gpio: sx150x: add Semtech I2C sx150x gpio expander driver

Add support for Semtech SX150-series I2C GPIO expanders.  Compatible
models include:

8 bits:  sx1508q
16 bits: sx1509q

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Trilok Soni <tsoni@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 657 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 7face915b96..f623953b579 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -195,6 +195,17 @@ config GPIO_PCF857X
 	  This driver provides an in-kernel interface to those GPIOs using
 	  platform-neutral GPIO calls.
 
+config GPIO_SX150X
+	bool "Semtech SX150x I2C GPIO expander"
+	depends on I2C=y
+	default n
+	help
+	  Say yes here to provide support for Semtech SX150-series I2C
+	  GPIO expanders. Compatible models include:
+
+	  8 bits:  sx1508q
+	  16 bits: sx1509q
+
 config GPIO_TC35892
 	bool "TC35892 GPIOs"
 	depends on MFD_TC35892
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index e53dcff49b4..a69e0609ff7 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -35,3 +35,4 @@ obj-$(CONFIG_GPIO_WM8994)	+= wm8994-gpio.o
 obj-$(CONFIG_GPIO_SCH)		+= sch_gpio.o
 obj-$(CONFIG_GPIO_RDC321X)	+= rdc321x-gpio.o
 obj-$(CONFIG_GPIO_JANZ_TTL)	+= janz-ttl.o
+obj-$(CONFIG_GPIO_SX150X)	+= sx150x.o
diff --git a/drivers/gpio/sx150x.c b/drivers/gpio/sx150x.c
new file mode 100644
index 00000000000..b42f42ca70c
--- /dev/null
+++ b/drivers/gpio/sx150x.c
@@ -0,0 +1,645 @@
+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/i2c/sx150x.h>
+
+struct sx150x_device_data {
+	u8 reg_pullup;
+	u8 reg_pulldn;
+	u8 reg_drain;
+	u8 reg_polarity;
+	u8 reg_dir;
+	u8 reg_data;
+	u8 reg_irq_mask;
+	u8 reg_irq_src;
+	u8 reg_sense;
+	u8 reg_clock;
+	u8 reg_misc;
+	u8 reg_reset;
+	u8 ngpios;
+};
+
+struct sx150x_chip {
+	struct gpio_chip                 gpio_chip;
+	struct i2c_client               *client;
+	const struct sx150x_device_data *dev_cfg;
+	int                              irq_summary;
+	int                              irq_base;
+	u32                              irq_sense;
+	unsigned long                    irq_set_type_pending;
+	struct irq_chip                  irq_chip;
+	struct mutex                     lock;
+};
+
+static const struct sx150x_device_data sx150x_devices[] = {
+	[0] = { /* sx1508q */
+		.reg_pullup   = 0x03,
+		.reg_pulldn   = 0x04,
+		.reg_drain    = 0x05,
+		.reg_polarity = 0x06,
+		.reg_dir      = 0x07,
+		.reg_data     = 0x08,
+		.reg_irq_mask = 0x09,
+		.reg_irq_src  = 0x0c,
+		.reg_sense    = 0x0b,
+		.reg_clock    = 0x0f,
+		.reg_misc     = 0x10,
+		.reg_reset    = 0x7d,
+		.ngpios       = 8
+	},
+	[1] = { /* sx1509q */
+		.reg_pullup   = 0x07,
+		.reg_pulldn   = 0x09,
+		.reg_drain    = 0x0b,
+		.reg_polarity = 0x0d,
+		.reg_dir      = 0x0f,
+		.reg_data     = 0x11,
+		.reg_irq_mask = 0x13,
+		.reg_irq_src  = 0x19,
+		.reg_sense    = 0x17,
+		.reg_clock    = 0x1e,
+		.reg_misc     = 0x1f,
+		.reg_reset    = 0x7d,
+		.ngpios       = 16
+	},
+};
+
+static const struct i2c_device_id sx150x_id[] = {
+	{"sx1508q", 0},
+	{"sx1509q", 1},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, sx150x_id);
+
+static s32 sx150x_i2c_write(struct i2c_client *client, u8 reg, u8 val)
+{
+	s32 err = i2c_smbus_write_byte_data(client, reg, val);
+
+	if (err < 0)
+		dev_warn(&client->dev,
