Commit e952805d authored by Wolfram Sang's avatar Wolfram Sang Committed by Linus Torvalds
Browse files

gpio: add driver for MAX7300 I2C GPIO extender 



Add the MAX7300-I2C variant of the MAX7301-SPI version.  Both chips share
the same core logic, so the generic part of the in-kernel SPI-driver is
refactored into a generic part.  The I2C and SPI specific funtions are
then wrapped into seperate drivers picking up the generic part.

Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
Cc: Juergen Beisert <j.beisert@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5a98c04d

drivers/gpio/Kconfig

+12 −1
Original line number Diff line number Diff line
@@ -65,6 +65,9 @@ config GPIO_SYSFS 


# put expanders in the right section, in alphabetical order



config GPIO_MAX730X

	tristate



comment "Memory mapped GPIO expanders:"



config GPIO_PL061
@@ -87,6 +90,13 @@ config GPIO_VR41XX 


comment "I2C GPIO expanders:"



config GPIO_MAX7300

	tristate "Maxim MAX7300 GPIO expander"

	depends on I2C

	select GPIO_MAX730X

	help

	  GPIO driver for Maxim MAX7301 I2C-based GPIO expander.



config GPIO_MAX732X

	tristate "MAX7319, MAX7320-7327 I2C Port Expanders"

	depends on I2C
@@ -226,8 +236,9 @@ comment "SPI GPIO expanders:" 
config GPIO_MAX7301

	tristate "Maxim MAX7301 GPIO expander"

	depends on SPI_MASTER

	select GPIO_MAX730X

	help

	  gpio driver for Maxim MAX7301 SPI GPIO expander.

	  GPIO driver for Maxim MAX7301 SPI-based GPIO expander.



config GPIO_MCP23S08

	tristate "Microchip MCP23S08 I/O expander"

drivers/gpio/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -7,6 +7,8 @@ obj-$(CONFIG_GPIOLIB) += gpiolib.o 
obj-$(CONFIG_GPIO_ADP5520)	+= adp5520-gpio.o

obj-$(CONFIG_GPIO_ADP5588)	+= adp5588-gpio.o

obj-$(CONFIG_GPIO_LANGWELL)	+= langwell_gpio.o

obj-$(CONFIG_GPIO_MAX730X)	+= max730x.o

obj-$(CONFIG_GPIO_MAX7300)	+= max7300.o

obj-$(CONFIG_GPIO_MAX7301)	+= max7301.o

obj-$(CONFIG_GPIO_MAX732X)	+= max732x.o

obj-$(CONFIG_GPIO_MC33880)	+= mc33880.o

drivers/gpio/max7300.c

0 → 100644
+94 −0
Original line number Diff line number Diff line 
/*

 * drivers/gpio/max7300.c

 *

 * Copyright (C) 2009 Wolfram Sang, Pengutronix

 *

 * 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.

 *

 * Check max730x.c for further details.

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/mutex.h>

#include <linux/i2c.h>

#include <linux/spi/max7301.h>



static int max7300_i2c_write(struct device *dev, unsigned int reg,

				unsigned int val)

{

	struct i2c_client *client = to_i2c_client(dev);



	return i2c_smbus_write_byte_data(client, reg, val);

}



static int max7300_i2c_read(struct device *dev, unsigned int reg)

{

	struct i2c_client *client = to_i2c_client(dev);



	return i2c_smbus_read_byte_data(client, reg);

}



static int __devinit max7300_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct max7301 *ts;

	int ret;



	if (!i2c_check_functionality(client->adapter,

			I2C_FUNC_SMBUS_BYTE_DATA))

		return -EIO;



	ts = kzalloc(sizeof(struct max7301), GFP_KERNEL);

	if (!ts)

		return -ENOMEM;



	ts->read = max7300_i2c_read;

	ts->write = max7300_i2c_write;

	ts->dev = &client->dev;



	ret = __max730x_probe(ts);

	if (ret)

		kfree(ts);

	return ret;

}



static int __devexit max7300_remove(struct i2c_client *client)

{

	return __max730x_remove(&client->dev);

