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/mod_devicetable.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. */
29struct 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
36static 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 || ret == -EOPNOTSUPP) {
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
150static 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		if (ret == 0) {
205			st->core.range_updated = true;
206			st->core.curr_range = val;
207		}
208		break;
209	default:
210		ret = cros_ec_sensors_core_write(
211				&st->core, chan, val, val2, mask);
212		break;
213	}
214
215	mutex_unlock(&st->core.cmd_lock);
216
217	return ret;
218}
219
220static const struct iio_info ec_sensors_info = {
221	.read_raw = &cros_ec_sensors_read,
222	.write_raw = &cros_ec_sensors_write,
223	.read_avail = &cros_ec_sensors_core_read_avail,
224};
225
226static int cros_ec_sensors_probe(struct platform_device *pdev)
227{
228	struct device *dev = &pdev->dev;
229	struct iio_dev *indio_dev;
230	struct cros_ec_sensors_state *state;
231	struct iio_chan_spec *channel;
232	int ret, i;
233
234	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
235	if (!indio_dev)
236		return -ENOMEM;
237
238	ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
239					cros_ec_sensors_capture);
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 cros_ec_sensors_core_register(dev, indio_dev,
301			cros_ec_sensors_push_data);
302}
303
304static const struct platform_device_id cros_ec_sensors_ids[] = {
305	{
306		.name = "cros-ec-accel",
307	},
308	{
309		.name = "cros-ec-gyro",
310	},
311	{
312		.name = "cros-ec-mag",
313	},
314	{ /* sentinel */ }
315};
316MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
317
318static struct platform_driver cros_ec_sensors_platform_driver = {
319	.driver = {
320		.name	= "cros-ec-sensors",
321		.pm	= &cros_ec_sensors_pm_ops,
322	},
323	.probe		= cros_ec_sensors_probe,
324	.id_table	= cros_ec_sensors_ids,
325};
326module_platform_driver(cros_ec_sensors_platform_driver);
327
328MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
329MODULE_LICENSE("GPL v2");
330