[mirror_ubuntu-artful-kernel.git] / arch / powerpc / platforms / 83xx / mcu_mpc8349emitx.c

/*
 * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
 *
 * Copyright (c) 2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
#include <asm/prom.h>
#include <asm/machdep.h>

/*
 * I don't have specifications for the MCU firmware, I found this register
 * and bits positions by the trial&error method.
 */
#define MCU_REG_CTRL	0x20
#define MCU_CTRL_POFF	0x40

#define MCU_NUM_GPIO	2

struct mcu {
	struct mutex lock;
	struct device_node *np;
	struct i2c_client *client;
	struct gpio_chip gc;
	u8 reg_ctrl;
};

static struct mcu *glob_mcu;

static void mcu_power_off(void)
{
	struct mcu *mcu = glob_mcu;

	pr_info("Sending power-off request to the MCU...\n");
	mutex_lock(&mcu->lock);
	i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
				  mcu->reg_ctrl | MCU_CTRL_POFF);
	mutex_unlock(&mcu->lock);
}

static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
	struct mcu *mcu = container_of(gc, struct mcu, gc);
	u8 bit = 1 << (4 + gpio);

	mutex_lock(&mcu->lock);
	if (val)
		mcu->reg_ctrl &= ~bit;
	else
		mcu->reg_ctrl |= bit;

	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
	mutex_unlock(&mcu->lock);
}

static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
	mcu_gpio_set(gc, gpio, val);
	return 0;
}

static int mcu_gpiochip_add(struct mcu *mcu)
{
	struct device_node *np;
	struct gpio_chip *gc = &mcu->gc;
	int ret;

	np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
	if (!np)
		return -ENODEV;

	gc->owner = THIS_MODULE;
	gc->label = np->full_name;
	gc->can_sleep = 1;
	gc->ngpio = MCU_NUM_GPIO;
	gc->base = -1;
	gc->set = mcu_gpio_set;
	gc->direction_output = mcu_gpio_dir_out;
	gc->of_gpio_n_cells = 2;
	gc->of_xlate = of_gpio_simple_xlate;

	mcu->np = np;

	/*
	 * We don't want to lose the node, its ->data and ->full_name...
	 * So, if succeeded, we don't put the node here.
	 */
	ret = gpiochip_add(gc);
	if (ret)
		of_node_put(np);
	return ret;
}

static int mcu_gpiochip_remove(struct mcu *mcu)
{
	int ret;

	ret = gpiochip_remove(&mcu->gc);
	if (ret)
		return ret;
	of_node_put(mcu->np);

	return 0;
}

static int __devinit mcu_probe(struct i2c_client *client,
			       const struct i2c_device_id *id)
{
	struct mcu *mcu;
	int ret;

	mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
	if (!mcu)
		return -ENOMEM;

	mutex_init(&mcu->lock);
	mcu->client = client;
	i2c_set_clientdata(client, mcu);

	ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
	if (ret < 0)
		goto err;
	mcu->reg_ctrl = ret;

	ret = mcu_gpiochip_add(mcu);
	if (ret)
		goto err;

	/* XXX: this is potentially racy, but there is no lock for ppc_md */
	if (!ppc_md.power_off) {
		glob_mcu = mcu;
		ppc_md.power_off = mcu_power_off;
		dev_info(&client->dev, "will provide power-off service\n");
	}

	return 0;
err:
	kfree(mcu);
	return ret;
}

static int __devexit mcu_remove(struct i2c_client *client)
{
	struct mcu *mcu = i2c_get_clientdata(client);
	int ret;

	if (glob_mcu == mcu) {
		ppc_md.power_off = NULL;
		glob_mcu = NULL;
	}

	ret = mcu_gpiochip_remove(mcu);
	if (ret)
		return ret;
	i2c_set_clientdata(client, NULL);
	kfree(mcu);
	return 0;
}

static const struct i2c_device_id mcu_ids[] = {
	{ "mcu-mpc8349emitx", },
	{},
};
MODULE_DEVICE_TABLE(i2c, mcu_ids);

static struct i2c_driver mcu_driver = {
	.driver = {
		.name = "mcu-mpc8349emitx",
		.owner = THIS_MODULE,
	},
	.probe = mcu_probe,
	.remove	= __devexit_p(mcu_remove),
	.id_table = mcu_ids,
};

static int __init mcu_init(void)
{
	return i2c_add_driver(&mcu_driver);
}
module_init(mcu_init);

static void __exit mcu_exit(void)
{
	i2c_del_driver(&mcu_driver);
}
module_exit(mcu_exit);

MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
		   "MPC8349E-mITX-compatible MCU");
MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
d6c3db83 AV	1	/*
	2	* Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
	3	*
	4	* Copyright (c) 2008 MontaVista Software, Inc.
	5	*
	6	* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
	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 as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*/
	13
	14	#include <linux/init.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/device.h>
	18	#include <linux/mutex.h>
	19	#include <linux/i2c.h>
	20	#include <linux/gpio.h>
	21	#include <linux/of.h>
	22	#include <linux/of_gpio.h>
5a0e3ad6	23	#include <linux/slab.h>
d6c3db83 AV	24	#include <asm/prom.h>
	25	#include <asm/machdep.h>
	26
	27	/*
	28	* I don't have specifications for the MCU firmware, I found this register
	29	* and bits positions by the trial&error method.
	30	*/
	31	#define MCU_REG_CTRL 0x20
	32	#define MCU_CTRL_POFF 0x40
	33
	34	#define MCU_NUM_GPIO 2
	35
	36	struct mcu {
	37	struct mutex lock;
	38	struct device_node *np;
	39	struct i2c_client *client;
a19e3da5	40	struct gpio_chip gc;
d6c3db83 AV	41	u8 reg_ctrl;
	42	};
	43
	44	static struct mcu *glob_mcu;
	45
	46	static void mcu_power_off(void)
	47	{
	48	struct mcu *mcu = glob_mcu;
	49
	50	pr_info("Sending power-off request to the MCU...\n");
	51	mutex_lock(&mcu->lock);
	52	i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
	53	mcu->reg_ctrl \| MCU_CTRL_POFF);
	54	mutex_unlock(&mcu->lock);
	55	}
	56
	57	static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
	58	{
a19e3da5	59	struct mcu *mcu = container_of(gc, struct mcu, gc);
d6c3db83 AV	60	u8 bit = 1 << (4 + gpio);
	61
	62	mutex_lock(&mcu->lock);
	63	if (val)
	64	mcu->reg_ctrl &= ~bit;
	65	else
	66	mcu->reg_ctrl \|= bit;
	67
	68	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
	69	mutex_unlock(&mcu->lock);
	70	}
	71
	72	static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
	73	{
	74	mcu_gpio_set(gc, gpio, val);
	75	return 0;
	76	}
	77
	78	static int mcu_gpiochip_add(struct mcu *mcu)
	79	{
	80	struct device_node *np;
a19e3da5	81	struct gpio_chip *gc = &mcu->gc;
d6c3db83 AV	82	int ret;
	83
	84	np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
	85	if (!np)
	86	return -ENODEV;
	87
	88	gc->owner = THIS_MODULE;
	89	gc->label = np->full_name;
	90	gc->can_sleep = 1;
	91	gc->ngpio = MCU_NUM_GPIO;
	92	gc->base = -1;
	93	gc->set = mcu_gpio_set;
	94	gc->direction_output = mcu_gpio_dir_out;
a19e3da5 AV	95	gc->of_gpio_n_cells = 2;
a19e3da5 AV	96	gc->of_xlate = of_gpio_simple_xlate;
d6c3db83	97
d6c3db83 AV	98	mcu->np = np;
	99
	100	/*
	101	* We don't want to lose the node, its ->data and ->full_name...
	102	* So, if succeeded, we don't put the node here.
	103	*/
	104	ret = gpiochip_add(gc);
	105	if (ret)
	106	of_node_put(np);
	107	return ret;
	108	}
	109
	110	static int mcu_gpiochip_remove(struct mcu *mcu)
	111	{
	112	int ret;
	113
a19e3da5	114	ret = gpiochip_remove(&mcu->gc);
d6c3db83 AV	115	if (ret)
	116	return ret;
	117	of_node_put(mcu->np);
	118
	119	return 0;
	120	}
	121
	122	static int __devinit mcu_probe(struct i2c_client *client,
	123	const struct i2c_device_id *id)
	124	{
	125	struct mcu *mcu;
	126	int ret;
	127
	128	mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
	129	if (!mcu)
	130	return -ENOMEM;
	131
	132	mutex_init(&mcu->lock);
	133	mcu->client = client;
	134	i2c_set_clientdata(client, mcu);
	135
	136	ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
	137	if (ret < 0)
	138	goto err;
	139	mcu->reg_ctrl = ret;
	140
	141	ret = mcu_gpiochip_add(mcu);
	142	if (ret)
	143	goto err;
	144
	145	/* XXX: this is potentially racy, but there is no lock for ppc_md */
	146	if (!ppc_md.power_off) {
	147	glob_mcu = mcu;
	148	ppc_md.power_off = mcu_power_off;
	149	dev_info(&client->dev, "will provide power-off service\n");
	150	}
	151
	152	return 0;
	153	err:
	154	kfree(mcu);
	155	return ret;
	156	}
	157
	158	static int __devexit mcu_remove(struct i2c_client *client)
	159	{
	160	struct mcu *mcu = i2c_get_clientdata(client);
	161	int ret;
	162
	163	if (glob_mcu == mcu) {
	164	ppc_md.power_off = NULL;
	165	glob_mcu = NULL;
	166	}
	167
	168	ret = mcu_gpiochip_remove(mcu);
	169	if (ret)
	170	return ret;
	171	i2c_set_clientdata(client, NULL);
	172	kfree(mcu);
	173	return 0;
	174	}
	175
	176	static const struct i2c_device_id mcu_ids[] = {
	177	{ "mcu-mpc8349emitx", },
	178	{},
179	};
180	MODULE_DEVICE_TABLE(i2c, mcu_ids);
181
182	static struct i2c_driver mcu_driver = {
183	.driver = {
184	.name = "mcu-mpc8349emitx",
185	.owner = THIS_MODULE,
186	},
187	.probe = mcu_probe,
188	.remove = __devexit_p(mcu_remove),
189	.id_table = mcu_ids,
190	};
191
192	static int __init mcu_init(void)
193	{
194	return i2c_add_driver(&mcu_driver);
195	}
196	module_init(mcu_init);
197
198	static void __exit mcu_exit(void)
199	{
200	i2c_del_driver(&mcu_driver);
201	}
202	module_exit(mcu_exit);
203
204	MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
205	"MPC8349E-mITX-compatible MCU");
206	MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
207	MODULE_LICENSE("GPL");