/*
* 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 <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 of_gpio_chip of_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 of_gpio_chip *of_gc = to_of_gpio_chip(gc);
struct mcu *mcu = container_of(of_gc, struct mcu, of_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 of_gpio_chip *of_gc = &mcu->of_gc;
struct gpio_chip *gc = &of_gc->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;
of_gc->gpio_cells = 2;
of_gc->xlate = of_gpio_simple_xlate;
np->data = of_gc;
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->of_gc.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");
