/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
 25static 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 */
 50static 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	struct i2c_msg xfer[2];
 55	int ret;
 56
 57	reg = cpu_to_be16(reg);
 58
 59	xfer[0].addr = i2c->addr;
 60	xfer[0].flags = 0;
 61	xfer[0].len = 2;
 62	xfer[0].buf = (char *)&reg;
 63
 64	xfer[1].addr = i2c->addr;
 65	xfer[1].flags = I2C_M_NOSTART;
 66	xfer[1].len = bytes;
 67	xfer[1].buf = (char *)src;
 68
 69	ret = i2c_transfer(i2c->adapter, xfer, 2);
 70	if (ret < 0)
 71		return ret;
 72	if (ret != 2)
 73		return -EIO;
 74
 75	return 0;
 76}
 77
 78static int wm831x_i2c_probe(struct i2c_client *i2c,
 79			    const struct i2c_device_id *id)
 80{
 81	struct wm831x *wm831x;
 82
 83	wm831x = kzalloc(sizeof(struct wm831x), GFP_KERNEL);
 84	if (wm831x == NULL)
 85		return -ENOMEM;
 86
 87	i2c_set_clientdata(i2c, wm831x);
 88	wm831x->dev = &i2c->dev;
 89	wm831x->control_data = i2c;
 90	wm831x->read_dev = wm831x_i2c_read_device;
 91	wm831x->write_dev = wm831x_i2c_write_device;
 92
 93	return wm831x_device_init(wm831x, id->driver_data, i2c->irq);
 94}
 95
 96static int wm831x_i2c_remove(struct i2c_client *i2c)
 97{
 98	struct wm831x *wm831x = i2c_get_clientdata(i2c);
 99
100	wm831x_device_exit(wm831x);
101
102	return 0;
103}
104
105static int wm831x_i2c_suspend(struct device *dev)
106{
107	struct wm831x *wm831x = dev_get_drvdata(dev);
108
109	return wm831x_device_suspend(wm831x);
110}
111
112static const struct i2c_device_id wm831x_i2c_id[] = {
113	{ "wm8310", WM8310 },
114	{ "wm8311", WM8311 },
115	{ "wm8312", WM8312 },
116	{ "wm8320", WM8320 },
117	{ "wm8321", WM8321 },
118	{ "wm8325", WM8325 },
119	{ "wm8326", WM8326 },
120	{ }
121};
122MODULE_DEVICE_TABLE(i2c, wm831x_i2c_id);
123
124static const struct dev_pm_ops wm831x_pm_ops = {
125	.suspend = wm831x_i2c_suspend,
126};
127
128static struct i2c_driver wm831x_i2c_driver = {
129	.driver = {
130		.name = "wm831x",
131		.owner = THIS_MODULE,
132		.pm = &wm831x_pm_ops,
133	},
134	.probe = wm831x_i2c_probe,
135	.remove = wm831x_i2c_remove,
136	.id_table = wm831x_i2c_id,
137};
138
139static int __init wm831x_i2c_init(void)
140{
141	int ret;
142
143	ret = i2c_add_driver(&wm831x_i2c_driver);
144	if (ret != 0)
145		pr_err("Failed to register wm831x I2C driver: %d\n", ret);
146
147	return ret;
148}
149subsys_initcall(wm831x_i2c_init);
150
151static void __exit wm831x_i2c_exit(void)
152{
153	i2c_del_driver(&wm831x_i2c_driver);
154}
155module_exit(wm831x_i2c_exit);