Joachim Eastwood | a84ef0d | 2015-10-31 13:49:16 +0100 | [diff] [blame] | 1 | /* |
| 2 | * IIO accel core driver for Freescale MMA7455L 3-axis 10-bit accelerometer |
| 3 | * Copyright 2015 Joachim Eastwood <manabian@gmail.com> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * UNSUPPORTED hardware features: |
| 10 | * - 8-bit mode with different scales |
| 11 | * - INT1/INT2 interrupts |
| 12 | * - Offset calibration |
| 13 | * - Events |
| 14 | */ |
| 15 | |
| 16 | #include <linux/delay.h> |
| 17 | #include <linux/iio/iio.h> |
| 18 | #include <linux/iio/sysfs.h> |
| 19 | #include <linux/iio/buffer.h> |
| 20 | #include <linux/iio/trigger.h> |
| 21 | #include <linux/iio/trigger_consumer.h> |
| 22 | #include <linux/iio/triggered_buffer.h> |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/regmap.h> |
| 25 | |
| 26 | #include "mma7455.h" |
| 27 | |
| 28 | #define MMA7455_REG_XOUTL 0x00 |
| 29 | #define MMA7455_REG_XOUTH 0x01 |
| 30 | #define MMA7455_REG_YOUTL 0x02 |
| 31 | #define MMA7455_REG_YOUTH 0x03 |
| 32 | #define MMA7455_REG_ZOUTL 0x04 |
| 33 | #define MMA7455_REG_ZOUTH 0x05 |
| 34 | #define MMA7455_REG_STATUS 0x09 |
| 35 | #define MMA7455_STATUS_DRDY BIT(0) |
| 36 | #define MMA7455_REG_WHOAMI 0x0f |
| 37 | #define MMA7455_WHOAMI_ID 0x55 |
| 38 | #define MMA7455_REG_MCTL 0x16 |
| 39 | #define MMA7455_MCTL_MODE_STANDBY 0x00 |
| 40 | #define MMA7455_MCTL_MODE_MEASURE 0x01 |
| 41 | #define MMA7455_REG_CTL1 0x18 |
| 42 | #define MMA7455_CTL1_DFBW_MASK BIT(7) |
| 43 | #define MMA7455_CTL1_DFBW_125HZ BIT(7) |
| 44 | #define MMA7455_CTL1_DFBW_62_5HZ 0 |
| 45 | #define MMA7455_REG_TW 0x1e |
| 46 | |
| 47 | /* |
| 48 | * When MMA7455 is used in 10-bit it has a fullscale of -8g |
| 49 | * corresponding to raw value -512. The userspace interface |
| 50 | * uses m/s^2 and we declare micro units. |
| 51 | * So scale factor is given by: |
| 52 | * g * 8 * 1e6 / 512 = 153228.90625, with g = 9.80665 |
| 53 | */ |
| 54 | #define MMA7455_10BIT_SCALE 153229 |
| 55 | |
| 56 | struct mma7455_data { |
| 57 | struct regmap *regmap; |
Joachim Eastwood | a84ef0d | 2015-10-31 13:49:16 +0100 | [diff] [blame] | 58 | }; |
| 59 | |
| 60 | static int mma7455_drdy(struct mma7455_data *mma7455) |
| 61 | { |
Alison Schofield | c455e58 | 2016-04-05 22:18:44 -0700 | [diff] [blame] | 62 | struct device *dev = regmap_get_device(mma7455->regmap); |
Joachim Eastwood | a84ef0d | 2015-10-31 13:49:16 +0100 | [diff] [blame] | 63 | unsigned int reg; |
| 64 | int tries = 3; |
| 65 | int ret; |
| 66 | |
| 67 | while (tries-- > 0) { |
| 68 | ret = regmap_read(mma7455->regmap, MMA7455_REG_STATUS, ®); |
| 69 | if (ret) |
| 70 | return ret; |
| 71 | |
| 72 | if (reg & MMA7455_STATUS_DRDY) |
| 73 | return 0; |
| 74 | |
| 75 | msleep(20); |
| 76 | } |
| 77 | |
Alison Schofield | c455e58 | 2016-04-05 22:18:44 -0700 | [diff] [blame] | 78 | dev_warn(dev, "data not ready\n"); |
Joachim Eastwood | a84ef0d | 2015-10-31 13:49:16 +0100 | [diff] [blame] | 79 | |
| 80 | return -EIO; |
| 81 | } |
| 82 | |
| 83 | static irqreturn_t mma7455_trigger_handler(int irq, void *p) |
| 84 | { |
| 85 | struct iio_poll_func *pf = p; |
| 86 | struct iio_dev *indio_dev = pf->indio_dev; |
| 87 | struct mma7455_data *mma7455 = iio_priv(indio_dev); |
| 88 | u8 buf[16]; /* 3 x 16-bit channels + padding + ts */ |
| 89 | int ret; |
| 90 | |
| 91 | ret = mma7455_drdy(mma7455); |
| 92 | if (ret) |
| 93 | goto done; |
| 94 | |
| 95 | ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf, |
