gpio: add GPIO support for SMSC SCH311x

This patch adds support for the GPIOs found on the SMSC "Super I/
SCH311x.

The chip detection and I/O functions are copied from sch311x_wdt.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 441 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 02e8d5350f8b..f456b93bb953 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -244,6 +244,15 @@ config GPIO_SAMSUNG
 	  Legacy GPIO support. Use only for platforms without support for
 	  pinctrl.
 
+config GPIO_SCH311X
+	tristate "SMSC SCH311x SuperI/O GPIO"
+	help
+	  Driver to enable the GPIOs found on SMSC SMSC SCH3112, SCH3114 and
+	  SCH3116 "Super I/O" chipsets.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gpio-sch311x.
+
 config GPIO_SPEAR_SPICS
 	bool "ST SPEAr13xx SPI Chip Select as GPIO support"
 	depends on PLAT_SPEAR
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 699e7cd96584..c44fffac9519 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_GPIO_RCAR)		+= gpio-rcar.o
 obj-$(CONFIG_GPIO_SAMSUNG)	+= gpio-samsung.o
 obj-$(CONFIG_ARCH_SA1100)	+= gpio-sa1100.o
 obj-$(CONFIG_GPIO_SCH)		+= gpio-sch.o
+obj-$(CONFIG_GPIO_SCH311X)	+= gpio-sch311x.o
 obj-$(CONFIG_GPIO_SODAVILLE)	+= gpio-sodaville.o
 obj-$(CONFIG_GPIO_SPEAR_SPICS)	+= gpio-spear-spics.o
 obj-$(CONFIG_GPIO_STA2X11)	+= gpio-sta2x11.o
diff --git a/drivers/gpio/gpio-sch311x.c b/drivers/gpio/gpio-sch311x.c
new file mode 100644
index 000000000000..483a6f8bd958
--- /dev/null
+++ b/drivers/gpio/gpio-sch311x.c
@@ -0,0 +1,431 @@
+/*
+ * GPIO driver for the SMSC SCH311x Super-I/O chips
+ *
+ * Copyright (C) 2013 Bruno Randolf <br1@einfach.org>
+ *
+ * SuperIO functions and chip detection:
+ * (c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/bitops.h>
+
+#define DRV_NAME			"gpio-sch311x"
+
+#define SCH311X_GPIO_CONF_OUT		0x00
+#define SCH311X_GPIO_CONF_IN		0x01
+#define SCH311X_GPIO_CONF_INVERT	0x02
+#define SCH311X_GPIO_CONF_OPEN_DRAIN	0x80
+
+#define SIO_CONFIG_KEY_ENTER		0x55
+#define SIO_CONFIG_KEY_EXIT		0xaa
+
+#define GP1				0x4b
+
+static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e };
+
+static struct platform_device *sch311x_gpio_pdev;
+
+struct sch311x_pdev_data {		/* platform device data */
+	unsigned short runtime_reg;	/* runtime register base address */
+};
+
+struct sch311x_gpio_block {		/* one GPIO block runtime data */
+	struct gpio_chip chip;
+	unsigned short data_reg;	/* from definition below */
+	unsigned short *config_regs;	/* pointer to definition below */
+	unsigned short runtime_reg;	/* runtime register */
+	spinlock_t lock;		/* lock for this GPIO block */
+};
+
+struct sch311x_gpio_priv {		/* driver private data */
+	struct sch311x_gpio_block blocks[6];
+};
+
+struct sch311x_gpio_block_def {		/* register address definitions */
+	unsigned short data_reg;
+	unsigned short config_regs[8];
+	unsigned short base;
+};
+
+/* Note: some GPIOs are not available, these are marked with 0x00 */
+
+static struct sch311x_gpio_block_def sch311x_gpio_blocks[] = {
+	{
+		.data_reg = 0x4b,	/* GP1 */
+		.config_regs = {0x23, 0x24, 0x25, 0x26, 0x27, 0x29, 0x2a, 0x2b},
+		.base = 10,
+	},
+	{
+		.data_reg = 0x4c,	/* GP2 */
+		.config_regs = {0x00, 0x2c, 0x2d, 0x00, 0x00, 0x00, 0x00, 0x32},
+		.base = 20,
+	},
+	{
+		.data_reg = 0x4d,	/* GP3 */
+		.config_regs = {0x33, 0x34, 0x35, 0x36, 0x37, 0x00, 0x39, 0x3a},
+		.base = 30,
+	},
+	{
+		.data_reg = 0x4e,	/* GP4 */
+		.config_regs = {0x3b, 0x00, 0x3d, 0x00, 0x6e, 0x6f, 0x72, 0x73},
+		.base = 40,
+	},
+	{
+		.data_reg = 0x4f,	/* GP5 */
+		.config_regs = {0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46},
+		.base = 50,
+	},
+	{
+		.data_reg = 0x50,	/* GP6 */
+		.config_regs = {0x47, 0x48, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59},
+		.base = 60,
+	},
+};
+
+static inline struct sch311x_gpio_block *
+to_sch311x_gpio_block(struct gpio_chip *chip)
+{
+	return container_of(chip, struct sch311x_gpio_block, chip);
+}
+
+
+/*
+ *	Super-IO functions
+ */
+
+static inline int sch311x_sio_enter(int sio_config_port)
+{
+	/* Don't step on other drivers' I/O space by accident. */
