[linux.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;
	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);

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;
	57	u8 offset_bits;
	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
	66	mutex_lock(&ts->lock);
	67
	68	/* Standard GPIO API doesn't support pull-ups, has to be extended.
	69	* Hard-coding no pollup for now. */
	70	config = (config & ~(PIN_CONFIG_MASK << offset_bits))
	71	\| (PIN_CONFIG_IN_WO_PULLUP << offset_bits);
	72
	73	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
	74
	75	mutex_unlock(&ts->lock);
	76
	77	return ret;
	78	}
	79
	80	static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
	81	{
	82	if (value) {
	83	ts->out_level \|= 1 << offset;
	84	return ts->write(ts->dev, 0x20 + offset, 0x01);
	85	} else {
	86	ts->out_level &= ~(1 << offset);
	87	return ts->write(ts->dev, 0x20 + offset, 0x00);
	88	}
	89	}
	90
	91	static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
	92	int value)
	93	{
	94	struct max7301 *ts = container_of(chip, struct max7301, chip);
	95	u8 *config;
	96	u8 offset_bits;
	97	int ret;
	98
	99	/* First 4 pins are unused in the controller */
	100	offset += 4;
	101	offset_bits = (offset & 3) << 1;
	102
	103	config = &ts->port_config[offset >> 2];
	104
	105	mutex_lock(&ts->lock);
106
107	config = (config & ~(PIN_CONFIG_MASK << offset_bits))
108	\| (PIN_CONFIG_OUT << offset_bits);
109
110	ret = __max7301_set(ts, offset, value);
111
112	if (!ret)
113	ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
114
115	mutex_unlock(&ts->lock);
116
117	return ret;
118	}
119
120	static int max7301_get(struct gpio_chip *chip, unsigned offset)
121	{
122	struct max7301 *ts = container_of(chip, struct max7301, chip);
123	int config, level = -EINVAL;
124
125	/* First 4 pins are unused in the controller */
126	offset += 4;
127
128	mutex_lock(&ts->lock);
129
130	config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
131	& PIN_CONFIG_MASK;
132
133	switch (config) {
134	case PIN_CONFIG_OUT:
135	/* Output: return cached level */
136	level = !!(ts->out_level & (1 << offset));
137	break;
138	case PIN_CONFIG_IN_WO_PULLUP:
139	case PIN_CONFIG_IN_PULLUP:
140	/* Input: read out */
141	level = ts->read(ts->dev, 0x20 + offset) & 0x01;
142	}
143	mutex_unlock(&ts->lock);
144
145	return level;
146	}
147
148	static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
149	{
150	struct max7301 *ts = container_of(chip, struct max7301, chip);
151
152	/* First 4 pins are unused in the controller */
153	offset += 4;
154
155	mutex_lock(&ts->lock);
156
157	__max7301_set(ts, offset, value);
158
159	mutex_unlock(&ts->lock);
160	}
161
162	int __devinit __max730x_probe(struct max7301 *ts)
163	{
164	struct device *dev = ts->dev;
165	struct max7301_platform_data *pdata;
166	int i, ret;
167
168	pdata = dev->platform_data;
169	if (!pdata \|\| !pdata->base) {
170	dev_err(dev, "incorrect or missing platform data\n");
171	return -EINVAL;
172	}
173
174	mutex_init(&ts->lock);
175	dev_set_drvdata(dev, ts);
176
177	/* Power up the chip and disable IRQ output */
178	ts->write(dev, 0x04, 0x01);
179
180	ts->chip.label = dev->driver->name;
181
182	ts->chip.direction_input = max7301_direction_input;
183	ts->chip.get = max7301_get;
184	ts->chip.direction_output = max7301_direction_output;
185	ts->chip.set = max7301_set;
186
187	ts->chip.base = pdata->base;
188	ts->chip.ngpio = PIN_NUMBER;
189	ts->chip.can_sleep = 1;
190	ts->chip.dev = dev;
191	ts->chip.owner = THIS_MODULE;
192
193	/*
194	* tristate all pins in hardware and cache the
195	* register values for later use.
196	*/
197	for (i = 1; i < 8; i++) {
198	int j;
199	/* 0xAA means input with internal pullup disabled */
200	ts->write(dev, 0x08 + i, 0xAA);
201	ts->port_config[i] = 0xAA;
202	for (j = 0; j < 4; j++) {
203	int offset = (i - 1) * 4 + j;
204	ret = max7301_direction_input(&ts->chip, offset);
205	if (ret)
206	goto exit_destroy;
207	}
208	}
209
210	ret = gpiochip_add(&ts->chip);
211	if (ret)
212	goto exit_destroy;
213
214	return ret;
215
216	exit_destroy:
217	dev_set_drvdata(dev, NULL);
218	mutex_destroy(&ts->lock);
219	return ret;
220	}
221	EXPORT_SYMBOL_GPL(__max730x_probe);
222
223	int __devexit __max730x_remove(struct device *dev)
224	{
225	struct max7301 *ts = dev_get_drvdata(dev);
226	int ret;
227
228	if (ts == NULL)
229	return -ENODEV;
230
231	dev_set_drvdata(dev, NULL);
232
233	/* Power down the chip and disable IRQ output */
234	ts->write(dev, 0x04, 0x00);
235
236	ret = gpiochip_remove(&ts->chip);
237	if (!ret) {
238	mutex_destroy(&ts->lock);
239	kfree(ts);
240	} else
241	dev_err(dev, "Failed to remove GPIO controller: %d\n", ret);
242
243	return ret;
244	}
245	EXPORT_SYMBOL_GPL(__max730x_remove);
06ca02b0 RR	246
	247	MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
	248	MODULE_LICENSE("GPL v2");
	249	MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");