+			"i2c write fail: can't write %02x to %02x: %d\n",
+			val, reg, err);
+	return err;
+}
+
+static s32 sx150x_i2c_read(struct i2c_client *client, u8 reg, u8 *val)
+{
+	s32 err = i2c_smbus_read_byte_data(client, reg);
+
+	if (err >= 0)
+		*val = err;
+	else
+		dev_warn(&client->dev,
+			"i2c read fail: can't read from %02x: %d\n",
+			reg, err);
+	return err;
+}
+
+static inline bool offset_is_oscio(struct sx150x_chip *chip, unsigned offset)
+{
+	return (chip->dev_cfg->ngpios == offset);
+}
+
+/*
+ * These utility functions solve the common problem of locating and setting
+ * configuration bits.  Configuration bits are grouped into registers
+ * whose indexes increase downwards.  For example, with eight-bit registers,
+ * sixteen gpios would have their config bits grouped in the following order:
+ * REGISTER N-1 [ f e d c b a 9 8 ]
+ *          N   [ 7 6 5 4 3 2 1 0 ]
+ *
+ * For multi-bit configurations, the pattern gets wider:
+ * REGISTER N-3 [ f f e e d d c c ]
+ *          N-2 [ b b a a 9 9 8 8 ]
+ *          N-1 [ 7 7 6 6 5 5 4 4 ]
+ *          N   [ 3 3 2 2 1 1 0 0 ]
+ *
+ * Given the address of the starting register 'N', the index of the gpio
+ * whose configuration we seek to change, and the width in bits of that
+ * configuration, these functions allow us to locate the correct
+ * register and mask the correct bits.
+ */
+static inline void sx150x_find_cfg(u8 offset, u8 width,
+				u8 *reg, u8 *mask, u8 *shift)
+{
+	*reg   -= offset * width / 8;
+	*mask   = (1 << width) - 1;
+	*shift  = (offset * width) % 8;
+	*mask <<= *shift;
+}
+
+static s32 sx150x_write_cfg(struct sx150x_chip *chip,
+			u8 offset, u8 width, u8 reg, u8 val)
+{
+	u8  mask;
+	u8  data;
+	u8  shift;
+	s32 err;
+
+	sx150x_find_cfg(offset, width, &reg, &mask, &shift);
+	err = sx150x_i2c_read(chip->client, reg, &data);
+	if (err < 0)
+		return err;
+
+	data &= ~mask;
+	data |= (val << shift) & mask;
+	return sx150x_i2c_write(chip->client, reg, data);
+}
+
+static int sx150x_get_io(struct sx150x_chip *chip, unsigned offset)
+{
+	u8  reg = chip->dev_cfg->reg_data;
+	u8  mask;
+	u8  data;
+	u8  shift;
+	s32 err;
+
+	sx150x_find_cfg(offset, 1, &reg, &mask, &shift);
+	err = sx150x_i2c_read(chip->client, reg, &data);
+	if (err >= 0)
+		err = (data & mask) != 0 ? 1 : 0;
+
+	return err;
+}
+
+static void sx150x_set_oscio(struct sx150x_chip *chip, int val)
+{
+	sx150x_i2c_write(chip->client,
+			chip->dev_cfg->reg_clock,
+			(val ? 0x1f : 0x10));
+}
+
+static void sx150x_set_io(struct sx150x_chip *chip, unsigned offset, int val)
+{
+	sx150x_write_cfg(chip,
+			offset,
+			1,
+			chip->dev_cfg->reg_data,
+			(val ? 1 : 0));
+}
+
+static int sx150x_io_input(struct sx150x_chip *chip, unsigned offset)
+{
+	return sx150x_write_cfg(chip,
+				offset,
+				1,
+				chip->dev_cfg->reg_dir,
+				1);
+}
+
+static int sx150x_io_output(struct sx150x_chip *chip, unsigned offset, int val)
+{
+	int err;
+
+	err = sx150x_write_cfg(chip,
+			offset,
+			1,
+			chip->dev_cfg->reg_data,
+			(val ? 1 : 0));
+	if (err >= 0)
+		err = sx150x_write_cfg(chip,
+				offset,
+				1,
+				chip->dev_cfg->reg_dir,
+				0);
+	return err;
+}
+
+static int sx150x_gpio_get(struct gpio_chip *gc, unsigned offset)
+{
+	struct sx150x_chip *chip;
+	int status = -EINVAL;
+
+	chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+	if (!offset_is_oscio(chip, offset)) {
