[PATCH v6 7/9] gpio: Add gpio driver for Actions OWL S900 SoC

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

Add gpio driver for Actions Semi OWL family S900 SoC. Set of registers
controlling the gpio shares the same register range with pinctrl block.

GPIO registers are organized as 6 banks and each bank controls the
maximum of 32 gpios.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
 drivers/gpio/Kconfig    |   8 +++
 drivers/gpio/Makefile   |   1 +
 drivers/gpio/gpio-owl.c | 168 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 177 insertions(+)
 create mode 100644 drivers/gpio/gpio-owl.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 8dbb2280538d..75533f55ad0e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -364,6 +364,14 @@ config GPIO_OMAP
 	help
 	  Say yes here to enable GPIO support for TI OMAP SoCs.
 
+config GPIO_OWL
+	tristate "Actions Semi OWL GPIO support"
+	default ARCH_ACTIONS
+	depends on ARCH_ACTIONS || COMPILE_TEST
+	depends on OF_GPIO
+	help
+	  Say yes here to enable GPIO support for Actions Semi OWL SoCs.
+
 config GPIO_PL061
 	bool "PrimeCell PL061 GPIO support"
 	depends on ARM_AMBA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index cccb0d40846c..b2bb11d4675f 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_GPIO_MXC)		+= gpio-mxc.o
 obj-$(CONFIG_GPIO_MXS)		+= gpio-mxs.o
 obj-$(CONFIG_GPIO_OCTEON)	+= gpio-octeon.o
 obj-$(CONFIG_GPIO_OMAP)		+= gpio-omap.o
+obj-$(CONFIG_GPIO_OWL)		+= gpio-owl.o
 obj-$(CONFIG_GPIO_PCA953X)	+= gpio-pca953x.o
 obj-$(CONFIG_GPIO_PCF857X)	+= gpio-pcf857x.o
 obj-$(CONFIG_GPIO_PCH)		+= gpio-pch.o
diff --git a/drivers/gpio/gpio-owl.c b/drivers/gpio/gpio-owl.c
new file mode 100644
index 000000000000..459ebcdd9174
--- /dev/null
+++ b/drivers/gpio/gpio-owl.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * OWL SoC's GPIO driver
+ *
+ * Copyright (c) 2018 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define GPIO_OUTEN	0x0000
+#define GPIO_INEN	0x0004
+#define GPIO_DAT	0x0008
+
+struct owl_gpio {
+	struct gpio_chip gpio;
+	void __iomem *base;
+};
+
+static void owl_gpio_update_reg(void __iomem *base, unsigned int pin, int flag)
+{
+	u32 val;
+
+	val = readl_relaxed(base);
+
+	if (flag)
+		val |= BIT(pin);
+	else
+		val &= ~BIT(pin);
+
+	writel_relaxed(val, base);
+}
+
+static int owl_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	struct owl_gpio *gpio = gpiochip_get_data(chip);
+
+	/*
+	 * GPIOs have higher priority over other modules, so either setting
+	 * them as OUT or IN is sufficient
+	 */
+	owl_gpio_update_reg(gpio->base + GPIO_OUTEN, offset, true);
+
+	return 0;
+}
+
+static void owl_gpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+	struct owl_gpio *gpio = gpiochip_get_data(chip);
+
+	/* disable gpio output */
+	owl_gpio_update_reg(gpio->base + GPIO_OUTEN, offset, false);
+
+	/* disable gpio input */
+	owl_gpio_update_reg(gpio->base + GPIO_INEN, offset, false);
+}
+
+static int owl_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct owl_gpio *gpio = gpiochip_get_data(chip);
+	u32 val;
+
+	val = readl_relaxed(gpio->base + GPIO_DAT);
+
+	return !!(val & BIT(offset));
+}
+
+static void owl_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	struct owl_gpio *gpio = gpiochip_get_data(chip);
+
+	owl_gpio_update_reg(gpio->base + GPIO_DAT, offset, value);
+}
+
+static int owl_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+	struct owl_gpio *gpio = gpiochip_get_data(chip);
+
+	owl_gpio_update_reg(gpio->base + GPIO_OUTEN, offset, false);
+	owl_gpio_update_reg(gpio->base + GPIO_INEN, offset, true);
+
+	return 0;
+}
+
+static int owl_gpio_direction_output(struct gpio_chip *chip,
+				unsigned int offset, int value)
+{
+	struct owl_gpio *gpio = gpiochip_get_data(chip);
+
+	owl_gpio_update_reg(gpio->base + GPIO_INEN, offset, false);
+	owl_gpio_update_reg(gpio->base + GPIO_OUTEN, offset, true);
+	owl_gpio_update_reg(gpio->base + GPIO_DAT, offset, value);
+
+	return 0;
+}
+
+static int owl_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct owl_gpio *gpio;
+	u32 ngpios;
+	int ret;
+
+	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	gpio->base = of_iomap(dev->of_node, 0);
+	if (IS_ERR(gpio->base))
+		return PTR_ERR(gpio->base);
+
+	/*
+	 * Get the number of gpio's for this bank. If none specified,
+	 * then fall back to 32.
+	 */
+	ret = of_property_read_u32(dev->of_node, "ngpios", &ngpios);
+	if (ret)
+		ngpios = 32;
+
+	gpio->gpio.request = owl_gpio_request;
+	gpio->gpio.free = owl_gpio_free;
+	gpio->gpio.get = owl_gpio_get;
+	gpio->gpio.set = owl_gpio_set;
+	gpio->gpio.direction_input = owl_gpio_direction_input;
+	gpio->gpio.direction_output = owl_gpio_direction_output;
+
+	gpio->gpio.base = -1;
+	gpio->gpio.parent = dev;
+	gpio->gpio.label = dev_name(dev);
+	gpio->gpio.ngpio = ngpios;
+
+	platform_set_drvdata(pdev, gpio);
+
+	ret = devm_gpiochip_add_data(dev, &gpio->gpio, gpio);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register gpiochip\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id owl_gpio_of_match[] = {
+	{ .compatible = "actions,s900-gpio", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, owl_gpio_of_match);
+
+static struct platform_driver owl_gpio_driver = {
+	.driver		= {
+		.name	= "owl-gpio",
+		.of_match_table = owl_gpio_of_match,
+	},
+	.probe		= owl_gpio_probe
+};
+module_platform_driver(owl_gpio_driver);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_DESCRIPTION("Actions Semi OWL SoCs GPIO driver");
+MODULE_LICENSE("GPL");
-- 
2.14.1