1/*
2 * itg3200_core.c -- support InvenSense ITG3200
3 *                   Digital 3-Axis Gyroscope driver
4 *
5 * Copyright (c) 2011 Christian Strobel <christian.strobel@iis.fraunhofer.de>
6 * Copyright (c) 2011 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
7 * Copyright (c) 2012 Thorsten Nowak <thorsten.nowak@iis.fraunhofer.de>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * TODO:
14 * - Support digital low pass filter
15 * - Support power management
16 */
17
18#include <linux/interrupt.h>
19#include <linux/irq.h>
20#include <linux/i2c.h>
21#include <linux/gpio.h>
22#include <linux/slab.h>
23#include <linux/stat.h>
24#include <linux/module.h>
25#include <linux/delay.h>
26
27#include <linux/iio/iio.h>
28#include <linux/iio/sysfs.h>
29#include <linux/iio/events.h>
30#include <linux/iio/buffer.h>
31
32#include <linux/iio/gyro/itg3200.h>
33
34
35int itg3200_write_reg_8(struct iio_dev *indio_dev,
36		u8 reg_address, u8 val)
37{
38	struct itg3200 *st = iio_priv(indio_dev);
39
40	return i2c_smbus_write_byte_data(st->i2c, 0x80 | reg_address, val);
41}
42
43int itg3200_read_reg_8(struct iio_dev *indio_dev,
44		u8 reg_address, u8 *val)
45{
46	struct itg3200 *st = iio_priv(indio_dev);
47	int ret;
48
49	ret = i2c_smbus_read_byte_data(st->i2c, reg_address);
50	if (ret < 0)
51		return ret;
52	*val = ret;
53	return 0;
54}
55
56static int itg3200_read_reg_s16(struct iio_dev *indio_dev, u8 lower_reg_address,
57		int *val)
58{
59	struct itg3200 *st = iio_priv(indio_dev);
60	struct i2c_client *client = st->i2c;
61	int ret;
62	s16 out;
63
64	struct i2c_msg msg[2] = {
65		{
66			.addr = client->addr,
67			.flags = client->flags,
68			.len = 1,
69			.buf = (char *)&lower_reg_address,
70		},
71		{
72			.addr = client->addr,
73			.flags = client->flags | I2C_M_RD,
74			.len = 2,
75			.buf = (char *)&out,
76		},
77	};
78
79	lower_reg_address |= 0x80;
80	ret = i2c_transfer(client->adapter, msg, 2);
81	be16_to_cpus(&out);
82	*val = out;
83
84	return (ret == 2) ? 0 : ret;
85}
86
87static int itg3200_read_raw(struct iio_dev *indio_dev,
88		const struct iio_chan_spec *chan,
89		int *val, int *val2, long info)
90{
91	int ret = 0;
92	u8 reg;
93	u8 regval;
94
95	switch (info) {
96	case IIO_CHAN_INFO_RAW:
97		reg = (u8)chan->address;
98		ret = itg3200_read_reg_s16(indio_dev, reg, val);
99		return IIO_VAL_INT;
100	case IIO_CHAN_INFO_SCALE:
101		*val = 0;
102		if (chan->type == IIO_TEMP)
103			*val2 = 1000000000/280;
104		else
105			*val2 = 1214142; /* (1 / 14,375) * (PI / 180) */
106		return IIO_VAL_INT_PLUS_NANO;
107	case IIO_CHAN_INFO_OFFSET:
108		/* Only the temperature channel has an offset */
109		*val = 23000;
110		return IIO_VAL_INT;
111	case IIO_CHAN_INFO_SAMP_FREQ:
112		ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &regval);
113		if (ret)
114			return ret;
115
116		*val = (regval & ITG3200_DLPF_CFG_MASK) ? 1000 : 8000;
117
118		ret = itg3200_read_reg_8(indio_dev,
119					 ITG3200_REG_SAMPLE_RATE_DIV,
120					 &regval);
121		if (ret)
122			return ret;
123
124		*val /= regval + 1;
125		return IIO_VAL_INT;
126
127	default:
128		return -EINVAL;
129	}
130}
131
