[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_adapter(&priv->adap);			\
	*val = get##wire(&priv->bit_data);		\
	i2c_unlock_adapter(&priv->adap);		\
	return 0;					\
}							\
static int fops_##wire##_set(void *data, u64 val)	\
{							\
	struct i2c_gpio_private_data *priv = data;	\
							\
	i2c_lock_adapter(&priv->adap);			\
	set##wire(&priv->bit_data, val);		\
	i2c_unlock_adapter(&priv->adap);		\
	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_adapter(&priv->adap);

	/* 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_adapter(&priv->adap);
}

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 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);
}

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) \
	81	static int fops_##wire##_get(void data, u64 val) \
	82	{ \
	83	struct i2c_gpio_private_data *priv = data; \
	84	\
	85	i2c_lock_adapter(&priv->adap); \
	86	*val = get##wire(&priv->bit_data); \
	87	i2c_unlock_adapter(&priv->adap); \
	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_adapter(&priv->adap); \
	95	set##wire(&priv->bit_data, val); \
	96	i2c_unlock_adapter(&priv->adap); \
	97	return 0; \
	98	} \
	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 WS	109
	110	i2c_lock_adapter(&priv->adap);
	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
	126	i2c_unlock_adapter(&priv->adap);
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 WS	145
	146	static void i2c_gpio_fault_injector_init(struct platform_device *pdev)
	147	{
	148	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
	149
	150	/*
	151	* If there will be a debugfs-dir per i2c adapter somewhen, put the
	152	* 'fault-injector' dir there. Until then, we have a global dir with
	153	* all adapters as subdirs.
	154	*/
	155	if (!i2c_gpio_debug_dir) {
	156	i2c_gpio_debug_dir = debugfs_create_dir("i2c-fault-injector", NULL);
	157	if (!i2c_gpio_debug_dir)
	158	return;
	159	}
	160
	161	priv->debug_dir = debugfs_create_dir(pdev->name, i2c_gpio_debug_dir);
	162	if (!priv->debug_dir)
	163	return;
	164
	165	debugfs_create_file_unsafe("scl", 0600, priv->debug_dir, priv, &fops_scl);
	166	debugfs_create_file_unsafe("sda", 0600, priv->debug_dir, priv, &fops_sda);
16d55daa WS	167	debugfs_create_file_unsafe("incomplete_address_phase", 0200, priv->debug_dir,
16d55daa WS	168	priv, &fops_incomplete_addr_phase);
14911c6f WS	169	}
	170
	171	static void i2c_gpio_fault_injector_exit(struct platform_device *pdev)
	172	{
	173	struct i2c_gpio_private_data *priv = platform_get_drvdata(pdev);
	174
	175	debugfs_remove_recursive(priv->debug_dir);
	176	}
	177	#else
	178	static inline void i2c_gpio_fault_injector_init(struct platform_device *pdev) {}
	179	static inline void i2c_gpio_fault_injector_exit(struct platform_device *pdev) {}
	180	#endif /* CONFIG_I2C_GPIO_FAULT_INJECTOR*/
	181
1b295c83 JD	182	static void of_i2c_gpio_get_props(struct device_node *np,
	183	struct i2c_gpio_platform_data *pdata)
	184	{
	185	u32 reg;
	186
8ffaa0f4 JCPV	187	of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
	188
	189	if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
	190	pdata->timeout = msecs_to_jiffies(reg);
	191
	192	pdata->sda_is_open_drain =
	193	of_property_read_bool(np, "i2c-gpio,sda-open-drain");
	194	pdata->scl_is_open_drain =
