xref: /openbmc/linux/drivers/macintosh/ams/ams-i2c.c (revision 2612e3bbc0386368a850140a6c9b990cd496a5ec)
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