1/*
2 * Apple Motion Sensor driver (I2C variant)
3 *
4 * Copyright (C) 2005 Stelian Pop (stelian@popies.net)
5 * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
6 *
7 * Clean room implementation based on the reverse engineered Mac OS X driver by
8 * Johannes Berg <johannes@sipsolutions.net>, documentation available at
9 * http://johannes.sipsolutions.net/PowerBook/Apple_Motion_Sensor_Specification
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 */
16
17#include <linux/module.h>
18#include <linux/types.h>
19#include <linux/errno.h>
20#include <linux/init.h>
21#include <linux/delay.h>
22
23#include "ams.h"
24
25/* AMS registers */
26#define AMS_COMMAND	0x00	/* command register */
27#define AMS_STATUS	0x01	/* status register */
28#define AMS_CTRL1	0x02	/* read control 1 (number of values) */
29#define AMS_CTRL2	0x03	/* read control 2 (offset?) */
30#define AMS_CTRL3	0x04	/* read control 3 (size of each value?) */
31#define AMS_DATA1	0x05	/* read data 1 */
32#define AMS_DATA2	0x06	/* read data 2 */
33#define AMS_DATA3	0x07	/* read data 3 */
34#define AMS_DATA4	0x08	/* read data 4 */
35#define AMS_DATAX	0x20	/* data X */
36#define AMS_DATAY	0x21	/* data Y */
37#define AMS_DATAZ	0x22	/* data Z */
38#define AMS_FREEFALL	0x24	/* freefall int control */
39#define AMS_SHOCK	0x25	/* shock int control */
40#define AMS_SENSLOW	0x26	/* sensitivity low limit */
41#define AMS_SENSHIGH	0x27	/* sensitivity high limit */
42#define AMS_CTRLX	0x28	/* control X */
43#define AMS_CTRLY	0x29	/* control Y */
44#define AMS_CTRLZ	0x2A	/* control Z */
45#define AMS_UNKNOWN1	0x2B	/* unknown 1 */
46#define AMS_UNKNOWN2	0x2C	/* unknown 2 */
47#define AMS_UNKNOWN3	0x2D	/* unknown 3 */
48#define AMS_VENDOR	0x2E	/* vendor */
49
50/* AMS commands - use with the AMS_COMMAND register */
51enum ams_i2c_cmd {
52	AMS_CMD_NOOP = 0,
53	AMS_CMD_VERSION,
54	AMS_CMD_READMEM,
55	AMS_CMD_WRITEMEM,
56	AMS_CMD_ERASEMEM,
57	AMS_CMD_READEE,
58	AMS_CMD_WRITEEE,
59	AMS_CMD_RESET,
60	AMS_CMD_START,
61};
62
63static int ams_i2c_probe(struct i2c_client *client,
64			 const struct i2c_device_id *id);
65static int ams_i2c_remove(struct i2c_client *client);
66
67static const struct i2c_device_id ams_id[] = {
68	{ "MAC,accelerometer_1", 0 },
69	{ }
70};
71MODULE_DEVICE_TABLE(i2c, ams_id);
72
73static struct i2c_driver ams_i2c_driver = {
74	.driver = {
75		.name   = "ams",
76		.owner  = THIS_MODULE,
77	},
78	.probe          = ams_i2c_probe,
79	.remove         = ams_i2c_remove,
80	.id_table       = ams_id,
81};
82
83static s32 ams_i2c_read(u8 reg)
84{
85	return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
86}
87
88static int ams_i2c_write(u8 reg, u8 value)
89{
90	return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
91}
92
93static int ams_i2c_cmd(enum ams_i2c_cmd cmd)
94{
95	s32 result;
96	int count = 3;
97
98	ams_i2c_write(AMS_COMMAND, cmd);
99	msleep(5);
100
101	while (count--) {
102		result = ams_i2c_read(AMS_COMMAND);
103		if (result == 0 || result & 0x80)
104			return 0;
105
106		schedule_timeout_uninterruptible(HZ / 20);
107	}
108
109	return -1;
110}
111
112static void ams_i2c_set_irq(enum ams_irq reg, char enable)
113{
114	if (reg & AMS_IRQ_FREEFALL) {
115		u8 val = ams_i2c_read(AMS_CTRLX);
116		if (enable)
117			val |= 0x80;
118		else
119			val &= ~0x80;
120		ams_i2c_write(AMS_CTRLX, val);
121	}
122
123	if (reg & AMS_IRQ_SHOCK) {
124		u8 val = ams_i2c_read(AMS_CTRLY);
125		if (enable)
126			val |= 0x80;
127		else