	195	of_property_read_bool(np, "i2c-gpio,scl-open-drain");
	196	pdata->scl_is_output_only =
	197	of_property_read_bool(np, "i2c-gpio,scl-output-only");
8ffaa0f4 JCPV	198	}
8ffaa0f4 JCPV	199
05c74778 LW	200	static struct gpio_desc i2c_gpio_get_desc(struct device dev,
	201	const char *con_id,
	202	unsigned int index,
	203	enum gpiod_flags gflags)
	204	{
	205	struct gpio_desc *retdesc;
	206	int ret;
	207
	208	retdesc = devm_gpiod_get(dev, con_id, gflags);
	209	if (!IS_ERR(retdesc)) {
	210	dev_dbg(dev, "got GPIO from name %s\n", con_id);
	211	return retdesc;
	212	}
	213
	214	retdesc = devm_gpiod_get_index(dev, NULL, index, gflags);
	215	if (!IS_ERR(retdesc)) {
	216	dev_dbg(dev, "got GPIO from index %u\n", index);
	217	return retdesc;
	218	}
	219
	220	ret = PTR_ERR(retdesc);
	221
	222	/* FIXME: hack in the old code, is this really necessary? */
	223	if (ret == -EINVAL)
	224	retdesc = ERR_PTR(-EPROBE_DEFER);
	225
	226	/* This happens if the GPIO driver is not yet probed, let's defer */
	227	if (ret == -ENOENT)
	228	retdesc = ERR_PTR(-EPROBE_DEFER);
	229
	230	if (ret != -EPROBE_DEFER)
	231	dev_err(dev, "error trying to get descriptor: %d\n", ret);
	232
	233	return retdesc;
	234	}
	235
0b255e92	236	static int i2c_gpio_probe(struct platform_device *pdev)
1c23af90	237	{
8ffaa0f4	238	struct i2c_gpio_private_data *priv;
1c23af90 HS	239	struct i2c_gpio_platform_data *pdata;
	240	struct i2c_algo_bit_data *bit_data;
	241	struct i2c_adapter *adap;
b9ab0517 LW	242	struct device *dev = &pdev->dev;
b9ab0517 LW	243	struct device_node *np = dev->of_node;
7bb75029	244	enum gpiod_flags gflags;
1c23af90 HS	245	int ret;
1c23af90 HS	246
b9ab0517	247	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
b2e63555 LW	248	if (!priv)
b2e63555 LW	249	return -ENOMEM;
1c23af90	250
1b295c83 JD	251	adap = &priv->adap;
	252	bit_data = &priv->bit_data;
	253	pdata = &priv->pdata;
	254
b9ab0517 LW	255	if (np) {
b9ab0517 LW	256	of_i2c_gpio_get_props(np, pdata);
1b295c83	257	} else {
b2e63555 LW	258	/*
	259	* If all platform data settings are zero it is OK
	260	* to not provide any platform data from the board.
	261	*/
b9ab0517 LW	262	if (dev_get_platdata(dev))
b9ab0517 LW	263	memcpy(pdata, dev_get_platdata(dev), sizeof(*pdata));
1b295c83	264	}
1c23af90	265
b2e63555	266	/*
7bb75029 LW	267	* First get the GPIO pins; if it fails, we'll defer the probe.
	268	* If the SDA line is marked from platform data or device tree as
	269	* "open drain" it means something outside of our control is making
	270	* this line being handled as open drain, and we should just handle
	271	* it as any other output. Else we enforce open drain as this is
	272	* required for an I2C bus.
b2e63555	273	*/
7bb75029 LW	274	if (pdata->sda_is_open_drain)
	275	gflags = GPIOD_OUT_HIGH;
	276	else
	277	gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
05c74778 LW	278	priv->sda = i2c_gpio_get_desc(dev, "sda", 0, gflags);
	279	if (IS_ERR(priv->sda))
	280	return PTR_ERR(priv->sda);
	281
7bb75029 LW	282	/*
	283	* If the SCL line is marked from platform data or device tree as
	284	* "open drain" it means something outside of our control is making
	285	* this line being handled as open drain, and we should just handle
	286	* it as any other output. Else we enforce open drain as this is
	287	* required for an I2C bus.
