1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ADXL345 3-Axis Digital Accelerometer IIO core driver
4 *
5 * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>
6 *
7 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf
8 */
9
10 #include <linux/module.h>
11 #include <linux/property.h>
12 #include <linux/regmap.h>
13 #include <linux/units.h>
14
15 #include <linux/iio/iio.h>
16 #include <linux/iio/sysfs.h>
17
18 #include "adxl345.h"
19
20 #define ADXL345_REG_DEVID 0x00
21 #define ADXL345_REG_OFSX 0x1e
22 #define ADXL345_REG_OFSY 0x1f
23 #define ADXL345_REG_OFSZ 0x20
24 #define ADXL345_REG_OFS_AXIS(index) (ADXL345_REG_OFSX + (index))
25 #define ADXL345_REG_BW_RATE 0x2C
26 #define ADXL345_REG_POWER_CTL 0x2D
27 #define ADXL345_REG_DATA_FORMAT 0x31
28 #define ADXL345_REG_DATAX0 0x32
29 #define ADXL345_REG_DATAY0 0x34
30 #define ADXL345_REG_DATAZ0 0x36
31 #define ADXL345_REG_DATA_AXIS(index) \
32 (ADXL345_REG_DATAX0 + (index) * sizeof(__le16))
33
34 #define ADXL345_BW_RATE GENMASK(3, 0)
35 #define ADXL345_BASE_RATE_NANO_HZ 97656250LL
36
37 #define ADXL345_POWER_CTL_MEASURE BIT(3)
38 #define ADXL345_POWER_CTL_STANDBY 0x00
39
40 #define ADXL345_DATA_FORMAT_FULL_RES BIT(3) /* Up to 13-bits resolution */
41 #define ADXL345_DATA_FORMAT_2G 0
42 #define ADXL345_DATA_FORMAT_4G 1
43 #define ADXL345_DATA_FORMAT_8G 2
44 #define ADXL345_DATA_FORMAT_16G 3
45
46 #define ADXL345_DEVID 0xE5
47
48 /*
49 * In full-resolution mode, scale factor is maintained at ~4 mg/LSB
50 * in all g ranges.
51 *
52 * At +/- 16g with 13-bit resolution, scale is computed as:
53 * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383
54 */
55 static const int adxl345_uscale = 38300;
56
57 /*
58 * The Datasheet lists a resolution of Resolution is ~49 mg per LSB. That's
59 * ~480mm/s**2 per LSB.
60 */
61 static const int adxl375_uscale = 480000;
62
63 struct adxl345_data {
64 struct regmap *regmap;
65 u8 data_range;
66 enum adxl345_device_type type;
67 };
68
69 #define ADXL345_CHANNEL(index, axis) { \
70 .type = IIO_ACCEL, \
71 .modified = 1, \
72 .channel2 = IIO_MOD_##axis, \
73 .address = index, \
74 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
75 BIT(IIO_CHAN_INFO_CALIBBIAS), \
76 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
77 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
78 }
79
80 static const struct iio_chan_spec adxl345_channels[] = {
81 ADXL345_CHANNEL(0, X),
82 ADXL345_CHANNEL(1, Y),
83 ADXL345_CHANNEL(2, Z),
84 };
85
adxl345_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)86 static int adxl345_read_raw(struct iio_dev *indio_dev,
87 struct iio_chan_spec const *chan,
88 int *val, int *val2, long mask)
89 {
90 struct adxl345_data *data = iio_priv(indio_dev);
91 __le16 accel;
92 long long samp_freq_nhz;
93 unsigned int regval;
94 int ret;
95
96 switch (mask) {
97 case IIO_CHAN_INFO_RAW:
98 /*
99 * Data is stored in adjacent registers:
100 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte
101 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte
102 */
103 ret = regmap_bulk_read(data->regmap,
104 ADXL345_REG_DATA_AXIS(chan->address),
105 &accel, sizeof(accel));
106 if (ret < 0)
107 return ret;
108
109 *val = sign_extend32(le16_to_cpu(accel), 12);
110 return IIO_VAL_INT;
111 case IIO_CHAN_INFO_SCALE:
112 *val = 0;
113 switch (data->type) {
114 case ADXL345:
115 *val2 = adxl345_uscale;
116 break;
117 case ADXL375:
118 *val2 = adxl375_uscale;
119 break;
120 }
121
122 return IIO_VAL_INT_PLUS_MICRO;
123 case IIO_CHAN_INFO_CALIBBIAS:
124 ret = regmap_read(data->regmap,
125 ADXL345_REG_OFS_AXIS(chan->address), ®val);
126 if (ret < 0)
127 return ret;
128 /*
129 * 8-bit resolution at +/- 2g, that is 4x accel data scale
130 * factor
131 */
132 *val = sign_extend32(regval, 7) * 4;
133
134 return IIO_VAL_INT;
135 case IIO_CHAN_INFO_SAMP_FREQ:
136 ret = regmap_read(data->regmap, ADXL345_REG_BW_RATE, ®val);
137 if (ret < 0)
138 return ret;
139
140 samp_freq_nhz = ADXL345_BASE_RATE_NANO_HZ <<
141 (regval & ADXL345_BW_RATE);
142 *val = div_s64_rem(samp_freq_nhz, NANOHZ_PER_HZ, val2);
143
144 return IIO_VAL_INT_PLUS_NANO;
145 }
146
147 return -EINVAL;
148 }
149
