Subject: [PATCH] gpio: sx150x: Add Semtech I2C sx150x gpio expander driver.

From: [email-masked] (Trilok Soni)
Date: Wed, 07 Jul 2010 13:53:48 +0530

On 7/7/2010 4:07 AM, Gregory Bean wrote:
> Add support for Semtech SX150-series I2C GPIO expanders.
> Compatible models include:
> 
> 8 bits:  sx1508q
> 16 bits: sx1509q
> 
> Signed-off-by: Gregory Bean <[email-masked]>

Added linux-i2c and Jean Delvare for i2c bits, so not deleting any lines from the code.

> ---
>  drivers/gpio/Kconfig       |   11 +
>  drivers/gpio/Makefile      |    1 +
>  drivers/gpio/sx150x.c      |  720 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/i2c/sx150x.h |   78 +++++
>  4 files changed, 810 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/gpio/sx150x.c
>  create mode 100644 include/linux/i2c/sx150x.h
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 724038d..62d7758 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
> +	tristate "Semtech SX150x I2C GPIO expander"
> +	depends on I2C
> +	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 51c3cdd..ccb804d 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -31,3 +31,4 @@ 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 0000000..0594150
> --- /dev/null
> +++ b/drivers/gpio/sx150x.c
> @@ -0,0 +1,720 @@
> +/* 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/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;
> +};
> +
> +/*
> + * irq_cmds:
> + *
> + * A bitmap containing all the commands issued by the interrupt system
> + * for processing by the work-queue once out of interrupt context.
> + * A nice, static bitmap avoids the risk of dynamic memory allocation
> + * and the bitmap is small enough that the wasted space of a worst-case
> + * allocation is minimal.
> + * Bits for each gpio are as follows:
> + *
> + * 0 - mask
> + * 1 - unmask
> + * 2 - sense rising edge
> + * 3 - sense falling edge
> + *
> + * Every group of four bits is for a unique gpio, so bits 0-3 are for IO
> + * pin 0, 4-7, for pin 1, &c.
> + */
> +enum {
> +	CMD_MASK    = 0,
> +	CMD_UNMASK  = 1,
> +	CMD_RISING  = 2,
> +	CMD_FALLING = 3,
> +	CMDS_PER_IO = 4,
> +};
> +
> +#define NCMDBITS (16 * CMDS_PER_IO)
> +
> +static inline unsigned cmd_bit(unsigned pin, unsigned cmd)
> +{
> +	return pin * CMDS_PER_IO + cmd;
> +}
> +
> +struct sx150x_chip {
> +	struct gpio_chip                 gpio_chip;
> +	struct i2c_client               *client;
> +	const struct sx150x_device_data *dev_cfg;
> +	struct mutex                     mutex;
> +	int                              irq_summary;
> +	int                              irq_base;
> +	u32                              irq_sense;
> +	struct irq_chip                  irq_chip;
> +	struct work_struct               irq_mask_ws;
> +	struct work_struct               irq_unmask_ws;
> +	struct work_struct               irq_set_type_ws;
> +	DECLARE_BITMAP(irq_cmds, NCMDBITS);
> +};
> +
> +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);
> +	mutex_lock(&chip->mutex);
> +	err = sx150x_i2c_read(chip->client, reg, &data);
> +	mutex_unlock(&chip->mutex);
> +	if (err >= 0)
