1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Apple Motion Sensor driver (I2C variant)
4 *
5 * Copyright (C) 2005 Stelian Pop (stelian@popies.net)
6 * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
7 *
8 * Clean room implementation based on the reverse engineered Mac OS X driver by
9 * Johannes Berg <johannes@sipsolutions.net>, documentation available at
10 * http://johannes.sipsolutions.net/PowerBook/Apple_Motion_Sensor_Specification
11 */
12
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/delay.h>
18
19 #include "ams.h"
20
21 /* AMS registers */
22 #define AMS_COMMAND 0x00 /* command register */
23 #define AMS_STATUS 0x01 /* status register */
24 #define AMS_CTRL1 0x02 /* read control 1 (number of values) */
25 #define AMS_CTRL2 0x03 /* read control 2 (offset?) */
26 #define AMS_CTRL3 0x04 /* read control 3 (size of each value?) */
27 #define AMS_DATA1 0x05 /* read data 1 */
28 #define AMS_DATA2 0x06 /* read data 2 */
29 #define AMS_DATA3 0x07 /* read data 3 */
30 #define AMS_DATA4 0x08 /* read data 4 */
31 #define AMS_DATAX 0x20 /* data X */
32 #define AMS_DATAY 0x21 /* data Y */
33 #define AMS_DATAZ 0x22 /* data Z */
34 #define AMS_FREEFALL 0x24 /* freefall int control */
35 #define AMS_SHOCK 0x25 /* shock int control */
36 #define AMS_SENSLOW 0x26 /* sensitivity low limit */
37 #define AMS_SENSHIGH 0x27 /* sensitivity high limit */
38 #define AMS_CTRLX 0x28 /* control X */
39 #define AMS_CTRLY 0x29 /* control Y */
40 #define AMS_CTRLZ 0x2A /* control Z */
41 #define AMS_UNKNOWN1 0x2B /* unknown 1 */
42 #define AMS_UNKNOWN2 0x2C /* unknown 2 */
43 #define AMS_UNKNOWN3 0x2D /* unknown 3 */
44 #define AMS_VENDOR 0x2E /* vendor */
45
46 /* AMS commands - use with the AMS_COMMAND register */
47 enum ams_i2c_cmd {
48 AMS_CMD_NOOP = 0,
49 AMS_CMD_VERSION,
50 AMS_CMD_READMEM,
51 AMS_CMD_WRITEMEM,
52 AMS_CMD_ERASEMEM,
53 AMS_CMD_READEE,
54 AMS_CMD_WRITEEE,
55 AMS_CMD_RESET,
56 AMS_CMD_START,
57 };
58
59 static int ams_i2c_probe(struct i2c_client *client);
60 static void ams_i2c_remove(struct i2c_client *client);
61
62 static const struct i2c_device_id ams_id[] = {
63 { "MAC,accelerometer_1", 0 },
64 { }
65 };
66 MODULE_DEVICE_TABLE(i2c, ams_id);
67
68 static struct i2c_driver ams_i2c_driver = {
69 .driver = {
70 .name = "ams",
71 },
72 .probe = ams_i2c_probe,
73 .remove = ams_i2c_remove,
74 .id_table = ams_id,
75 };
76
ams_i2c_read(u8 reg)77 static s32 ams_i2c_read(u8 reg)
78 {
79 return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
80 }
81
ams_i2c_write(u8 reg,u8 value)82 static int ams_i2c_write(u8 reg, u8 value)
83 {
84 return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
85 }
86
ams_i2c_cmd(enum ams_i2c_cmd cmd)87 static int ams_i2c_cmd(enum ams_i2c_cmd cmd)
88 {
89 s32 result;
90 int count = 3;
91
92 ams_i2c_write(AMS_COMMAND, cmd);
93 msleep(5);
94
95 while (count--) {
96 result = ams_i2c_read(AMS_COMMAND);
97 if (result == 0 || result & 0x80)
98 return 0;
99
100 schedule_timeout_uninterruptible(HZ / 20);
101 }
102
103 return -1;
104 }
105
ams_i2c_set_irq(enum ams_irq reg,char enable)106 static void ams_i2c_set_irq(enum ams_irq reg, char enable)
107 {
108 if (reg & AMS_IRQ_FREEFALL) {
109 u8 val = ams_i2c_read(AMS_CTRLX);
110 if (enable)
111 val |= 0x80;
112 else
113 val &= ~0x80;
114 ams_i2c_write(AMS_CTRLX, val);
115 }
116
117 if (reg & AMS_IRQ_SHOCK) {
118 u8 val = ams_i2c_read(AMS_CTRLY);
119 if (enable)
120 val |= 0x80;
121 else
122 val &= ~0x80;
123 ams_i2c_write(AMS_CTRLY, val);
124 }
125
