1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * cros_ec_sensors - Driver for Chrome OS Embedded Controller sensors.
4 *
5 * Copyright (C) 2016 Google, Inc
6 *
7 * This driver uses the cros-ec interface to communicate with the Chrome OS
8 * EC about sensors data. Data access is presented through iio sysfs.
9 */
10
11 #include <linux/device.h>
12 #include <linux/iio/buffer.h>
13 #include <linux/iio/common/cros_ec_sensors_core.h>
14 #include <linux/iio/iio.h>
15 #include <linux/iio/kfifo_buf.h>
16 #include <linux/iio/trigger_consumer.h>
17 #include <linux/iio/triggered_buffer.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/platform_data/cros_ec_commands.h>
21 #include <linux/platform_data/cros_ec_proto.h>
22 #include <linux/platform_device.h>
23 #include <linux/slab.h>
24
25 #define CROS_EC_SENSORS_MAX_CHANNELS 4
26
27 /* State data for ec_sensors iio driver. */
28 struct cros_ec_sensors_state {
29 /* Shared by all sensors */
30 struct cros_ec_sensors_core_state core;
31
32 struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
33 };
34
cros_ec_sensors_read(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)35 static int cros_ec_sensors_read(struct iio_dev *indio_dev,
36 struct iio_chan_spec const *chan,
37 int *val, int *val2, long mask)
38 {
39 struct cros_ec_sensors_state *st = iio_priv(indio_dev);
40 s16 data = 0;
41 s64 val64;
42 int i;
43 int ret;
44 int idx = chan->scan_index;
45
46 mutex_lock(&st->core.cmd_lock);
47
48 switch (mask) {
49 case IIO_CHAN_INFO_RAW:
50 ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
51 if (ret < 0)
52 break;
53 ret = IIO_VAL_INT;
54 *val = data;
55 break;
56 case IIO_CHAN_INFO_CALIBBIAS:
57 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
58 st->core.param.sensor_offset.flags = 0;
59
60 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
61 if (ret < 0)
62 break;
63
64 /* Save values */
65 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
66 st->core.calib[i].offset =
67 st->core.resp->sensor_offset.offset[i];
68 ret = IIO_VAL_INT;
69 *val = st->core.calib[idx].offset;
70 break;
71 case IIO_CHAN_INFO_CALIBSCALE:
72 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
73 st->core.param.sensor_offset.flags = 0;
74
75 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
76 if (ret == -EPROTO || ret == -EOPNOTSUPP) {
77 /* Reading calibscale is not supported on older EC. */
78 *val = 1;
79 *val2 = 0;
80 ret = IIO_VAL_INT_PLUS_MICRO;
81 break;
82 } else if (ret) {
83 break;
84 }
85
86 /* Save values */
87 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
88 st->core.calib[i].scale =
89 st->core.resp->sensor_scale.scale[i];
90
91 *val = st->core.calib[idx].scale >> 15;
92 *val2 = ((st->core.calib[idx].scale & 0x7FFF) * 1000000LL) /
93 MOTION_SENSE_DEFAULT_SCALE;
94 ret = IIO_VAL_INT_PLUS_MICRO;
95 break;
96 case IIO_CHAN_INFO_SCALE:
97 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
98 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
99
100 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
101 if (ret < 0)
102 break;
103
104 val64 = st->core.resp->sensor_range.ret;
105 switch (st->core.type) {
106 case MOTIONSENSE_TYPE_ACCEL:
107 /*
108 * EC returns data in g, iio exepects m/s^2.
109 * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
110 */
111 *val = div_s64(val64 * 980665, 10);
112 *val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
113 ret = IIO_VAL_FRACTIONAL;
114 break;
115 case MOTIONSENSE_TYPE_GYRO:
116 /*
117 * EC returns data in dps, iio expects rad/s.
118 * Do not use IIO_DEGREE_TO_RAD to avoid precision
119 * loss. Round to the nearest integer.
