| /* |
| * 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 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; |
| |
| 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; |
| gc->of_node = np; |
| |
| return gpiochip_add(gc); |
| } |
| |
| static int mcu_gpiochip_remove(struct mcu *mcu) |
| { |
| return gpiochip_remove(&mcu->gc); |
| } |
| |
| 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"); |