> +		err = (data & mask) != 0 ? 1 : 0;
> +
> +	return err;
> +}
> +
> +static void sx150x_set_oscio(struct sx150x_chip *chip, int val)
> +{
> +	mutex_lock(&chip->mutex);
> +	sx150x_i2c_write(chip->client,
> +			chip->dev_cfg->reg_clock,
> +			(val ? 0x1f : 0x10));
> +	mutex_unlock(&chip->mutex);
> +}
> +
> +static void sx150x_set_io(struct sx150x_chip *chip, unsigned offset, int val)
> +{
> +	mutex_lock(&chip->mutex);
> +	sx150x_write_cfg(chip,
> +			offset,
> +			1,
> +			chip->dev_cfg->reg_data,
> +			(val ? 1 : 0));
> +	mutex_unlock(&chip->mutex);
> +}
> +
> +static int sx150x_io_input(struct sx150x_chip *chip, unsigned offset)
> +{
> +	int err;
> +
> +	mutex_lock(&chip->mutex);
> +	err = sx150x_write_cfg(chip,
> +			offset,
> +			1,
> +			chip->dev_cfg->reg_dir,
> +			1);
> +	mutex_unlock(&chip->mutex);
> +	return err;
> +}
> +
> +static int sx150x_io_output(struct sx150x_chip *chip, unsigned offset, int val)
> +{
> +	int err;
> +
> +	mutex_lock(&chip->mutex);
> +	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);
> +	mutex_unlock(&chip->mutex);
> +	return err;
> +}
> +
> +static int sx150x_gpio_get(struct gpio_chip *gc, unsigned offset)
> +{
> +	struct sx150x_chip *chip;
> +
> +	chip = container_of(gc, struct sx150x_chip, gpio_chip);
> +
> +	if (offset_is_oscio(chip, offset))
> +		return -ENOTSUPP;
> +	else
> +		return sx150x_get_io(chip, offset);
> +}
> +
> +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);
> +
> +	if (offset_is_oscio(chip, offset))
> +		sx150x_set_oscio(chip, val);
> +	else
> +		sx150x_set_io(chip, offset, val);
> +}
> +
> +static int sx150x_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
> +{
> +	struct sx150x_chip *chip;
> +
> +	chip = container_of(gc, struct sx150x_chip, gpio_chip);
> +
> +	if (offset_is_oscio(chip, offset))
> +		return -ENOTSUPP;
> +	else
> +		return sx150x_io_input(chip, offset);
> +}
> +
> +static int sx150x_gpio_direction_output(struct gpio_chip *gc,
> +					unsigned offset,
> +					int val)
> +{
> +	struct sx150x_chip *chip;
> +
> +	chip = container_of(gc, struct sx150x_chip, gpio_chip);
> +
> +	if (offset_is_oscio(chip, offset))
> +		return 0;
> +	else
> +		return sx150x_io_output(chip, offset, val);
> +}
> +
> +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 -ENOTSUPP;
> +
> +	return chip->irq_base + offset;
> +}
> +
> +static void sx150x_irq_mask(unsigned int irq)
> +{
> +	struct irq_chip *ic;
> +	struct sx150x_chip *chip;
> +
> +	ic   = get_irq_chip(irq);
> +	chip = container_of(ic, struct sx150x_chip, irq_chip);
> +
> +	set_bit(cmd_bit(irq - chip->irq_base, CMD_MASK), chip->irq_cmds);
> +	schedule_work(&chip->irq_mask_ws);
> +}
> +
> +static void sx150x_irq_mask_wfn(struct work_struct *work)
> +{
> +	struct sx150x_chip *chip;
> +	unsigned n;
> +
> +	chip = container_of(work, struct sx150x_chip, irq_mask_ws);
> +
> +	mutex_lock(&chip->mutex);
> +	for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
> +		if (test_and_clear_bit(cmd_bit(n, CMD_MASK),
> +					chip->irq_cmds)) {
> +			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);
> +		}
> +	}
> +	mutex_unlock(&chip->mutex);
> +}

