1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for older Chrome OS EC accelerometer
4 *
5 * Copyright 2017 Google, Inc
6 *
7 * This driver uses the memory mapper cros-ec interface to communicate
8 * with the Chrome OS EC about accelerometer data or older commands.
9 * Accelerometer access is presented through iio sysfs.
10 */
11
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/iio/buffer.h>
15 #include <linux/iio/common/cros_ec_sensors_core.h>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/kfifo_buf.h>
18 #include <linux/iio/trigger_consumer.h>
19 #include <linux/iio/triggered_buffer.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/platform_data/cros_ec_commands.h>
24 #include <linux/platform_data/cros_ec_proto.h>
25 #include <linux/platform_device.h>
26
27 #define DRV_NAME "cros-ec-accel-legacy"
28
29 #define CROS_EC_SENSOR_LEGACY_NUM 2
30 /*
31 * Sensor scale hard coded at 10 bits per g, computed as:
32 * g / (2^10 - 1) = 0.009586168; with g = 9.80665 m.s^-2
33 */
34 #define ACCEL_LEGACY_NSCALE 9586168
35
36 /*
37 * Sensor frequency is hard-coded to 10Hz.
38 */
39 static const int cros_ec_legacy_sample_freq[] = { 10, 0 };
40
cros_ec_accel_legacy_read_cmd(struct iio_dev * indio_dev,unsigned long scan_mask,s16 * data)41 static int cros_ec_accel_legacy_read_cmd(struct iio_dev *indio_dev,
42 unsigned long scan_mask, s16 *data)
43 {
44 struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
45 int ret;
46 unsigned int i;
47 u8 sensor_num;
48
49 /*
50 * Read all sensor data through a command.
51 * Save sensor_num, it is assumed to stay.
52 */
53 sensor_num = st->param.info.sensor_num;
54 st->param.cmd = MOTIONSENSE_CMD_DUMP;
55 st->param.dump.max_sensor_count = CROS_EC_SENSOR_LEGACY_NUM;
56 ret = cros_ec_motion_send_host_cmd(st,
57 sizeof(st->resp->dump) + CROS_EC_SENSOR_LEGACY_NUM *
58 sizeof(struct ec_response_motion_sensor_data));
59 st->param.info.sensor_num = sensor_num;
60 if (ret != 0) {
61 dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
62 return ret;
63 }
64
65 for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
66 *data = st->resp->dump.sensor[sensor_num].data[i] *
67 st->sign[i];
68 data++;
69 }
70
71 return 0;
72 }
73
cros_ec_accel_legacy_read(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)74 static int cros_ec_accel_legacy_read(struct iio_dev *indio_dev,
75 struct iio_chan_spec const *chan,
76 int *val, int *val2, long mask)
77 {
78 struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
79 s16 data = 0;
80 int ret;
81 int idx = chan->scan_index;
82
83 mutex_lock(&st->cmd_lock);
84
85 switch (mask) {
86 case IIO_CHAN_INFO_RAW:
87 ret = st->read_ec_sensors_data(indio_dev, 1 << idx, &data);
88 if (ret < 0)
89 break;
90 ret = IIO_VAL_INT;
91 *val = data;
92 break;
93 case IIO_CHAN_INFO_SCALE:
94 WARN_ON(st->type != MOTIONSENSE_TYPE_ACCEL);
95 *val = 0;
96 *val2 = ACCEL_LEGACY_NSCALE;
97 ret = IIO_VAL_INT_PLUS_NANO;
98 break;
99 case IIO_CHAN_INFO_CALIBBIAS:
100 /* Calibration not supported. */
101 *val = 0;
102 ret = IIO_VAL_INT;
103 break;
104 case IIO_CHAN_INFO_SAMP_FREQ:
105 *val = cros_ec_legacy_sample_freq[0];
106 *val2 = cros_ec_legacy_sample_freq[1];
107 ret = IIO_VAL_INT_PLUS_MICRO;
108 break;
109 default:
110 ret = cros_ec_sensors_core_read(st, chan, val, val2,
111 mask);
112 break;
113 }
114 mutex_unlock(&st->cmd_lock);
115
116 return ret;
117 }
118
cros_ec_accel_legacy_write(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)119 static int cros_ec_accel_legacy_write(struct iio_dev *indio_dev,
120 struct iio_chan_spec const *chan,
121 int val, int val2, long mask)
122 {
123 /*
124 * Do nothing but don't return an error code to allow calibration
125 * script to work.
