1/*
2 * kxsd9.c	simple support for the Kionix KXSD9 3D
3 *		accelerometer.
4 *
5 * Copyright (c) 2008-2009 Jonathan Cameron <jic23@kernel.org>
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 <linux/iio/iio.h>
27#include <linux/iio/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	int ret;
98	struct kxsd9_state *st = iio_priv(indio_dev);
99	struct spi_transfer xfers[] = {
100		{
101			.bits_per_word = 8,
102			.len = 1,
103			.delay_usecs = 200,
104			.tx_buf = st->tx,
105		}, {
106			.bits_per_word = 8,
107			.len = 2,
108			.rx_buf = st->rx,
109		},
110	};
111
112	mutex_lock(&st->buf_lock);
113	st->tx[0] = KXSD9_READ(address);
114	ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
115	if (!ret)
116		ret = (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0);
117	mutex_unlock(&st->buf_lock);
118	return ret;
119}
120
121static IIO_CONST_ATTR(accel_scale_available,
122		KXSD9_SCALE_2G " "
123		KXSD9_SCALE_4G " "
124		KXSD9_SCALE_6G " "
125		KXSD9_SCALE_8G);
126
127static struct attribute *kxsd9_attributes[] = {
128	&iio_const_attr_accel_scale_available.dev_attr.attr,
129	NULL,
130};
131
132static int kxsd9_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 = -EINVAL;
139
140	if (mask == IIO_CHAN_INFO_SCALE) {
141		/* Check no integer component */
142		if (val)
143			return -EINVAL;
144		ret = kxsd9_write_scale(indio_dev, val2);
145	}
146
147	return ret;
148}
149
150static int kxsd9_read_raw(struct iio_dev *indio_dev,
151			  struct iio_chan_spec const *chan,
152			  int *val, int *val2, long mask)
153{
154	int ret = -EINVAL;
155	struct kxsd9_state *st = iio_priv(indio_dev);
156
157	switch (mask) {
158	case IIO_CHAN_INFO_RAW:
159		ret = kxsd9_read(indio_dev, chan->address);
160		if (ret < 0)
161			goto error_ret;
162		*val = ret;
163		break;
164	case IIO_CHAN_INFO_SCALE:
165		ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
166		if (ret)
167			goto error_ret;
168		*val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
169		ret = IIO_VAL_INT_PLUS_MICRO;
170		break;
171	}
172
173error_ret:
174	return ret;
175};
176#define KXSD9_ACCEL_CHAN(axis)						\
177	{								\
178		.type = IIO_ACCEL,					\
179		.modified = 1,						\
180		.channel2 = IIO_MOD_##axis,				\
181		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
182		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
183		.address = KXSD9_REG_##axis,				\
184	}
185
186static const struct iio_chan_spec kxsd9_channels[] = {
187	KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z),
188	{
189		.type = IIO_VOLTAGE,
190		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
191		.indexed = 1,
192		.address = KXSD9_REG_AUX,
193	}
194};
195
196static const struct attribute_group kxsd9_attribute_group = {
197	.attrs = kxsd9_attributes,
198};
199
200static int kxsd9_power_up(struct kxsd9_state *st)
201{
202	int ret;
203
204	st->tx[0] = 0x0d;
205	st->tx[1] = 0x40;
206	ret = spi_write(st->us, st->tx, 2);
207	if (ret)
208		return ret;
209
210	st->tx[0] = 0x0c;
211	st->tx[1] = 0x9b;
212	return spi_write(st->us, st->tx, 2);
213};
214
215static const struct iio_info kxsd9_info = {
216	.read_raw = &kxsd9_read_raw,
217	.write_raw = &kxsd9_write_raw,
218	.attrs = &kxsd9_attribute_group,
219	.driver_module = THIS_MODULE,
220};
221
222static int kxsd9_probe(struct spi_device *spi)
223{
224	struct iio_dev *indio_dev;
225	struct kxsd9_state *st;
226
227	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
228	if (!indio_dev)
229		return -ENOMEM;
230
231	st = iio_priv(indio_dev);
232	spi_set_drvdata(spi, indio_dev);
233
234	st->us = spi;
235	mutex_init(&st->buf_lock);
236	indio_dev->channels = kxsd9_channels;
237	indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
238	indio_dev->name = spi_get_device_id(spi)->name;
239	indio_dev->dev.parent = &spi->dev;
240	indio_dev->info = &kxsd9_info;
241	indio_dev->modes = INDIO_DIRECT_MODE;
242
243	spi->mode = SPI_MODE_0;
244	spi_setup(spi);
245	kxsd9_power_up(st);
246
247	return iio_device_register(indio_dev);
248}
249
250static int kxsd9_remove(struct spi_device *spi)
251{
252	iio_device_unregister(spi_get_drvdata(spi));
253
254	return 0;
255}
256
257static const struct spi_device_id kxsd9_id[] = {
258	{"kxsd9", 0},
259	{ },
260};
261MODULE_DEVICE_TABLE(spi, kxsd9_id);
262
263static struct spi_driver kxsd9_driver = {
264	.driver = {
265		.name = "kxsd9",
266		.owner = THIS_MODULE,
267	},
268	.probe = kxsd9_probe,
269	.remove = kxsd9_remove,
270	.id_table = kxsd9_id,
271};
272module_spi_driver(kxsd9_driver);
273
274MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
275MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
276MODULE_LICENSE("GPL v2");
277