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/mfd/cros_ec.h> 22 #include <linux/module.h> 23 #include <linux/slab.h> 24 #include <linux/platform_data/cros_ec_commands.h> 25 #include <linux/platform_data/cros_ec_proto.h> 26 #include <linux/platform_device.h> 27 28 #define DRV_NAME "cros-ec-accel-legacy" 29 30 #define CROS_EC_SENSOR_LEGACY_NUM 2 31 /* 32 * Sensor scale hard coded at 10 bits per g, computed as: 33 * g / (2^10 - 1) = 0.009586168; with g = 9.80665 m.s^-2 34 */ 35 #define ACCEL_LEGACY_NSCALE 9586168 36 37 static int cros_ec_accel_legacy_read_cmd(struct iio_dev *indio_dev, 38 unsigned long scan_mask, s16 *data) 39 { 40 struct cros_ec_sensors_core_state *st = iio_priv(indio_dev); 41 int ret; 42 unsigned int i; 43 u8 sensor_num; 44 45 /* 46 * Read all sensor data through a command. 47 * Save sensor_num, it is assumed to stay. 48 */ 49 sensor_num = st->param.info.sensor_num; 50 st->param.cmd = MOTIONSENSE_CMD_DUMP; 51 st->param.dump.max_sensor_count = CROS_EC_SENSOR_LEGACY_NUM; 52 ret = cros_ec_motion_send_host_cmd(st, 53 sizeof(st->resp->dump) + CROS_EC_SENSOR_LEGACY_NUM * 54 sizeof(struct ec_response_motion_sensor_data)); 55 st->param.info.sensor_num = sensor_num; 56 if (ret != 0) { 57 dev_warn(&indio_dev->dev, "Unable to read sensor data\n"); 58 return ret; 59 } 60 61 for_each_set_bit(i, &scan_mask, indio_dev->masklength) { 62 *data = st->resp->dump.sensor[sensor_num].data[i] * 63 st->sign[i]; 64 data++; 65 } 66 67 return 0; 68 } 69 70 static int cros_ec_accel_legacy_read(struct iio_dev *indio_dev, 71 struct iio_chan_spec const *chan, 72 int *val, int *val2, long mask) 73 { 74 struct cros_ec_sensors_core_state *st = iio_priv(indio_dev); 75 s16 data = 0; 76 int ret; 77 int idx = chan->scan_index; 78 79 mutex_lock(&st->cmd_lock); 80 81 switch (mask) { 82 case IIO_CHAN_INFO_RAW: 83 ret = st->read_ec_sensors_data(indio_dev, 1 << idx, &data); 84 if (ret < 0) 85 break; 86 ret = IIO_VAL_INT; 87 *val = data; 88 break; 89 case IIO_CHAN_INFO_SCALE: 90 WARN_ON(st->type != MOTIONSENSE_TYPE_ACCEL); 91 *val = 0; 92 *val2 = ACCEL_LEGACY_NSCALE; 93 ret = IIO_VAL_INT_PLUS_NANO; 94 break; 95 case IIO_CHAN_INFO_CALIBBIAS: 96 /* Calibration not supported. */ 97 *val = 0; 98 ret = IIO_VAL_INT; 99 break; 100 default: 101 ret = cros_ec_sensors_core_read(st, chan, val, val2, 102 mask); 103 break; 104 } 105 mutex_unlock(&st->cmd_lock); 106 107 return ret; 108 } 109 110 static int cros_ec_accel_legacy_write(struct iio_dev *indio_dev, 111 struct iio_chan_spec const *chan, 112 int val, int val2, long mask) 113 { 114 /* 115 * Do nothing but don't return an error code to allow calibration 116 * script to work. 117 */ 118 if (mask == IIO_CHAN_INFO_CALIBBIAS) 119 return 0; 120 121 return -EINVAL; 122 } 123 124 static const struct iio_info cros_ec_accel_legacy_info = { 125 .read_raw = &cros_ec_accel_legacy_read, 126 .write_raw = &cros_ec_accel_legacy_write, 127 }; 128 129 /* 130 * Present