[linux-2.6-block.git] / drivers / i2c / busses / i2c-gpio.c

/*
 * Bitbanging I2C bus driver using the GPIO API
 *
 * Copyright (C) 2007 Atmel Corporation
 *
 * 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.
 */
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/platform_data/i2c-gpio.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>

struct i2c_gpio_private_data {
	struct gpio_desc *sda;
	struct gpio_desc *scl;
	struct i2c_adapter adap;
	struct i2c_algo_bit_data bit_data;
	struct i2c_gpio_platform_data pdata;
#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
	struct dentry *debug_dir;
#endif
};

/*
 * Toggle SDA by changing the output value of the pin. This is only
 * valid for pins configured as open drain (i.e. setting the value
 * high effectively turns off the output driver.)
 */
static void i2c_gpio_setsda_val(void *data, int state)
{
	struct i2c_gpio_private_data *priv = data;

	gpiod_set_value_cansleep(priv->sda, state);
}

/*
 * Toggle SCL by changing the output value of the pin. This is used
 * for pins that are configured as open drain and for output-only
 * pins. The latter case will break the i2c protocol, but it will
 * often work in practice.
 */
static void i2c_gpio_setscl_val(void *data, int state)
{
	struct i2c_gpio_private_data *priv = data;

	gpiod_set_value_cansleep(priv->scl, state);
}

static int i2c_gpio_getsda(void *data)
{
	struct i2c_gpio_private_data *priv = data;

	return gpiod_get_value_cansleep(priv->sda);
}

static int i2c_gpio_getscl(void *data)
{
	struct i2c_gpio_private_data *priv = data;

	return gpiod_get_value_cansleep(priv->scl);
}

#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
static struct dentry *i2c_gpio_debug_dir;

#define setsda(bd, val)	((bd)->setsda((bd)->data, val))
#define setscl(bd, val)	((bd)->setscl((bd)->data, val))
#define getsda(bd)	((bd)->getsda((bd)->data))
#define getscl(bd)	((bd)->getscl((bd)->data))

#define WIRE_ATTRIBUTE(wire) \
static int fops_##wire##_get(void *data, u64 *val)		\
{								\
	struct i2c_gpio_private_data *priv = data;		\
								\
	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);	\
	*val = get##wire(&priv->bit_data);			\
	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);	\
	return 0;						\
}								\
static int fops_##wire##_set(void *data, u64 val)		\
{								\
	struct i2c_gpio_private_data *priv = data;		\
								\
	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);	\
	set##wire(&priv->bit_data, val);			\
	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);	\
	return 0;						\
}								\
DEFINE_DEBUGFS_ATTRIBUTE(fops_##wire, fops_##wire##_get, fops_##wire##_set, "%llu\n")

WIRE_ATTRIBUTE(scl);
WIRE_ATTRIBUTE(sda);

static void i2c_gpio_incomplete_transfer(struct i2c_gpio_private_data *priv,
					u32 pattern, u8 pattern_size)
{
	struct i2c_algo_bit_data *bit_data = &priv->bit_data;
	int i;

	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);

	/* START condition */
	setsda(bit_data, 0);
	udelay(bit_data->udelay);

	/* Send pattern, request ACK, don't send STOP */
	for (i = pattern_size - 1; i >= 0; i--) {
		setscl(bit_data, 0);
		udelay(bit_data->udelay / 2);
		setsda(bit_data, (pattern >> i) & 1);
		udelay((bit_data->udelay + 1) / 2);
		setscl(bit_data, 1);
		udelay(bit_data->udelay);
	}

	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
}

static int fops_incomplete_addr_phase_set(void *data, u64 addr)
{
	struct i2c_gpio_private_data *priv = data;
	u32 pattern;

	if (addr > 0x7f)
		return -EINVAL;

	/* ADDR (7 bit) + RD (1 bit) + Client ACK, keep SDA hi (1 bit) */
	pattern = (addr << 2) | 3;

	i2c_gpio_incomplete_transfer(priv, pattern, 9);

