drivers/mfd/tps65912-i2c.c

   1 /*
   2  * tps65912-i2c.c  --  I2C access for TI TPS65912x PMIC
   3  *
   4  * Copyright 2011 Texas Instruments Inc.
   5  *
   6  * Author: Margarita Olaya Cabrera <magi@slimlogic.co.uk>
   7  *
   8  *  This program is free software; you can redistribute it and/or modify it
   9  *  under  the terms of the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the License, or (at your
  11  *  option) any later version.
  12  *
  13  *  This driver is based on wm8350 implementation.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/gpio.h>
  21 #include <linux/i2c.h>
  22 #include <linux/mfd/core.h>
  23 #include <linux/mfd/tps65912.h>
  24
  25 static int tps65912_i2c_read(struct tps65912 *tps65912, u8 reg,
  26                                   int bytes, void *dest)
  27 {
  28         struct i2c_client *i2c = tps65912->control_data;
  29         struct i2c_msg xfer[2];
  30         int ret;
  31
  32         /* Write register */
  33         xfer[0].addr = i2c->addr;
  34         xfer[0].flags = 0;
  35         xfer[0].len = 1;
  36         xfer[0].buf = &reg;
  37
  38         /* Read data */
  39         xfer[1].addr = i2c->addr;
  40         xfer[1].flags = I2C_M_RD;
  41         xfer[1].len = bytes;
  42         xfer[1].buf = dest;
  43
  44         ret = i2c_transfer(i2c->adapter, xfer, 2);
  45         if (ret == 2)
  46                 ret = 0;
  47         else if (ret >= 0)
  48                 ret = -EIO;
  49         return ret;
  50 }
  51
  52 static int tps65912_i2c_write(struct tps65912 *tps65912, u8 reg,
  53                                    int bytes, void *src)
  54 {
  55         struct i2c_client *i2c = tps65912->control_data;
  56         /* we add 1 byte for device register */
  57         u8 msg[TPS6591X_MAX_REGISTER + 1];
  58         int ret;
  59
  60         if (bytes > TPS6591X_MAX_REGISTER)
  61                 return -EINVAL;
  62
  63         msg[0] = reg;
  64         memcpy(&msg[1], src, bytes);
  65
  66         ret = i2c_master_send(i2c, msg, bytes + 1);
  67         if (ret < 0)
  68                 return ret;
  69         if (ret != bytes + 1)
  70                 return -EIO;
  71
  72         return 0;
  73 }
  74
  75 static int tps65912_i2c_probe(struct i2c_client *i2c,
  76                             const struct i2c_device_id *id)
  77 {
  78         struct tps65912 *tps65912;
  79
  80         tps65912 = kzalloc(sizeof(struct tps65912), GFP_KERNEL);
  81         if (tps65912 == NULL)
  82                 return -ENOMEM;
  83
  84         i2c_set_clientdata(i2c, tps65912);
  85         tps65912->dev = &i2c->dev;
  86         tps65912->control_data = i2c;
  87         tps65912->read = tps65912_i2c_read;
  88         tps65912->write = tps65912_i2c_write;
  89
  90         return tps65912_device_init(tps65912);
  91 }
  92
  93 static int tps65912_i2c_remove(struct i2c_client *i2c)
  94 {
  95         struct tps65912 *tps65912 = i2c_get_clientdata(i2c);
  96
  97         tps65912_device_exit(tps65912);
  98
  99         return 0;
 100 }
 101
 102 static const struct i2c_device_id tps65912_i2c_id[] = {
 103         {"tps65912", 0 },
 104         { }
 105 };
 106 MODULE_DEVICE_TABLE(i2c, tps65912_i2c_id);
 107
 108 static struct i2c_driver tps65912_i2c_driver = {
 109         .driver = {
 110                    .name = "tps65912",
 111                    .owner = THIS_MODULE,
 112         },
 113         .probe = tps65912_i2c_probe,
 114         .remove = tps65912_i2c_remove,
 115         .id_table = tps65912_i2c_id,
 116 };
 117
 118 static int __init tps65912_i2c_init(void)
 119 {
 120         int ret;
 121
 122         ret = i2c_add_driver(&tps65912_i2c_driver);
 123         if (ret != 0)
 124                 pr_err("Failed to register TPS65912 I2C driver: %d\n", ret);
 125
 126         return ret;
 127 }
 128 /* init early so consumer devices can complete system boot */
 129 subsys_initcall(tps65912_i2c_init);
 130
 131 static void __exit tps65912_i2c_exit(void)
 132 {
 133         i2c_del_driver(&tps65912_i2c_driver);
 134 }
 135 module_exit(tps65912_i2c_exit);
 136
 137 MODULE_AUTHOR("Margarita Olaya  <magi@slimlogic.co.uk>");
 138 MODULE_DESCRIPTION("TPS6591x chip family multi-function driver");
 139 MODULE_LICENSE("GPL");