| 96 | sizeof(__le16) * 3); |
| 97 | if (ret) |
| 98 | goto done; |
| 99 | |
Gregor Boirie | bc2b7da | 2016-03-09 19:05:49 +0100 | [diff] [blame] | 100 | iio_push_to_buffers_with_timestamp(indio_dev, buf, |
| 101 | iio_get_time_ns(indio_dev)); |
Joachim Eastwood | a84ef0d | 2015-10-31 13:49:16 +0100 | [diff] [blame] | 102 | |
| 103 | done: |
| 104 | iio_trigger_notify_done(indio_dev->trig); |
| 105 | |
| 106 | return IRQ_HANDLED; |
| 107 | } |
| 108 | |
| 109 | static int mma7455_read_raw(struct iio_dev *indio_dev, |
| 110 | struct iio_chan_spec const *chan, |
| 111 | int *val, int *val2, long mask) |
| 112 | { |
| 113 | struct mma7455_data *mma7455 = iio_priv(indio_dev); |
| 114 | unsigned int reg; |
| 115 | __le16 data; |
| 116 | int ret; |
| 117 | |
| 118 | switch (mask) { |
| 119 | case IIO_CHAN_INFO_RAW: |
| 120 | if (iio_buffer_enabled(indio_dev)) |
| 121 | return -EBUSY; |
| 122 | |
| 123 | ret = mma7455_drdy(mma7455); |
| 124 | if (ret) |
| 125 | return ret; |
| 126 | |
| 127 | ret = regmap_bulk_read(mma7455->regmap, chan->address, &data, |
| 128 | sizeof(data)); |
| 129 | if (ret) |
| 130 | return ret; |
| 131 | |
| 132 | *val = sign_extend32(le16_to_cpu(data), 9); |
| 133 | |
| 134 | return IIO_VAL_INT; |
| 135 | |
| 136 | case IIO_CHAN_INFO_SCALE: |
| 137 | *val = 0; |
| 138 | *val2 = MMA7455_10BIT_SCALE; |
| 139 | |
| 140 | return IIO_VAL_INT_PLUS_MICRO; |
| 141 | |
| 142 | case IIO_CHAN_INFO_SAMP_FREQ: |
| 143 | ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, ®); |
| 144 | if (ret) |
| 145 | return ret; |
| 146 | |
| 147 | if (reg & MMA7455_CTL1_DFBW_MASK) |
| 148 | *val = 250; |
| 149 | else |
| 150 | *val = 125; |
| 151 | |
| 152 | return IIO_VAL_INT; |
| 153 | } |
| 154 | |
| 155 | return -EINVAL; |
| 156 | } |
| 157 | |
| 158 | static int mma7455_write_raw(struct iio_dev *indio_dev, |
| 159 | struct iio_chan_spec const *chan, |
| 160 | int val, int val2, long mask) |
| 161 | { |
| 162 | struct mma7455_data *mma7455 = iio_priv(indio_dev); |
| 163 | int i; |
| 164 | |
| 165 | switch (mask) { |
| 166 | case IIO_CHAN_INFO_SAMP_FREQ: |
| 167 | if (val == 250 && val2 == 0) |
| 168 | i = MMA7455_CTL1_DFBW_125HZ; |
| 169 | else if (val == 125 && val2 == 0) |
| 170 | i = MMA7455_CTL1_DFBW_62_5HZ; |
| 171 | else |
| 172 | return -EINVAL; |
| 173 | |
| 174 | return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1, |
| 175 | MMA7455_CTL1_DFBW_MASK, i); |
| 176 | |
| 177 | case IIO_CHAN_INFO_SCALE: |
| 178 | /* In 10-bit mode there is only one scale available */ |
| 179 | if (val == 0 && val2 == MMA7455_10BIT_SCALE) |
| 180 | return 0; |
| 181 | break; |
| 182 | } |
| 183 | |
| 184 | return -EINVAL; |
| 185 | } |
| 186 | |
| 187 | static IIO_CONST_ATTR(sampling_frequency_available, "125 250"); |
| 188 | |
| 189 | static struct attribute *mma7455_attributes[] = { |
| 190 | &iio_const_attr_sampling_frequency_available.dev_attr.attr, |
| 191 | NULL |
| 192 | }; |
| 193 | |
| 194 | static const struct attribute_group mma7455_group = { |
| 195 | .attrs = mma7455_attributes, |
| 196 | }; |
| 197 | |
| 198 | static const struct iio_info mma7455_info = { |
| 199 | .attrs = &mma7455_group, |
| 200 | .read_raw = mma7455_read_raw, |
| 201 | .write_raw = mma7455_write_raw, |
| 202 | .driver_module = THIS_MODULE, |
| 203 | }; |
| 204 | |
| 205 | #define MMA7455_CHANNEL(axis, idx) { \ |
| 206 | .type = IIO_ACCEL, \ |
| 207 | .modified = 1, \ |
| 208 | .address = MMA7455_REG_##axis##OUTL,\ |
| 209 | .channel2 = IIO_MOD_##axis, \ |