132static int itg3200_write_raw(struct iio_dev *indio_dev,
133			     struct iio_chan_spec const *chan,
134			     int val,
135			     int val2,
136			     long mask)
137{
138	int ret;
139	u8 t;
140
141	switch (mask) {
142	case IIO_CHAN_INFO_SAMP_FREQ:
143		if (val == 0 || val2 != 0)
144			return -EINVAL;
145
146		mutex_lock(&indio_dev->mlock);
147
148		ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &t);
149		if (ret) {
150			mutex_unlock(&indio_dev->mlock);
151			return ret;
152		}
153		t = ((t & ITG3200_DLPF_CFG_MASK) ? 1000u : 8000u) / val - 1;
154
155		ret = itg3200_write_reg_8(indio_dev,
156					  ITG3200_REG_SAMPLE_RATE_DIV,
157					  t);
158
159		mutex_unlock(&indio_dev->mlock);
160	return ret;
161
162	default:
163		return -EINVAL;
164	}
165}
166
167/*
168 * Reset device and internal registers to the power-up-default settings
169 * Use the gyro clock as reference, as suggested by the datasheet
170 */
171static int itg3200_reset(struct iio_dev *indio_dev)
172{
173	struct itg3200 *st = iio_priv(indio_dev);
174	int ret;
175
176	dev_dbg(&st->i2c->dev, "reset device");
177
178	ret = itg3200_write_reg_8(indio_dev,
179			ITG3200_REG_POWER_MANAGEMENT,
180			ITG3200_RESET);
181	if (ret) {
182		dev_err(&st->i2c->dev, "error resetting device");
183		goto error_ret;
184	}
185
186	/* Wait for PLL (1ms according to datasheet) */
187	udelay(1500);
188
189	ret = itg3200_write_reg_8(indio_dev,
190			ITG3200_REG_IRQ_CONFIG,
191			ITG3200_IRQ_ACTIVE_HIGH |
192			ITG3200_IRQ_PUSH_PULL |
193			ITG3200_IRQ_LATCH_50US_PULSE |
194			ITG3200_IRQ_LATCH_CLEAR_ANY);
195
196	if (ret)
197		dev_err(&st->i2c->dev, "error init device");
198
199error_ret:
200	return ret;
201}
202
203/* itg3200_enable_full_scale() - Disables the digital low pass filter */
204static int itg3200_enable_full_scale(struct iio_dev *indio_dev)
205{
206	u8 val;
207	int ret;
208
209	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
210	if (ret)
211		goto err_ret;
212
213	val |= ITG3200_DLPF_FS_SEL_2000;
214	return itg3200_write_reg_8(indio_dev, ITG3200_REG_DLPF, val);
215
216err_ret:
217	return ret;
218}
219
220static int itg3200_initial_setup(struct iio_dev *indio_dev)
221{
222	struct itg3200 *st = iio_priv(indio_dev);
223	int ret;
224	u8 val;
225
226	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_ADDRESS, &val);
227	if (ret)
228		goto err_ret;
229
230	if (((val >> 1) & 0x3f) != 0x34) {
231		dev_err(&st->i2c->dev, "invalid reg value 0x%02x", val);
232		ret = -ENXIO;
233		goto err_ret;
234	}
235
236	ret = itg3200_reset(indio_dev);
237	if (ret)
238		goto err_ret;
239
240	ret = itg3200_enable_full_scale(indio_dev);
241err_ret:
242	return ret;
243}
244
245#define ITG3200_ST						\
246	{ .sign = 's', .realbits = 16, .storagebits = 16, .endianness = IIO_BE }
247
248#define ITG3200_GYRO_CHAN(_mod) { \
249	.type = IIO_ANGL_VEL, \
250	.modified = 1, \
251	.channel2 = IIO_MOD_ ## _mod, \
252	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
253	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
254	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
255	.address = ITG3200_REG_GYRO_ ## _mod ## OUT_H, \
256	.scan_index = ITG3200_SCAN_GYRO_ ## _mod, \
