[net-next-2.6.git] / drivers / gpio / max730x.c

/**
 * 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>
#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 = container_of(chip, struct max7301, 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 = 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->input_pullup_active = pdata->input_pullup_active;
	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;

	/*
	 * 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(&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);

MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");
Commit	Line	Data
e952805d WS	1	/**
	2	* drivers/gpio/max7301.c
	3	*
	4	* Copyright (C) 2006 Juergen Beisert, Pengutronix
	5	* Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
	6	* Copyright (C) 2009 Wolfram Sang, Pengutronix
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	* The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
	13	* 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
	14	* details
	15	* Note:
	16	* - DIN must be stable at the rising edge of clock.
	17	* - when writing:
	18	* - always clock in 16 clocks at once
	19	* - at DIN: D15 first, D0 last
	20	* - D0..D7 = databyte, D8..D14 = commandbyte
	21	* - D15 = low -> write command
	22	* - when reading
	23	* - always clock in 16 clocks at once
	24	* - at DIN: D15 first, D0 last
	25	* - D0..D7 = dummy, D8..D14 = register address
	26	* - D15 = high -> read command
	27	* - raise CS and assert it again
	28	* - always clock in 16 clocks at once
	29	* - at DOUT: D15 first, D0 last
	30	* - D0..D7 contains the data from the first cycle
	31	*
	32	* The driver exports a standard gpiochip interface
	33	*/
	34
	35	#include <linux/module.h>
	36	#include <linux/init.h>
	37	#include <linux/platform_device.h>
	38	#include <linux/mutex.h>
	39	#include <linux/spi/max7301.h>
	40	#include <linux/gpio.h>
5a0e3ad6	41	#include <linux/slab.h>
e952805d WS	42
	43	/*
	44	* Pin configurations, see MAX7301 datasheet page 6
	45	*/
	46	#define PIN_CONFIG_MASK 0x03
	47	#define PIN_CONFIG_IN_PULLUP 0x03
	48	#define PIN_CONFIG_IN_WO_PULLUP 0x02
	49	#define PIN_CONFIG_OUT 0x01
	50
	51	#define PIN_NUMBER 28
	52
	53	static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
	54	{
	55	struct max7301 *ts = container_of(chip, struct max7301, chip);
	56	u8 *config;
4a22b8a4	57	u8 offset_bits, pin_config;
e952805d WS	58	int ret;
	59
	60	/* First 4 pins are unused in the controller */
	61	offset += 4;
	62	offset_bits = (offset & 3) << 1;
	63
	64	config = &ts->port_config[offset >> 2];
	65
4a22b8a4 MKB	66	if (ts->input_pullup_active & BIT(offset))
	67	pin_config = PIN_CONFIG_IN_PULLUP;
	68	else
	69	pin_config = PIN_CONFIG_IN_WO_PULLUP;
	70
e952805d WS	71	mutex_lock(&ts->lock);
e952805d WS	72
e952805d	73	config = (config & ~(PIN_CONFIG_MASK << offset_bits))
4a22b8a4	74	\| (pin_config << offset_bits);
e952805d WS	75
	76	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
	77
	78	mutex_unlock(&ts->lock);
	79
	80	return ret;
	81	}
	82
	83	static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
	84	{
	85	if (value) {
	86	ts->out_level \|= 1 << offset;
	87	return ts->write(ts->dev, 0x20 + offset, 0x01);
	88	} else {
	89	ts->out_level &= ~(1 << offset);
	90	return ts->write(ts->dev, 0x20 + offset, 0x00);
	91	}
	92	}
	93
	94	static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
	95	int value)
	96	{
	97	struct max7301 *ts = container_of(chip, struct max7301, chip);
	98	u8 *config;
	99	u8 offset_bits;
	100	int ret;
	101
	102	/* First 4 pins are unused in the controller */
	103	offset += 4;
	104	offset_bits = (offset & 3) << 1;
	105
	106	config = &ts->port_config[offset >> 2];
	107
	108	mutex_lock(&ts->lock);
	109
	110	config = (config & ~(PIN_CONFIG_MASK << offset_bits))
	111	\| (PIN_CONFIG_OUT << offset_bits);
	112
