl {
+	struct gpio_chip gc;
+	void __iomem *data;
+	void __iomem *dir[2];
+	void __iomem *output;
+};
+
+static struct airoha_gpio_ctrl *gc_to_ctrl(struct gpio_chip *gc)
+{
+	return container_of(gc, struct airoha_gpio_ctrl, gc);
+}
+
+static int airoha_dir_set(struct gpio_chip *gc, unsigned int gpio,
+			  int val, int out)
+{
+	struct airoha_gpio_ctrl *ctrl = gc_to_ctrl(gc);
+	u32 dir = ioread32(ctrl->dir[gpio / 16]);
+	u32 output = ioread32(ctrl->output);
+	u32 mask = BIT((gpio % 16) * 2);
+
+	if (out) {
+		dir |= mask;
+		output |= BIT(gpio);
+	} else {
+		dir &= ~mask;
+		output &= ~BIT(gpio);
+	}
+
+	iowrite32(dir, ctrl->dir[gpio / 16]);
+
+	if (out)
+		gc->set(gc, gpio, val);
+
+	iowrite32(output, ctrl->output);
+
+	return 0;
+}
+
+static int airoha_dir_out(struct gpio_chip *gc, unsigned int gpio,
+			  int val)
+{
+	return airoha_dir_set(gc, gpio, val, 1);
+}
+
+static int airoha_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+	return airoha_dir_set(gc, gpio, 0, 0);
+}
+
+static int airoha_get_dir(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct airoha_gpio_ctrl *ctrl = gc_to_ctrl(gc);
+	u32 dir = ioread32(ctrl->dir[gpio / 16]);
+	u32 mask = BIT((gpio % 16) * 2);
+
+	return (dir & mask) ? GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int airoha_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct airoha_gpio_ctrl *ctrl;
+	int err;
+
+	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
+	if (!ctrl)
+		return -ENOMEM;
+
+	ctrl->data = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ctrl->data))
+		return PTR_ERR(ctrl->data);
+
+	ctrl->dir[0] = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(ctrl->dir[0]))
+		return PTR_ERR(ctrl->dir[0]);
+
+	ctrl->dir[1] = devm_platform_ioremap_resource(pdev, 2);
+	if (IS_ERR(ctrl->dir[1]))
+		return PTR_ERR(ctrl->dir[1]);
+
+	ctrl->output = devm_platform_ioremap_resource(pdev, 3);
+	if (IS_ERR(ctrl->output))
+		return PTR_ERR(ctrl->output);
+
+	err = bgpio_init(&ctrl->gc, dev, 4, ctrl->data, NULL,
+			 NULL, NULL, NULL, 0);
+	if (err)
+		return dev_err_probe(dev, err, "unable to init generic GPIO");
+
+	ctrl->gc.ngpio = AIROHA_GPIO_MAX;
+	ctrl->gc.owner = THIS_MODULE;
+	ctrl->gc.direction_output = airoha_dir_out;
+	ctrl->gc.direction_input = airoha_dir_in;
+	ctrl->gc.get_direction = airoha_get_dir;
+
+	return devm_gpiochip_add_data(dev, &ctrl->gc, ctrl);
+}
+
+static const struct of_device_id airoha_gpio_of_match[] = {
+	{ .compatible = "airoha,en7523-gpio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, airoha_gpio_of_match);
+
+static struct platform_driver airoha_gpio_driver = {
+	.driver = {
+		.name = "airoha-gpio",
+		.of_match_table	= airoha_gpio_of_match,
+	},
+	.probe = airoha_gpio_probe,
+};
+module_platform_driver(airoha_gpio_driver);
+
+MODULE_DESCRIPTION("Airoha GPIO support");
+MODULE_AUTHOR("John Crispin <john@phrozen.org>");
+MODULE_LICENSE("GPL v2");