[deliverable/linux.git] / drivers / i2c / muxes / i2c-mux-gpio.c

/*
 * I2C multiplexer using GPIO API
 *
 * Peter Korsgaard <peter.korsgaard@barco.com>
 *
 * 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/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/i2c-mux-gpio.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/gpio.h>

struct gpiomux {
	struct i2c_adapter *parent;
	struct i2c_adapter **adap; /* child busses */
	struct i2c_mux_gpio_platform_data data;
};

static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
{
	int i;

	for (i = 0; i < mux->data.n_gpios; i++)
		gpio_set_value(mux->data.gpios[i], val & (1 << i));
}

static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
{
	struct gpiomux *mux = data;

	i2c_mux_gpio_set(mux, mux->data.values[chan]);

	return 0;
}

static int i2c_mux_gpio_deselect(struct i2c_adapter *adap, void *data, u32 chan)
{
	struct gpiomux *mux = data;

	i2c_mux_gpio_set(mux, mux->data.idle);

	return 0;
}

static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev)
{
	struct gpiomux *mux;
	struct i2c_mux_gpio_platform_data *pdata;
	struct i2c_adapter *parent;
	int (*deselect) (struct i2c_adapter *, void *, u32);
	unsigned initial_state;
	int i, ret;

	pdata = pdev->dev.platform_data;
	if (!pdata) {
		dev_err(&pdev->dev, "Missing platform data\n");
		return -ENODEV;
	}

	parent = i2c_get_adapter(pdata->parent);
	if (!parent) {
		dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
			pdata->parent);
		return -ENODEV;
	}

	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
	if (!mux) {
		ret = -ENOMEM;
		goto alloc_failed;
	}

	mux->parent = parent;
	mux->data = *pdata;
	mux->adap = kzalloc(sizeof(struct i2c_adapter *) * pdata->n_values,
			    GFP_KERNEL);
	if (!mux->adap) {
		ret = -ENOMEM;
		goto alloc_failed2;
	}

	if (pdata->idle != I2C_MUX_GPIO_NO_IDLE) {
		initial_state = pdata->idle;
		deselect = i2c_mux_gpio_deselect;
	} else {
		initial_state = pdata->values[0];
		deselect = NULL;
	}

	for (i = 0; i < pdata->n_gpios; i++) {
		ret = gpio_request(pdata->gpios[i], "i2c-mux-gpio");
		if (ret)
			goto err_request_gpio;
		gpio_direction_output(pdata->gpios[i],
				      initial_state & (1 << i));
	}

	for (i = 0; i < pdata->n_values; i++) {
		u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;

		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, i,
						   i2c_mux_gpio_select, deselect);
		if (!mux->adap[i]) {
			ret = -ENODEV;
			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
			goto add_adapter_failed;
		}
	}

	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
		 pdata->n_values, parent->name);

	platform_set_drvdata(pdev, mux);

	return 0;

add_adapter_failed:
	for (; i > 0; i--)
		i2c_del_mux_adapter(mux->adap[i - 1]);
	i = pdata->n_gpios;
err_request_gpio:
	for (; i > 0; i--)
		gpio_free(pdata->gpios[i - 1]);
	kfree(mux->adap);
alloc_failed2:
	kfree(mux);
alloc_failed:
	i2c_put_adapter(parent);

	return ret;
}

static int __devexit i2c_mux_gpio_remove(struct platform_device *pdev)
{
	struct gpiomux *mux = platform_get_drvdata(pdev);
	int i;

	for (i = 0; i < mux->data.n_values; i++)
		i2c_del_mux_adapter(mux->adap[i]);

	for (i = 0; i < mux->data.n_gpios; i++)
		gpio_free(mux->data.gpios[i]);

	platform_set_drvdata(pdev, NULL);
	i2c_put_adapter(mux->parent);
	kfree(mux->adap);
	kfree(mux);

	return 0;
}

static struct platform_driver i2c_mux_gpio_driver = {
	.probe	= i2c_mux_gpio_probe,
	.remove	= __devexit_p(i2c_mux_gpio_remove),
	.driver	= {
		.owner	= THIS_MODULE,
		.name	= "i2c-mux-gpio",
	},
};

module_platform_driver(i2c_mux_gpio_driver);

MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-mux-gpio");
Commit	Line	Data
92ed1a76 PK	1	/*
	2	* I2C multiplexer using GPIO API
	3	*
	4	* Peter Korsgaard <peter.korsgaard@barco.com>
	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
	11	#include <linux/i2c.h>
	12	#include <linux/i2c-mux.h>
e7065e20	13	#include <linux/i2c-mux-gpio.h>
92ed1a76 PK	14	#include <linux/platform_device.h>
	15	#include <linux/init.h>
	16	#include <linux/module.h>
	17	#include <linux/slab.h>
	18	#include <linux/gpio.h>
	19
	20	struct gpiomux {
	21	struct i2c_adapter *parent;
	22	struct i2c_adapter *adap; / child busses */
e7065e20	23	struct i2c_mux_gpio_platform_data data;
92ed1a76 PK	24	};
92ed1a76 PK	25
e7065e20	26	static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
92ed1a76 PK	27	{
	28	int i;
	29
	30	for (i = 0; i < mux->data.n_gpios; i++)
	31	gpio_set_value(mux->data.gpios[i], val & (1 << i));
	32	}
	33
e7065e20	34	static int i2c_mux_gpio_select(struct i2c_adapter adap, void data, u32 chan)
92ed1a76 PK	35	{
	36	struct gpiomux *mux = data;
	37
e7065e20	38	i2c_mux_gpio_set(mux, mux->data.values[chan]);
92ed1a76 PK	39
	40	return 0;
	41	}
	42
e7065e20	43	static int i2c_mux_gpio_deselect(struct i2c_adapter adap, void data, u32 chan)
92ed1a76 PK	44	{
	45	struct gpiomux *mux = data;
	46
e7065e20	47	i2c_mux_gpio_set(mux, mux->data.idle);
92ed1a76 PK	48
	49	return 0;
	50	}
	51
e7065e20	52	static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev)
92ed1a76 PK	53	{
92ed1a76 PK	54	struct gpiomux *mux;
e7065e20	55	struct i2c_mux_gpio_platform_data *pdata;
92ed1a76 PK	56	struct i2c_adapter *parent;
	57	int (deselect) (struct i2c_adapter , void *, u32);
	58	unsigned initial_state;
	59	int i, ret;
	60
	61	pdata = pdev->dev.platform_data;
	62	if (!pdata) {
	63	dev_err(&pdev->dev, "Missing platform data\n");
	64	return -ENODEV;
	65	}
	66
	67	parent = i2c_get_adapter(pdata->parent);
	68	if (!parent) {
	69	dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
	70	pdata->parent);
	71	return -ENODEV;
	72	}
	73
	74	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
	75	if (!mux) {
	76	ret = -ENOMEM;
	77	goto alloc_failed;
	78	}
	79
	80	mux->parent = parent;
	81	mux->data = *pdata;
	82	mux->adap = kzalloc(sizeof(struct i2c_adapter ) pdata->n_values,
	83	GFP_KERNEL);
	84	if (!mux->adap) {
	85	ret = -ENOMEM;
	86	goto alloc_failed2;
	87	}
	88
e7065e20	89	if (pdata->idle != I2C_MUX_GPIO_NO_IDLE) {
92ed1a76	90	initial_state = pdata->idle;
e7065e20	91	deselect = i2c_mux_gpio_deselect;
92ed1a76 PK	92	} else {
	93	initial_state = pdata->values[0];
	94	deselect = NULL;
	95	}
	96
	97	for (i = 0; i < pdata->n_gpios; i++) {
e7065e20	98	ret = gpio_request(pdata->gpios[i], "i2c-mux-gpio");
92ed1a76 PK	99	if (ret)
	100	goto err_request_gpio;
	101	gpio_direction_output(pdata->gpios[i],
	102	initial_state & (1 << i));
	103	}
	104
	105	for (i = 0; i < pdata->n_values; i++) {
	106	u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
	107
e7065e20 JD	108	mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, i,
e7065e20 JD	109	i2c_mux_gpio_select, deselect);
92ed1a76 PK	110	if (!mux->adap[i]) {
	111	ret = -ENODEV;
	112	dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
	113	goto add_adapter_failed;
	114	}
	115	}
	116
	117	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
	118	pdata->n_values, parent->name);
	119
	120	platform_set_drvdata(pdev, mux);
	121
	122	return 0;
	123
	124	add_adapter_failed:
	125	for (; i > 0; i--)
	126	i2c_del_mux_adapter(mux->adap[i - 1]);
	127	i = pdata->n_gpios;
	128	err_request_gpio:
	129	for (; i > 0; i--)
	130	gpio_free(pdata->gpios[i - 1]);
	131	kfree(mux->adap);
	132	alloc_failed2:
	133	kfree(mux);
	134	alloc_failed:
	135	i2c_put_adapter(parent);
	136
	137	return ret;
	138	}
	139
e7065e20	140	static int __devexit i2c_mux_gpio_remove(struct platform_device *pdev)
92ed1a76 PK	141	{
	142	struct gpiomux *mux = platform_get_drvdata(pdev);
	143	int i;
	144
	145	for (i = 0; i < mux->data.n_values; i++)
	146	i2c_del_mux_adapter(mux->adap[i]);
	147
	148	for (i = 0; i < mux->data.n_gpios; i++)
	149	gpio_free(mux->data.gpios[i]);
	150
	151	platform_set_drvdata(pdev, NULL);
	152	i2c_put_adapter(mux->parent);
	153	kfree(mux->adap);
	154	kfree(mux);
	155
	156	return 0;
	157	}
	158
e7065e20 JD	159	static struct platform_driver i2c_mux_gpio_driver = {
	160	.probe = i2c_mux_gpio_probe,
	161	.remove = __devexit_p(i2c_mux_gpio_remove),
92ed1a76 PK	162	.driver = {
92ed1a76 PK	163	.owner = THIS_MODULE,
e7065e20	164	.name = "i2c-mux-gpio",
92ed1a76 PK	165	},
	166	};
	167
e7065e20	168	module_platform_driver(i2c_mux_gpio_driver);
92ed1a76 PK	169
	170	MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
	171	MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
	172	MODULE_LICENSE("GPL");
e7065e20	173	MODULE_ALIAS("platform:i2c-mux-gpio");