}



static const struct i2c_device_id max7300_id[] = {

	{ "max7300", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, max7300_id);



static struct i2c_driver max7300_driver = {

	.driver = {

		.name = "max7300",

		.owner = THIS_MODULE,

	},

	.probe = max7300_probe,

	.remove = __devexit_p(max7300_remove),

	.id_table = max7300_id,

};



static int __init max7300_init(void)

{

	return i2c_add_driver(&max7300_driver);

}

subsys_initcall(max7300_init);



static void __exit max7300_exit(void)

{

	i2c_del_driver(&max7300_driver);

}

module_exit(max7300_exit);



MODULE_AUTHOR("Wolfram Sang");

MODULE_LICENSE("GPL v2");

MODULE_DESCRIPTION("MAX7300 GPIO-Expander");

drivers/gpio/max7301.c

+34 −259
Original line number Diff line number Diff line 
/**

/*

 * drivers/gpio/max7301.c

 *

 * Copyright (C) 2006 Juergen Beisert, Pengutronix

 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix

 * Copyright (C) 2009 Wolfram Sang, Pengutronix

 *

 * 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.

 *

 * The Maxim's MAX7301 device is an SPI driven GPIO expander. There are

 * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more

 * details

 * Note:

 * - DIN must be stable at the rising edge of clock.

 * - when writing:

 *   - always clock in 16 clocks at once

 *   - at DIN: D15 first, D0 last

 *   - D0..D7 = databyte, D8..D14 = commandbyte

 *   - D15 = low -> write command

 * - when reading

 *   - always clock in 16 clocks at once

 *   - at DIN: D15 first, D0 last

 *   - D0..D7 = dummy, D8..D14 = register address

 *   - D15 = high -> read command

 *   - raise CS and assert it again

 *   - always clock in 16 clocks at once

 *   - at DOUT: D15 first, D0 last

 *   - D0..D7 contains the data from the first cycle

 *

 * The driver exports a standard gpiochip interface

 * Check max730x.c for further details.

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/mutex.h>

#include <linux/spi/spi.h>

#include <linux/spi/max7301.h>

#include <linux/gpio.h>



#define DRIVER_NAME "max7301"



/*

 * Pin configurations, see MAX7301 datasheet page 6

 */

#define PIN_CONFIG_MASK 0x03

#define PIN_CONFIG_IN_PULLUP 0x03

#define PIN_CONFIG_IN_WO_PULLUP 0x02

#define PIN_CONFIG_OUT 0x01



#define PIN_NUMBER 28





/*

 * Some registers must be read back to modify.

 * To save time we cache them here in memory

 */

struct max7301 {

	struct mutex	lock;

	u8		port_config[8];	/* field 0 is unused */

	u32		out_level;	/* cached output levels */

	struct gpio_chip chip;

	struct spi_device *spi;

};



/**

 * max7301_write - Write a new register content

 * @spi: The SPI device

 * @reg: Register offset

 * @val: Value to write

 *

 * A write to the MAX7301 means one message with one transfer

 *

 * Returns 0 if successful or a negative value on error

 */

static int max7301_write(struct spi_device *spi, unsigned int reg, unsigned int val)

/* A write to the MAX7301 means one message with one transfer */

static int max7301_spi_write(struct device *dev, unsigned int reg,

				unsigned int val)

{

	struct spi_device *spi = to_spi_device(dev);

	u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);



	return spi_write(spi, (const u8 *)&word, sizeof(word));

}



/**

 * max7301_read - Read back register content

 * @spi: The SPI device

 * @reg: Register offset

 *

 * A read from the MAX7301 means two transfers; here, one message each

 *

 * Returns positive 8 bit value from device if successful or a

 * negative value on error

 */

static int max7301_read(struct spi_device *spi, unsigned int reg)

/* A read from the MAX7301 means two transfers; here, one message each */



static int max7301_spi_read(struct device *dev, unsigned int reg)

{

	int ret;

	u16 word;

	struct spi_device *spi = to_spi_device(dev);



	word = 0x8000 | (reg << 8);

	ret = spi_write(spi, (const u8 *)&word, sizeof(word));
@@ -108,125 +51,13 @@ static int max7301_read(struct spi_device *spi, unsigned int reg) 
	return word & 0xff;

}



static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);

	u8 *config;

	int ret;



	/* First 4 pins are unused in the controller */

	offset += 4;



	config = &ts->port_config[offset >> 2];



	mutex_lock(&ts->lock);



	/* Standard GPIO API doesn't support pull-ups, has to be extended.