+	if (!request_muxed_region(sio_config_port, 2, DRV_NAME)) {
+		pr_err(DRV_NAME "I/O address 0x%04x already in use\n",
+		       sio_config_port);
+		return -EBUSY;
+	}
+
+	outb(SIO_CONFIG_KEY_ENTER, sio_config_port);
+	return 0;
+}
+
+static inline void sch311x_sio_exit(int sio_config_port)
+{
+	outb(SIO_CONFIG_KEY_EXIT, sio_config_port);
+	release_region(sio_config_port, 2);
+}
+
+static inline int sch311x_sio_inb(int sio_config_port, int reg)
+{
+	outb(reg, sio_config_port);
+	return inb(sio_config_port + 1);
+}
+
+static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
+{
+	outb(reg, sio_config_port);
+	outb(val, sio_config_port + 1);
+}
+
+
+/*
+ *	GPIO functions
+ */
+
+static int sch311x_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct sch311x_gpio_block *block = to_sch311x_gpio_block(chip);
+
+	if (block->config_regs[offset] == 0) /* GPIO is not available */
+		return -ENODEV;
+
+	if (!request_region(block->runtime_reg + block->config_regs[offset],
+			    1, DRV_NAME)) {
+		dev_err(chip->dev, "Failed to request region 0x%04x.\n",
+			block->runtime_reg + block->config_regs[offset]);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static void sch311x_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct sch311x_gpio_block *block = to_sch311x_gpio_block(chip);
+
+	if (block->config_regs[offset] == 0) /* GPIO is not available */
+		return;
+
+	release_region(block->runtime_reg + block->config_regs[offset], 1);
+}
+
+static int sch311x_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct sch311x_gpio_block *block = to_sch311x_gpio_block(chip);
+	unsigned char data;
+
+	spin_lock(&block->lock);
+	data = inb(block->runtime_reg + block->data_reg);
+	spin_unlock(&block->lock);
+
+	return !!(data & BIT(offset));
+}
+
+static void __sch311x_gpio_set(struct sch311x_gpio_block *block,
+			       unsigned offset, int value)
+{
+	unsigned char data = inb(block->runtime_reg + block->data_reg);
+	if (value)
+		data |= BIT(offset);
+	else
+		data &= ~BIT(offset);
+	outb(data, block->runtime_reg + block->data_reg);
+}
+
+static void sch311x_gpio_set(struct gpio_chip *chip, unsigned offset,
+			     int value)
+{
+	struct sch311x_gpio_block *block = to_sch311x_gpio_block(chip);
+
+	spin_lock(&block->lock);
+	 __sch311x_gpio_set(block, offset, value);
+	spin_unlock(&block->lock);
+}
+
+static int sch311x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
+{
+	struct sch311x_gpio_block *block = to_sch311x_gpio_block(chip);
+
+	spin_lock(&block->lock);
+	outb(SCH311X_GPIO_CONF_IN, block->runtime_reg +
+	     block->config_regs[offset]);
+	spin_unlock(&block->lock);
+
+	return 0;
+}
+
+static int sch311x_gpio_direction_out(struct gpio_chip *chip, unsigned offset,
+				      int value)
+{
+	struct sch311x_gpio_block *block = to_sch311x_gpio_block(chip);
+
+	spin_lock(&block->lock);
+
+	outb(SCH311X_GPIO_CONF_OUT, block->runtime_reg +
+	     block->config_regs[offset]);
+
+	__sch311x_gpio_set(block, offset, value);
+
+	spin_unlock(&block->lock);
+	return 0;
+}
+
+static int sch311x_gpio_probe(struct platform_device *pdev)
+{
+	struct sch311x_pdev_data *pdata = pdev->dev.platform_data;
+	struct sch311x_gpio_priv *priv;
+	struct sch311x_gpio_block *block;
+	int err, i;
+
+	/* we can register all GPIO data registers at once */
+	if (!request_region(pdata->runtime_reg + GP1, 6, DRV_NAME)) {
+		dev_err(&pdev->dev, "Failed to request region 0x%04x-0x%04x.\n",
+			pdata->runtime_reg + GP1, pdata->runtime_reg + GP1 + 5);
+		return -EBUSY;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	for (i = 0; i < ARRAY_SIZE(priv->blocks); i++) {
+		block = &priv->blocks[i];
+
+		spin_lock_init(&block->lock);
+
+		block->chip.label = DRV_NAME;
+		block->chip.owner = THIS_MODULE;
+		block->chip.request = sch311x_gpio_request;
+		block->chip.free = sch311x_gpio_free;
+		block->chip.direction_input = sch311x_gpio_direction_in;
+		block->chip.direction_output = sch311x_gpio_direction_out;
+		block->chip.get = sch311x_gpio_get;
+		block->chip.set = sch311x_gpio_set;
+		block->chip.ngpio = 8;
+		block->chip.dev = &pdev->dev;
