drivers/mfd/max8925-i2c.c

   1 /*
   2  * I2C driver for Maxim MAX8925
   3  *
   4  * Copyright (C) 2009 Marvell International Ltd.
   5  *      Haojian Zhuang <haojian.zhuang@marvell.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/i2c.h>
  15 #include <linux/mfd/max8925.h>
  16 #include <linux/slab.h>
  17
  18 #define RTC_I2C_ADDR            0x68
  19 #define ADC_I2C_ADDR            0x47
  20
  21 static inline int max8925_read_device(struct i2c_client *i2c,
  22                                       int reg, int bytes, void *dest)
  23 {
  24         int ret;
  25
  26         if (bytes > 1)
  27                 ret = i2c_smbus_read_i2c_block_data(i2c, reg, bytes, dest);
  28         else {
  29                 ret = i2c_smbus_read_byte_data(i2c, reg);
  30                 if (ret < 0)
  31                         return ret;
  32                 *(unsigned char *)dest = (unsigned char)ret;
  33         }
  34         return ret;
  35 }
  36
  37 static inline int max8925_write_device(struct i2c_client *i2c,
  38                                        int reg, int bytes, void *src)
  39 {
  40         unsigned char buf[bytes + 1];
  41         int ret;
  42
  43         buf[0] = (unsigned char)reg;
  44         memcpy(&buf[1], src, bytes);
  45
  46         ret = i2c_master_send(i2c, buf, bytes + 1);
  47         if (ret < 0)
  48                 return ret;
  49         return 0;
  50 }
  51
  52 int max8925_reg_read(struct i2c_client *i2c, int reg)
  53 {
  54         struct max8925_chip *chip = i2c_get_clientdata(i2c);
  55         unsigned char data = 0;
  56         int ret;
  57
  58         mutex_lock(&chip->io_lock);
  59         ret = max8925_read_device(i2c, reg, 1, &data);
  60         mutex_unlock(&chip->io_lock);
  61
  62         if (ret < 0)
  63                 return ret;
  64         else
  65                 return (int)data;
  66 }
  67 EXPORT_SYMBOL(max8925_reg_read);
  68
  69 int max8925_reg_write(struct i2c_client *i2c, int reg,
  70                 unsigned char data)
  71 {
  72         struct max8925_chip *chip = i2c_get_clientdata(i2c);
  73         int ret;
  74
  75         mutex_lock(&chip->io_lock);
  76         ret = max8925_write_device(i2c, reg, 1, &data);
  77         mutex_unlock(&chip->io_lock);
  78
  79         return ret;
  80 }
  81 EXPORT_SYMBOL(max8925_reg_write);
  82
  83 int max8925_bulk_read(struct i2c_client *i2c, int reg,
  84                 int count, unsigned char *buf)
  85 {
  86         struct max8925_chip *chip = i2c_get_clientdata(i2c);
  87         int ret;
  88
  89         mutex_lock(&chip->io_lock);
  90         ret = max8925_read_device(i2c, reg, count, buf);
  91         mutex_unlock(&chip->io_lock);
  92
  93         return ret;
  94 }
  95 EXPORT_SYMBOL(max8925_bulk_read);
  96
  97 int max8925_bulk_write(struct i2c_client *i2c, int reg,
  98                 int count, unsigned char *buf)
  99 {
 100         struct max8925_chip *chip = i2c_get_clientdata(i2c);
 101         int ret;
 102
 103         mutex_lock(&chip->io_lock);
 104         ret = max8925_write_device(i2c, reg, count, buf);
 105         mutex_unlock(&chip->io_lock);
 106
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(max8925_bulk_write);
 110
 111 int max8925_set_bits(struct i2c_client *i2c, int reg,
 112                 unsigned char mask, unsigned char data)
 113 {
 114         struct max8925_chip *chip = i2c_get_clientdata(i2c);
 115         unsigned char value;
 116         int ret;
 117
 118         mutex_lock(&chip->io_lock);
 119         ret = max8925_read_device(i2c, reg, 1, &value);
 120         if (ret < 0)
 121                 goto out;
 122         value &= ~mask;
 123         value |= data;
 124         ret = max8925_write_device(i2c, reg, 1, &value);
 125 out:
 126         mutex_unlock(&chip->io_lock);
 127         return ret;
 128 }
 129 EXPORT_SYMBOL(max8925_set_bits);
 130
 131
 132 static const struct i2c_device_id max8925_id_table[] = {
 133         { "max8925", 0 },
 134         { },
 135 };
 136 MODULE_DEVICE_TABLE(i2c, max8925_id_table);
 137
 138 static int __devinit max8925_probe(struct i2c_client *client,
 139                                    const struct i2c_device_id *id)
 140 {
 141         struct max8925_platform_data *pdata = client->dev.platform_data;
 142         static struct max8925_chip *chip;
 143
 144         if (!pdata) {
 145                 pr_info("%s: platform data is missing\n", __func__);
 146                 return -EINVAL;
 147         }
 148
 149         chip = kzalloc(sizeof(struct max8925_chip), GFP_KERNEL);
 150         if (chip == NULL)
 151                 return -ENOMEM;
 152         chip->i2c = client;
 153         chip->dev = &client->dev;
 154         i2c_set_clientdata(client, chip);
 155         dev_set_drvdata(chip->dev, chip);
 156         mutex_init(&chip->io_lock);
 157
 158         chip->rtc = i2c_new_dummy(chip->i2c->adapter, RTC_I2C_ADDR);
 159         i2c_set_clientdata(chip->rtc, chip);
 160
 161         chip->adc = i2c_new_dummy(chip->i2c->adapter, ADC_I2C_ADDR);
 162         i2c_set_clientdata(chip->adc, chip);
 163
 164         max8925_device_init(chip, pdata);
 165
 166         return 0;
 167 }
 168
 169 static int __devexit max8925_remove(struct i2c_client *client)
 170 {
 171         struct max8925_chip *chip = i2c_get_clientdata(client);
 172
 173         max8925_device_exit(chip);
 174         i2c_unregister_device(chip->adc);
 175         i2c_unregister_device(chip->rtc);
 176         kfree(chip);
 177         return 0;
 178 }
 179
 180 static struct i2c_driver max8925_driver = {
 181         .driver = {
 182                 .name   = "max8925",
 183                 .owner  = THIS_MODULE,
 184         },
 185         .probe          = max8925_probe,
 186         .remove         = __devexit_p(max8925_remove),
 187         .id_table       = max8925_id_table,
 188 };
 189
 190 static int __init max8925_i2c_init(void)
 191 {
 192         int ret;
 193
 194         ret = i2c_add_driver(&max8925_driver);
 195         if (ret != 0)
 196                 pr_err("Failed to register MAX8925 I2C driver: %d\n", ret);
 197         return ret;
 198 }
 199 subsys_initcall(max8925_i2c_init);
 200
 201 static void __exit max8925_i2c_exit(void)
 202 {
 203         i2c_del_driver(&max8925_driver);
 204 }
 205 module_exit(max8925_i2c_exit);
 206
 207 MODULE_DESCRIPTION("I2C Driver for Maxim 8925");
 208 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 209 MODULE_LICENSE("GPL");