the channel using HTML5 standard: 131 * need to invert X and Y and invert some lid axis. 132 */ 133 #define CROS_EC_ACCEL_ROTATE_AXIS(_axis) \ 134 ((_axis) == CROS_EC_SENSOR_Z ? CROS_EC_SENSOR_Z : \ 135 ((_axis) == CROS_EC_SENSOR_X ? CROS_EC_SENSOR_Y : \ 136 CROS_EC_SENSOR_X)) 137 138 #define CROS_EC_ACCEL_LEGACY_CHAN(_axis) \ 139 { \ 140 .type = IIO_ACCEL, \ 141 .channel2 = IIO_MOD_X + (_axis), \ 142 .modified = 1, \ 143 .info_mask_separate = \ 144 BIT(IIO_CHAN_INFO_RAW) | \ 145 BIT(IIO_CHAN_INFO_CALIBBIAS), \ 146 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \ 147 .ext_info = cros_ec_sensors_ext_info, \ 148 .scan_type = { \ 149 .sign = 's', \ 150 .realbits = CROS_EC_SENSOR_BITS, \ 151 .storagebits = CROS_EC_SENSOR_BITS, \ 152 }, \ 153 .scan_index = CROS_EC_ACCEL_ROTATE_AXIS(_axis), \ 154 } \ 155 156 static const struct iio_chan_spec cros_ec_accel_legacy_channels[] = { 157 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_X), 158 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Y), 159 CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Z), 160 IIO_CHAN_SOFT_TIMESTAMP(CROS_EC_SENSOR_MAX_AXIS) 161 }; 162 163 static int cros_ec_accel_legacy_probe(struct platform_device *pdev) 164 { 165 struct device *dev = &pdev->dev; 166 struct cros_ec_dev *ec = dev_get_drvdata(dev->parent); 167 struct iio_dev *indio_dev; 168 struct cros_ec_sensors_core_state *state; 169 int ret; 170 171 if (!ec || !ec->ec_dev) { 172 dev_warn(&pdev->dev, "No EC device found.\n"); 173 return -EINVAL; 174 } 175 176 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state)); 177 if (!indio_dev) 178 return -ENOMEM; 179 180 ret = cros_ec_sensors_core_init(pdev, indio_dev, true); 181 if (ret) 182 return ret; 183 184 indio_dev->info = &cros_ec_accel_legacy_info; 185 state = iio_priv(indio_dev); 186 187 if (state->ec->cmd_readmem != NULL) 188 state->read_ec_sensors_data = cros_ec_sensors_read_lpc; 189 else 190 state->read_ec_sensors_data = cros_ec_accel_legacy_read_cmd; 191 192 indio_dev->channels = cros_ec_accel_legacy_channels; 193 indio_dev->num_channels = ARRAY_SIZE(cros_ec_accel_legacy_channels); 194 /* The lid sensor needs to be presented inverted. */ 195 if (state->loc == MOTIONSENSE_LOC_LID) { 196 state->sign[CROS_EC_SENSOR_X] = -1; 197 state->sign[CROS_EC_SENSOR_Z] = -1; 198 } 199 200 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, 201 cros_ec_sensors_capture, NULL); 202 if (ret) 203 return ret; 204 205 return devm_iio_device_register(dev, indio_dev); 206 } 207 208 static struct platform_driver cros_ec_accel_platform_driver = { 209 .driver = { 210 .name = DRV_NAME, 211 }, 212 .probe = cros_ec_accel_legacy_probe, 213 }; 214 module_platform_driver(cros_ec_accel_platform_driver); 215 216 MODULE_DESCRIPTION("ChromeOS EC legacy accelerometer driver"); 217 MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>"); 218 MODULE_LICENSE("GPL v2"); 219 MODULE_ALIAS("platform:" DRV_NAME); 220