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 */
47enum 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
59static int ams_i2c_probe(struct i2c_client *client);
60static void ams_i2c_remove(struct i2c_client *client);
61
62static const struct i2c_device_id ams_id[] = {
63	{ "MAC,accelerometer_1", 0 },
64	{ }
65};
66MODULE_DEVICE_TABLE(i2c, ams_id);
67
68static 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
77static s32 ams_i2c_read(u8 reg)
78{
79	return i2c_smbus_read_byte_data(ams_info.i2c_client, reg);
80}
81
82static int ams_i2c_write(u8 reg, u8 value)
83{
84	return i2c_smbus_write_byte_data(ams_info.i2c_client, reg, value);
85}
86
87static 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
106static 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
136static 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
145static u8 ams_i2c_get_vendor(void)
146{
147	return ams_i2c_read(AMS_VENDOR);
148}
149
150static 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
157static 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
231static 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
248static void ams_i2c_exit(void)
249{
250	i2c_del_driver(&ams_i2c_driver);
251}
252
253int __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