	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_addr_phase, NULL, fops_incomplete_addr_phase_set, "%llu\n");

static int fops_incomplete_write_byte_set(void *data, u64 addr)
{
	struct i2c_gpio_private_data *priv = data;
	u32 pattern;

	if (addr > 0x7f)
		return -EINVAL;

	/* ADDR (7 bit) + WR (1 bit) + Client ACK (1 bit) */
	pattern = (addr << 2) | 1;
	/* 0x00 (8 bit) + Client ACK, keep SDA hi (1 bit) */
	pattern = (pattern << 9) | 1;

	i2c_gpio_incomplete_transfer(priv, pattern, 18);

	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_write_byte, NULL, fops_incomplete_write_byte_set, "%llu\n");

static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
{
	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);

	/*
	 * If there will be a debugfs-dir per i2c adapter somewhen, put the
	 * 'fault-injector' dir there. Until then, we have a global dir with
	 * all adapters as subdirs.
	 */
	if (!i2c_gpio_debug_dir) {
		i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
		if (!i2c_gpio_debug_dir)
			return;
	}

	priv->debug_dir = debugfs_create_dir(pdev->name, i2c_gpio_debug_dir);
	if (!priv->debug_dir)
		return;

	debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl);
	debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda);
	debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->debug_dir,
				   priv, &fops_incomplete_addr_phase);
	debugfs_create_file_unsafe("incomplete_write_byte", 0200, priv->debug_dir,
				   priv, &fops_incomplete_write_byte);
}

static void i2c_gpio_fault_injector_exit(struct platform_device *pdev)
{
	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);

	debugfs_remove_recursive(priv->debug_dir);
}
#else
static inline void i2c_gpio_fault_injector_init(struct platform_device *pdev) {}
static inline void i2c_gpio_fault_injector_exit(struct platform_device *pdev) {}
#endif /* CONFIG_I2C_GPIO_FAULT_INJECTOR*/

static void of_i2c_gpio_get_props(struct device_node *np,
				  struct i2c_gpio_platform_data *pdata)
{
	u32 reg;

	of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);

	if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
		pdata->timeout = msecs_to_jiffies(reg);

	pdata->sda_is_open_drain =
		of_property_read_bool(np, "i2c-gpio,sda-open-drain");
	pdata->scl_is_open_drain =
		of_property_read_bool(np, "i2c-gpio,scl-open-drain");
	pdata->scl_is_output_only =
		of_property_read_bool(np, "i2c-gpio,scl-output-only");
}

static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
					   const char *con_id,
					   unsigned int index,
					   enum gpiod_flags gflags)
{
	struct gpio_desc *retdesc;
	int ret;

	retdesc = devm_gpiod_get(dev, con_id, gflags);
	if (!IS_ERR(retdesc)) {
		dev_dbg(dev, "got GPIO from name %s\n", con_id);
		return retdesc;
	}

	retdesc = devm_gpiod_get_index(dev, NULL, index, gflags);
	if (!IS_ERR(retdesc)) {
		dev_dbg(dev, "got GPIO from index %u\n", index);
		return retdesc;
	}

	ret = PTR_ERR(retdesc);

	/* FIXME: hack in the old code, is this really necessary? */
	if (ret == -EINVAL)
		retdesc = ERR_PTR(-EPROBE_DEFER);

