gpio: Add APM X-Gene SoC GPIO controller support

Add APM X-Gene SoC gpio controller driver.
Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -334,6 +334,15 @@ config GPIO_TZ1090_PDC
 	help
 	  Say yes here to support Toumaz Xenif TZ1090 PDC GPIOs.
 
+config GPIO_XGENE
+	bool "APM X-Gene GPIO controller support"
+	depends on ARM64 && OF_GPIO
+	help
+	  This driver is to support the GPIO block within the APM X-Gene SoC
+	  platform's generic flash controller. The GPIO pins are muxed with
+	  the generic flash controller's address and data pins. Say yes
+	  here to enable the GFC GPIO functionality.
+
 config GPIO_XILINX
 	bool "Xilinx GPIO support"
 	depends on PPC_OF || MICROBLAZE || ARCH_ZYNQ

drivers/gpio/Makefile

@@ -101,6 +101,7 @@ obj-$(CONFIG_GPIO_VX855)	+= gpio-vx855.o
 obj-$(CONFIG_GPIO_WM831X)	+= gpio-wm831x.o
 obj-$(CONFIG_GPIO_WM8350)	+= gpio-wm8350.o
 obj-$(CONFIG_GPIO_WM8994)	+= gpio-wm8994.o
+obj-$(CONFIG_GPIO_XGENE)	+= gpio-xgene.o
 obj-$(CONFIG_GPIO_XILINX)	+= gpio-xilinx.o
 obj-$(CONFIG_GPIO_XTENSA)	+= gpio-xtensa.o
 obj-$(CONFIG_GPIO_ZEVIO)	+= gpio-zevio.o