126 if (reg & AMS_IRQ_GLOBAL) {
127 u8 val = ams_i2c_read(AMS_CTRLZ);
128 if (enable)
129 val |= 0x80;
130 else
131 val &= ~0x80;
132 ams_i2c_write(AMS_CTRLZ, val);
133 }
134 }
135
ams_i2c_clear_irq(enum ams_irq reg)136 static void ams_i2c_clear_irq(enum ams_irq reg)
137 {
138 if (reg & AMS_IRQ_FREEFALL)
139 ams_i2c_write(AMS_FREEFALL, 0);
140
141 if (reg & AMS_IRQ_SHOCK)
142 ams_i2c_write(AMS_SHOCK, 0);
143 }
144
ams_i2c_get_vendor(void)145 static u8 ams_i2c_get_vendor(void)
146 {
147 return ams_i2c_read(AMS_VENDOR);
148 }
149
ams_i2c_get_xyz(s8 * x,s8 * y,s8 * z)150 static void ams_i2c_get_xyz(s8 *x, s8 *y, s8 *z)
151 {
152 *x = ams_i2c_read(AMS_DATAX);
153 *y = ams_i2c_read(AMS_DATAY);
154 *z = ams_i2c_read(AMS_DATAZ);
155 }
156
ams_i2c_probe(struct i2c_client * client)157 static int ams_i2c_probe(struct i2c_client *client)
158 {
159 int vmaj, vmin;
160 int result;
161
162 /* There can be only one */
163 if (unlikely(ams_info.has_device))
164 return -ENODEV;
165
166 ams_info.i2c_client = client;
167
168 if (ams_i2c_cmd(AMS_CMD_RESET)) {
169 printk(KERN_INFO "ams: Failed to reset the device\n");
170 return -ENODEV;
171 }
172
173 if (ams_i2c_cmd(AMS_CMD_START)) {
174 printk(KERN_INFO "ams: Failed to start the device\n");
175 return -ENODEV;
176 }
177
178 /* get version/vendor information */
179 ams_i2c_write(AMS_CTRL1, 0x02);
180 ams_i2c_write(AMS_CTRL2, 0x85);
181 ams_i2c_write(AMS_CTRL3, 0x01);
182
183 ams_i2c_cmd(AMS_CMD_READMEM);
184
185 vmaj = ams_i2c_read(AMS_DATA1);
186 vmin = ams_i2c_read(AMS_DATA2);
187 if (vmaj != 1 || vmin != 52) {
188 printk(KERN_INFO "ams: Incorrect device version (%d.%d)\n",
189 vmaj, vmin);
190 return -ENODEV;
191 }
192
193 ams_i2c_cmd(AMS_CMD_VERSION);
194
195 vmaj = ams_i2c_read(AMS_DATA1);
196 vmin = ams_i2c_read(AMS_DATA2);
197 if (vmaj != 0 || vmin != 1) {
198 printk(KERN_INFO "ams: Incorrect firmware version (%d.%d)\n",
199 vmaj, vmin);
200 return -ENODEV;
201 }
202
203 /* Disable interrupts */
204 ams_i2c_set_irq(AMS_IRQ_ALL, 0);
205
206 result = ams_sensor_attach();
207 if (result < 0)
208 return result;
209
210 /* Set default values */
211 ams_i2c_write(AMS_SENSLOW, 0x15);
212 ams_i2c_write(AMS_SENSHIGH, 0x60);
213 ams_i2c_write(AMS_CTRLX, 0x08);
214 ams_i2c_write(AMS_CTRLY, 0x0F);
215 ams_i2c_write(AMS_CTRLZ, 0x4F);
216 ams_i2c_write(AMS_UNKNOWN1, 0x14);
217
218 /* Clear interrupts */
219 ams_i2c_clear_irq(AMS_IRQ_ALL);
220
221 ams_info.has_device = 1;
222
223 /* Enable interrupts */
224 ams_i2c_set_irq(AMS_IRQ_ALL, 1);
225
226 printk(KERN_INFO "ams: Found I2C based motion sensor\n");
227
228 return 0;
229 }
230
ams_i2c_remove(struct i2c_client * client)231 static void ams_i2c_remove(struct i2c_client *client)
232 {
233 if (ams_info.has_device) {
234 ams_sensor_detach();
235
236 /* Disable interrupts */
237 ams_i2c_set_irq(AMS_IRQ_ALL, 0);
238
239 /* Clear interrupts */
240 ams_i2c_clear_irq(AMS_IRQ_ALL);
241
242 printk(KERN_INFO "ams: Unloading\n");
243
244 ams_info.has_device = 0;
245 }
246 }
247
ams_i2c_exit(void)248 static void ams_i2c_exit(void)
249 {
250 i2c_del_driver(&ams_i2c_driver);
251 }
252
ams_i2c_init(struct device_node * np)253 int __init ams_i2c_init(struct device_node *np)
254 {
255 /* Set implementation stuff */
256 ams_info.of_node = np;
257 ams_info.exit = ams_i2c_exit;
258 ams_info.get_vendor = ams_i2c_get_vendor;
259 ams_info.get_xyz = ams_i2c_get_xyz;
260 ams_info.clear_irq = ams_i2c_clear_irq;
261 ams_info.bustype = BUS_I2C;
262
263 return i2c_add_driver(&ams_i2c_driver);
264 }
265