	/* This happens if the GPIO driver is not yet probed, let's defer */
	if (ret == -ENOENT)
		retdesc = ERR_PTR(-EPROBE_DEFER);

	if (ret != -EPROBE_DEFER)
		dev_err(dev, "error trying to get descriptor: %d\n", ret);

	return retdesc;
}

static int i2c_gpio_probe(struct platform_device *pdev)
{
	struct i2c_gpio_private_data *priv;
	struct i2c_gpio_platform_data *pdata;
	struct i2c_algo_bit_data *bit_data;
	struct i2c_adapter *adap;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	enum gpiod_flags gflags;
	int ret;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	adap = &priv->adap;
	bit_data = &priv->bit_data;
	pdata = &priv->pdata;

	if (np) {
		of_i2c_gpio_get_props(np, pdata);
	} else {
		/*
		 * If all platform data settings are zero it is OK
		 * to not provide any platform data from the board.
		 */
		if (dev_get_platdata(dev))
			memcpy(pdata, dev_get_platdata(dev), sizeof(*pdata));
	}

	/*
	 * First get the GPIO pins; if it fails, we'll defer the probe.
	 * If the SDA line is marked from platform data or device tree as
	 * "open drain" it means something outside of our control is making
	 * this line being handled as open drain, and we should just handle
	 * it as any other output. Else we enforce open drain as this is
	 * required for an I2C bus.
	 */
	if (pdata->sda_is_open_drain)
		gflags = GPIOD_OUT_HIGH;
	else
		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
	priv->sda = i2c_gpio_get_desc(dev, "sda", 0, gflags);
	if (IS_ERR(priv->sda))
		return PTR_ERR(priv->sda);

	/*
	 * If the SCL line is marked from platform data or device tree as
	 * "open drain" it means something outside of our control is making
	 * this line being handled as open drain, and we should just handle
	 * it as any other output. Else we enforce open drain as this is
	 * required for an I2C bus.
	 */
	if (pdata->scl_is_open_drain)
		gflags = GPIOD_OUT_HIGH;
	else
		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
	priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
	if (IS_ERR(priv->scl))
		return PTR_ERR(priv->scl);

	if (gpiod_cansleep(priv->sda) || gpiod_cansleep(priv->scl))
		dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");

	bit_data->setsda = i2c_gpio_setsda_val;
	bit_data->setscl = i2c_gpio_setscl_val;

	if (!pdata->scl_is_output_only)
		bit_data->getscl = i2c_gpio_getscl;
	bit_data->getsda = i2c_gpio_getsda;

	if (pdata->udelay)
		bit_data->udelay = pdata->udelay;
	else if (pdata->scl_is_output_only)
		bit_data->udelay = 50;			/* 10 kHz */
	else
		bit_data->udelay = 5;			/* 100 kHz */

	if (pdata->timeout)
		bit_data->timeout = pdata->timeout;
	else
		bit_data->timeout = HZ / 10;		/* 100 ms */

	bit_data->data = priv;

	adap->owner = THIS_MODULE;
	if (np)
		strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
	else
		snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);

	adap->algo_data = bit_data;
	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
	adap->dev.parent = dev;
	adap->dev.of_node = np;

	adap->nr = pdev->id;
	ret = i2c_bit_add_numbered_bus(adap);
	if (ret)
		return ret;

	platform_set_drvdata(pdev, priv);

	/*
	 * FIXME: using global GPIO numbers is not helpful. If/when we
	 * get accessors to get the actual name of the GPIO line,
	 * from the descriptor, then provide that instead.
	 */
	dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
		 desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
		 pdata->scl_is_output_only
		 ? ", no clock stretching" : "");

	i2c_gpio_fault_injector_init(pdev);

	return 0;
}

static int i2c_gpio_remove(struct platform_device *pdev)
{
	struct i2c_gpio_private_data *priv;
	struct i2c_adapter *adap;

	i2c_gpio_fault_injector_exit(pdev);

	priv = platform_get_drvdata(pdev);
	adap = &priv->adap;

	i2c_del_adapter(adap);

	return 0;
}

#if defined(CONFIG_OF)
static const struct of_device_id i2c_gpio_dt_ids[] = {
	{ .compatible = "i2c-gpio", },
	{ /* sentinel */ }
};

MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
#endif

static struct platform_driver i2c_gpio_driver = {
	.driver		= {
		.name	= "i2c-gpio",
		.of_match_table	= of_match_ptr(i2c_gpio_dt_ids),
	},
	.probe		= i2c_gpio_probe,
	.remove		= i2c_gpio_remove,
};

static int __init i2c_gpio_init(void)
{
	int ret;

	ret = platform_driver_register(&i2c_gpio_driver);
	if (ret)
		printk(KERN_ERR "i2c-gpio: probe failed: %d\n", ret);

	return ret;
}
subsys_initcall(i2c_gpio_init);

static void __exit i2c_gpio_exit(void)
{
	platform_driver_unregister(&i2c_gpio_driver);
}
module_exit(i2c_gpio_exit);

MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-gpio");
Commit	Line	Data
1c23af90 HS	1	/*
	2	* Bitbanging I2C bus driver using the GPIO API
	3	*
	4	* Copyright (C) 2007 Atmel Corporation
	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	*/
14911c6f WS	10	#include <linux/debugfs.h>
14911c6f WS	11	#include <linux/delay.h>
1c23af90 HS	12	#include <linux/i2c.h>
1c23af90 HS	13	#include <linux/i2c-algo-bit.h>
1e9d4219	14	#include <linux/platform_data/i2c-gpio.h>
1c23af90 HS	15	#include <linux/init.h>
1c23af90 HS	16	#include <linux/module.h>
5a0e3ad6	17	#include <linux/slab.h>
1c23af90	18	#include <linux/platform_device.h>
b2e63555	19	#include <linux/gpio/consumer.h>
4edd65e6	20	#include <linux/of.h>
8ffaa0f4 JCPV	21
8ffaa0f4 JCPV	22	struct i2c_gpio_private_data {
b2e63555 LW	23	struct gpio_desc *sda;
b2e63555 LW	24	struct gpio_desc *scl;
8ffaa0f4 JCPV	25	struct i2c_adapter adap;
	26	struct i2c_algo_bit_data bit_data;
	27	struct i2c_gpio_platform_data pdata;
14911c6f WS	28	#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
	29	struct dentry *debug_dir;
	30	#endif
8ffaa0f4	31	};
1c23af90	32
1c23af90 HS	33	/*
	34	* Toggle SDA by changing the output value of the pin. This is only
	35	* valid for pins configured as open drain (i.e. setting the value
	36	* high effectively turns off the output driver.)
	37	*/
	38	static void i2c_gpio_setsda_val(void *data, int state)
	39	{
b2e63555	40	struct i2c_gpio_private_data *priv = data;
1c23af90	41
f11a0446	42	gpiod_set_value_cansleep(priv->sda, state);
1c23af90 HS	43	}
1c23af90 HS	44
1c23af90 HS	45	/*
	46	* Toggle SCL by changing the output value of the pin. This is used
	47	* for pins that are configured as open drain and for output-only
	48	* pins. The latter case will break the i2c protocol, but it will
	49	* often work in practice.
	50	*/
	51	static void i2c_gpio_setscl_val(void *data, int state)
	52	{
b2e63555	53	struct i2c_gpio_private_data *priv = data;
1c23af90	54
f11a0446	55	gpiod_set_value_cansleep(priv->scl, state);
1c23af90 HS	56	}
1c23af90 HS	57
4d6ceed4	58	static int i2c_gpio_getsda(void *data)
1c23af90	59	{
b2e63555	60	struct i2c_gpio_private_data *priv = data;
1c23af90	61
f11a0446	62	return gpiod_get_value_cansleep(priv->sda);
1c23af90 HS	63	}
1c23af90 HS	64
4d6ceed4	65	static int i2c_gpio_getscl(void *data)
1c23af90	66	{
b2e63555	67	struct i2c_gpio_private_data *priv = data;
1c23af90	68
f11a0446	69	return gpiod_get_value_cansleep(priv->scl);
1b295c83 JD	70	}
1b295c83 JD	71
