1/*
2 * kxsd9.c	simple support for the Kionix KXSD9 3D
3 *		accelerometer.
4 *
5 * Copyright (c) 2008-2009 Jonathan Cameron <jic23@cam.ac.uk>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * The i2c interface is very similar, so shouldn't be a problem once
12 * I have a suitable wire made up.
13 *
14 * TODO:	Support the motion detector
15 *		Uses register address incrementing so could have a
16 *		heavily optimized ring buffer access function.
17 */
18
19#include <linux/device.h>
20#include <linux/kernel.h>
21#include <linux/spi/spi.h>
22#include <linux/sysfs.h>
23#include <linux/slab.h>
24#include <linux/module.h>
25
26#include "../iio.h"
27#include "../sysfs.h"
28
29#define KXSD9_REG_X		0x00
30#define KXSD9_REG_Y		0x02
31#define KXSD9_REG_Z		0x04
32#define KXSD9_REG_AUX		0x06
33#define KXSD9_REG_RESET		0x0a
34#define KXSD9_REG_CTRL_C	0x0c
35
36#define KXSD9_FS_MASK		0x03
37
38#define KXSD9_REG_CTRL_B	0x0d
39#define KXSD9_REG_CTRL_A	0x0e
40
41#define KXSD9_READ(a) (0x80 | (a))
42#define KXSD9_WRITE(a) (a)
43
44#define KXSD9_STATE_RX_SIZE 2
45#define KXSD9_STATE_TX_SIZE 2
46/**
47 * struct kxsd9_state - device related storage
48 * @buf_lock:	protect the rx and tx buffers.
49 * @us:		spi device
50 * @rx:		single rx buffer storage
51 * @tx:		single tx buffer storage
52 **/
53struct kxsd9_state {
54	struct mutex buf_lock;
55	struct spi_device *us;
56	u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
57	u8 tx[KXSD9_STATE_TX_SIZE];
58};
59
60#define KXSD9_SCALE_2G "0.011978"
61#define KXSD9_SCALE_4G "0.023927"
62#define KXSD9_SCALE_6G "0.035934"
63#define KXSD9_SCALE_8G "0.047853"
64
65/* reverse order */
66static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 };
67
68static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
69{
70	int ret, i;
71	struct kxsd9_state *st = iio_priv(indio_dev);
72	bool foundit = false;
73
74	for (i = 0; i < 4; i++)
75		if (micro == kxsd9_micro_scales[i]) {
76			foundit = true;
77			break;
78		}
79	if (!foundit)
80		return -EINVAL;
81
82	mutex_lock(&st->buf_lock);
83	ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
84	if (ret)
85		goto error_ret;
86	st->tx[0] = KXSD9_WRITE(KXSD9_REG_CTRL_C);
87	st->tx[1] = (ret & ~KXSD9_FS_MASK) | i;
88
89	ret = spi_write(st->us, st->tx, 2);
90error_ret:
91	mutex_unlock(&st->buf_lock);
92	return ret;
93}
94
95static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
96{
97	struct spi_message msg;
98	int ret;
99	struct kxsd9_state *st = iio_priv(indio_dev);
100	struct spi_transfer xfers[] = {
101		{
102			.bits_per_word = 8,
103			.len = 1,
104			.delay_usecs = 200,
105			.tx_buf = st->tx,
106		}, {
107			.bits_per_word = 8,
108			.len = 2,
109			.rx_buf = st->rx,
110		},
111	};
112
113	mutex_lock(&st->buf_lock);
114	st->tx[0] = KXSD9_READ(address);
115	spi_message_init(&msg);
116	spi_message_add_tail(&xfers[0], &msg);
117	spi_message_add_tail(&xfers[1], &msg);
118	ret = spi_sync(st->us, &msg);
119	if (ret)
120		return ret;
121	return (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0);
122}
123
124static IIO_CONST_ATTR(accel_scale_available,
125		KXSD9_SCALE_2G " "
126		KXSD9_SCALE_4G " "
127		KXSD9_SCALE_6G " "
128		KXSD9_SCALE_8G);
129
130static struct attribute *kxsd9_attributes[] = {
131	&iio_const_attr_accel_scale_available.dev_attr.attr,
132	NULL,
133};
134
135static int kxsd9_write_raw(struct iio_dev *indio_dev,
136			   struct iio_chan_spec const *chan,
137			   int val,
138			   int val2,
139			   long mask)
140{
141	int ret = -EINVAL;
142
143	if (mask == IIO_CHAN_INFO_SCALE) {