drivers/gpio/gpio-xgene.c

+/*
+ * AppliedMicro X-Gene SoC GPIO Driver
+ *
+ * Copyright (c) 2014, Applied Micro Circuits Corporation
+ * Author: Feng Kan <fkan@apm.com>.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+#include <linux/types.h>
+#include <linux/bitops.h>
+
+#define GPIO_SET_DR_OFFSET	0x0C
+#define GPIO_DATA_OFFSET	0x14
+#define GPIO_BANK_STRIDE	0x0C
+
+#define XGENE_GPIOS_PER_BANK	16
+#define XGENE_MAX_GPIO_BANKS	3
+#define XGENE_MAX_GPIOS		(XGENE_GPIOS_PER_BANK * XGENE_MAX_GPIO_BANKS)
+
+#define GPIO_BIT_OFFSET(x)	(x % XGENE_GPIOS_PER_BANK)
+#define GPIO_BANK_OFFSET(x)	((x / XGENE_GPIOS_PER_BANK) * GPIO_BANK_STRIDE)
+
+struct xgene_gpio;
+
+struct xgene_gpio {
+	struct gpio_chip	chip;
+	void __iomem		*base;
+	spinlock_t		lock;
+#ifdef CONFIG_PM
+	u32			set_dr_val[XGENE_MAX_GPIO_BANKS];
+#endif
+};
+
+static inline struct xgene_gpio *to_xgene_gpio(struct gpio_chip *chip)
+{
+	return container_of(chip, struct xgene_gpio, chip);
+}
+
+static int xgene_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct xgene_gpio *chip = to_xgene_gpio(gc);
+	unsigned long bank_offset;
+	u32 bit_offset;
+
+	bank_offset = GPIO_DATA_OFFSET + GPIO_BANK_OFFSET(offset);
+	bit_offset = GPIO_BIT_OFFSET(offset);
+	return !!(ioread32(chip->base + bank_offset) & BIT(bit_offset));
+}
+
+static void __xgene_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
+{
+	struct xgene_gpio *chip = to_xgene_gpio(gc);
+	unsigned long bank_offset;
+	u32 setval, bit_offset;
+
+	bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
+	bit_offset = GPIO_BIT_OFFSET(offset) + XGENE_GPIOS_PER_BANK;
+
+	setval = ioread32(chip->base + bank_offset);
+	if (val)
+		setval |= BIT(bit_offset);
+	else
+		setval &= ~BIT(bit_offset);
+	iowrite32(setval, chip->base + bank_offset);
+}
+
+static void xgene_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
+{
+	struct xgene_gpio *chip = to_xgene_gpio(gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	__xgene_gpio_set(gc, offset, val);
+	spin_unlock_irqrestore(&chip->lock, flags);
+}
+
+static int xgene_gpio_dir_in(struct gpio_chip *gc, unsigned int offset)
+{
+	struct xgene_gpio *chip = to_xgene_gpio(gc);
+	unsigned long flags, bank_offset;
+	u32 dirval, bit_offset;
+
+	bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
+	bit_offset = GPIO_BIT_OFFSET(offset);
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	dirval = ioread32(chip->base + bank_offset);
+	dirval |= BIT(bit_offset);
+	iowrite32(dirval, chip->base + bank_offset);
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	return 0;
+}
+
+static int xgene_gpio_dir_out(struct gpio_chip *gc,
+					unsigned int offset, int val)
+{
+	struct xgene_gpio *chip = to_xgene_gpio(gc);
+	unsigned long flags, bank_offset;
+	u32 dirval, bit_offset;
+
+	bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
+	bit_offset = GPIO_BIT_OFFSET(offset);
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	dirval = ioread32(chip->base + bank_offset);
+	dirval &= ~BIT(bit_offset);
+	iowrite32(dirval, chip->base + bank_offset);
+	__xgene_gpio_set(gc, offset, val);
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int xgene_gpio_suspend(struct device *dev)
+{
+	struct xgene_gpio *gpio = dev_get_drvdata(dev);
+	unsigned long bank_offset;
+	unsigned int bank;
+
+	for (bank = 0; bank < XGENE_MAX_GPIO_BANKS; bank++) {
+		bank_offset = GPIO_SET_DR_OFFSET + bank * GPIO_BANK_STRIDE;
+		gpio->set_dr_val[bank] = ioread32(gpio->base + bank_offset);
+	}
+	return 0;
+}
+
+static int xgene_gpio_resume(struct device *dev)
+{
+	struct xgene_gpio *gpio = dev_get_drvdata(dev);
+	unsigned long bank_offset;
+	unsigned int bank;
+
+	for (bank = 0; bank < XGENE_MAX_GPIO_BANKS; bank++) {
+		bank_offset = GPIO_SET_DR_OFFSET + bank * GPIO_BANK_STRIDE;
+		iowrite32(gpio->set_dr_val[bank], gpio->base + bank_offset);
+	}
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(xgene_gpio_pm, xgene_gpio_suspend, xgene_gpio_resume);
+#define XGENE_GPIO_PM_OPS	(&xgene_gpio_pm)
+#else
+#define XGENE_GPIO_PM_OPS	NULL
+#endif
+
+static int xgene_gpio_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct xgene_gpio *gpio;
+	int err = 0;
+
+	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	gpio->base = devm_ioremap_nocache(&pdev->dev, res->start,
+							resource_size(res));
+	if (IS_ERR(gpio->base)) {
+		err = PTR_ERR(gpio->base);
+		goto err;
+	}
+
+	gpio->chip.ngpio = XGENE_MAX_GPIOS;
+
+	gpio->chip.dev = &pdev->dev;
+	gpio->chip.direction_input = xgene_gpio_dir_in;
+	gpio->chip.direction_output = xgene_gpio_dir_out;
+	gpio->chip.get = xgene_gpio_get;
+	gpio->chip.set = xgene_gpio_set;
+	gpio->chip.label = dev_name(&pdev->dev);
+	gpio->chip.base = -1;
+
+	platform_set_drvdata(pdev, gpio);
+
+	err = gpiochip_add(&gpio->chip);
+	if (err) {
+		dev_err(&pdev->dev,
+			"failed to register gpiochip.\n");
+		goto err;
+	}
+
+	dev_info(&pdev->dev, "X-Gene GPIO driver registered.\n");
+	return 0;
+err:
+	dev_err(&pdev->dev, "X-Gene GPIO driver registration failed.\n");
+	return err;
+}
+
+static int xgene_gpio_remove(struct platform_device *pdev)
+{
+	struct xgene_gpio *gpio = platform_get_drvdata(pdev);
+	int ret = 0;
+
+	ret = gpiochip_remove(&gpio->chip);
+	if (ret)
+		dev_err(&pdev->dev, "unable to remove gpio_chip.\n");
+	return ret;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id xgene_gpio_of_match[] = {
+	{ .compatible = "apm,xgene-gpio", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, xgene_gpio_of_match);
+#endif
+
+static struct platform_driver xgene_gpio_driver = {
+	.driver = {
+		.name = "xgene-gpio",
+		.owner = THIS_MODULE,
+		.of_match_table = xgene_gpio_of_match,
+		.pm     = XGENE_GPIO_PM_OPS,
+	},
+	.probe = xgene_gpio_probe,
+	.remove = xgene_gpio_remove,
+};
+
+module_platform_driver(xgene_gpio_driver);
+
+MODULE_AUTHOR("Feng Kan <fkan@apm.com>");
+MODULE_DESCRIPTION("APM X-Gene GPIO driver");
+MODULE_LICENSE("GPL");