14911c6f WS	72	#ifdef CONFIG_I2C_GPIO_FAULT_INJECTOR
	73	static struct dentry *i2c_gpio_debug_dir;
	74
	75	#define setsda(bd, val) ((bd)->setsda((bd)->data, val))
	76	#define setscl(bd, val) ((bd)->setscl((bd)->data, val))
	77	#define getsda(bd) ((bd)->getsda((bd)->data))
	78	#define getscl(bd) ((bd)->getscl((bd)->data))
	79
	80	#define WIRE_ATTRIBUTE(wire) \
3f3a89e1 PR	81	static int fops_##wire##_get(void data, u64 val) \
	82	{ \
	83	struct i2c_gpio_private_data *priv = data; \
	84	\
	85	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
	86	*val = get##wire(&priv->bit_data); \
	87	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
	88	return 0; \
	89	} \
	90	static int fops_##wire##_set(void *data, u64 val) \
	91	{ \
	92	struct i2c_gpio_private_data *priv = data; \
	93	\
	94	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
	95	set##wire(&priv->bit_data, val); \
	96	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER); \
	97	return 0; \
	98	} \
14911c6f WS	99	DEFINE_DEBUGFS_ATTRIBUTE(fops_##wire, fops_##wire##_get, fops_##wire##_set, "%llu\n")
	100
	101	WIRE_ATTRIBUTE(scl);
	102	WIRE_ATTRIBUTE(sda);
	103
16d55daa WS	104	static void i2c_gpio_incomplete_transfer(struct i2c_gpio_private_data *priv,
16d55daa WS	105	u32 pattern, u8 pattern_size)
14911c6f	106	{
14911c6f	107	struct i2c_algo_bit_data *bit_data = &priv->bit_data;
16d55daa	108	int i;
14911c6f	109
3f3a89e1	110	i2c_lock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
14911c6f WS	111
	112	/* START condition */
	113	setsda(bit_data, 0);
	114	udelay(bit_data->udelay);
	115
16d55daa WS	116	/* Send pattern, request ACK, don't send STOP */
16d55daa WS	117	for (i = pattern_size - 1; i >= 0; i--) {
14911c6f WS	118	setscl(bit_data, 0);
	119	udelay(bit_data->udelay / 2);
	120	setsda(bit_data, (pattern >> i) & 1);
	121	udelay((bit_data->udelay + 1) / 2);
	122	setscl(bit_data, 1);
	123	udelay(bit_data->udelay);
	124	}
	125
3f3a89e1	126	i2c_unlock_bus(&priv->adap, I2C_LOCK_ROOT_ADAPTER);
16d55daa WS	127	}
	128
	129	static int fops_incomplete_addr_phase_set(void *data, u64 addr)
	130	{
	131	struct i2c_gpio_private_data *priv = data;
	132	u32 pattern;
	133
	134	if (addr > 0x7f)
	135	return -EINVAL;
	136
	137	/* ADDR (7 bit) + RD (1 bit) + Client ACK, keep SDA hi (1 bit) */
	138	pattern = (addr << 2) \| 3;
	139
	140	i2c_gpio_incomplete_transfer(priv, pattern, 9);
14911c6f WS	141
	142	return 0;
	143	}
16d55daa	144	DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_addr_phase, NULL, fops_incomplete_addr_phase_set, "%llu\n");
14911c6f	145
bbe89970 WS	146	static int fops_incomplete_write_byte_set(void *data, u64 addr)
	147	{
	148	struct i2c_gpio_private_data *priv = data;
	149	u32 pattern;
	150
	151	if (addr > 0x7f)
	152	return -EINVAL;
	153
	154	/* ADDR (7 bit) + WR (1 bit) + Client ACK (1 bit) */
	155	pattern = (addr << 2) \| 1;
	156	/* 0x00 (8 bit) + Client ACK, keep SDA hi (1 bit) */
	157	pattern = (pattern << 9) \| 1;
	158
	159	i2c_gpio_incomplete_transfer(priv, pattern, 18);
	160
	161	return 0;
	162	}