120 */
121 *val = 0;
122 *val2 = div_s64(val64 * 3141592653ULL,
123 180 << (CROS_EC_SENSOR_BITS - 1));
124 ret = IIO_VAL_INT_PLUS_NANO;
125 break;
126 case MOTIONSENSE_TYPE_MAG:
127 /*
128 * EC returns data in 16LSB / uT,
129 * iio expects Gauss
130 */
131 *val = val64;
132 *val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
133 ret = IIO_VAL_FRACTIONAL;
134 break;
135 default:
136 ret = -EINVAL;
137 }
138 break;
139 default:
140 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
141 mask);
142 break;
143 }
144 mutex_unlock(&st->core.cmd_lock);
145
146 return ret;
147 }
148
cros_ec_sensors_write(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)149 static int cros_ec_sensors_write(struct iio_dev *indio_dev,
150 struct iio_chan_spec const *chan,
151 int val, int val2, long mask)
152 {
153 struct cros_ec_sensors_state *st = iio_priv(indio_dev);
154 int i;
155 int ret;
156 int idx = chan->scan_index;
157
158 mutex_lock(&st->core.cmd_lock);
159
160 switch (mask) {
161 case IIO_CHAN_INFO_CALIBBIAS:
162 st->core.calib[idx].offset = val;
163
164 /* Send to EC for each axis, even if not complete */
165 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
166 st->core.param.sensor_offset.flags =
167 MOTION_SENSE_SET_OFFSET;
168 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
169 st->core.param.sensor_offset.offset[i] =
170 st->core.calib[i].offset;
171 st->core.param.sensor_offset.temp =
172 EC_MOTION_SENSE_INVALID_CALIB_TEMP;
173
174 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
175 break;
176 case IIO_CHAN_INFO_CALIBSCALE:
177 st->core.calib[idx].scale = val;
178 /* Send to EC for each axis, even if not complete */
179
180 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
181 st->core.param.sensor_offset.flags =
182 MOTION_SENSE_SET_OFFSET;
183 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
184 st->core.param.sensor_scale.scale[i] =
185 st->core.calib[i].scale;
186 st->core.param.sensor_scale.temp =
187 EC_MOTION_SENSE_INVALID_CALIB_TEMP;
188
189 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
190 break;
191 case IIO_CHAN_INFO_SCALE:
192 if (st->core.type == MOTIONSENSE_TYPE_MAG) {
193 ret = -EINVAL;
194 break;
195 }
196 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
197 st->core.param.sensor_range.data = val;
198
199 /* Always roundup, so caller gets at least what it asks for. */
200 st->core.param.sensor_range.roundup = 1;
201
202 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
203 if (ret == 0) {
204 st->core.range_updated = true;
205 st->core.curr_range = val;
206 }
207 break;
208 default:
209 ret = cros_ec_sensors_core_write(
210 &st->core, chan, val, val2, mask);
211 break;
212 }
213
214 mutex_unlock(&st->core.cmd_lock);
215
216 return ret;
217 }
218
219 static const struct iio_info ec_sensors_info = {
220 .read_raw = &cros_ec_sensors_read,
221 .write_raw = &cros_ec_sensors_write,
222 .read_avail = &cros_ec_sensors_core_read_avail,
223 };
224
cros_ec_sensors_probe(struct platform_device * pdev)225 static int cros_ec_sensors_probe(struct platform_device *pdev)
226 {
227 struct device *dev = &pdev->dev;
228 struct iio_dev *indio_dev;
229 struct cros_ec_sensors_state *state;
230 struct iio_chan_spec *channel;
231 int ret, i;
232
233 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
234 if (!indio_dev)
235 return -ENOMEM;
236
237 ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
238 cros_ec_sensors_capture,
239 cros_ec_sensors_push_data);
240 if (ret)
241 return ret;
242
243 indio_dev->info = &ec_sensors_info;
244 state = iio_priv(indio_dev);
245 for (channel = state->channels, i = CROS_EC_SENSOR_X;
246 i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
247 /* Common part */
248 channel->info_mask_separate =
249 BIT(IIO_CHAN_INFO_RAW) |
250 BIT(IIO_CHAN_INFO_CALIBBIAS) |
251 BIT(IIO_CHAN_INFO_CALIBSCALE);
252 channel->info_mask_shared_by_all =
253 BIT(IIO_CHAN_INFO_SCALE) |
254 BIT(IIO_CHAN_INFO_SAMP_FREQ);
255 channel->info_mask_shared_by_all_available =
256 BIT(IIO_CHAN_INFO_SAMP_FREQ);
257 channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
258 channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
259 channel->scan_index = i;
260 channel->ext_info = cros_ec_sensors_ext_info;
261 channel->modified = 1;
262 channel->channel2 = IIO_MOD_X + i;
263 channel->scan_type.sign = 's';
264
265 /* Sensor specific */
266 switch (state->core.type) {
267 case MOTIONSENSE_TYPE_ACCEL:
268 channel->type = IIO_ACCEL;
269 break;
270 case MOTIONSENSE_TYPE_GYRO:
271 channel->type = IIO_ANGL_VEL;
272 break;
273 case MOTIONSENSE_TYPE_MAG:
274 channel->type = IIO_MAGN;
275 break;
276 default:
277 dev_err(&pdev->dev, "Unknown motion sensor\n");
278 return -EINVAL;
279 }
280 }
281
282 /* Timestamp */
283 channel->type = IIO_TIMESTAMP;
284 channel->channel = -1;
285 channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
286 channel->scan_type.sign = 's';
287 channel->scan_type.realbits = 64;
288 channel->scan_type.storagebits = 64;
289
290 indio_dev->channels = state->channels;
291 indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
292
293 /* There is only enough room for accel and gyro in the io space */
294 if ((state->core.ec->cmd_readmem != NULL) &&
295 (state->core.type != MOTIONSENSE_TYPE_MAG))
296 state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
297 else
298 state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
299
300 return devm_iio_device_register(dev, indio_dev);
301 }
302
303 static const struct platform_device_id cros_ec_sensors_ids[] = {
304 {
305 .name = "cros-ec-accel",
306 },
307 {
308 .name = "cros-ec-gyro",
309 },
310 {
311 .name = "cros-ec-mag",
312 },
313 { /* sentinel */ }
314 };
315 MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
316
317 static struct platform_driver cros_ec_sensors_platform_driver = {
318 .driver = {
319 .name = "cros-ec-sensors",
320 .pm = &cros_ec_sensors_pm_ops,
321 },
322 .probe = cros_ec_sensors_probe,
323 .id_table = cros_ec_sensors_ids,
324 };
325 module_platform_driver(cros_ec_sensors_platform_driver);
326
327 MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
328 MODULE_LICENSE("GPL v2");
329