257	.scan_type = ITG3200_ST, \
258}
259
260static const struct iio_chan_spec itg3200_channels[] = {
261	{
262		.type = IIO_TEMP,
263		.channel2 = IIO_NO_MOD,
264		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
265		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
266		BIT(IIO_CHAN_INFO_SCALE),
267		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
268		.address = ITG3200_REG_TEMP_OUT_H,
269		.scan_index = ITG3200_SCAN_TEMP,
270		.scan_type = ITG3200_ST,
271	},
272	ITG3200_GYRO_CHAN(X),
273	ITG3200_GYRO_CHAN(Y),
274	ITG3200_GYRO_CHAN(Z),
275	IIO_CHAN_SOFT_TIMESTAMP(ITG3200_SCAN_ELEMENTS),
276};
277
278static const struct iio_info itg3200_info = {
279	.read_raw = &itg3200_read_raw,
280	.write_raw = &itg3200_write_raw,
281	.driver_module = THIS_MODULE,
282};
283
284static const unsigned long itg3200_available_scan_masks[] = { 0xffffffff, 0x0 };
285
286static int itg3200_probe(struct i2c_client *client,
287		const struct i2c_device_id *id)
288{
289	int ret;
290	struct itg3200 *st;
291	struct iio_dev *indio_dev;
292
293	dev_dbg(&client->dev, "probe I2C dev with IRQ %i", client->irq);
294
295	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
296	if (!indio_dev)
297		return -ENOMEM;
298
299	st = iio_priv(indio_dev);
300
301	i2c_set_clientdata(client, indio_dev);
302	st->i2c = client;
303
304	indio_dev->dev.parent = &client->dev;
305	indio_dev->name = client->dev.driver->name;
306	indio_dev->channels = itg3200_channels;
307	indio_dev->num_channels = ARRAY_SIZE(itg3200_channels);
308	indio_dev->available_scan_masks = itg3200_available_scan_masks;
309	indio_dev->info = &itg3200_info;
310	indio_dev->modes = INDIO_DIRECT_MODE;
311
312	ret = itg3200_buffer_configure(indio_dev);
313	if (ret)
314		return ret;
315
316	if (client->irq) {
317		ret = itg3200_probe_trigger(indio_dev);
318		if (ret)
319			goto error_unconfigure_buffer;
320	}
321
322	ret = itg3200_initial_setup(indio_dev);
323	if (ret)
324		goto error_remove_trigger;
325
326	ret = iio_device_register(indio_dev);
327	if (ret)
328		goto error_remove_trigger;
329
330	return 0;
331
332error_remove_trigger:
333	if (client->irq)
334		itg3200_remove_trigger(indio_dev);
335error_unconfigure_buffer:
336	itg3200_buffer_unconfigure(indio_dev);
337	return ret;
338}
339
340static int itg3200_remove(struct i2c_client *client)
341{
342	struct iio_dev *indio_dev = i2c_get_clientdata(client);
343
344	iio_device_unregister(indio_dev);
345
346	if (client->irq)
347		itg3200_remove_trigger(indio_dev);
348
349	itg3200_buffer_unconfigure(indio_dev);
350
351	return 0;
352}
353
354static const struct i2c_device_id itg3200_id[] = {
355	{ "itg3200", 0 },
356	{ }
357};
358MODULE_DEVICE_TABLE(i2c, itg3200_id);
359
360static struct i2c_driver itg3200_driver = {
361	.driver = {
362		.owner  = THIS_MODULE,
363		.name	= "itg3200",
364	},
365	.id_table	= itg3200_id,
366	.probe		= itg3200_probe,
367	.remove		= itg3200_remove,
368};
369
370module_i2c_driver(itg3200_driver);
371
372MODULE_AUTHOR("Christian Strobel <christian.strobel@iis.fraunhofer.de>");
373MODULE_DESCRIPTION("ITG3200 Gyroscope I2C driver");
374MODULE_LICENSE("GPL v2");
375