gpio: loongson: add gpio driver support

The Loongson platforms GPIO controller contains 60 GPIO pins in total,
4 of which are dedicated GPIO pins, and the remaining 56 are reused
with other functions. Each GPIO can set input/output and has the
interrupt capability.

This driver added support for Loongson GPIO controller and support to
use DTS or ACPI to descibe GPIO device resources.
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Signed-off-by: Liu Peibao <liupeibao@loongson.cn>
Signed-off-by: Juxin Gao <gaojuxin@loongson.cn>
Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

MAINTAINERS

@@ -12121,6 +12121,7 @@ M:	Yinbo Zhu <zhuyinbo@loongson.cn>
 L:	linux-gpio@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/gpio/loongson,ls-gpio.yaml
+F:	drivers/gpio/gpio-loongson-64bit.c
 
 LOONGSON-2 SOC SERIES CLOCK DRIVER
 M:	Yinbo Zhu <zhuyinbo@loongson.cn>

drivers/gpio/Kconfig

@@ -380,6 +380,18 @@ config GPIO_LOONGSON
 	help
 	  Driver for GPIO functionality on Loongson-2F/3A/3B processors.
 
+config GPIO_LOONGSON_64BIT
+	tristate "Loongson 64 bit GPIO support"
+	depends on LOONGARCH || COMPILE_TEST
+	select OF_GPIO
+	select GPIO_GENERIC
+	help
+	  Say yes here to support the GPIO functionality of a number of
+	  Loongson series of chips. The Loongson GPIO controller supports
+	  up to 60 GPIOS in total, 4 of which are dedicated GPIO pins, and
+	  the remaining 56 are reused with other functions, with edge or
+	  level triggered interrupts.
+
 config GPIO_LPC18XX
 	tristate "NXP LPC18XX/43XX GPIO support"
 	default y if ARCH_LPC18XX

drivers/gpio/Makefile

@@ -80,6 +80,7 @@ obj-$(CONFIG_GPIO_LATCH)		+= gpio-latch.o
 obj-$(CONFIG_GPIO_LOGICVC)		+= gpio-logicvc.o
 obj-$(CONFIG_GPIO_LOONGSON1)		+= gpio-loongson1.o
 obj-$(CONFIG_GPIO_LOONGSON)		+= gpio-loongson.o
+obj-$(CONFIG_GPIO_LOONGSON_64BIT)	+= gpio-loongson-64bit.o
 obj-$(CONFIG_GPIO_LP3943)		+= gpio-lp3943.o
 obj-$(CONFIG_GPIO_LP873X)		+= gpio-lp873x.o
 obj-$(CONFIG_GPIO_LP87565)		+= gpio-lp87565.o