Please explain why we are using workqueues for mask/unmasks hooks and irq thread context won't work?

> +
> +static void sx150x_irq_unmask(unsigned int irq)
> +{
> +	struct irq_chip *ic;
> +	struct sx150x_chip *chip;
> +
> +	ic   = get_irq_chip(irq);
> +	chip = container_of(ic, struct sx150x_chip, irq_chip);
> +
> +	set_bit(cmd_bit(irq - chip->irq_base, CMD_UNMASK), chip->irq_cmds);
> +	schedule_work(&chip->irq_unmask_ws);
> +}
> +
> +static void sx150x_irq_unmask_wfn(struct work_struct *work)
> +{
> +	struct sx150x_chip *chip;
> +	unsigned n;
> +
> +	chip = container_of(work, struct sx150x_chip, irq_unmask_ws);
> +
> +	mutex_lock(&chip->mutex);
> +	for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
> +		if (test_and_clear_bit(cmd_bit(n, CMD_UNMASK),
> +					chip->irq_cmds)) {
> +			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));
> +		}
> +	}
> +	mutex_unlock(&chip->mutex);
> +}
> +
> +static int sx150x_irq_set_type(unsigned int irq, unsigned int flow_type)
> +{
> +	struct irq_chip *ic;
> +	struct sx150x_chip *chip;
> +	unsigned offset;
> +
> +	if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
> +		return -EINVAL;
> +
> +	ic     = get_irq_chip(irq);
> +	chip   = container_of(ic, struct sx150x_chip, irq_chip);
> +	offset = irq - chip->irq_base;
> +
> +	if (flow_type & IRQ_TYPE_EDGE_RISING)
> +		set_bit(cmd_bit(offset, CMD_RISING), chip->irq_cmds);
> +	if (flow_type & IRQ_TYPE_EDGE_FALLING)
> +		set_bit(cmd_bit(offset, CMD_FALLING), chip->irq_cmds);
> +	schedule_work(&chip->irq_set_type_ws);
> +
> +	return 0;
> +}
> +
> +static void sx150x_irq_set_type_wfn(struct work_struct *work)
> +{
> +	struct sx150x_chip *chip;
> +	unsigned n;
> +	unsigned val;
> +	int irq;
> +
> +	chip = container_of(work, struct sx150x_chip, irq_set_type_ws);
> +
> +	mutex_lock(&chip->mutex);
> +	for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
> +		val = 0;
> +		if (test_and_clear_bit(cmd_bit(n, CMD_RISING),
> +					chip->irq_cmds))
> +			val |= 0x1;
> +		if (test_and_clear_bit(cmd_bit(n, CMD_FALLING),
> +					chip->irq_cmds))
> +			val |= 0x2;
> +
> +		chip->irq_sense &= ~(3UL << (n * 2));
> +		chip->irq_sense |= val << (n * 2);
> +
> +		irq = chip->irq_base + n;
> +		if (!(irq_to_desc(irq)->status & IRQ_MASKED))
> +			sx150x_write_cfg(chip, n, 2,
> +					chip->dev_cfg->reg_sense, val);
> +	}
> +	mutex_unlock(&chip->mutex);
> +}
> +
> +static irqreturn_t sx150x_irq_thread_fn(int irq, void *dev_id)
> +{
> +	struct sx150x_chip *chip = (struct sx150x_chip *)dev_id;
> +	int i;
> +	unsigned n;
> +	unsigned sub_irq;
> +	u8 val;
> +	unsigned nhandled = 0;
> +
> +	mutex_lock(&chip->mutex);
> +	for (i = (chip->dev_cfg->ngpios / 8) - 1; i >= 0; --i) {
> +		sx150x_i2c_read(chip->client,
> +				chip->dev_cfg->reg_irq_src - i,
> +				&val);
> +		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;
> +			}
> +		}
> +	}
> +	mutex_unlock(&chip->mutex);
> +
> +	return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);
> +}
> +
> +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->mutex);
> +
> +	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;

Why we are not using bus_lock/unlock hooks?