	163	DEFINE_DEBUGFS_ATTRIBUTE(fops_incomplete_write_byte, NULL, fops_incomplete_write_byte_set, "%llu\n");
	164
14911c6f WS	165	static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
	166	{
	167	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
	168
	169	/*
	170	* If there will be a debugfs-dir per i2c adapter somewhen, put the
	171	* 'fault-injector' dir there. Until then, we have a global dir with
	172	* all adapters as subdirs.
	173	*/
	174	if (!i2c_gpio_debug_dir) {
	175	i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
	176	if (!i2c_gpio_debug_dir)
	177	return;
	178	}
	179
	180	priv->debug_dir = debugfs_create_dir(pdev->name, i2c_gpio_debug_dir);
	181	if (!priv->debug_dir)
	182	return;
	183
	184	debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl);
	185	debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda);
16d55daa WS	186	debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->debug_dir,
16d55daa WS	187	priv, &fops_incomplete_addr_phase);
bbe89970 WS	188	debugfs_create_file_unsafe("incomplete_write_byte", 0200, priv->debug_dir,
bbe89970 WS	189	priv, &fops_incomplete_write_byte);
14911c6f WS	190	}
	191
	192	static void i2c_gpio_fault_injector_exit(struct platform_device *pdev)
	193	{
	194	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
	195
	196	debugfs_remove_recursive(priv->debug_dir);
	197	}
	198	#else
	199	static inline void i2c_gpio_fault_injector_init(struct platform_device *pdev) {}
	200	static inline void i2c_gpio_fault_injector_exit(struct platform_device *pdev) {}
	201	#endif /* CONFIG_I2C_GPIO_FAULT_INJECTOR*/
	202
1b295c83 JD	203	static void of_i2c_gpio_get_props(struct device_node *np,
	204	struct i2c_gpio_platform_data *pdata)
	205	{
	206	u32 reg;
	207
8ffaa0f4 JCPV	208	of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
	209
	210	if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
	211	pdata->timeout = msecs_to_jiffies(reg);
	212
	213	pdata->sda_is_open_drain =
	214	of_property_read_bool(np, "i2c-gpio,sda-open-drain");
	215	pdata->scl_is_open_drain =
	216	of_property_read_bool(np, "i2c-gpio,scl-open-drain");
	217	pdata->scl_is_output_only =
	218	of_property_read_bool(np, "i2c-gpio,scl-output-only");
8ffaa0f4 JCPV	219	}
8ffaa0f4 JCPV	220
05c74778 LW	221	static struct gpio_desc i2c_gpio_get_desc(struct device dev,
	222	const char *con_id,
	223	unsigned int index,
	224	enum gpiod_flags gflags)
	225	{
	226	struct gpio_desc *retdesc;
	227	int ret;
	228
	229	retdesc = devm_gpiod_get(dev, con_id, gflags);
	230	if (!IS_ERR(retdesc)) {
	231	dev_dbg(dev, "got GPIO from name %s\n", con_id);
	232	return retdesc;
	233	}
	234
	235	retdesc = devm_gpiod_get_index(dev, NULL, index, gflags);
	236	if (!IS_ERR(retdesc)) {
	237	dev_dbg(dev, "got GPIO from index %u\n", index);
	238	return retdesc;
	239	}
	240
	241	ret = PTR_ERR(retdesc);
	242
	243	/* FIXME: hack in the old code, is this really necessary? */
	244	if (ret == -EINVAL)
	245	retdesc = ERR_PTR(-EPROBE_DEFER);
	246
	247	/* This happens if the GPIO driver is not yet probed, let's defer */
	248	if (ret == -ENOENT)
	249	retdesc = ERR_PTR(-EPROBE_DEFER);
	250