+		mutex_lock(&chip->lock);
+		status = sx150x_get_io(chip, offset);
+		mutex_unlock(&chip->lock);
+	}
+
+	return status;
+}
+
+static void sx150x_gpio_set(struct gpio_chip *gc, unsigned offset, int val)
+{
+	struct sx150x_chip *chip;
+
+	chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+	mutex_lock(&chip->lock);
+	if (offset_is_oscio(chip, offset))
+		sx150x_set_oscio(chip, val);
+	else
+		sx150x_set_io(chip, offset, val);
+	mutex_unlock(&chip->lock);
+}
+
+static int sx150x_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	struct sx150x_chip *chip;
+	int status = -EINVAL;
+
+	chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+	if (!offset_is_oscio(chip, offset)) {
+		mutex_lock(&chip->lock);
+		status = sx150x_io_input(chip, offset);
+		mutex_unlock(&chip->lock);
+	}
+	return status;
+}
+
+static int sx150x_gpio_direction_output(struct gpio_chip *gc,
+					unsigned offset,
+					int val)
+{
+	struct sx150x_chip *chip;
+	int status = 0;
+
+	chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+	if (!offset_is_oscio(chip, offset)) {
+		mutex_lock(&chip->lock);
+		status = sx150x_io_output(chip, offset, val);
+		mutex_unlock(&chip->lock);
+	}
+	return status;
+}
+
+static int sx150x_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+	struct sx150x_chip *chip;
+
+	chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+	if (offset >= chip->dev_cfg->ngpios)
+		return -EINVAL;
+
+	if (chip->irq_base < 0)
+		return -EINVAL;
+
+	return chip->irq_base + offset;
+}
+
+static void sx150x_irq_mask(unsigned int irq)
+{
+	struct irq_chip *ic = get_irq_chip(irq);
+	struct sx150x_chip *chip;
+	unsigned n;
+
+	chip = container_of(ic, struct sx150x_chip, irq_chip);
+	n = irq - chip->irq_base;
+
+	sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 1);
+	sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense, 0);
+}
+
+static void sx150x_irq_unmask(unsigned int irq)
+{
+	struct irq_chip *ic = get_irq_chip(irq);
+	struct sx150x_chip *chip;
+	unsigned n;
+
+	chip = container_of(ic, struct sx150x_chip, irq_chip);
+	n = irq - chip->irq_base;
+
+	sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 0);
+	sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense,
+			 chip->irq_sense >> (n * 2));
+}
+
+static int sx150x_irq_set_type(unsigned int irq, unsigned int flow_type)
+{
+	struct irq_chip *ic = get_irq_chip(irq);
+	struct sx150x_chip *chip;
+	unsigned n, val = 0;
+
+	if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		return -EINVAL;
+
+	chip = container_of(ic, struct sx150x_chip, irq_chip);
+	n = irq - chip->irq_base;
+
+	if (flow_type & IRQ_TYPE_EDGE_RISING)
+		val |= 0x1;
+	if (flow_type & IRQ_TYPE_EDGE_FALLING)
+		val |= 0x2;
+
+	chip->irq_sense &= ~(3UL << (n * 2));
+	chip->irq_sense |= val << (n * 2);
+	chip->irq_set_type_pending |= BIT(n);
+	return 0;
+}
+
+static irqreturn_t sx150x_irq_thread_fn(int irq, void *dev_id)
+{
+	struct sx150x_chip *chip = (struct sx150x_chip *)dev_id;
+	unsigned nhandled = 0;
+	unsigned sub_irq;
+	unsigned n;
+	s32 err;
+	u8 val;
+	int i;
+
+	for (i = (chip->dev_cfg->ngpios / 8) - 1; i >= 0; --i) {
+		err = sx150x_i2c_read(chip->client,
+				      chip->dev_cfg->reg_irq_src - i,
+				      &val);
+		if (err < 0)
+			continue;
+
+		sx150x_i2c_write(chip->client,
+				chip->dev_cfg->reg_irq_src - i,