> +	chip->irq_summary           = -1;
> +	chip->irq_base              = -1;
> +	chip->irq_sense             = 0;
> +
> +	bitmap_zero(chip->irq_cmds, NCMDBITS);
> +
> +	INIT_WORK(&chip->irq_mask_ws, sx150x_irq_mask_wfn);
> +	INIT_WORK(&chip->irq_unmask_ws, sx150x_irq_unmask_wfn);
> +	INIT_WORK(&chip->irq_set_type_ws, sx150x_irq_set_type_wfn);
> +}
> +
> +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 = gpio_to_irq(chip->gpio_chip.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)
> +{
> +	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_FUNC_SMBUS_BYTE_DATA))
> +		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;
> +
> +	rc = gpiochip_add(&chip->gpio_chip);
> +	if (rc < 0)
> +		goto probe_fail;
> +
> +	i2c_set_clientdata(client, chip);
> +
> +	if (pdata->irq_summary >= 0) {
> +		rc = sx150x_install_irq_chip(chip,
> +					pdata->irq_summary,
> +					pdata->irq_base);
> +		if (rc < 0)
> +			goto probe_fail;
> +	}
> +
> +	return 0;
> +probe_fail:
> +	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);
> +
> +	flush_work(&chip->irq_mask_ws);
> +	flush_work(&chip->irq_unmask_ws);
> +	flush_work(&chip->irq_set_type_ws);
> +	kfree(chip);
> +
> +	return rc;
> +}
> +
> +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 <[email-masked]>");
> +MODULE_DESCRIPTION("Driver for Semtech SX150X I2C GPIO Expanders");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:sx150x");
> diff --git a/include/linux/i2c/sx150x.h b/include/linux/i2c/sx150x.h
> new file mode 100644
> index 0000000..ee3049c
> --- /dev/null
> +++ b/include/linux/i2c/sx150x.h
> @@ -0,0 +1,78 @@
> +/*
> + * Driver for the Semtech SX150x I2C GPIO Expanders
> + *
> + * 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.
> + */
> +#ifndef __LINUX_I2C_SX150X_H
> +#define __LINUX_I2C_SX150X_H
> +
> +/**
> + * struct sx150x_platform_data - config data for SX150x driver
> + * @gpio_base: The index number of the first GPIO assigned to this
> + *             GPIO expander.  The expander will create a block of
> + *             consecutively numbered gpios beginning at the given base,
> + *             with the size of the block depending on the model of the
> + *             expander chip.
> + * @oscio_is_gpo: If set to true, the driver will configure OSCIO as a GPO
> + *                instead of as an oscillator, increasing the size of the
> + *                GP(I)O pool created by this expander by one.  The
> + *                output-only GPO pin will be added at the end of the block.
> + * @io_pullup_ena: A bit-mask which enables or disables the pull-up resistor
> + *                 for each IO line in the expander.  Setting the bit at
> + *                 position n will enable the pull-up for the IO at
> + *                 the corresponding offset.  For chips with fewer than
> + *                 16 IO pins, high-end bits are ignored.
> + * @io_pulldn_ena: A bit-mask which enables-or disables the pull-down
> + *                 resistor for each IO line in the expander. Setting the
> + *                 bit at position n will enable the pull-down for the IO at
> + *                 the corresponding offset.  For chips with fewer than
> + *                 16 IO pins, high-end bits are ignored.
> + * @io_open_drain_ena: A bit-mask which enables-or disables open-drain
> + *                     operation for each IO line in the expander. Setting the
> + *                     bit at position n enables open-drain operation for
> + *                     the IO at the corresponding offset.  Clearing the bit
> + *                     enables regular push-pull operation for that IO.
> + *                     For chips with fewer than 16 IO pins, high-end bits
> + *                     are ignored.
> + * @io_polarity: A bit-mask which enables polarity inversion for each IO line
> + *               in the expander.  Setting the bit at position n inverts
> + *               the polarity of that IO line, while clearing it results
> + *               in normal polarity. For chips with fewer than 16 IO pins,
> + *               high-end bits are ignored.
> + * @irq_summary: The 'summary IRQ' line to which the GPIO expander's INT line
> + *               is connected, via which it reports interrupt events
> + *               across all GPIO lines.  This must be a real,
> + *               pre-existing IRQ line.
> + *               Setting this value < 0 disables the irq_chip functionality
> + *               of the driver.
> + * @irq_base: The first 'virtual IRQ' line at which our block of GPIO-based
> + *            IRQ lines will appear.  Similarly to gpio_base, the expander
> + *            will create a block of irqs beginning at this number.
> + *            This value is ignored if irq_summary is < 0.
> + */
> +struct sx150x_platform_data {
> +	unsigned gpio_base;
> +	bool     oscio_is_gpo;
> +	u16      io_pullup_ena;
> +	u16      io_pulldn_ena;
> +	u16      io_open_drain_ena;
> +	u16      io_polarity;
> +	int      irq_summary;
> +	unsigned irq_base;
> +};
> +
> +#endif /* __LINUX_I2C_SX150X_H */

-- 
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.