	251	if (ret != -EPROBE_DEFER)
	252	dev_err(dev, "error trying to get descriptor: %d\n", ret);
	253
	254	return retdesc;
	255	}
	256
0b255e92	257	static int i2c_gpio_probe(struct platform_device *pdev)
1c23af90	258	{
8ffaa0f4	259	struct i2c_gpio_private_data *priv;
1c23af90 HS	260	struct i2c_gpio_platform_data *pdata;
	261	struct i2c_algo_bit_data *bit_data;
	262	struct i2c_adapter *adap;
b9ab0517 LW	263	struct device *dev = &pdev->dev;
b9ab0517 LW	264	struct device_node *np = dev->of_node;
7bb75029	265	enum gpiod_flags gflags;
1c23af90 HS	266	int ret;
1c23af90 HS	267
b9ab0517	268	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
b2e63555 LW	269	if (!priv)
b2e63555 LW	270	return -ENOMEM;
1c23af90	271
1b295c83 JD	272	adap = &priv->adap;
	273	bit_data = &priv->bit_data;
	274	pdata = &priv->pdata;
	275
b9ab0517 LW	276	if (np) {
b9ab0517 LW	277	of_i2c_gpio_get_props(np, pdata);
1b295c83	278	} else {
b2e63555 LW	279	/*
	280	* If all platform data settings are zero it is OK
	281	* to not provide any platform data from the board.
	282	*/
b9ab0517 LW	283	if (dev_get_platdata(dev))
b9ab0517 LW	284	memcpy(pdata, dev_get_platdata(dev), sizeof(*pdata));
1b295c83	285	}
1c23af90	286
b2e63555	287	/*
7bb75029 LW	288	* First get the GPIO pins; if it fails, we'll defer the probe.
	289	* If the SDA line is marked from platform data or device tree as
	290	* "open drain" it means something outside of our control is making
	291	* this line being handled as open drain, and we should just handle
	292	* it as any other output. Else we enforce open drain as this is
	293	* required for an I2C bus.
b2e63555	294	*/
7bb75029 LW	295	if (pdata->sda_is_open_drain)
	296	gflags = GPIOD_OUT_HIGH;
	297	else
	298	gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
05c74778 LW	299	priv->sda = i2c_gpio_get_desc(dev, "sda", 0, gflags);
	300	if (IS_ERR(priv->sda))
	301	return PTR_ERR(priv->sda);
	302
7bb75029 LW	303	/*
	304	* If the SCL line is marked from platform data or device tree as
	305	* "open drain" it means something outside of our control is making
	306	* this line being handled as open drain, and we should just handle
	307	* it as any other output. Else we enforce open drain as this is
	308	* required for an I2C bus.
	309	*/
	310	if (pdata->scl_is_open_drain)
12b731dd	311	gflags = GPIOD_OUT_HIGH;
7bb75029	312	else
12b731dd	313	gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
05c74778 LW	314	priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
	315	if (IS_ERR(priv->scl))
	316	return PTR_ERR(priv->scl);
1c23af90	317
f11a0446 JK	318	if (gpiod_cansleep(priv->sda) \|\| gpiod_cansleep(priv->scl))
	319	dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");
	320
7bb75029 LW	321	bit_data->setsda = i2c_gpio_setsda_val;
	322	bit_data->setscl = i2c_gpio_setscl_val;
	323
1c23af90 HS	324	if (!pdata->scl_is_output_only)
	325	bit_data->getscl = i2c_gpio_getscl;
	326	bit_data->getsda = i2c_gpio_getsda;
	327
	328	if (pdata->udelay)
	329	bit_data->udelay = pdata->udelay;
	330	else if (pdata->scl_is_output_only)
	331	bit_data->udelay = 50; /* 10 kHz */
	332	else
