2 * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
4 * Copyright (c) 2008 MontaVista Software, Inc.
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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.
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>
22 #include <linux/of_gpio.h>
23 #include <linux/slab.h>
25 #include <asm/machdep.h>
28 * I don't have specifications for the MCU firmware, I found this register
29 * and bits positions by the trial&error method.
31 #define MCU_REG_CTRL 0x20
32 #define MCU_CTRL_POFF 0x40
34 #define MCU_NUM_GPIO 2
38 struct i2c_client *client;
43 static struct mcu *glob_mcu;
45 static void mcu_power_off(void)
47 struct mcu *mcu = glob_mcu;
49 pr_info("Sending power-off request to the MCU...\n");
50 mutex_lock(&mcu->lock);
51 i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
52 mcu->reg_ctrl | MCU_CTRL_POFF);
53 mutex_unlock(&mcu->lock);
56 static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
58 struct mcu *mcu = container_of(gc, struct mcu, gc);
59 u8 bit = 1 << (4 + gpio);
61 mutex_lock(&mcu->lock);
63 mcu->reg_ctrl &= ~bit;
67 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
68 mutex_unlock(&mcu->lock);
71 static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
73 mcu_gpio_set(gc, gpio, val);
77 static int mcu_gpiochip_add(struct mcu *mcu)
79 struct device_node *np;
80 struct gpio_chip *gc = &mcu->gc;
82 np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
86 gc->owner = THIS_MODULE;
87 gc->label = np->full_name;
89 gc->ngpio = MCU_NUM_GPIO;
91 gc->set = mcu_gpio_set;
92 gc->direction_output = mcu_gpio_dir_out;
95 return gpiochip_add(gc);
98 static int mcu_gpiochip_remove(struct mcu *mcu)
100 return gpiochip_remove(&mcu->gc);
103 static int __devinit mcu_probe(struct i2c_client *client,
104 const struct i2c_device_id *id)
109 mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
113 mutex_init(&mcu->lock);
114 mcu->client = client;
115 i2c_set_clientdata(client, mcu);
117 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
122 ret = mcu_gpiochip_add(mcu);
126 /* XXX: this is potentially racy, but there is no lock for ppc_md */
127 if (!ppc_md.power_off) {
129 ppc_md.power_off = mcu_power_off;
130 dev_info(&client->dev, "will provide power-off service\n");
139 static int __devexit mcu_remove(struct i2c_client *client)
141 struct mcu *mcu = i2c_get_clientdata(client);
144 if (glob_mcu == mcu) {
145 ppc_md.power_off = NULL;
149 ret = mcu_gpiochip_remove(mcu);
152 i2c_set_clientdata(client, NULL);
157 static const struct i2c_device_id mcu_ids[] = {
158 { "mcu-mpc8349emitx", },
161 MODULE_DEVICE_TABLE(i2c, mcu_ids);
163 static struct i2c_driver mcu_driver = {
165 .name = "mcu-mpc8349emitx",
166 .owner = THIS_MODULE,
169 .remove = __devexit_p(mcu_remove),
173 static int __init mcu_init(void)
175 return i2c_add_driver(&mcu_driver);
177 module_init(mcu_init);
179 static void __exit mcu_exit(void)
181 i2c_del_driver(&mcu_driver);
183 module_exit(mcu_exit);
185 MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
186 "MPC8349E-mITX-compatible MCU");
187 MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
188 MODULE_LICENSE("GPL");