adxl345_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)150 static int adxl345_write_raw(struct iio_dev *indio_dev,
151 struct iio_chan_spec const *chan,
152 int val, int val2, long mask)
153 {
154 struct adxl345_data *data = iio_priv(indio_dev);
155 s64 n;
156
157 switch (mask) {
158 case IIO_CHAN_INFO_CALIBBIAS:
159 /*
160 * 8-bit resolution at +/- 2g, that is 4x accel data scale
161 * factor
162 */
163 return regmap_write(data->regmap,
164 ADXL345_REG_OFS_AXIS(chan->address),
165 val / 4);
166 case IIO_CHAN_INFO_SAMP_FREQ:
167 n = div_s64(val * NANOHZ_PER_HZ + val2,
168 ADXL345_BASE_RATE_NANO_HZ);
169
170 return regmap_update_bits(data->regmap, ADXL345_REG_BW_RATE,
171 ADXL345_BW_RATE,
172 clamp_val(ilog2(n), 0,
173 ADXL345_BW_RATE));
174 }
175
176 return -EINVAL;
177 }
178
adxl345_write_raw_get_fmt(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,long mask)179 static int adxl345_write_raw_get_fmt(struct iio_dev *indio_dev,
180 struct iio_chan_spec const *chan,
181 long mask)
182 {
183 switch (mask) {
184 case IIO_CHAN_INFO_CALIBBIAS:
185 return IIO_VAL_INT;
186 case IIO_CHAN_INFO_SAMP_FREQ:
187 return IIO_VAL_INT_PLUS_NANO;
188 default:
189 return -EINVAL;
190 }
191 }
192
193 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
194 "0.09765625 0.1953125 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200"
195 );
196
197 static struct attribute *adxl345_attrs[] = {
198 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
199 NULL
200 };
201
202 static const struct attribute_group adxl345_attrs_group = {
203 .attrs = adxl345_attrs,
204 };
205
206 static const struct iio_info adxl345_info = {
207 .attrs = &adxl345_attrs_group,
208 .read_raw = adxl345_read_raw,
209 .write_raw = adxl345_write_raw,
210 .write_raw_get_fmt = adxl345_write_raw_get_fmt,
211 };
212
adxl345_powerup(void * regmap)213 static int adxl345_powerup(void *regmap)
214 {
215 return regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_MEASURE);
216 }
217
adxl345_powerdown(void * regmap)218 static void adxl345_powerdown(void *regmap)
219 {
220 regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY);
221 }
222
adxl345_core_probe(struct device * dev,struct regmap * regmap)223 int adxl345_core_probe(struct device *dev, struct regmap *regmap)
224 {
225 enum adxl345_device_type type;
226 struct adxl345_data *data;
227 struct iio_dev *indio_dev;
228 const char *name;
229 u32 regval;
230 int ret;
231
232 type = (uintptr_t)device_get_match_data(dev);
233 switch (type) {
234 case ADXL345:
235 name = "adxl345";
236 break;
237 case ADXL375:
238 name = "adxl375";
239 break;
240 default:
241 return -EINVAL;
242 }
243
244 ret = regmap_read(regmap, ADXL345_REG_DEVID, ®val);
245 if (ret < 0)
246 return dev_err_probe(dev, ret, "Error reading device ID\n");
247
248 if (regval != ADXL345_DEVID)
249 return dev_err_probe(dev, -ENODEV, "Invalid device ID: %x, expected %x\n",
250 regval, ADXL345_DEVID);
251
252 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
253 if (!indio_dev)
254 return -ENOMEM;
255
256 data = iio_priv(indio_dev);
257 data->regmap = regmap;
258 data->type = type;
259 /* Enable full-resolution mode */
260 data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
261
262 ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
263 data->data_range);
264 if (ret < 0)
265 return dev_err_probe(dev, ret, "Failed to set data range\n");
266
267 indio_dev->name = name;
268 indio_dev->info = &adxl345_info;
269 indio_dev->modes = INDIO_DIRECT_MODE;
270 indio_dev->channels = adxl345_channels;
271 indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
272
273 /* Enable measurement mode */
274 ret = adxl345_powerup(data->regmap);
275 if (ret < 0)
276 return dev_err_probe(dev, ret, "Failed to enable measurement mode\n");
277
278 ret = devm_add_action_or_reset(dev, adxl345_powerdown, data->regmap);
279 if (ret < 0)
280 return ret;
281
282 return devm_iio_device_register(dev, indio_dev);
283 }
284 EXPORT_SYMBOL_NS_GPL(adxl345_core_probe, IIO_ADXL345);
285
286 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@gmail.com>");
287 MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
288 MODULE_LICENSE("GPL v2");
289