	333	bit_data->udelay = 5; /* 100 kHz */
	334
	335	if (pdata->timeout)
	336	bit_data->timeout = pdata->timeout;
	337	else
	338	bit_data->timeout = HZ / 10; /* 100 ms */
	339
b2e63555	340	bit_data->data = priv;
1c23af90 HS	341
1c23af90 HS	342	adap->owner = THIS_MODULE;
b9ab0517 LW	343	if (np)
b9ab0517 LW	344	strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
58a7371a BS	345	else
	346	snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
	347
1c23af90	348	adap->algo_data = bit_data;
3401b2ff	349	adap->class = I2C_CLASS_HWMON \| I2C_CLASS_SPD;
b9ab0517 LW	350	adap->dev.parent = dev;
b9ab0517 LW	351	adap->dev.of_node = np;
1c23af90	352
44454baa	353	adap->nr = pdev->id;
7e69c3ac	354	ret = i2c_bit_add_numbered_bus(adap);
1c23af90	355	if (ret)
a0682a31	356	return ret;
1c23af90	357
8ffaa0f4	358	platform_set_drvdata(pdev, priv);
1c23af90	359
b2e63555 LW	360	/*
	361	* FIXME: using global GPIO numbers is not helpful. If/when we
	362	* get accessors to get the actual name of the GPIO line,
	363	* from the descriptor, then provide that instead.
	364	*/
b9ab0517	365	dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
b2e63555	366	desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
1c23af90 HS	367	pdata->scl_is_output_only
	368	? ", no clock stretching" : "");
	369
14911c6f WS	370	i2c_gpio_fault_injector_init(pdev);
14911c6f WS	371
1c23af90	372	return 0;
1c23af90 HS	373	}
1c23af90 HS	374
0b255e92	375	static int i2c_gpio_remove(struct platform_device *pdev)
1c23af90	376	{
8ffaa0f4	377	struct i2c_gpio_private_data *priv;
1c23af90 HS	378	struct i2c_adapter *adap;
1c23af90 HS	379
14911c6f WS	380	i2c_gpio_fault_injector_exit(pdev);
14911c6f WS	381
8ffaa0f4 JCPV	382	priv = platform_get_drvdata(pdev);
8ffaa0f4 JCPV	383	adap = &priv->adap;
1c23af90 HS	384
1c23af90 HS	385	i2c_del_adapter(adap);
1c23af90 HS	386
	387	return 0;
	388	}
	389
8ffaa0f4 JCPV	390	#if defined(CONFIG_OF)
	391	static const struct of_device_id i2c_gpio_dt_ids[] = {
	392	{ .compatible = "i2c-gpio", },
	393	{ /* sentinel */ }
	394	};
	395
	396	MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
	397	#endif
	398
1c23af90 HS	399	static struct platform_driver i2c_gpio_driver = {
	400	.driver = {
	401	.name = "i2c-gpio",
8ffaa0f4	402	.of_match_table = of_match_ptr(i2c_gpio_dt_ids),
1c23af90	403	},
1efe7c55	404	.probe = i2c_gpio_probe,
0b255e92	405	.remove = i2c_gpio_remove,
1c23af90 HS	406	};
	407
	408	static int __init i2c_gpio_init(void)
	409	{
	410	int ret;
	411
1efe7c55	412	ret = platform_driver_register(&i2c_gpio_driver);
1c23af90 HS	413	if (ret)
	414	printk(KERN_ERR "i2c-gpio: probe failed: %d\n", ret);
	415
	416	return ret;
	417	}
b8680784	418	subsys_initcall(i2c_gpio_init);
1c23af90 HS	419
	420	static void __exit i2c_gpio_exit(void)
	421	{
	422	platform_driver_unregister(&i2c_gpio_driver);
	423	}
	424	module_exit(i2c_gpio_exit);
	425
e05503ef	426	MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1c23af90 HS	427	MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
1c23af90 HS	428	MODULE_LICENSE("GPL");
add8eda7	429	MODULE_ALIAS("platform:i2c-gpio");