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 static int cros_ec_accel_legacy_read_cmd(struct iio_dev *indio_dev, 37 unsigned long scan_mask, s16 *data) 38 { 39 struct cros_ec_sensors_core_state *st = iio_priv(indio_dev); 40 int ret; 41 unsigned int i; 42 u8 sensor_num; 43 44 /* 45 * Read all sensor data through a command. 46 * Save sensor_num, it is assumed to stay. 47 */ 48 sensor_num = st->param.info.sensor_num; 49 st->param.cmd = MOTIONSENSE_CMD_DUMP; 50 st->param.dump.max_sensor_count = CROS_EC_SENSOR_LEGACY_NUM; 51 ret = cros_ec_motion_send_host_cmd(st, 52 sizeof(st->resp->dump) + CROS_EC_SENSOR_LEGACY_NUM * 53 sizeof(struct ec_response_motion_sensor_data)); 54 st->param.info.sensor_num = sensor_num; 55 if (ret != 0) { 56 dev_warn(&indio_dev->dev, "Unable to read sensor data\n"); 57 return ret; 58 } 59 60 for_each_set_bit(i, &scan_mask, indio_dev->masklength) { 61 *data = st->resp->dump.sensor[sensor_num].data[i] * 62 st->sign[i]; 63 data++; 64 } 65 66 return 0; 67 } 68 69 static int cros_ec_accel_legacy_read(struct iio_dev *indio_dev, 70 struct iio_chan_spec const *chan, 71 int *val, int *val2, long mask) 72 { 73 struct cros_ec_sensors_core_state *st = iio_priv(indio_dev); 74 s16 data = 0; 75 int ret; 76 int idx = chan->scan_index; 77 78 mutex_lock(&st->cmd_lock); 79 80 switch (mask) { 81 case IIO_CHAN_INFO_RAW: 82 ret = st->read_ec_sensors_data(indio_dev, 1 << idx, &data); 83 if (ret < 0) 84 break; 85 ret = IIO_VAL_INT; 86 *val = data; 87 break; 88 case IIO_CHAN_INFO_SCALE: 89 WARN_ON(st->type != MOTIONSENSE_TYPE_ACCEL); 90 *val = 0; 91 *val2 = ACCEL_LEGACY_NSCALE; 92 ret = IIO_VAL_INT_PLUS_NANO; 93 break; 94 case IIO_CHAN_INFO_CALIBBIAS: 95 /* Calibration not supported. */ 96 *val = 0; 97 ret = IIO_VAL_INT; 98 break; 99 default: 100 ret = cros_ec_sensors_core_read(st, chan, val, val2, 101 mask); 102 break; 103 } 104 mutex_unlock(&st->cmd_lock); 105 106 return ret; 107 } 108 109 static int cros_ec_accel_legacy_write(struct iio_dev *indio_dev, 110 struct iio_chan_spec const *chan, 111 int val, int val2, long mask) 112 { 113 /* 114 * Do nothing but don't return an error code to allow calibration 115 * script to work. 116 */ 117 if (mask == IIO_CHAN_INFO_CALIBBIAS) 118 return 0; 119 120 return -EINVAL; 121 } 122 123 static const struct iio_info cros_ec_accel_legacy_info = { 124 .read_raw = &cros_ec_accel_legacy_read, 125 .write_raw = &cros_ec_accel_legacy_write, 126 }; 127 128 /* 129 * Present the channel using HTML5 standard: 130 * need to invert X and Y and invert some lid axis. 131 */ 132 #define CROS_EC_ACCEL_ROTATE_AXIS(_axis) \ 133 ((_axis) == CROS_EC_SENSOR_Z ? CROS_EC_SENSOR_Z : \ 134 ((_axis) == CROS_EC_SENSOR_X ? CROS_EC_SENSOR_Y : \ 135 CROS_EC_SENSOR_X)) 136 137 #define CROS_EC_ACCEL_LEGACY_CHAN(_axis) \ 138 { \ 139 .type = IIO_ACCEL, \ 140 .channel2 = IIO_MOD_X + (_axis), \ 141 .modified = 1, \ 142 .info_mask_separate = \ 143 BIT(IIO_CHAN_INFO_RAW) | \ 144 BIT(IIO_CHAN_INFO_CALIBBIAS), \ 145 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \ 146 .ext_info = cros_ec_sensors_ext_info, \ 147 .scan_type = { \ 148 .sign = 's', \ 149 .realbits = CROS_EC_SENSOR_BITS, \ 150 .storagebits = CROS_EC_SENSOR_BITS, \ 151 }, \ 152 .scan_index = CROS_EC_ACCEL_ROTATE_AXIS(_axis), \ 153 } \ 154 155 static const struct iio_chan_spec cros_ec_accel_legacy_channels[] = { 156 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_X), 157 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Y), 158 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Z), 159 IIO_CHAN_SOFT_TIMESTAMP(CROS_EC_SENSOR_MAX_AXIS) 160 }; 161 162 static int cros_ec_accel_legacy_probe(struct platform_device *pdev) 163 { 164 struct device *dev = &pdev->dev; 165 struct iio_dev *indio_dev; 166 struct cros_ec_sensors_core_state *state; 167 int ret; 168 169 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state)); 170 if (!indio_dev) 171 return -ENOMEM; 172 173 ret = cros_ec_sensors_core_init(pdev, indio_dev, true); 174 if (ret) 175 return ret; 176 177 indio_dev->info = &cros_ec_accel_legacy_info; 178 state = iio_priv(indio_dev); 179 180 if (state->ec->cmd_readmem != NULL) 181 state->read_ec_sensors_data = cros_ec_sensors_read_lpc; 182 else 183 state->read_ec_sensors_data = cros_ec_accel_legacy_read_cmd; 184 185 indio_dev->channels = cros_ec_accel_legacy_channels; 186 indio_dev->num_channels = ARRAY_SIZE(cros_ec_accel_legacy_channels); 187 /* The lid sensor needs to be presented inverted. */ 188 if (state->loc == MOTIONSENSE_LOC_LID) { 189 state->sign[CROS_EC_SENSOR_X] = -1; 190 state->sign[CROS_EC_SENSOR_Z] = -1; 191 } 192 193 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, 194 cros_ec_sensors_capture, NULL); 195 if (ret) 196 return ret; 197 198 return devm_iio_device_register(dev, indio_dev); 199 } 200 201 static struct platform_driver cros_ec_accel_platform_driver = { 202 .driver = { 203 .name = DRV_NAME, 204 }, 205 .probe = cros_ec_accel_legacy_probe, 206 }; 207 module_platform_driver(cros_ec_accel_platform_driver); 208 209 MODULE_DESCRIPTION("ChromeOS EC legacy accelerometer driver"); 210 MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>"); 211 MODULE_LICENSE("GPL v2"); 212 MODULE_ALIAS("platform:" DRV_NAME); 213