144		/* Check no integer component */
145		if (val)
146			return -EINVAL;
147		ret = kxsd9_write_scale(indio_dev, val2);
148	}
149
150	return ret;
151}
152
153static int kxsd9_read_raw(struct iio_dev *indio_dev,
154			  struct iio_chan_spec const *chan,
155			  int *val, int *val2, long mask)
156{
157	int ret = -EINVAL;
158	struct kxsd9_state *st = iio_priv(indio_dev);
159
160	switch (mask) {
161	case 0:
162		ret = kxsd9_read(indio_dev, chan->address);
163		if (ret < 0)
164			goto error_ret;
165		*val = ret;
166		break;
167	case IIO_CHAN_INFO_SCALE:
168		ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
169		if (ret)
170			goto error_ret;
171		*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
172		ret = IIO_VAL_INT_PLUS_MICRO;
173		break;
174	};
175
176error_ret:
177	return ret;
178};
179#define KXSD9_ACCEL_CHAN(axis)						\
180	{								\
181		.type = IIO_ACCEL,					\
182		.modified = 1,						\
183		.channel2 = IIO_MOD_##axis,				\
184		.info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT,		\
185		.address = KXSD9_REG_##axis,				\
186	}
187
188static struct iio_chan_spec kxsd9_channels[] = {
189	KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z),
190	{
191		.type = IIO_VOLTAGE,
192		.indexed = 1,
193		.address = KXSD9_REG_AUX,
194	}
195};
196
197static const struct attribute_group kxsd9_attribute_group = {
198	.attrs = kxsd9_attributes,
199};
200
201static int __devinit kxsd9_power_up(struct kxsd9_state *st)
202{
203	int ret;
204
205	st->tx[0] = 0x0d;
206	st->tx[1] = 0x40;
207	ret = spi_write(st->us, st->tx, 2);
208	if (ret)
209		return ret;
210
211	st->tx[0] = 0x0c;
212	st->tx[1] = 0x9b;
213	return spi_write(st->us, st->tx, 2);
214};
215
216static const struct iio_info kxsd9_info = {
217	.read_raw = &kxsd9_read_raw,
218	.write_raw = &kxsd9_write_raw,
219	.attrs = &kxsd9_attribute_group,
220	.driver_module = THIS_MODULE,
221};
222
223static int __devinit kxsd9_probe(struct spi_device *spi)
224{
225	struct iio_dev *indio_dev;
226	struct kxsd9_state *st;
227	int ret = 0;
228
229	indio_dev = iio_allocate_device(sizeof(*st));
230	if (indio_dev == NULL) {
231		ret = -ENOMEM;
232		goto error_ret;
233	}
234	st = iio_priv(indio_dev);
235	spi_set_drvdata(spi, indio_dev);
236
237	st->us = spi;
238	mutex_init(&st->buf_lock);
239	indio_dev->channels = kxsd9_channels;
240	indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
241	indio_dev->name = spi_get_device_id(spi)->name;
242	indio_dev->dev.parent = &spi->dev;
243	indio_dev->info = &kxsd9_info;
244	indio_dev->modes = INDIO_DIRECT_MODE;
245
246	ret = iio_device_register(indio_dev);
247	if (ret)
248		goto error_free_dev;
249
250	spi->mode = SPI_MODE_0;
251	spi_setup(spi);
252	kxsd9_power_up(st);
253
254	return 0;
255
256error_free_dev:
257	iio_free_device(indio_dev);
258error_ret:
259	return ret;
260}
261
262static int __devexit kxsd9_remove(struct spi_device *spi)
263{
264	iio_device_unregister(spi_get_drvdata(spi));
265	iio_free_device(spi_get_drvdata(spi));
266
267	return 0;
268}
269
270static const struct spi_device_id kxsd9_id[] = {
271	{"kxsd9", 0},
272	{ },
273};
274MODULE_DEVICE_TABLE(spi, kxsd9_id);
275
276static struct spi_driver kxsd9_driver = {
277	.driver = {
278		.name = "kxsd9",
279		.owner = THIS_MODULE,
280	},
281	.probe = kxsd9_probe,
282	.remove = __devexit_p(kxsd9_remove),
283	.id_table = kxsd9_id,
284};
285module_spi_driver(kxsd9_driver);
286
287MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
288MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
289MODULE_LICENSE("GPL v2");
290