	 * Hard-coding no pollup for now. */

	*config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3));



	ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config);



	mutex_unlock(&ts->lock);



	return ret;

}



static int __max7301_set(struct max7301 *ts, unsigned offset, int value)

{

	if (value) {

		ts->out_level |= 1 << offset;

		return max7301_write(ts->spi, 0x20 + offset, 0x01);

	} else {

		ts->out_level &= ~(1 << offset);

		return max7301_write(ts->spi, 0x20 + offset, 0x00);

	}

}



static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,

				    int value)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);

	u8 *config;

	int ret;



	/* First 4 pins are unused in the controller */

	offset += 4;



	config = &ts->port_config[offset >> 2];



	mutex_lock(&ts->lock);



	*config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3));



	ret = __max7301_set(ts, offset, value);



	if (!ret)

		ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config);



	mutex_unlock(&ts->lock);



	return ret;

}



static int max7301_get(struct gpio_chip *chip, unsigned offset)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);

	int config, level = -EINVAL;



	/* First 4 pins are unused in the controller */

	offset += 4;



	mutex_lock(&ts->lock);



	config = (ts->port_config[offset >> 2] >> ((offset & 3) * 2)) & 3;



	switch (config) {

	case 1:

		/* Output: return cached level */

		level =  !!(ts->out_level & (1 << offset));

		break;

	case 2:

	case 3:

		/* Input: read out */

		level = max7301_read(ts->spi, 0x20 + offset) & 0x01;

	}

	mutex_unlock(&ts->lock);



	return level;

}



static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);



	/* First 4 pins are unused in the controller */

	offset += 4;



	mutex_lock(&ts->lock);



	__max7301_set(ts, offset, value);



	mutex_unlock(&ts->lock);

}



static int __devinit max7301_probe(struct spi_device *spi)

{

	struct max7301 *ts;

	struct max7301_platform_data *pdata;

	int i, ret;



	pdata = spi->dev.platform_data;

	if (!pdata || !pdata->base) {

		dev_dbg(&spi->dev, "incorrect or missing platform data\n");

		return -EINVAL;

	}

	int ret;



	/*

	 * bits_per_word cannot be configured in platform data

	 */

	/* bits_per_word cannot be configured in platform data */

	spi->bits_per_word = 16;



	ret = spi_setup(spi);

	if (ret < 0)

		return ret;
@@ -235,90 +66,35 @@ static int __devinit max7301_probe(struct spi_device *spi) 
	if (!ts)

		return -ENOMEM;



	mutex_init(&ts->lock);



	dev_set_drvdata(&spi->dev, ts);



	/* Power up the chip and disable IRQ output */

	max7301_write(spi, 0x04, 0x01);

	ts->read = max7301_spi_read;

	ts->write = max7301_spi_write;

	ts->dev = &spi->dev;



	ts->spi = spi;



	ts->chip.label = DRIVER_NAME,



	ts->chip.direction_input = max7301_direction_input;

	ts->chip.get = max7301_get;

	ts->chip.direction_output = max7301_direction_output;

	ts->chip.set = max7301_set;



	ts->chip.base = pdata->base;

	ts->chip.ngpio = PIN_NUMBER;

	ts->chip.can_sleep = 1;

	ts->chip.dev = &spi->dev;

	ts->chip.owner = THIS_MODULE;



	/*

	 * tristate all pins in hardware and cache the

	 * register values for later use.

