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 */
51 enum 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
63 static int ams_i2c_probe(struct i2c_client *client,
64 const struct i2c_device_id *id);
65 static int ams_i2c_remove(struct i2c_client *client);
66
67 static const struct i2c_device_id ams_id[] = {
68 { "ams", 0 },
69 { }
70 };
71 MODULE_DEVICE_TABLE(i2c, ams_id);
72
73 static 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
83 static s32 ams_i2c_read(u8 reg)
84 {
85 return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
86 }
87
88 static int ams_i2c_write(u8 reg, u8 value)
89 {
90 return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
91 }
92
93 static 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
112 static 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
142 static 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
151 static u8 ams_i2c_get_vendor(void)
152 {
153 return ams_i2c_read(AMS_VENDOR);
154 }
155
156 static 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
163 static 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
238 static int ams_i2c_remove(struct i2c_client *client)
239 {
240 if (ams_info.has_device) {
241 /* Disable interrupts */
242 ams_i2c_set_irq(AMS_IRQ_ALL, 0);
243
244 /* Clear interrupts */
245 ams_i2c_clear_irq(AMS_IRQ_ALL);
246
247 printk(KERN_INFO "ams: Unloading\n");
248
249 ams_info.has_device = 0;
250 }
251
252 return 0;
253 }
254
255 static void ams_i2c_exit(void)
256 {
257 i2c_del_driver(&ams_i2c_driver);
258 }
259
260 int __init ams_i2c_init(struct device_node *np)
261 {
262 int result;
263
264 /* Set implementation stuff */
265 ams_info.of_node = np;
266 ams_info.exit = ams_i2c_exit;
267 ams_info.get_vendor = ams_i2c_get_vendor;
268 ams_info.get_xyz = ams_i2c_get_xyz;
269 ams_info.clear_irq = ams_i2c_clear_irq;
270 ams_info.bustype = BUS_I2C;
271
272 result = i2c_add_driver(&ams_i2c_driver);
273
274 return result;
275 }
276
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