+				val);
+		for (n = 0; n < 8; ++n) {
+			if (val & (1 << n)) {
+				sub_irq = chip->irq_base + (i * 8) + n;
+				handle_nested_irq(sub_irq);
+				++nhandled;
+			}
+		}
+	}
+
+	return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);
+}
+
+static void sx150x_irq_bus_lock(unsigned int irq)
+{
+	struct irq_chip *ic = get_irq_chip(irq);
+	struct sx150x_chip *chip;
+
+	chip = container_of(ic, struct sx150x_chip, irq_chip);
+
+	mutex_lock(&chip->lock);
+}
+
+static void sx150x_irq_bus_sync_unlock(unsigned int irq)
+{
+	struct irq_chip *ic = get_irq_chip(irq);
+	struct sx150x_chip *chip;
+	unsigned n;
+
+	chip = container_of(ic, struct sx150x_chip, irq_chip);
+
+	while (chip->irq_set_type_pending) {
+		n = __ffs(chip->irq_set_type_pending);
+		chip->irq_set_type_pending &= ~BIT(n);
+		if (!(irq_to_desc(n + chip->irq_base)->status & IRQ_MASKED))
+			sx150x_write_cfg(chip, n, 2,
+					chip->dev_cfg->reg_sense,
+					chip->irq_sense >> (n * 2));
+	}
+
+	mutex_unlock(&chip->lock);
+}
+
+static void sx150x_init_chip(struct sx150x_chip *chip,
+			struct i2c_client *client,
+			kernel_ulong_t driver_data,
+			struct sx150x_platform_data *pdata)
+{
+	mutex_init(&chip->lock);
+
+	chip->client                     = client;
+	chip->dev_cfg                    = &sx150x_devices[driver_data];
+	chip->gpio_chip.label            = client->name;
+	chip->gpio_chip.direction_input  = sx150x_gpio_direction_input;
+	chip->gpio_chip.direction_output = sx150x_gpio_direction_output;
+	chip->gpio_chip.get              = sx150x_gpio_get;
+	chip->gpio_chip.set              = sx150x_gpio_set;
+	chip->gpio_chip.to_irq           = sx150x_gpio_to_irq;
+	chip->gpio_chip.base             = pdata->gpio_base;
+	chip->gpio_chip.can_sleep        = 1;
+	chip->gpio_chip.ngpio            = chip->dev_cfg->ngpios;
+	if (pdata->oscio_is_gpo)
+		++chip->gpio_chip.ngpio;
+
+	chip->irq_chip.name            = client->name;
+	chip->irq_chip.mask            = sx150x_irq_mask;
+	chip->irq_chip.unmask          = sx150x_irq_unmask;
+	chip->irq_chip.set_type        = sx150x_irq_set_type;
+	chip->irq_chip.bus_lock        = sx150x_irq_bus_lock;
+	chip->irq_chip.bus_sync_unlock = sx150x_irq_bus_sync_unlock;
+	chip->irq_summary              = -1;
+	chip->irq_base                 = -1;
+	chip->irq_sense                = 0;
+	chip->irq_set_type_pending     = 0;
+}
+
+static int sx150x_init_io(struct sx150x_chip *chip, u8 base, u16 cfg)
+{
+	int err = 0;
+	unsigned n;
+
+	for (n = 0; err >= 0 && n < (chip->dev_cfg->ngpios / 8); ++n)
+		err = sx150x_i2c_write(chip->client, base - n, cfg >> (n * 8));
+	return err;
+}
+
+static int sx150x_init_hw(struct sx150x_chip *chip,
+			struct sx150x_platform_data *pdata)
+{
+	int err = 0;
+
+	err = i2c_smbus_write_word_data(chip->client,
+					chip->dev_cfg->reg_reset,
+					0x3412);
+	if (err < 0)
+		return err;
+
+	err = sx150x_i2c_write(chip->client,
+			chip->dev_cfg->reg_misc,
+			0x01);
+	if (err < 0)
+		return err;
+
+	err = sx150x_init_io(chip, chip->dev_cfg->reg_pullup,
+			pdata->io_pullup_ena);
+	if (err < 0)
+		return err;
+
+	err = sx150x_init_io(chip, chip->dev_cfg->reg_pulldn,
+			pdata->io_pulldn_ena);
+	if (err < 0)
+		return err;
+
+	err = sx150x_init_io(chip, chip->dev_cfg->reg_drain,
+			pdata->io_open_drain_ena);
+	if (err < 0)
+		return err;
+
