[linux.git] / drivers / gpio / gpio-max730x.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>
#include <linux/slab.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 = gpiochip_get_data(chip);
	u8 *config;
	u8 offset_bits, pin_config;
	int ret;

	/* First 4 pins are unused in the controller */
	offset += 4;
	offset_bits = (offset & 3) << 1;

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

	if (ts->input_pullup_active & BIT(offset))
		pin_config = PIN_CONFIG_IN_PULLUP;
	else
		pin_config = PIN_CONFIG_IN_WO_PULLUP;

	mutex_lock(&ts->lock);

	*config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
			   | (pin_config << 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 = gpiochip_get_data(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 = gpiochip_get_data(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 = gpiochip_get_data(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 __max730x_probe(struct max7301 *ts)
{
	struct device *dev = ts->dev;
	struct max7301_platform_data *pdata;
	int i, ret;

	pdata = dev_get_platdata(dev);

	mutex_init(&ts->lock);
	dev_set_drvdata(dev, ts);

	/* Power up the chip and disable IRQ output */
	ts->write(dev, 0x04, 0x01);

	if (pdata) {
		ts->input_pullup_active = pdata->input_pullup_active;
		ts->chip.base = pdata->base;
	} else {
		ts->chip.base = -1;
	}
	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.ngpio = PIN_NUMBER;
	ts->chip.can_sleep = true;
	ts->chip.parent = dev;
	ts->chip.owner = THIS_MODULE;

	/*
	 * initialize pullups according to platform data and cache the
	 * register values for later use.
	 */
	for (i = 1; i < 8; i++) {
		int j;
		/*
		 * initialize port_config with "0xAA", which means
		 * input with internal pullup disabled. This is needed
		 * to avoid writing zeros (in the inner for loop),
		 * which is not allowed according to the datasheet.
		 */
		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_data(&ts->chip, ts);
	if (ret)
		goto exit_destroy;

	return ret;

exit_destroy:
	mutex_destroy(&ts->lock);
	return ret;
}
EXPORT_SYMBOL_GPL(__max730x_probe);

int __max730x_remove(struct device *dev)
{
	struct max7301 *ts = dev_get_drvdata(dev);

	if (ts == NULL)
		return -ENODEV;

	/* Power down the chip and disable IRQ output */
	ts->write(dev, 0x04, 0x00);
	gpiochip_remove(&ts->chip);
	mutex_destroy(&ts->lock);
	return 0;
}
EXPORT_SYMBOL_GPL(__max730x_remove);

MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");
Commit	Line	Data
e952805d	1	/**
e952805d WS	2	* Copyright (C) 2006 Juergen Beisert, Pengutronix
	3	* Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
	4	* Copyright (C) 2009 Wolfram Sang, Pengutronix
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
	11	* 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
	12	* details
	13	* Note:
	14	* - DIN must be stable at the rising edge of clock.
	15	* - when writing:
	16	* - always clock in 16 clocks at once
	17	* - at DIN: D15 first, D0 last
	18	* - D0..D7 = databyte, D8..D14 = commandbyte
	19	* - D15 = low -> write command
	20	* - when reading
	21	* - always clock in 16 clocks at once
	22	* - at DIN: D15 first, D0 last
	23	* - D0..D7 = dummy, D8..D14 = register address
	24	* - D15 = high -> read command
	25	* - raise CS and assert it again
	26	* - always clock in 16 clocks at once
	27	* - at DOUT: D15 first, D0 last
	28	* - D0..D7 contains the data from the first cycle
	29	*
	30	* The driver exports a standard gpiochip interface
	31	*/
	32
	33	#include <linux/module.h>
	34	#include <linux/init.h>
	35	#include <linux/platform_device.h>
	36	#include <linux/mutex.h>
	37	#include <linux/spi/max7301.h>
	38	#include <linux/gpio.h>
5a0e3ad6	39	#include <linux/slab.h>
e952805d WS	40
	41	/*
	42	* Pin configurations, see MAX7301 datasheet page 6
	43	*/
	44	#define PIN_CONFIG_MASK 0x03
	45	#define PIN_CONFIG_IN_PULLUP 0x03
	46	#define PIN_CONFIG_IN_WO_PULLUP 0x02
	47	#define PIN_CONFIG_OUT 0x01
	48
	49	#define PIN_NUMBER 28
	50
	51	static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
	52	{
5e45e019	53	struct max7301 *ts = gpiochip_get_data(chip);
e952805d	54	u8 *config;
4a22b8a4	55	u8 offset_bits, pin_config;
e952805d WS	56	int ret;
	57
	58	/* First 4 pins are unused in the controller */
	59	offset += 4;
	60	offset_bits = (offset & 3) << 1;
	61
	62	config = &ts->port_config[offset >> 2];
	63
4a22b8a4 MKB	64	if (ts->input_pullup_active & BIT(offset))
	65	pin_config = PIN_CONFIG_IN_PULLUP;
	66	else
	67	pin_config = PIN_CONFIG_IN_WO_PULLUP;
	68
e952805d WS	69	mutex_lock(&ts->lock);
e952805d WS	70
e952805d	71	config = (config & ~(PIN_CONFIG_MASK << offset_bits))
4a22b8a4	72	\| (pin_config << offset_bits);
e952805d WS	73
	74	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
	75
	76	mutex_unlock(&ts->lock);
	77
	78	return ret;
	79	}
	80
	81	static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
	82	{
	83	if (value) {
	84	ts->out_level \|= 1 << offset;
	85	return ts->write(ts->dev, 0x20 + offset, 0x01);
	86	} else {
	87	ts->out_level &= ~(1 << offset);
	88	return ts->write(ts->dev, 0x20 + offset, 0x00);
	89	}
	90	}
	91
	92	static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
	93	int value)
	94	{
5e45e019	95	struct max7301 *ts = gpiochip_get_data(chip);
e952805d WS	96	u8 *config;
	97	u8 offset_bits;
	98	int ret;
	99
	100	/* First 4 pins are unused in the controller */
	101	offset += 4;
	102	offset_bits = (offset & 3) << 1;
	103
	104	config = &ts->port_config[offset >> 2];
	105
	106	mutex_lock(&ts->lock);
	107
	108	config = (config & ~(PIN_CONFIG_MASK << offset_bits))
	109	\| (PIN_CONFIG_OUT << offset_bits);
	110
	111	ret = __max7301_set(ts, offset, value);
	112
	113	if (!ret)
	114	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
	115
	116	mutex_unlock(&ts->lock);
	117
	118	return ret;
	119	}
	120
	121	static int max7301_get(struct gpio_chip *chip, unsigned offset)
	122	{
5e45e019	123	struct max7301 *ts = gpiochip_get_data(chip);
e952805d WS	124	int config, level = -EINVAL;
	125
	126	/* First 4 pins are unused in the controller */
	127	offset += 4;
	128
	129	mutex_lock(&ts->lock);
	130
	131	config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
	132	& PIN_CONFIG_MASK;
	133
	134	switch (config) {
	135	case PIN_CONFIG_OUT:
	136	/* Output: return cached level */
	137	level = !!(ts->out_level & (1 << offset));
	138	break;
	139	case PIN_CONFIG_IN_WO_PULLUP:
	140	case PIN_CONFIG_IN_PULLUP:
	141	/* Input: read out */
	142	level = ts->read(ts->dev, 0x20 + offset) & 0x01;
	143	}
	144	mutex_unlock(&ts->lock);
	145
	146	return level;
	147	}
	148
	149	static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
	150	{
5e45e019	151	struct max7301 *ts = gpiochip_get_data(chip);
e952805d WS	152
	153	/* First 4 pins are unused in the controller */
	154	offset += 4;
	155
	156	mutex_lock(&ts->lock);
	157
	158	__max7301_set(ts, offset, value);
	159
	160	mutex_unlock(&ts->lock);
	161	}
	162
3836309d	163	int __max730x_probe(struct max7301 *ts)
e952805d WS	164	{
	165	struct device *dev = ts->dev;
	166	struct max7301_platform_data *pdata;
	167	int i, ret;
	168
e56aee18	169	pdata = dev_get_platdata(dev);
e952805d WS	170
	171	mutex_init(&ts->lock);
	172	dev_set_drvdata(dev, ts);
	173
	174	/* Power up the chip and disable IRQ output */
	175	ts->write(dev, 0x04, 0x01);
	176
8754fccb RS	177	if (pdata) {
	178	ts->input_pullup_active = pdata->input_pullup_active;
	179	ts->chip.base = pdata->base;
	180	} else {
	181	ts->chip.base = -1;
	182	}
e952805d WS	183	ts->chip.label = dev->driver->name;
	184
	185	ts->chip.direction_input = max7301_direction_input;
	186	ts->chip.get = max7301_get;
	187	ts->chip.direction_output = max7301_direction_output;
	188	ts->chip.set = max7301_set;
	189
e952805d	190	ts->chip.ngpio = PIN_NUMBER;
9fb1f39e	191	ts->chip.can_sleep = true;
58383c78	192	ts->chip.parent = dev;
e952805d WS	193	ts->chip.owner = THIS_MODULE;
	194
	195	/*
4a22b8a4	196	* initialize pullups according to platform data and cache the
e952805d WS	197	* register values for later use.
	198	*/
	199	for (i = 1; i < 8; i++) {
	200	int j;
4a22b8a4 MKB	201	/*
	202	* initialize port_config with "0xAA", which means
	203	* input with internal pullup disabled. This is needed
	204	* to avoid writing zeros (in the inner for loop),
	205	* which is not allowed according to the datasheet.
	206	*/
e952805d WS	207	ts->port_config[i] = 0xAA;
	208	for (j = 0; j < 4; j++) {
	209	int offset = (i - 1) * 4 + j;
	210	ret = max7301_direction_input(&ts->chip, offset);
	211	if (ret)
	212	goto exit_destroy;
	213	}
	214	}
	215
5e45e019	216	ret = gpiochip_add_data(&ts->chip, ts);
e952805d WS	217	if (ret)
	218	goto exit_destroy;
	219
	220	return ret;
	221
	222	exit_destroy:
e952805d WS	223	mutex_destroy(&ts->lock);
	224	return ret;
	225	}
	226	EXPORT_SYMBOL_GPL(__max730x_probe);
	227
206210ce	228	int __max730x_remove(struct device *dev)
e952805d WS	229	{
e952805d WS	230	struct max7301 *ts = dev_get_drvdata(dev);
e952805d WS	231
	232	if (ts == NULL)
	233	return -ENODEV;
	234
e952805d WS	235	/* Power down the chip and disable IRQ output */
e952805d WS	236	ts->write(dev, 0x04, 0x00);
9f5132ae	237	gpiochip_remove(&ts->chip);
9f5132ae	238	mutex_destroy(&ts->lock);
9f5132ae	239	return 0;
e952805d WS	240	}
e952805d WS	241	EXPORT_SYMBOL_GPL(__max730x_remove);
06ca02b0 RR	242
	243	MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
	244	MODULE_LICENSE("GPL v2");
	245	MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");