gpio: add TS-4800 fpga GPIO support

The TS-4800 GPIO driver provide support for the GPIOs available
on the Technologic Sytems board FPGA. It allows to set
direction and read/write states.

It uses the generic gpio driver.

Signed-off-by: Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -382,6 +382,13 @@ config GPIO_TB10X
 	select GENERIC_IRQ_CHIP
 	select OF_GPIO
 
+config GPIO_TS4800
+	tristate "TS-4800 DIO blocks and compatibles"
+	depends on OF_GPIO
+	select GPIO_GENERIC
+	help
+	  This driver support TS-4800 FPGA GPIO controllers.
+
 config GPIO_TZ1090
 	bool "Toumaz Xenif TZ1090 GPIO support"
 	depends on SOC_TZ1090

drivers/gpio/Makefile

@@ -99,6 +99,7 @@ obj-$(CONFIG_GPIO_PALMAS)	+= gpio-palmas.o
 obj-$(CONFIG_GPIO_TPS6586X)	+= gpio-tps6586x.o
 obj-$(CONFIG_GPIO_TPS65910)	+= gpio-tps65910.o
 obj-$(CONFIG_GPIO_TPS65912)	+= gpio-tps65912.o
+obj-$(CONFIG_GPIO_TS4800)	+= gpio-ts4800.o
 obj-$(CONFIG_GPIO_TS5500)	+= gpio-ts5500.o
 obj-$(CONFIG_GPIO_TWL4030)	+= gpio-twl4030.o
 obj-$(CONFIG_GPIO_TWL6040)	+= gpio-twl6040.o

drivers/gpio/gpio-ts4800.c

@@ -0,0 +1,94 @@
+/*
+ * GPIO driver for the TS-4800 board
+ *
+ * Copyright (c) 2016 - Savoir-faire Linux
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define DEFAULT_PIN_NUMBER      16
+#define INPUT_REG_OFFSET        0x00
+#define OUTPUT_REG_OFFSET       0x02
+#define DIRECTION_REG_OFFSET    0x04
+
+static int ts4800_gpio_probe(struct platform_device *pdev)
+{
+	struct device_node *node;
+	struct gpio_chip *chip;
+	struct resource *res;
+	void __iomem *base_addr;
+	int retval;
+	u32 ngpios;
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(struct gpio_chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base_addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base_addr))
+		return PTR_ERR(base_addr);
+
+	node = pdev->dev.of_node;
+	if (!node)
+		return -EINVAL;
+
+	retval = of_property_read_u32(node, "ngpios", &ngpios);
+	if (retval == -EINVAL)
+		ngpios = DEFAULT_PIN_NUMBER;
+	else if (retval)
+		return retval;
+
+	retval = bgpio_init(chip, &pdev->dev, 2, base_addr + INPUT_REG_OFFSET,
+			    base_addr + OUTPUT_REG_OFFSET, NULL,
+			    base_addr + DIRECTION_REG_OFFSET, NULL,
+			    BGPIOF_BIG_ENDIAN & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
+	if (retval) {
+		dev_err(&pdev->dev, "bgpio_init failed\n");
+		return retval;
+	}
+
+	chip->base = -1;
+	chip->label = dev_name(&pdev->dev);
+	chip->ngpio = ngpios;
+
+	platform_set_drvdata(pdev, chip);
+
+	return gpiochip_add_data(chip, NULL);
+}
+
+static int ts4800_gpio_remove(struct platform_device *pdev)
+{
+	struct gpio_chip *chip = platform_get_drvdata(pdev);
+
+	gpiochip_remove(chip);
+
+	return 0;
+}
+
+static const struct of_device_id ts4800_gpio_of_match[] = {
+	{ .compatible = "technologic,ts4800-gpio", },
+	{},
+};
+
+static struct platform_driver ts4800_gpio_driver = {
+	.driver = {
+		   .name = "ts4800-gpio",
+		   .of_match_table = ts4800_gpio_of_match,
+		   },
+	.probe = ts4800_gpio_probe,
+	.remove = ts4800_gpio_remove,
+};
+
+module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe);
+
+MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>");
+MODULE_DESCRIPTION("TS4800 FPGA GPIO driver");
+MODULE_LICENSE("GPL v2");