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/mfd/cros_ec.h>
20 #include <linux/module.h>
21 #include <linux/platform_data/cros_ec_commands.h>
22 #include <linux/platform_data/cros_ec_proto.h>
23 #include <linux/platform_device.h>
24 #include <linux/slab.h>
25
26 #define CROS_EC_SENSORS_MAX_CHANNELS 4
27
28 /* State data for ec_sensors iio driver. */
29 struct cros_ec_sensors_state {
30 /* Shared by all sensors */
31 struct cros_ec_sensors_core_state core;
32
33 struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
34 };
35
cros_ec_sensors_read(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)36 static int cros_ec_sensors_read(struct iio_dev *indio_dev,
37 struct iio_chan_spec const *chan,
38 int *val, int *val2, long mask)
39 {
40 struct cros_ec_sensors_state *st = iio_priv(indio_dev);
41 s16 data = 0;
42 s64 val64;
43 int i;
44 int ret;
45 int idx = chan->scan_index;
46
47 mutex_lock(&st->core.cmd_lock);
48
49 switch (mask) {
50 case IIO_CHAN_INFO_RAW:
51 ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
52 if (ret < 0)
53 break;
54 ret = IIO_VAL_INT;
55 *val = data;
56 break;
57 case IIO_CHAN_INFO_CALIBBIAS:
58 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
59 st->core.param.sensor_offset.flags = 0;
60
61 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
62 if (ret < 0)
63 break;
64
65 /* Save values */
66 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
67 st->core.calib[i].offset =
68 st->core.resp->sensor_offset.offset[i];
69 ret = IIO_VAL_INT;
70 *val = st->core.calib[idx].offset;
71 break;
72 case IIO_CHAN_INFO_CALIBSCALE:
73 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
74 st->core.param.sensor_offset.flags = 0;
75
76 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
77 if (ret == -EPROTO) {
78 /* Reading calibscale is not supported on older EC. */
79 *val = 1;
80 *val2 = 0;
81 ret = IIO_VAL_INT_PLUS_MICRO;
82 break;
83 } else if (ret) {
84 break;
85 }
86
87 /* Save values */
88 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
89 st->core.calib[i].scale =
90 st->core.resp->sensor_scale.scale[i];
91
92 *val = st->core.calib[idx].scale >> 15;
93 *val2 = ((st->core.calib[idx].scale & 0x7FFF) * 1000000LL) /
94 MOTION_SENSE_DEFAULT_SCALE;
95 ret = IIO_VAL_INT_PLUS_MICRO;
96 break;
97 case IIO_CHAN_INFO_SCALE:
98 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
99 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
100
101 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
102 if (ret < 0)
103 break;
104
105 val64 = st->core.resp->sensor_range.ret;
106 switch (st->core.type) {
107 case MOTIONSENSE_TYPE_ACCEL:
108 /*
109 * EC returns data in g, iio exepects m/s^2.
110 * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
111 */
112 *val = div_s64(val64 * 980665, 10);
113 *val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
114 ret = IIO_VAL_FRACTIONAL;
115 break;
116 case MOTIONSENSE_TYPE_GYRO:
117 /*
118 * EC returns data in dps, iio expects rad/s.
119 * Do not use IIO_DEGREE_TO_RAD to avoid precision
120 * loss. Round to the nearest integer.
121 */
122 *val = 0;
123 *val2 = div_s64(val64 * 3141592653ULL,
124 180 << (CROS_EC_SENSOR_BITS - 1));
125 ret = IIO_VAL_INT_PLUS_NANO;
126 break;
127 case MOTIONSENSE_TYPE_MAG:
128 /*
129 * EC returns data in 16LSB / uT,
130 * iio expects Gauss
131 */
132 *val = val64;
133 *val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
134 ret = IIO_VAL_FRACTIONAL;
135 break;
136 default:
137 ret = -EINVAL;
138 }
139 break;
140 default:
141 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
142 mask);
143 break;
144 }
145 mutex_unlock(&st->core.cmd_lock);
146
147 return ret;
148 }
149
cros_ec_sensors_write(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)150 static int cros_ec_sensors_write(struct iio_dev *indio_dev,
151 struct iio_chan_spec const *chan,
152 int val, int val2, long mask)
153 {
154 struct cros_ec_sensors_state *st = iio_priv(indio_dev);
155 int i;
156 int ret;
157 int idx = chan->scan_index;
158
159 mutex_lock(&st->core.cmd_lock);
160
161 switch (mask) {
162 case IIO_CHAN_INFO_CALIBBIAS:
163 st->core.calib[idx].offset = val;
164
165 /* Send to EC for each axis, even if not complete */
166 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
167 st->core.param.sensor_offset.flags =
168 MOTION_SENSE_SET_OFFSET;
169 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
170 st->core.param.sensor_offset.offset[i] =
171 st->core.calib[i].offset;
172 st->core.param.sensor_offset.temp =
173 EC_MOTION_SENSE_INVALID_CALIB_TEMP;
174
175 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
176 break;
177 case IIO_CHAN_INFO_CALIBSCALE:
178 st->core.calib[idx].scale = val;