| 210 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| 211 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ |
| 212 | BIT(IIO_CHAN_INFO_SCALE), \ |
| 213 | .scan_index = idx, \ |
| 214 | .scan_type = { \ |
| 215 | .sign = 's', \ |
| 216 | .realbits = 10, \ |
| 217 | .storagebits = 16, \ |
| 218 | .endianness = IIO_LE, \ |
| 219 | }, \ |
| 220 | } |
| 221 | |
| 222 | static const struct iio_chan_spec mma7455_channels[] = { |
| 223 | MMA7455_CHANNEL(X, 0), |
| 224 | MMA7455_CHANNEL(Y, 1), |
| 225 | MMA7455_CHANNEL(Z, 2), |
| 226 | IIO_CHAN_SOFT_TIMESTAMP(3), |
| 227 | }; |
| 228 | |
| 229 | static const unsigned long mma7455_scan_masks[] = {0x7, 0}; |
| 230 | |
| 231 | const struct regmap_config mma7455_core_regmap = { |
| 232 | .reg_bits = 8, |
| 233 | .val_bits = 8, |
| 234 | .max_register = MMA7455_REG_TW, |
| 235 | }; |
| 236 | EXPORT_SYMBOL_GPL(mma7455_core_regmap); |
| 237 | |
| 238 | int mma7455_core_probe(struct device *dev, struct regmap *regmap, |
| 239 | const char *name) |
| 240 | { |
| 241 | struct mma7455_data *mma7455; |
| 242 | struct iio_dev *indio_dev; |
| 243 | unsigned int reg; |
| 244 | int ret; |
| 245 | |
| 246 | ret = regmap_read(regmap, MMA7455_REG_WHOAMI, ®); |
| 247 | if (ret) { |
| 248 | dev_err(dev, "unable to read reg\n"); |
| 249 | return ret; |
| 250 | } |
| 251 | |
| 252 | if (reg != MMA7455_WHOAMI_ID) { |
| 253 | dev_err(dev, "device id mismatch\n"); |
| 254 | return -ENODEV; |
| 255 | } |
| 256 | |
| 257 | indio_dev = devm_iio_device_alloc(dev, sizeof(*mma7455)); |
| 258 | if (!indio_dev) |
| 259 | return -ENOMEM; |
| 260 | |
| 261 | dev_set_drvdata(dev, indio_dev); |
| 262 | mma7455 = iio_priv(indio_dev); |
| 263 | mma7455->regmap = regmap; |
Joachim Eastwood | a84ef0d | 2015-10-31 13:49:16 +0100 | [diff] [blame] | 264 | |
| 265 | indio_dev->info = &mma7455_info; |
| 266 | indio_dev->name = name; |
| 267 | indio_dev->dev.parent = dev; |
| 268 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 269 | indio_dev->channels = mma7455_channels; |
| 270 | indio_dev->num_channels = ARRAY_SIZE(mma7455_channels); |
| 271 | indio_dev->available_scan_masks = mma7455_scan_masks; |
| 272 | |
| 273 | regmap_write(mma7455->regmap, MMA7455_REG_MCTL, |
| 274 | MMA7455_MCTL_MODE_MEASURE); |
| 275 | |
| 276 | ret = iio_triggered_buffer_setup(indio_dev, NULL, |
| 277 | mma7455_trigger_handler, NULL); |
| 278 | if (ret) { |
| 279 | dev_err(dev, "unable to setup triggered buffer\n"); |
| 280 | return ret; |
| 281 | } |
| 282 | |
| 283 | ret = iio_device_register(indio_dev); |
| 284 | if (ret) { |
| 285 | dev_err(dev, "unable to register device\n"); |
| 286 | iio_triggered_buffer_cleanup(indio_dev); |
| 287 | return ret; |
| 288 | } |
| 289 | |
| 290 | return 0; |
| 291 | } |
| 292 | EXPORT_SYMBOL_GPL(mma7455_core_probe); |
| 293 | |
| 294 | int mma7455_core_remove(struct device *dev) |
| 295 | { |
| 296 | struct iio_dev *indio_dev = dev_get_drvdata(dev); |
| 297 | struct mma7455_data *mma7455 = iio_priv(indio_dev); |
| 298 | |
| 299 | iio_device_unregister(indio_dev); |
| 300 | iio_triggered_buffer_cleanup(indio_dev); |
| 301 | |
| 302 | regmap_write(mma7455->regmap, MMA7455_REG_MCTL, |
| 303 | MMA7455_MCTL_MODE_STANDBY); |
| 304 | |
| 305 | return 0; |
| 306 | } |
| 307 | EXPORT_SYMBOL_GPL(mma7455_core_remove); |
| 308 | |
| 309 | MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>"); |
| 310 | MODULE_DESCRIPTION("Freescale MMA7455L core accelerometer driver"); |
| 311 | MODULE_LICENSE("GPL v2"); |