drivers/gpio/gpio-loongson-64bit.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Loongson GPIO Support
+ *
+ * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/bitops.h>
+#include <asm/types.h>
+
+enum loongson_gpio_mode {
+	BIT_CTRL_MODE,
+	BYTE_CTRL_MODE,
+};
+
+struct loongson_gpio_chip_data {
+	const char		*label;
+	enum loongson_gpio_mode	mode;
+	unsigned int		conf_offset;
+	unsigned int		out_offset;
+	unsigned int		in_offset;
+};
+
+struct loongson_gpio_chip {
+	struct gpio_chip	chip;
+	struct fwnode_handle	*fwnode;
+	spinlock_t		lock;
+	void __iomem		*reg_base;
+	const struct loongson_gpio_chip_data *chip_data;
+};
+
+static inline struct loongson_gpio_chip *to_loongson_gpio_chip(struct gpio_chip *chip)
+{
+	return container_of(chip, struct loongson_gpio_chip, chip);
+}
+
+static inline void loongson_commit_direction(struct loongson_gpio_chip *lgpio, unsigned int pin,
+					     int input)
+{
+	u8 bval = input ? 1 : 0;
+
+	writeb(bval, lgpio->reg_base + lgpio->chip_data->conf_offset + pin);
+}
+
+static void loongson_commit_level(struct loongson_gpio_chip *lgpio, unsigned int pin, int high)
+{
+	u8 bval = high ? 1 : 0;
+
+	writeb(bval, lgpio->reg_base + lgpio->chip_data->out_offset + pin);
+}
+
+static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned int pin)
+{
+	unsigned long flags;
+	struct loongson_gpio_chip *lgpio = to_loongson_gpio_chip(chip);
+
+	spin_lock_irqsave(&lgpio->lock, flags);
+	loongson_commit_direction(lgpio, pin, 1);
+	spin_unlock_irqrestore(&lgpio->lock, flags);
+
+	return 0;
+}
+
+static int loongson_gpio_direction_output(struct gpio_chip *chip, unsigned int pin, int value)
+{
+	unsigned long flags;
+	struct loongson_gpio_chip *lgpio = to_loongson_gpio_chip(chip);
+
+	spin_lock_irqsave(&lgpio->lock, flags);
+	loongson_commit_level(lgpio, pin, value);
+	loongson_commit_direction(lgpio, pin, 0);
+	spin_unlock_irqrestore(&lgpio->lock, flags);
+
+	return 0;
+}
+
+static int loongson_gpio_get(struct gpio_chip *chip, unsigned int pin)
+{
+	u8  bval;
+	int val;
+	struct loongson_gpio_chip *lgpio = to_loongson_gpio_chip(chip);
+
+	bval = readb(lgpio->reg_base + lgpio->chip_data->in_offset + pin);
+	val = bval & 1;
+
+	return val;
+}
+
+static int loongson_gpio_get_direction(struct gpio_chip *chip, unsigned int pin)
+{
+	u8  bval;
+	struct loongson_gpio_chip *lgpio = to_loongson_gpio_chip(chip);
+
+	bval = readb(lgpio->reg_base + lgpio->chip_data->conf_offset + pin);
+	if (bval & 1)
+		return GPIO_LINE_DIRECTION_IN;
+
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static void loongson_gpio_set(struct gpio_chip *chip, unsigned int pin, int value)
+{
+	unsigned long flags;
+	struct loongson_gpio_chip *lgpio = to_loongson_gpio_chip(chip);
+
+	spin_lock_irqsave(&lgpio->lock, flags);
+	loongson_commit_level(lgpio, pin, value);
+	spin_unlock_irqrestore(&lgpio->lock, flags);
+}
+
+static int loongson_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
+{
+	struct platform_device *pdev = to_platform_device(chip->parent);
+
+	return platform_get_irq(pdev, offset);
+}
+
+static int loongson_gpio_init(struct device *dev, struct loongson_gpio_chip *lgpio,
+			      struct device_node *np, void __iomem *reg_base)
+{
+	int ret;
+	u32 ngpios;
+
+	lgpio->reg_base = reg_base;
+
+	if (lgpio->chip_data->mode == BIT_CTRL_MODE) {
+		ret = bgpio_init(&lgpio->chip, dev, 8,
+				lgpio->reg_base + lgpio->chip_data->in_offset,
+				lgpio->reg_base + lgpio->chip_data->out_offset,
+				NULL, NULL,
+				lgpio->reg_base + lgpio->chip_data->conf_offset,
+				0);
+		if (ret) {
+			dev_err(dev, "unable to init generic GPIO\n");
+			return ret;
+		}
+	} else {
+		lgpio->chip.direction_input = loongson_gpio_direction_input;
+		lgpio->chip.get = loongson_gpio_get;
+		lgpio->chip.get_direction = loongson_gpio_get_direction;
+		lgpio->chip.direction_output = loongson_gpio_direction_output;
+		lgpio->chip.set = loongson_gpio_set;
+		lgpio->chip.parent = dev;
+		spin_lock_init(&lgpio->lock);
+	}
+
+	device_property_read_u32(dev, "ngpios", &ngpios);
+
+	lgpio->chip.can_sleep = 0;
+	lgpio->chip.ngpio = ngpios;
+	lgpio->chip.label = lgpio->chip_data->label;
+	lgpio->chip.to_irq = loongson_gpio_to_irq;
+
+	return devm_gpiochip_add_data(dev, &lgpio->chip, lgpio);
+}
+
+static int loongson_gpio_probe(struct platform_device *pdev)
+{
+	void __iomem *reg_base;
+	struct loongson_gpio_chip *lgpio;
+	struct device_node *np = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+
+	lgpio = devm_kzalloc(dev, sizeof(*lgpio), GFP_KERNEL);
+	if (!lgpio)
+		return -ENOMEM;
+
+	lgpio->chip_data = device_get_match_data(dev);
+
+	reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(reg_base))
+		return PTR_ERR(reg_base);
+
+	return loongson_gpio_init(dev, lgpio, np, reg_base);
+}
+
+static const struct loongson_gpio_chip_data loongson_gpio_ls2k_data = {
+	.label = "ls2k_gpio",
+	.mode = BIT_CTRL_MODE,
+	.conf_offset = 0x0,
+	.in_offset = 0x20,
+	.out_offset = 0x10,
+};
+
+static const struct loongson_gpio_chip_data loongson_gpio_ls7a_data = {
+	.label = "ls7a_gpio",
+	.mode = BYTE_CTRL_MODE,
+	.conf_offset = 0x800,
+	.in_offset = 0xa00,
+	.out_offset = 0x900,
+};
+
+static const struct of_device_id loongson_gpio_of_match[] = {
+	{
+		.compatible = "loongson,ls2k-gpio",
+		.data = &loongson_gpio_ls2k_data,
+	},
+	{
+		.compatible = "loongson,ls7a-gpio",
+		.data = &loongson_gpio_ls7a_data,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, loongson_gpio_of_match);
+
+static const struct acpi_device_id loongson_gpio_acpi_match[] = {
+	{
+		.id = "LOON0002",
+		.driver_data = (kernel_ulong_t)&loongson_gpio_ls7a_data,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, loongson_gpio_acpi_match);
+
+static struct platform_driver loongson_gpio_driver = {
+	.driver = {
+		.name = "loongson-gpio",
+		.owner = THIS_MODULE,
+		.of_match_table = loongson_gpio_of_match,
+		.acpi_match_table = loongson_gpio_acpi_match,
+	},
+	.probe = loongson_gpio_probe,
+};
+
+static int __init loongson_gpio_setup(void)
+{
+	return platform_driver_register(&loongson_gpio_driver);
+}
+postcore_initcall(loongson_gpio_setup);
+
+MODULE_DESCRIPTION("Loongson gpio driver");
+MODULE_LICENSE("GPL");