+	err = sx150x_init_io(chip, chip->dev_cfg->reg_polarity,
+			pdata->io_polarity);
+	if (err < 0)
+		return err;
+
+	if (pdata->oscio_is_gpo)
+		sx150x_set_oscio(chip, 0);
+
+	return err;
+}
+
+static int sx150x_install_irq_chip(struct sx150x_chip *chip,
+				int irq_summary,
+				int irq_base)
+{
+	int err;
+	unsigned n;
+	unsigned irq;
+
+	chip->irq_summary = irq_summary;
+	chip->irq_base    = irq_base;
+
+	for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
+		irq = irq_base + n;
+		set_irq_chip_and_handler(irq, &chip->irq_chip, handle_edge_irq);
+		set_irq_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+		set_irq_flags(irq, IRQF_VALID);
+#else
+		set_irq_noprobe(irq);
+#endif
+	}
+
+	err = request_threaded_irq(irq_summary,
+				NULL,
+				sx150x_irq_thread_fn,
+				IRQF_SHARED | IRQF_TRIGGER_FALLING,
+				chip->irq_chip.name,
+				chip);
+	if (err < 0) {
+		chip->irq_summary = -1;
+		chip->irq_base    = -1;
+	}
+
+	return err;
+}
+
+static void sx150x_remove_irq_chip(struct sx150x_chip *chip)
+{
+	unsigned n;
+	unsigned irq;
+
+	free_irq(chip->irq_summary, chip);
+
+	for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
+		irq = chip->irq_base + n;
+		set_irq_handler(irq, NULL);
+		set_irq_chip(irq, NULL);
+	}
+}
+
+static int __devinit sx150x_probe(struct i2c_client *client,
+				const struct i2c_device_id *id)
+{
+	static const u32 i2c_funcs = I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_WRITE_WORD_DATA;
+	struct sx150x_platform_data *pdata;
+	struct sx150x_chip *chip;
+	int rc;
+
+	pdata = client->dev.platform_data;
+	if (!pdata)
+		return -EINVAL;
+
+	if (!i2c_check_functionality(client->adapter, i2c_funcs))
+		return -ENOSYS;
+
+	chip = kzalloc(sizeof(struct sx150x_chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	sx150x_init_chip(chip, client, id->driver_data, pdata);
+	rc = sx150x_init_hw(chip, pdata);
+	if (rc < 0)
+		goto probe_fail_pre_gpiochip_add;
+
+	rc = gpiochip_add(&chip->gpio_chip);
+	if (rc < 0)
+		goto probe_fail_pre_gpiochip_add;
+
+	if (pdata->irq_summary >= 0) {
+		rc = sx150x_install_irq_chip(chip,
+					pdata->irq_summary,
+					pdata->irq_base);
+		if (rc < 0)
+			goto probe_fail_post_gpiochip_add;
+	}
+
+	i2c_set_clientdata(client, chip);
+
+	return 0;
+probe_fail_post_gpiochip_add:
+	WARN_ON(gpiochip_remove(&chip->gpio_chip) < 0);
+probe_fail_pre_gpiochip_add:
+	kfree(chip);
+	return rc;
+}
+
+static int __devexit sx150x_remove(struct i2c_client *client)
+{
+	struct sx150x_chip *chip;
+	int rc;
+
+	chip = i2c_get_clientdata(client);
+	rc = gpiochip_remove(&chip->gpio_chip);
+	if (rc < 0)
+		return rc;
+
+	if (chip->irq_summary >= 0)
+		sx150x_remove_irq_chip(chip);
+
+	kfree(chip);
+
+	return 0;
+}
+
+static struct i2c_driver sx150x_driver = {
+	.driver = {
+		.name = "sx150x",
+		.owner = THIS_MODULE
+	},
+	.probe    = sx150x_probe,
+	.remove   = __devexit_p(sx150x_remove),
+	.id_table = sx150x_id,
+};
+
+static int __init sx150x_init(void)
+{
+	return i2c_add_driver(&sx150x_driver);
+}
+subsys_initcall(sx150x_init);
+
+static void __exit sx150x_exit(void)
+{
+	return i2c_del_driver(&sx150x_driver);
+}
+module_exit(sx150x_exit);
+
+MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
+MODULE_DESCRIPTION("Driver for Semtech SX150X I2C GPIO Expanders");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("i2c:sx150x");