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 | |
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 | opt_length: 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 | |
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(lock: &st->cmd_lock); |
115 | |
116 | return ret; |
117 | } |
118 | |
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 | */ |
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 | |
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(parent: &pdev->dev, sizeof_priv: sizeof(*state)); |
214 | if (!indio_dev) |
215 | return -ENOMEM; |
216 | |
217 | ret = cros_ec_sensors_core_init(pdev, indio_dev, physical_device: true, |
218 | trigger_capture: 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 | |