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 <asm/prom.h> 24 #include <asm/machdep.h> 25 26 /* 27 * I don't have specifications for the MCU firmware, I found this register 28 * and bits positions by the trial&error method. 29 */ 30 #define MCU_REG_CTRL 0x20 31 #define MCU_CTRL_POFF 0x40 32 33 #define MCU_NUM_GPIO 2 34 35 struct mcu { 36 struct mutex lock; 37 struct device_node *np; 38 struct i2c_client *client; 39 struct of_gpio_chip of_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 of_gpio_chip *of_gc = to_of_gpio_chip(gc); 59 struct mcu *mcu = container_of(of_gc, struct mcu, of_gc); 60 u8 bit = 1 << (4 + gpio); 61 62 mutex_lock(&mcu->lock); 63 if (val) 64 mcu->reg_ctrl &= ~bit; 65 else 66 mcu->reg_ctrl |= bit; 67 68 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl); 69 mutex_unlock(&mcu->lock); 70 } 71 72 static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) 73 { 74 mcu_gpio_set(gc, gpio, val); 75 return 0; 76 } 77 78 static int mcu_gpiochip_add(struct mcu *mcu) 79 { 80 struct device_node *np; 81 struct of_gpio_chip *of_gc = &mcu->of_gc; 82 struct gpio_chip *gc = &of_gc->gc; 83 int ret; 84 85 np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx"); 86 if (!np) 87 return -ENODEV; 88 89 gc->owner = THIS_MODULE; 90 gc->label = np->full_name; 91 gc->can_sleep = 1; 92 gc->ngpio = MCU_NUM_GPIO; 93 gc->base = -1; 94 gc->set = mcu_gpio_set; 95 gc->direction_output = mcu_gpio_dir_out; 96 of_gc->gpio_cells = 2; 97 of_gc->xlate = of_gpio_simple_xlate; 98 99 np->data = of_gc; 100 mcu->np = np; 101 102 /* 103 * We don't want to lose the node, its ->data and ->full_name... 104 * So, if succeeded, we don't put the node here. 105 */ 106 ret = gpiochip_add(gc); 107 if (ret) 108 of_node_put(np); 109 return ret; 110 } 111 112 static int mcu_gpiochip_remove(struct mcu *mcu) 113 { 114 int ret; 115 116 ret = gpiochip_remove(&mcu->of_gc.gc); 117 if (ret) 118 return ret; 119 of_node_put(mcu->np); 120 121 return 0; 122 } 123 124 static int __devinit mcu_probe(struct i2c_client *client, 125 const struct i2c_device_id *id) 126 { 127 struct mcu *mcu; 128 int ret; 129 130 mcu = kzalloc(sizeof(*mcu), GFP_KERNEL); 131 if (!mcu) 132 return -ENOMEM; 133 134 mutex_init(&mcu->lock); 135 mcu->client = client; 136 i2c_set_clientdata(client, mcu); 137 138 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL); 139 if (ret < 0) 140 goto err; 141 mcu->reg_ctrl = ret; 142 143 ret = mcu_gpiochip_add(mcu); 144 if (ret) 145 goto err; 146 147 /* XXX: this is potentially racy, but there is no lock for ppc_md */ 148 if (!ppc_md.power_off) { 149 glob_mcu = mcu; 150 ppc_md.power_off = mcu_power_off; 151 dev_info(&client->dev, "will provide power-off service\n"); 152 } 153 154 return 0; 155 err: 156 kfree(mcu); 157 return ret; 158 } 159 160 static int __devexit mcu_remove(struct i2c_client *client) 161 { 162 struct mcu *mcu = i2c_get_clientdata(client); 163 int ret; 164 165 if (glob_mcu == mcu) { 166 ppc_md.power_off = NULL; 167 glob_mcu = NULL; 168 } 169 170 ret = mcu_gpiochip_remove(mcu); 171 if (ret) 172 return ret; 173 i2c_set_clientdata(client, NULL); 174 kfree(mcu); 175 return 0; 176 } 177 178 static const struct i2c_device_id mcu_ids[] = { 179 { "mcu-mpc8349emitx", }, 180 {}, 181 }; 182 MODULE_DEVICE_TABLE(i2c, mcu_ids); 183 184 static struct i2c_driver mcu_driver = { 185 .driver = { 186 .name = "mcu-mpc8349emitx", 187 .owner = THIS_MODULE, 188 }, 189 .probe = mcu_probe, 190 .remove = __devexit_p(mcu_remove), 191 .id_table = mcu_ids, 192 }; 193 194 static int __init mcu_init(void) 195 { 196 return i2c_add_driver(&mcu_driver); 197 } 198 module_init(mcu_init); 199 200 static void __exit mcu_exit(void) 201 { 202 i2c_del_driver(&mcu_driver); 203 } 204 module_exit(mcu_exit); 205 206 MODULE_DESCRIPTION("Power Management and GPIO expander driver for " 207 "MPC8349E-mITX-compatible MCU"); 208 MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>"); 209 MODULE_LICENSE("GPL"); 210