drivers/mfd/wm831x-i2c.c

   1 /*
   2  * wm831x-i2c.c  --  I2C access for Wolfson WM831x PMICs
   3  *
   4  * Copyright 2009,2010 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   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  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/i2c.h>
  18 #include <linux/delay.h>
  19 #include <linux/mfd/core.h>
  20 #include <linux/slab.h>
  21
  22 #include <linux/mfd/wm831x/core.h>
  23 #include <linux/mfd/wm831x/pdata.h>
  24
  25 static int wm831x_i2c_read_device(struct wm831x *wm831x, unsigned short reg,
  26                                   int bytes, void *dest)
  27 {
  28         struct i2c_client *i2c = wm831x->control_data;
  29         int ret;
  30         u16 r = cpu_to_be16(reg);
  31
  32         ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
  33         if (ret < 0)
  34                 return ret;
  35         if (ret != 2)
  36                 return -EIO;
  37
  38         ret = i2c_master_recv(i2c, dest, bytes);
  39         if (ret < 0)
  40                 return ret;
  41         if (ret != bytes)
  42                 return -EIO;
  43         return 0;
  44 }
  45
  46 /* Currently we allocate the write buffer on the stack; this is OK for
  47  * small writes - if we need to do large writes this will need to be
  48  * revised.
  49  */
  50 static int wm831x_i2c_write_device(struct wm831x *wm831x, unsigned short reg,
  51                                    int bytes, void *src)
  52 {
  53         struct i2c_client *i2c = wm831x->control_data;
  54         unsigned char msg[bytes + 2];
  55         int ret;
  56
  57         reg = cpu_to_be16(reg);
  58         memcpy(&msg[0], &reg, 2);
  59         memcpy(&msg[2], src, bytes);
  60
  61         ret = i2c_master_send(i2c, msg, bytes + 2);
  62         if (ret < 0)
  63                 return ret;
  64         if (ret < bytes + 2)
  65                 return -EIO;
  66
  67         return 0;
  68 }
  69
  70 static int wm831x_i2c_probe(struct i2c_client *i2c,
  71                             const struct i2c_device_id *id)
  72 {
  73         struct wm831x *wm831x;
  74
  75         wm831x = kzalloc(sizeof(struct wm831x), GFP_KERNEL);
  76         if (wm831x == NULL)
  77                 return -ENOMEM;
  78
  79         i2c_set_clientdata(i2c, wm831x);
  80         wm831x->dev = &i2c->dev;
  81         wm831x->control_data = i2c;
  82         wm831x->read_dev = wm831x_i2c_read_device;
  83         wm831x->write_dev = wm831x_i2c_write_device;
  84
  85         return wm831x_device_init(wm831x, id->driver_data, i2c->irq);
  86 }
  87
  88 static int wm831x_i2c_remove(struct i2c_client *i2c)
  89 {
  90         struct wm831x *wm831x = i2c_get_clientdata(i2c);
  91
  92         wm831x_device_exit(wm831x);
  93
  94         return 0;
  95 }
  96
  97 static int wm831x_i2c_suspend(struct i2c_client *i2c, pm_message_t mesg)
  98 {
  99         struct wm831x *wm831x = i2c_get_clientdata(i2c);
 100
 101         return wm831x_device_suspend(wm831x);
 102 }
 103
 104 static const struct i2c_device_id wm831x_i2c_id[] = {
 105         { "wm8310", WM8310 },
 106         { "wm8311", WM8311 },
 107         { "wm8312", WM8312 },
 108         { "wm8320", WM8320 },
 109         { "wm8321", WM8321 },
 110         { "wm8325", WM8325 },
 111         { }
 112 };
 113 MODULE_DEVICE_TABLE(i2c, wm831x_i2c_id);
 114
 115
 116 static struct i2c_driver wm831x_i2c_driver = {
 117         .driver = {
 118                    .name = "wm831x",
 119                    .owner = THIS_MODULE,
 120         },
 121         .probe = wm831x_i2c_probe,
 122         .remove = wm831x_i2c_remove,
 123         .suspend = wm831x_i2c_suspend,
 124         .id_table = wm831x_i2c_id,
 125 };
 126
 127 static int __init wm831x_i2c_init(void)
 128 {
 129         int ret;
 130
 131         ret = i2c_add_driver(&wm831x_i2c_driver);
 132         if (ret != 0)
 133                 pr_err("Failed to register wm831x I2C driver: %d\n", ret);
 134
 135         return ret;
 136 }
 137 subsys_initcall(wm831x_i2c_init);
 138
 139 static void __exit wm831x_i2c_exit(void)
 140 {
 141         i2c_del_driver(&wm831x_i2c_driver);
 142 }
 143 module_exit(wm831x_i2c_exit);