	288	*/
	289	if (pdata->scl_is_open_drain)
12b731dd	290	gflags = GPIOD_OUT_HIGH;
7bb75029	291	else
12b731dd	292	gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
05c74778 LW	293	priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
	294	if (IS_ERR(priv->scl))
	295	return PTR_ERR(priv->scl);
1c23af90	296
f11a0446 JK	297	if (gpiod_cansleep(priv->sda) \|\| gpiod_cansleep(priv->scl))
	298	dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");
	299
7bb75029 LW	300	bit_data->setsda = i2c_gpio_setsda_val;
	301	bit_data->setscl = i2c_gpio_setscl_val;
	302
1c23af90 HS	303	if (!pdata->scl_is_output_only)
	304	bit_data->getscl = i2c_gpio_getscl;
	305	bit_data->getsda = i2c_gpio_getsda;
	306
	307	if (pdata->udelay)
	308	bit_data->udelay = pdata->udelay;
	309	else if (pdata->scl_is_output_only)
	310	bit_data->udelay = 50; /* 10 kHz */
	311	else
	312	bit_data->udelay = 5; /* 100 kHz */
	313
	314	if (pdata->timeout)
	315	bit_data->timeout = pdata->timeout;
	316	else
	317	bit_data->timeout = HZ / 10; /* 100 ms */
	318
b2e63555	319	bit_data->data = priv;
1c23af90 HS	320
1c23af90 HS	321	adap->owner = THIS_MODULE;
b9ab0517 LW	322	if (np)
b9ab0517 LW	323	strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
58a7371a BS	324	else
	325	snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
	326
1c23af90	327	adap->algo_data = bit_data;
3401b2ff	328	adap->class = I2C_CLASS_HWMON \| I2C_CLASS_SPD;
b9ab0517 LW	329	adap->dev.parent = dev;
b9ab0517 LW	330	adap->dev.of_node = np;
1c23af90	331
44454baa	332	adap->nr = pdev->id;
7e69c3ac	333	ret = i2c_bit_add_numbered_bus(adap);
1c23af90	334	if (ret)
a0682a31	335	return ret;
1c23af90	336
8ffaa0f4	337	platform_set_drvdata(pdev, priv);
1c23af90	338
b2e63555 LW	339	/*
	340	* FIXME: using global GPIO numbers is not helpful. If/when we
	341	* get accessors to get the actual name of the GPIO line,
	342	* from the descriptor, then provide that instead.
	343	*/
b9ab0517	344	dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
b2e63555	345	desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
1c23af90 HS	346	pdata->scl_is_output_only
	347	? ", no clock stretching" : "");
	348
14911c6f WS	349	i2c_gpio_fault_injector_init(pdev);
14911c6f WS	350
1c23af90	351	return 0;
1c23af90 HS	352	}
1c23af90 HS	353
0b255e92	354	static int i2c_gpio_remove(struct platform_device *pdev)
1c23af90	355	{
8ffaa0f4	356	struct i2c_gpio_private_data *priv;
1c23af90 HS	357	struct i2c_adapter *adap;
1c23af90 HS	358
14911c6f WS	359	i2c_gpio_fault_injector_exit(pdev);
14911c6f WS	360
8ffaa0f4 JCPV	361	priv = platform_get_drvdata(pdev);
8ffaa0f4 JCPV	362	adap = &priv->adap;
1c23af90 HS	363
1c23af90 HS	364	i2c_del_adapter(adap);
1c23af90 HS	365
	366	return 0;
	367	}
	368
8ffaa0f4 JCPV	369	#if defined(CONFIG_OF)
	370	static const struct of_device_id i2c_gpio_dt_ids[] = {
	371	{ .compatible = "i2c-gpio", },
	372	{ /* sentinel */ }
	373	};
	374
	375	MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
	376	#endif
	377
1c23af90 HS	378	static struct platform_driver i2c_gpio_driver = {
	379	.driver = {
	380	.name = "i2c-gpio",
8ffaa0f4	381	.of_match_table = of_match_ptr(i2c_gpio_dt_ids),
1c23af90	382	},
1efe7c55	383	.probe = i2c_gpio_probe,
0b255e92	384	.remove = i2c_gpio_remove,
1c23af90 HS	385	};
	386
	387	static int __init i2c_gpio_init(void)
	388	{
	389	int ret;
	390
1efe7c55	391	ret = platform_driver_register(&i2c_gpio_driver);
1c23af90 HS	392	if (ret)
	393	printk(KERN_ERR "i2c-gpio: probe failed: %d\n", ret);
	394
	395	return ret;
	396	}
b8680784	397	subsys_initcall(i2c_gpio_init);
1c23af90 HS	398
	399	static void __exit i2c_gpio_exit(void)
	400	{
	401	platform_driver_unregister(&i2c_gpio_driver);
	402	}
	403	module_exit(i2c_gpio_exit);
	404
e05503ef	405	MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1c23af90 HS	406	MODULE_DESCRIPTION("Platform-independent bitbanging I2C driver");
1c23af90 HS	407	MODULE_LICENSE("GPL");
add8eda7	408	MODULE_ALIAS("platform:i2c-gpio");