summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/iio/accel/kxsd9.c
blob: 98ba761cbb9ce6943913c03b0a65d861e6956661 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/*
 * kxsd9.c	simple support for the Kionix KXSD9 3D
 *		accelerometer.
 *
 * Copyright (c) 2008-2009 Jonathan Cameron <jic23@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * The i2c interface is very similar, so shouldn't be a problem once
 * I have a suitable wire made up.
 *
 * TODO:	Support the motion detector
 *		Uses register address incrementing so could have a
 *		heavily optimized ring buffer access function.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define KXSD9_REG_X		0x00
#define KXSD9_REG_Y		0x02
#define KXSD9_REG_Z		0x04
#define KXSD9_REG_AUX		0x06
#define KXSD9_REG_RESET		0x0a
#define KXSD9_REG_CTRL_C	0x0c

#define KXSD9_FS_MASK		0x03

#define KXSD9_REG_CTRL_B	0x0d
#define KXSD9_REG_CTRL_A	0x0e

#define KXSD9_READ(a) (0x80 | (a))
#define KXSD9_WRITE(a) (a)

#define KXSD9_STATE_RX_SIZE 2
#define KXSD9_STATE_TX_SIZE 2
/**
 * struct kxsd9_state - device related storage
 * @buf_lock:	protect the rx and tx buffers.
 * @us:		spi device
 * @rx:		single rx buffer storage
 * @tx:		single tx buffer storage
 **/
struct kxsd9_state {
	struct mutex buf_lock;
	struct spi_device *us;
	u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
	u8 tx[KXSD9_STATE_TX_SIZE];
};

#define KXSD9_SCALE_2G "0.011978"
#define KXSD9_SCALE_4G "0.023927"
#define KXSD9_SCALE_6G "0.035934"
#define KXSD9_SCALE_8G "0.047853"

/* reverse order */
static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 };

static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
{
	int ret, i;
	struct kxsd9_state *st = iio_priv(indio_dev);
	bool foundit = false;

	for (i = 0; i < 4; i++)
		if (micro == kxsd9_micro_scales[i]) {
			foundit = true;
			break;
		}
	if (!foundit)
		return -EINVAL;

	mutex_lock(&st->buf_lock);
	ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
	if (ret)
		goto error_ret;
	st->tx[0] = KXSD9_WRITE(KXSD9_REG_CTRL_C);
	st->tx[1] = (ret & ~KXSD9_FS_MASK) | i;

	ret = spi_write(st->us, st->tx, 2);
error_ret:
	mutex_unlock(&st->buf_lock);
	return ret;
}

static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
{
	int ret;
	struct kxsd9_state *st = iio_priv(indio_dev);
	struct spi_transfer xfers[] = {
		{
			.bits_per_word = 8,
			.len = 1,
			.delay_usecs = 200,
			.tx_buf = st->tx,
		}, {
			.bits_per_word = 8,
			.len = 2,
			.rx_buf = st->rx,
		},
	};

	mutex_lock(&st->buf_lock);
	st->tx[0] = KXSD9_READ(address);
	ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
	if (!ret)
		ret = (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0);
	mutex_unlock(&st->buf_lock);
	return ret;
}

static IIO_CONST_ATTR(accel_scale_available,
		KXSD9_SCALE_2G " "
		KXSD9_SCALE_4G " "
		KXSD9_SCALE_6G " "
		KXSD9_SCALE_8G);

static struct attribute *kxsd9_attributes[] = {
	&iio_const_attr_accel_scale_available.dev_attr.attr,
	NULL,
};

static int kxsd9_write_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int val,
			   int val2,
			   long mask)
{
	int ret = -EINVAL;

	if (mask == IIO_CHAN_INFO_SCALE) {
		/* Check no integer component */
		if (val)
			return -EINVAL;
		ret = kxsd9_write_scale(indio_dev, val2);
	}

	return ret;
}

static int kxsd9_read_raw(struct iio_dev *indio_dev,
			  struct iio_chan_spec const *chan,
			  int *val, int *val2, long mask)
{
	int ret = -EINVAL;
	struct kxsd9_state *st = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = kxsd9_read(indio_dev, chan->address);
		if (ret < 0)
			goto error_ret;
		*val = ret;
		break;
	case IIO_CHAN_INFO_SCALE:
		ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
		if (ret)
			goto error_ret;
		*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
		ret = IIO_VAL_INT_PLUS_MICRO;
		break;
	}

error_ret:
	return ret;
};
#define KXSD9_ACCEL_CHAN(axis)						\
	{								\
		.type = IIO_ACCEL,					\
		.modified = 1,						\
		.channel2 = IIO_MOD_##axis,				\
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
		.address = KXSD9_REG_##axis,				\
	}

static const struct iio_chan_spec kxsd9_channels[] = {
	KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z),
	{
		.type = IIO_VOLTAGE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.indexed = 1,
		.address = KXSD9_REG_AUX,
	}
};

static const struct attribute_group kxsd9_attribute_group = {
	.attrs = kxsd9_attributes,
};

static int kxsd9_power_up(struct kxsd9_state *st)
{
	int ret;

	st->tx[0] = 0x0d;
	st->tx[1] = 0x40;
	ret = spi_write(st->us, st->tx, 2);
	if (ret)
		return ret;

	st->tx[0] = 0x0c;
	st->tx[1] = 0x9b;
	return spi_write(st->us, st->tx, 2);
};

static const struct iio_info kxsd9_info = {
	.read_raw = &kxsd9_read_raw,
	.write_raw = &kxsd9_write_raw,
	.attrs = &kxsd9_attribute_group,
	.driver_module = THIS_MODULE,
};

static int kxsd9_probe(struct spi_device *spi)
{
	struct iio_dev *indio_dev;
	struct kxsd9_state *st;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (!indio_dev)
		return -ENOMEM;

	st = iio_priv(indio_dev);
	spi_set_drvdata(spi, indio_dev);

	st->us = spi;
	mutex_init(&st->buf_lock);
	indio_dev->channels = kxsd9_channels;
	indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->dev.parent = &spi->dev;
	indio_dev->info = &kxsd9_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	spi->mode = SPI_MODE_0;
	spi_setup(spi);
	kxsd9_power_up(st);

	return iio_device_register(indio_dev);
}

static int kxsd9_remove(struct spi_device *spi)
{
	iio_device_unregister(spi_get_drvdata(spi));

	return 0;
}

static const struct spi_device_id kxsd9_id[] = {
	{"kxsd9", 0},
	{ },
};
MODULE_DEVICE_TABLE(spi, kxsd9_id);

static struct spi_driver kxsd9_driver = {
	.driver = {
		.name = "kxsd9",
		.owner = THIS_MODULE,
	},
	.probe = kxsd9_probe,
	.remove = kxsd9_remove,
	.id_table = kxsd9_id,
};
module_spi_driver(kxsd9_driver);

MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
MODULE_LICENSE("GPL v2");