	 */

	for (i = 1; i < 8; i++) {

		int j;

		/* 0xAA means input with internal pullup disabled */

		max7301_write(spi, 0x08 + i, 0xAA);

		ts->port_config[i] = 0xAA;

		for (j = 0; j < 4; j++) {

			int offset = (i - 1) * 4 + j;

			ret = max7301_direction_input(&ts->chip, offset);

	ret = __max730x_probe(ts);

	if (ret)

				goto exit_destroy;

		}

	}



	ret = gpiochip_add(&ts->chip);

	if (ret)

		goto exit_destroy;



	return ret;



exit_destroy:

	dev_set_drvdata(&spi->dev, NULL);

	mutex_destroy(&ts->lock);

		kfree(ts);

	return ret;

}



static int __devexit max7301_remove(struct spi_device *spi)

{

	struct max7301 *ts;

	int ret;



	ts = dev_get_drvdata(&spi->dev);

	if (ts == NULL)

		return -ENODEV;



	dev_set_drvdata(&spi->dev, NULL);



	/* Power down the chip and disable IRQ output */

	max7301_write(spi, 0x04, 0x00);



	ret = gpiochip_remove(&ts->chip);

	if (!ret) {

		mutex_destroy(&ts->lock);

		kfree(ts);

	} else

		dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",

			ret);



	return ret;

	return __max730x_remove(&spi->dev);

}



static const struct spi_device_id max7301_id[] = {

	{ "max7301", 0 },

	{ }

};

MODULE_DEVICE_TABLE(spi, max7301_id);



static struct spi_driver max7301_driver = {

	.driver = {

		.name		= DRIVER_NAME,

		.name = "max7301",

		.owner = THIS_MODULE,

	},

	.probe = max7301_probe,

	.remove = __devexit_p(max7301_remove),

	.id_table = max7301_id,

};



static int __init max7301_init(void)
@@ -336,7 +112,6 @@ static void __exit max7301_exit(void) 
}

module_exit(max7301_exit);



MODULE_AUTHOR("Juergen Beisert");

MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");

MODULE_LICENSE("GPL v2");

MODULE_DESCRIPTION("MAX7301 SPI based GPIO-Expander");

MODULE_ALIAS("spi:" DRIVER_NAME);
 
MODULE_DESCRIPTION("MAX7301 GPIO-Expander");

drivers/gpio/max730x.c

0 → 100644
+244 −0
Original line number Diff line number Diff line 
/**

 * drivers/gpio/max7301.c

 *

 * Copyright (C) 2006 Juergen Beisert, Pengutronix

 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix

 * Copyright (C) 2009 Wolfram Sang, Pengutronix

 *

 * 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.

 *

 * The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are

 * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more

 * details

 * Note:

 * - DIN must be stable at the rising edge of clock.

 * - when writing:

 *   - always clock in 16 clocks at once

 *   - at DIN: D15 first, D0 last

 *   - D0..D7 = databyte, D8..D14 = commandbyte

 *   - D15 = low -> write command

 * - when reading

 *   - always clock in 16 clocks at once

 *   - at DIN: D15 first, D0 last

 *   - D0..D7 = dummy, D8..D14 = register address

 *   - D15 = high -> read command

 *   - raise CS and assert it again

 *   - always clock in 16 clocks at once

 *   - at DOUT: D15 first, D0 last

 *   - D0..D7 contains the data from the first cycle

 *

 * The driver exports a standard gpiochip interface

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/mutex.h>

#include <linux/spi/max7301.h>

#include <linux/gpio.h>



/*

 * Pin configurations, see MAX7301 datasheet page 6

 */

#define PIN_CONFIG_MASK 0x03

#define PIN_CONFIG_IN_PULLUP 0x03

#define PIN_CONFIG_IN_WO_PULLUP 0x02

#define PIN_CONFIG_OUT 0x01



#define PIN_NUMBER 28



static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);

	u8 *config;

	u8 offset_bits;

	int ret;



	/* First 4 pins are unused in the controller */

	offset += 4;

	offset_bits = (offset & 3) << 1;



	config = &ts->port_config[offset >> 2];



	mutex_lock(&ts->lock);



	/* Standard GPIO API doesn't support pull-ups, has to be extended.