	113	ret = __max7301_set(ts, offset, value);
	114
	115	if (!ret)
	116	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
	117
	118	mutex_unlock(&ts->lock);
	119
	120	return ret;
	121	}
	122
	123	static int max7301_get(struct gpio_chip *chip, unsigned offset)
	124	{
	125	struct max7301 *ts = container_of(chip, struct max7301, chip);
	126	int config, level = -EINVAL;
	127
	128	/* First 4 pins are unused in the controller */
	129	offset += 4;
	130
	131	mutex_lock(&ts->lock);
	132
	133	config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
	134	& PIN_CONFIG_MASK;
	135
	136	switch (config) {
	137	case PIN_CONFIG_OUT:
	138	/* Output: return cached level */
139	level = !!(ts->out_level & (1 << offset));
140	break;
141	case PIN_CONFIG_IN_WO_PULLUP:
142	case PIN_CONFIG_IN_PULLUP:
143	/* Input: read out */
144	level = ts->read(ts->dev, 0x20 + offset) & 0x01;
145	}
146	mutex_unlock(&ts->lock);
147
148	return level;
149	}
150
151	static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
152	{
153	struct max7301 *ts = container_of(chip, struct max7301, chip);
154
155	/* First 4 pins are unused in the controller */
156	offset += 4;
157
158	mutex_lock(&ts->lock);
159
160	__max7301_set(ts, offset, value);
161
162	mutex_unlock(&ts->lock);
163	}
164
165	int __devinit __max730x_probe(struct max7301 *ts)
166	{
167	struct device *dev = ts->dev;
168	struct max7301_platform_data *pdata;
169	int i, ret;
170
171	pdata = dev->platform_data;
172	if (!pdata \|\| !pdata->base) {
173	dev_err(dev, "incorrect or missing platform data\n");
174	return -EINVAL;
175	}
176
177	mutex_init(&ts->lock);
178	dev_set_drvdata(dev, ts);
179
180	/* Power up the chip and disable IRQ output */
181	ts->write(dev, 0x04, 0x01);
182
4a22b8a4	183	ts->input_pullup_active = pdata->input_pullup_active;
e952805d WS	184	ts->chip.label = dev->driver->name;
	185
	186	ts->chip.direction_input = max7301_direction_input;
	187	ts->chip.get = max7301_get;
	188	ts->chip.direction_output = max7301_direction_output;
	189	ts->chip.set = max7301_set;
	190
	191	ts->chip.base = pdata->base;
	192	ts->chip.ngpio = PIN_NUMBER;
	193	ts->chip.can_sleep = 1;
	194	ts->chip.dev = dev;
	195	ts->chip.owner = THIS_MODULE;
	196
	197	/*
4a22b8a4	198	* initialize pullups according to platform data and cache the
e952805d WS	199	* register values for later use.
	200	*/
	201	for (i = 1; i < 8; i++) {
	202	int j;
4a22b8a4 MKB	203	/*
	204	* initialize port_config with "0xAA", which means
	205	* input with internal pullup disabled. This is needed
	206	* to avoid writing zeros (in the inner for loop),
	207	* which is not allowed according to the datasheet.
	208	*/
e952805d WS	209	ts->port_config[i] = 0xAA;
	210	for (j = 0; j < 4; j++) {
	211	int offset = (i - 1) * 4 + j;
	212	ret = max7301_direction_input(&ts->chip, offset);
	213	if (ret)
	214	goto exit_destroy;
	215	}
	216	}
	217
	218	ret = gpiochip_add(&ts->chip);
	219	if (ret)
	220	goto exit_destroy;
	221
	222	return ret;
	223
	224	exit_destroy:
	225	dev_set_drvdata(dev, NULL);
	226	mutex_destroy(&ts->lock);
	227	return ret;
	228	}
	229	EXPORT_SYMBOL_GPL(__max730x_probe);
	230
	231	int __devexit __max730x_remove(struct device *dev)
	232	{
	233	struct max7301 *ts = dev_get_drvdata(dev);
	234	int ret;
	235
	236	if (ts == NULL)
	237	return -ENODEV;
	238
	239	dev_set_drvdata(dev, NULL);
	240
	241	/* Power down the chip and disable IRQ output */
	242	ts->write(dev, 0x04, 0x00);
	243
	244	ret = gpiochip_remove(&ts->chip);
	245	if (!ret) {
	246	mutex_destroy(&ts->lock);
	247	kfree(ts);
	248	} else
	249	dev_err(dev, "Failed to remove GPIO controller: %d\n", ret);
	250
	251	return ret;
	252	}
	253	EXPORT_SYMBOL_GPL(__max730x_remove);
06ca02b0 RR	254
	255	MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
	256	MODULE_LICENSE("GPL v2");
	257	MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");