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 **/
53 struct 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 */
66 static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 };
67
kxsd9_write_scale(struct iio_dev * indio_dev,int micro)68 static 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 < 0)
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);
90 error_ret:
91 mutex_unlock(&st->buf_lock);
92 return ret;
93 }
94
kxsd9_read(struct iio_dev * indio_dev,u8 address)95 static 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
121 static IIO_CONST_ATTR(accel_scale_available,
122 KXSD9_SCALE_2G " "
123 KXSD9_SCALE_4G " "
124 KXSD9_SCALE_6G " "
125 KXSD9_SCALE_8G);
126
127 static struct attribute *kxsd9_attributes[] = {
128 &iio_const_attr_accel_scale_available.dev_attr.attr,
129 NULL,
130 };
131
kxsd9_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)132 static 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
kxsd9_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)150 static 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 ret = IIO_VAL_INT;
164 break;
165 case IIO_CHAN_INFO_SCALE:
166 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
167 if (ret < 0)
168 goto error_ret;
169 *val = 0;
170 *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
171 ret = IIO_VAL_INT_PLUS_MICRO;
172 break;
173 }
174
175 error_ret:
176 return ret;
177 };
178 #define KXSD9_ACCEL_CHAN(axis) \
179 { \
180 .type = IIO_ACCEL, \
181 .modified = 1, \
182 .channel2 = IIO_MOD_##axis, \
183 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
184 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
185 .address = KXSD9_REG_##axis, \
186 }
187
188 static const 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 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
193 .indexed = 1,
194 .address = KXSD9_REG_AUX,
195 }
196 };
197
198 static const struct attribute_group kxsd9_attribute_group = {
199 .attrs = kxsd9_attributes,
200 };
201
kxsd9_power_up(struct kxsd9_state * st)202 static int kxsd9_power_up(struct kxsd9_state *st)
203 {
204 int ret;
205
206 st->tx[0] = 0x0d;
207 st->tx[1] = 0x40;
208 ret = spi_write(st->us, st->tx, 2);
209 if (ret)
210 return ret;
211
212 st->tx[0] = 0x0c;
213 st->tx[1] = 0x9b;
214 return spi_write(st->us, st->tx, 2);
215 };
216
217 static const struct iio_info kxsd9_info = {
218 .read_raw = &kxsd9_read_raw,
219 .write_raw = &kxsd9_write_raw,
220 .attrs = &kxsd9_attribute_group,
221 .driver_module = THIS_MODULE,
222 };
223
kxsd9_probe(struct spi_device * spi)224 static int kxsd9_probe(struct spi_device *spi)
225 {
226 struct iio_dev *indio_dev;
227 struct kxsd9_state *st;
228
229 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
230 if (!indio_dev)
231 return -ENOMEM;
232
233 st = iio_priv(indio_dev);
234 spi_set_drvdata(spi, indio_dev);
235
236 st->us = spi;
237 mutex_init(&st->buf_lock);
238 indio_dev->channels = kxsd9_channels;
239 indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
240 indio_dev->name = spi_get_device_id(spi)->name;
241 indio_dev->dev.parent = &spi->dev;
242 indio_dev->info = &kxsd9_info;
243 indio_dev->modes = INDIO_DIRECT_MODE;
244
245 spi->mode = SPI_MODE_0;
246 spi_setup(spi);
247 kxsd9_power_up(st);
248
249 return iio_device_register(indio_dev);
250 }
251
kxsd9_remove(struct spi_device * spi)252 static int kxsd9_remove(struct spi_device *spi)
253 {
254 iio_device_unregister(spi_get_drvdata(spi));
255
256 return 0;
257 }
258
259 static const struct spi_device_id kxsd9_id[] = {
260 {"kxsd9", 0},
261 { },
262 };
263 MODULE_DEVICE_TABLE(spi, kxsd9_id);
264
265 static struct spi_driver kxsd9_driver = {
266 .driver = {
267 .name = "kxsd9",
268 },
269 .probe = kxsd9_probe,
270 .remove = kxsd9_remove,
271 .id_table = kxsd9_id,
272 };
273 module_spi_driver(kxsd9_driver);
274
275 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
276 MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
277 MODULE_LICENSE("GPL v2");
278