126 */
127 if (mask == IIO_CHAN_INFO_CALIBBIAS)
128 return 0;
129
130 return -EINVAL;
131 }
132
133 /**
134 * cros_ec_accel_legacy_read_avail() - get available values
135 * @indio_dev: pointer to state information for device
136 * @chan: channel specification structure table
137 * @vals: list of available values
138 * @type: type of data returned
139 * @length: number of data returned in the array
140 * @mask: specifies which values to be requested
141 *
142 * Return: an error code or IIO_AVAIL_LIST
143 */
cros_ec_accel_legacy_read_avail(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)144 static int cros_ec_accel_legacy_read_avail(struct iio_dev *indio_dev,
145 struct iio_chan_spec const *chan,
146 const int **vals,
147 int *type,
148 int *length,
149 long mask)
150 {
151 switch (mask) {
152 case IIO_CHAN_INFO_SAMP_FREQ:
153 *length = ARRAY_SIZE(cros_ec_legacy_sample_freq);
154 *vals = cros_ec_legacy_sample_freq;
155 *type = IIO_VAL_INT_PLUS_MICRO;
156 return IIO_AVAIL_LIST;
157 }
158
159 return -EINVAL;
160 }
161
162 static const struct iio_info cros_ec_accel_legacy_info = {
163 .read_raw = &cros_ec_accel_legacy_read,
164 .write_raw = &cros_ec_accel_legacy_write,
165 .read_avail = &cros_ec_accel_legacy_read_avail,
166 };
167
168 /*
169 * Present the channel using HTML5 standard:
170 * need to invert X and Y and invert some lid axis.
171 */
172 #define CROS_EC_ACCEL_ROTATE_AXIS(_axis) \
173 ((_axis) == CROS_EC_SENSOR_Z ? CROS_EC_SENSOR_Z : \
174 ((_axis) == CROS_EC_SENSOR_X ? CROS_EC_SENSOR_Y : \
175 CROS_EC_SENSOR_X))
176
177 #define CROS_EC_ACCEL_LEGACY_CHAN(_axis) \
178 { \
179 .type = IIO_ACCEL, \
180 .channel2 = IIO_MOD_X + (_axis), \
181 .modified = 1, \
182 .info_mask_separate = \
183 BIT(IIO_CHAN_INFO_RAW) | \
184 BIT(IIO_CHAN_INFO_CALIBBIAS), \
185 .info_mask_shared_by_all = \
186 BIT(IIO_CHAN_INFO_SCALE) | \
187 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
188 .info_mask_shared_by_all_available = \
189 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
190 .ext_info = cros_ec_sensors_ext_info, \
191 .scan_type = { \
192 .sign = 's', \
193 .realbits = CROS_EC_SENSOR_BITS, \
194 .storagebits = CROS_EC_SENSOR_BITS, \
195 }, \
196 .scan_index = CROS_EC_ACCEL_ROTATE_AXIS(_axis), \
197 } \
198
199 static const struct iio_chan_spec cros_ec_accel_legacy_channels[] = {
200 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_X),
201 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Y),
202 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Z),
203 IIO_CHAN_SOFT_TIMESTAMP(CROS_EC_SENSOR_MAX_AXIS)
204 };
205
cros_ec_accel_legacy_probe(struct platform_device * pdev)206 static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
207 {
208 struct device *dev = &pdev->dev;
209 struct iio_dev *indio_dev;
210 struct cros_ec_sensors_core_state *state;
211 int ret;
212
213 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
214 if (!indio_dev)
215 return -ENOMEM;
216
217 ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
218 cros_ec_sensors_capture);
219 if (ret)
220 return ret;
221
222 indio_dev->info = &cros_ec_accel_legacy_info;
223 state = iio_priv(indio_dev);
224
225 if (state->ec->cmd_readmem != NULL)
226 state->read_ec_sensors_data = cros_ec_sensors_read_lpc;
227 else
228 state->read_ec_sensors_data = cros_ec_accel_legacy_read_cmd;
229
230 indio_dev->channels = cros_ec_accel_legacy_channels;
231 indio_dev->num_channels = ARRAY_SIZE(cros_ec_accel_legacy_channels);
232 /* The lid sensor needs to be presented inverted. */
233 if (!strcmp(indio_dev->label, "accel-display")) {
234 state->sign[CROS_EC_SENSOR_X] = -1;
235 state->sign[CROS_EC_SENSOR_Z] = -1;
236 }
237
238 return cros_ec_sensors_core_register(dev, indio_dev, NULL);
239 }
240
241 static struct platform_driver cros_ec_accel_platform_driver = {
242 .driver = {
243 .name = DRV_NAME,
244 },
245 .probe = cros_ec_accel_legacy_probe,
246 };
247 module_platform_driver(cros_ec_accel_platform_driver);
248
249 MODULE_DESCRIPTION("ChromeOS EC legacy accelerometer driver");
250 MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
251 MODULE_LICENSE("GPL v2");
252 MODULE_ALIAS("platform:" DRV_NAME);
253