+		block->chip.base = sch311x_gpio_blocks[i].base;
+		block->config_regs = sch311x_gpio_blocks[i].config_regs;
+		block->data_reg = sch311x_gpio_blocks[i].data_reg;
+		block->runtime_reg = pdata->runtime_reg;
+
+		err = gpiochip_add(&block->chip);
+		if (err < 0) {
+			dev_err(&pdev->dev,
+				"Could not register gpiochip, %d\n", err);
+			goto exit_err;
+		}
+		dev_info(&pdev->dev,
+			 "SMSC SCH311x GPIO block %d registered.\n", i);
+	}
+
+	return 0;
+
+exit_err:
+	release_region(pdata->runtime_reg + GP1, 6);
+	/* release already registered chips */
+	for (--i; i >= 0; i--)
+		gpiochip_remove(&priv->blocks[i].chip);
+	return err;
+}
+
+static int sch311x_gpio_remove(struct platform_device *pdev)
+{
+	struct sch311x_pdev_data *pdata = pdev->dev.platform_data;
+	struct sch311x_gpio_priv *priv = platform_get_drvdata(pdev);
+	int err, i;
+
+	release_region(pdata->runtime_reg + GP1, 6);
+
+	for (i = 0; i < ARRAY_SIZE(priv->blocks); i++) {
+		err = gpiochip_remove(&priv->blocks[i].chip);
+		if (err)
+			return err;
+		dev_info(&pdev->dev,
+			 "SMSC SCH311x GPIO block %d unregistered.\n", i);
+	}
+	return 0;
+}
+
+static struct platform_driver sch311x_gpio_driver = {
+	.driver.name	= DRV_NAME,
+	.driver.owner	= THIS_MODULE,
+	.probe		= sch311x_gpio_probe,
+	.remove		= sch311x_gpio_remove,
+};
+
+
+/*
+ *	Init & exit routines
+ */
+
+static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
+{
+	int err = 0, reg;
+	unsigned short base_addr;
+	unsigned char dev_id;
+
+	err = sch311x_sio_enter(sio_config_port);
+	if (err)
+		return err;
+
+	/* Check device ID. We currently know about:
+	 * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
+	reg = sch311x_sio_inb(sio_config_port, 0x20);
+	if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
+		err = -ENODEV;
+		goto exit;
+	}
+	dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
+
+	/* Select logical device A (runtime registers) */
+	sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
+
+	/* Check if Logical Device Register is currently active */
+	if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
+		pr_info("Seems that LDN 0x0a is not active...\n");
+
+	/* Get the base address of the runtime registers */
+	base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
+			   sch311x_sio_inb(sio_config_port, 0x61);
+	if (!base_addr) {
+		pr_err("Base address not set\n");
+		err = -ENODEV;
+		goto exit;
+	}
+	*addr = base_addr;
+
+	pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
+
+exit:
+	sch311x_sio_exit(sio_config_port);
+	return err;
+}
+
+static int __init sch311x_gpio_pdev_add(const unsigned short addr)
+{
+	struct sch311x_pdev_data pdata;
+	int err;
+
+	pdata.runtime_reg = addr;
+
+	sch311x_gpio_pdev = platform_device_alloc(DRV_NAME, -1);
+	if (!sch311x_gpio_pdev)
+		return -ENOMEM;
+
+	err = platform_device_add_data(sch311x_gpio_pdev,
+				       &pdata, sizeof(pdata));
+	if (err) {
+		pr_err(DRV_NAME "Platform data allocation failed\n");
+		goto err;
+	}
+
+	err = platform_device_add(sch311x_gpio_pdev);
+	if (err) {
+		pr_err(DRV_NAME "Device addition failed\n");
+		goto err;
+	}
+	return 0;
+
+err:
+	platform_device_put(sch311x_gpio_pdev);
+	return err;
+}
+
+static int __init sch311x_gpio_init(void)
+{
+	int err, i;
+	unsigned short addr = 0;
+
+	for (i = 0; i < ARRAY_SIZE(sch311x_ioports); i++)
+		if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
+			break;
+
+	if (!addr)
+		return -ENODEV;
+
+	err = platform_driver_register(&sch311x_gpio_driver);
+	if (err)
+		return err;
+
+	err = sch311x_gpio_pdev_add(addr);
+	if (err)
+		goto unreg_platform_driver;
+
+	return 0;
+
+unreg_platform_driver:
+	platform_driver_unregister(&sch311x_gpio_driver);
+	return err;
+}
+
+static void __exit sch311x_gpio_exit(void)
+{
+	platform_device_unregister(sch311x_gpio_pdev);
+	platform_driver_unregister(&sch311x_gpio_driver);
+}
+
+module_init(sch311x_gpio_init);
+module_exit(sch311x_gpio_exit);
+
+MODULE_AUTHOR("Bruno Randolf <br1@einfach.org>");
+MODULE_DESCRIPTION("SMSC SCH311x GPIO Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-sch311x");