179 /* Send to EC for each axis, even if not complete */
180
181 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
182 st->core.param.sensor_offset.flags =
183 MOTION_SENSE_SET_OFFSET;
184 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
185 st->core.param.sensor_scale.scale[i] =
186 st->core.calib[i].scale;
187 st->core.param.sensor_scale.temp =
188 EC_MOTION_SENSE_INVALID_CALIB_TEMP;
189
190 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
191 break;
192 case IIO_CHAN_INFO_SCALE:
193 if (st->core.type == MOTIONSENSE_TYPE_MAG) {
194 ret = -EINVAL;
195 break;
196 }
197 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
198 st->core.param.sensor_range.data = val;
199
200 /* Always roundup, so caller gets at least what it asks for. */
201 st->core.param.sensor_range.roundup = 1;
202
203 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
204 break;
205 default:
206 ret = cros_ec_sensors_core_write(
207 &st->core, chan, val, val2, mask);
208 break;
209 }
210
211 mutex_unlock(&st->core.cmd_lock);
212
213 return ret;
214 }
215
216 static const struct iio_info ec_sensors_info = {
217 .read_raw = &cros_ec_sensors_read,
218 .write_raw = &cros_ec_sensors_write,
219 .read_avail = &cros_ec_sensors_core_read_avail,
220 };
221
cros_ec_sensors_probe(struct platform_device * pdev)222 static int cros_ec_sensors_probe(struct platform_device *pdev)
223 {
224 struct device *dev = &pdev->dev;
225 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
226 struct iio_dev *indio_dev;
227 struct cros_ec_sensors_state *state;
228 struct iio_chan_spec *channel;
229 int ret, i;
230
231 if (!ec_dev || !ec_dev->ec_dev) {
232 dev_warn(&pdev->dev, "No CROS EC device found.\n");
233 return -EINVAL;
234 }
235
236 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
237 if (!indio_dev)
238 return -ENOMEM;
239
240 ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
241 if (ret)
242 return ret;
243
244 indio_dev->info = &ec_sensors_info;
245 state = iio_priv(indio_dev);
246 for (channel = state->channels, i = CROS_EC_SENSOR_X;
247 i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
248 /* Common part */
249 channel->info_mask_separate =
250 BIT(IIO_CHAN_INFO_RAW) |
251 BIT(IIO_CHAN_INFO_CALIBBIAS) |
252 BIT(IIO_CHAN_INFO_CALIBSCALE);
253 channel->info_mask_shared_by_all =
254 BIT(IIO_CHAN_INFO_SCALE) |
255 BIT(IIO_CHAN_INFO_FREQUENCY) |
256 BIT(IIO_CHAN_INFO_SAMP_FREQ);
257 channel->info_mask_shared_by_all_available =
258 BIT(IIO_CHAN_INFO_SAMP_FREQ);
259 channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
260 channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
261 channel->scan_index = i;
262 channel->ext_info = cros_ec_sensors_ext_info;
263 channel->modified = 1;
264 channel->channel2 = IIO_MOD_X + i;
265 channel->scan_type.sign = 's';
266
267 /* Sensor specific */
268 switch (state->core.type) {
269 case MOTIONSENSE_TYPE_ACCEL:
270 channel->type = IIO_ACCEL;
271 break;
272 case MOTIONSENSE_TYPE_GYRO:
273 channel->type = IIO_ANGL_VEL;
274 break;
275 case MOTIONSENSE_TYPE_MAG:
276 channel->type = IIO_MAGN;
277 break;
278 default:
279 dev_err(&pdev->dev, "Unknown motion sensor\n");
280 return -EINVAL;
281 }
282 }
283
284 /* Timestamp */
285 channel->type = IIO_TIMESTAMP;
286 channel->channel = -1;
287 channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
288 channel->scan_type.sign = 's';
289 channel->scan_type.realbits = 64;
290 channel->scan_type.storagebits = 64;
291
292 indio_dev->channels = state->channels;
293 indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
294
295 /* There is only enough room for accel and gyro in the io space */
296 if ((state->core.ec->cmd_readmem != NULL) &&
297 (state->core.type != MOTIONSENSE_TYPE_MAG))
298 state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
299 else
300 state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
301
302 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
303 cros_ec_sensors_capture, NULL);
304 if (ret)
305 return ret;
306
307 return devm_iio_device_register(dev, indio_dev);
308 }
309
310 static const struct platform_device_id cros_ec_sensors_ids[] = {
311 {
312 .name = "cros-ec-accel",
313 },
314 {
315 .name = "cros-ec-gyro",
316 },
317 {
318 .name = "cros-ec-mag",
319 },
320 { /* sentinel */ }
321 };
322 MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
323
324 static struct platform_driver cros_ec_sensors_platform_driver = {
325 .driver = {
326 .name = "cros-ec-sensors",
327 .pm = &cros_ec_sensors_pm_ops,
328 },
329 .probe = cros_ec_sensors_probe,
330 .id_table = cros_ec_sensors_ids,
331 };
332 module_platform_driver(cros_ec_sensors_platform_driver);
333
334 MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
335 MODULE_LICENSE("GPL v2");
336