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> 23#include <linux/slab.h> 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 36struct mcu { 37 struct mutex lock; 38 struct i2c_client *client; 39 struct gpio_chip gc; 40 u8 reg_ctrl; 41}; 42 43static struct mcu *glob_mcu; 44 45static void mcu_power_off(void) 46{ 47 struct mcu *mcu = glob_mcu; 48 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); 54} 55 56static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) 57{ 58 struct mcu *mcu = container_of(gc, struct mcu, gc); 59 u8 bit = 1 << (4 + gpio); 60 61 mutex_lock(&mcu->lock); 62 if (val) 63 mcu->reg_ctrl &= ~bit; 64 else 65 mcu->reg_ctrl |= bit; 66 67 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl); 68 mutex_unlock(&mcu->lock); 69} 70 71static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) 72{ 73 mcu_gpio_set(gc, gpio, val); 74 return 0; 75} 76 77static int mcu_gpiochip_add(struct mcu *mcu) 78{ 79 struct device_node *np; 80 struct gpio_chip *gc = &mcu->gc; 81 82 np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx"); 83 if (!np) 84 return -ENODEV; 85 86 gc->owner = THIS_MODULE; 87 gc->label = np->full_name; 88 gc->can_sleep = 1; 89 gc->ngpio = MCU_NUM_GPIO; 90 gc->base = -1; 91 gc->set = mcu_gpio_set; 92 gc->direction_output = mcu_gpio_dir_out; 93 gc->of_node = np; 94 95 return gpiochip_add(gc); 96} 97 98static int mcu_gpiochip_remove(struct mcu *mcu) 99{ 100 return gpiochip_remove(&mcu->gc); 101} 102 103static int __devinit mcu_probe(struct i2c_client *client, 104 const struct i2c_device_id *id) 105{ 106 struct mcu *mcu; 107 int ret; 108 109 mcu = kzalloc(sizeof(*mcu), GFP_KERNEL); 110 if (!mcu) 111 return -ENOMEM; 112 113 mutex_init(&mcu->lock); 114 mcu->client = client; 115 i2c_set_clientdata(client, mcu); 116 117 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL); 118 if (ret < 0) 119 goto err; 120 mcu->reg_ctrl = ret; 121 122 ret = mcu_gpiochip_add(mcu); 123 if (ret) 124 goto err; 125 126 if (!ppc_md.power_off) { 127 glob_mcu = mcu; 128 ppc_md.power_off = mcu_power_off; 129 dev_info(&client->dev, "will provide power-off service\n"); 130 } 131 132 return 0; 133err: 134 kfree(mcu); 135 return ret; 136} 137 138static int __devexit mcu_remove(struct i2c_client *client) 139{ 140 struct mcu *mcu = i2c_get_clientdata(client); 141 int ret; 142 143 if (glob_mcu == mcu) { 144 ppc_md.power_off = NULL; 145 glob_mcu = NULL; 146 } 147 148 ret = mcu_gpiochip_remove(mcu); 149 if (ret) 150 return ret; 151 i2c_set_clientdata(client, NULL); 152 kfree(mcu); 153 return 0; 154} 155 156static const struct i2c_device_id mcu_ids[] = { 157 { "mcu-mpc8349emitx", }, 158 {}, 159}; 160MODULE_DEVICE_TABLE(i2c, mcu_ids); 161 162static struct of_device_id mcu_of_match_table[] __devinitdata = { 163 { .compatible = "fsl,mcu-mpc8349emitx", }, 164 { }, 165}; 166 167static struct i2c_driver mcu_driver = { 168 .driver = { 169 .name = "mcu-mpc8349emitx", 170 .owner = THIS_MODULE, 171 .of_match_table = mcu_of_match_table, 172 }, 173 .probe = mcu_probe, 174 .remove = __devexit_p(mcu_remove), 175 .id_table = mcu_ids, 176}; 177 178static int __init mcu_init(void) 179{ 180 return i2c_add_driver(&mcu_driver); 181} 182module_init(mcu_init); 183 184static void __exit mcu_exit(void) 185{ 186 i2c_del_driver(&mcu_driver); 187} 188module_exit(mcu_exit); 189 190MODULE_DESCRIPTION("Power Management and GPIO expander driver for " 191 "MPC8349E-mITX-compatible MCU"); 192MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>"); 193MODULE_LICENSE("GPL"); 194