	 * Hard-coding no pollup for now. */

	*config = (*config & ~(PIN_CONFIG_MASK << offset_bits))

			   | (PIN_CONFIG_IN_WO_PULLUP << offset_bits);



	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);



	mutex_unlock(&ts->lock);



	return ret;

}



static int __max7301_set(struct max7301 *ts, unsigned offset, int value)

{

	if (value) {

		ts->out_level |= 1 << offset;

		return ts->write(ts->dev, 0x20 + offset, 0x01);

	} else {

		ts->out_level &= ~(1 << offset);

		return ts->write(ts->dev, 0x20 + offset, 0x00);

	}

}



static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,

				    int value)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);

	u8 *config;

	u8 offset_bits;

	int ret;



	/* First 4 pins are unused in the controller */

	offset += 4;

	offset_bits = (offset & 3) << 1;



	config = &ts->port_config[offset >> 2];



	mutex_lock(&ts->lock);



	*config = (*config & ~(PIN_CONFIG_MASK << offset_bits))

			   | (PIN_CONFIG_OUT << offset_bits);



	ret = __max7301_set(ts, offset, value);



	if (!ret)

		ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);



	mutex_unlock(&ts->lock);



	return ret;

}



static int max7301_get(struct gpio_chip *chip, unsigned offset)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);

	int config, level = -EINVAL;



	/* First 4 pins are unused in the controller */

	offset += 4;



	mutex_lock(&ts->lock);



	config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))

			& PIN_CONFIG_MASK;



	switch (config) {

	case PIN_CONFIG_OUT:

		/* Output: return cached level */

		level =  !!(ts->out_level & (1 << offset));

		break;

	case PIN_CONFIG_IN_WO_PULLUP:

	case PIN_CONFIG_IN_PULLUP:

		/* Input: read out */

		level = ts->read(ts->dev, 0x20 + offset) & 0x01;

	}

	mutex_unlock(&ts->lock);



	return level;

}



static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)

{

	struct max7301 *ts = container_of(chip, struct max7301, chip);



	/* First 4 pins are unused in the controller */

	offset += 4;



	mutex_lock(&ts->lock);



	__max7301_set(ts, offset, value);



	mutex_unlock(&ts->lock);

}



int __devinit __max730x_probe(struct max7301 *ts)

{

	struct device *dev = ts->dev;

	struct max7301_platform_data *pdata;

	int i, ret;



	pdata = dev->platform_data;

	if (!pdata || !pdata->base) {

		dev_err(dev, "incorrect or missing platform data\n");

		return -EINVAL;

	}



	mutex_init(&ts->lock);

	dev_set_drvdata(dev, ts);



	/* Power up the chip and disable IRQ output */

	ts->write(dev, 0x04, 0x01);



	ts->chip.label = dev->driver->name;



	ts->chip.direction_input = max7301_direction_input;

	ts->chip.get = max7301_get;

	ts->chip.direction_output = max7301_direction_output;

	ts->chip.set = max7301_set;



	ts->chip.base = pdata->base;

	ts->chip.ngpio = PIN_NUMBER;

	ts->chip.can_sleep = 1;

	ts->chip.dev = dev;

	ts->chip.owner = THIS_MODULE;



	/*

	 * tristate all pins in hardware and cache the

	 * register values for later use.

	 */

	for (i = 1; i < 8; i++) {

		int j;

		/* 0xAA means input with internal pullup disabled */

		ts->write(dev, 0x08 + i, 0xAA);

		ts->port_config[i] = 0xAA;

		for (j = 0; j < 4; j++) {

			int offset = (i - 1) * 4 + j;

			ret = max7301_direction_input(&ts->chip, offset);

			if (ret)

				goto exit_destroy;

		}

	}



	ret = gpiochip_add(&ts->chip);

	if (ret)

		goto exit_destroy;



	return ret;



exit_destroy:

	dev_set_drvdata(dev, NULL);

	mutex_destroy(&ts->lock);

	return ret;

}

EXPORT_SYMBOL_GPL(__max730x_probe);



int __devexit __max730x_remove(struct device *dev)

{

	struct max7301 *ts = dev_get_drvdata(dev);

	int ret;



	if (ts == NULL)

		return -ENODEV;



	dev_set_drvdata(dev, NULL);



	/* Power down the chip and disable IRQ output */

	ts->write(dev, 0x04, 0x00);



	ret = gpiochip_remove(&ts->chip);

	if (!ret) {

		mutex_destroy(&ts->lock);

		kfree(ts);

	} else

		dev_err(dev, "Failed to remove GPIO controller: %d\n", ret);



	return ret;

}

EXPORT_SYMBOL_GPL(__max730x_remove);

CRA Git | Maintained and supported by SUSTech CRA and CCSE