128			val &= ~0x80;
129		ams_i2c_write(AMS_CTRLY, val);
130	}
131
132	if (reg & AMS_IRQ_GLOBAL) {
133		u8 val = ams_i2c_read(AMS_CTRLZ);
134		if (enable)
135			val |= 0x80;
136		else
137			val &= ~0x80;
138		ams_i2c_write(AMS_CTRLZ, val);
139	}
140}
141
142static void ams_i2c_clear_irq(enum ams_irq reg)
143{
144	if (reg & AMS_IRQ_FREEFALL)
145		ams_i2c_write(AMS_FREEFALL, 0);
146
147	if (reg & AMS_IRQ_SHOCK)
148		ams_i2c_write(AMS_SHOCK, 0);
149}
150
151static u8 ams_i2c_get_vendor(void)
152{
153	return ams_i2c_read(AMS_VENDOR);
154}
155
156static void ams_i2c_get_xyz(s8 *x, s8 *y, s8 *z)
157{
158	*x = ams_i2c_read(AMS_DATAX);
159	*y = ams_i2c_read(AMS_DATAY);
160	*z = ams_i2c_read(AMS_DATAZ);
161}
162
163static int ams_i2c_probe(struct i2c_client *client,
164			 const struct i2c_device_id *id)
165{
166	int vmaj, vmin;
167	int result;
168
169	/* There can be only one */
170	if (unlikely(ams_info.has_device))
171		return -ENODEV;
172
173	ams_info.i2c_client = client;
174
175	if (ams_i2c_cmd(AMS_CMD_RESET)) {
176		printk(KERN_INFO "ams: Failed to reset the device\n");
177		return -ENODEV;
178	}
179
180	if (ams_i2c_cmd(AMS_CMD_START)) {
181		printk(KERN_INFO "ams: Failed to start the device\n");
182		return -ENODEV;
183	}
184
185	/* get version/vendor information */
186	ams_i2c_write(AMS_CTRL1, 0x02);
187	ams_i2c_write(AMS_CTRL2, 0x85);
188	ams_i2c_write(AMS_CTRL3, 0x01);
189
190	ams_i2c_cmd(AMS_CMD_READMEM);
191
192	vmaj = ams_i2c_read(AMS_DATA1);
193	vmin = ams_i2c_read(AMS_DATA2);
194	if (vmaj != 1 || vmin != 52) {
195		printk(KERN_INFO "ams: Incorrect device version (%d.%d)\n",
196			vmaj, vmin);
197		return -ENODEV;
198	}
199
200	ams_i2c_cmd(AMS_CMD_VERSION);
201
202	vmaj = ams_i2c_read(AMS_DATA1);
203	vmin = ams_i2c_read(AMS_DATA2);
204	if (vmaj != 0 || vmin != 1) {
205		printk(KERN_INFO "ams: Incorrect firmware version (%d.%d)\n",
206			vmaj, vmin);
207		return -ENODEV;
208	}
209
210	/* Disable interrupts */
211	ams_i2c_set_irq(AMS_IRQ_ALL, 0);
212
213	result = ams_sensor_attach();
214	if (result < 0)
215		return result;
216
217	/* Set default values */
218	ams_i2c_write(AMS_SENSLOW, 0x15);
219	ams_i2c_write(AMS_SENSHIGH, 0x60);
220	ams_i2c_write(AMS_CTRLX, 0x08);
221	ams_i2c_write(AMS_CTRLY, 0x0F);
222	ams_i2c_write(AMS_CTRLZ, 0x4F);
223	ams_i2c_write(AMS_UNKNOWN1, 0x14);
224
225	/* Clear interrupts */
226	ams_i2c_clear_irq(AMS_IRQ_ALL);
227
228	ams_info.has_device = 1;
229
230	/* Enable interrupts */
231	ams_i2c_set_irq(AMS_IRQ_ALL, 1);
232
233	printk(KERN_INFO "ams: Found I2C based motion sensor\n");
234
235	return 0;
236}
237
238static int ams_i2c_remove(struct i2c_client *client)
239{
240	if (ams_info.has_device) {
241		ams_sensor_detach();
242
243		/* Disable interrupts */
244		ams_i2c_set_irq(AMS_IRQ_ALL, 0);
245
246		/* Clear interrupts */
247		ams_i2c_clear_irq(AMS_IRQ_ALL);
248
249		printk(KERN_INFO "ams: Unloading\n");
250
251		ams_info.has_device = 0;
252	}
253
254	return 0;
255}
256
257static void ams_i2c_exit(void)
258{
259	i2c_del_driver(&ams_i2c_driver);
260}
261
262int __init ams_i2c_init(struct device_node *np)
263{
264	int result;
265
266	/* Set implementation stuff */
267	ams_info.of_node = np;
268	ams_info.exit = ams_i2c_exit;
269	ams_info.get_vendor = ams_i2c_get_vendor;
270	ams_info.get_xyz = ams_i2c_get_xyz;
271	ams_info.clear_irq = ams_i2c_clear_irq;
272	ams_info.bustype = BUS_I2C;
273
274	result = i2c_add_driver(&ams_i2c_driver);
275
276	return result;
277}
278