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 36 struct mcu { 37 struct mutex lock; 38 struct i2c_client *client; 39 struct gpio_chip gc; 40 u8 reg_ctrl; 41 }; 42 43 static struct mcu *glob_mcu; 44 45 static 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 56 static 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 71 static 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 77 static 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 98 static int mcu_gpiochip_remove(struct mcu *mcu) 99 { 100 return gpiochip_remove(&mcu->gc); 101 } 102 103 static 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 /* XXX: this is potentially racy, but there is no lock for ppc_md */ 127 if (!ppc_md.power_off) { 128 glob_mcu = mcu; 129 ppc_md.power_off = mcu_power_off; 130 dev_info(&client->dev, "will provide power-off service\n"); 131 } 132 133 return 0; 134 err: 135 kfree(mcu); 136 return ret; 137 } 138 139 static int __devexit mcu_remove(struct i2c_client *client) 140 { 141 struct mcu *mcu = i2c_get_clientdata(client); 142 int ret; 143 144 if (glob_mcu == mcu) { 145 ppc_md.power_off = NULL; 146 glob_mcu = NULL; 147 } 148 149 ret = mcu_gpiochip_remove(mcu); 150 if (ret) 151 return ret; 152 i2c_set_clientdata(client, NULL); 153 kfree(mcu); 154 return 0; 155 } 156 157 static const struct i2c_device_id mcu_ids[] = { 158 { "mcu-mpc8349emitx", }, 159 {}, 160 }; 161 MODULE_DEVICE_TABLE(i2c, mcu_ids); 162 163 static struct of_device_id mcu_of_match_table[] __devinitdata = { 164 { .compatible = "fsl,mcu-mpc8349emitx", }, 165 { }, 166 }; 167 168 static struct i2c_driver mcu_driver = { 169 .driver = { 170 .name = "mcu-mpc8349emitx", 171 .owner = THIS_MODULE, 172 .of_match_table = mcu_of_match_table, 173 }, 174 .probe = mcu_probe, 175 .remove = __devexit_p(mcu_remove), 176 .id_table = mcu_ids, 177 }; 178 179 static int __init mcu_init(void) 180 { 181 return i2c_add_driver(&mcu_driver); 182 } 183 module_init(mcu_init); 184 185 static void __exit mcu_exit(void) 186 { 187 i2c_del_driver(&mcu_driver); 188 } 189 module_exit(mcu_exit); 190 191 MODULE_DESCRIPTION("Power Management and GPIO expander driver for " 192 "MPC8349E-mITX-compatible MCU"); 193 MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>"); 194 MODULE_LICENSE("GPL"); 195