diff options
Diffstat (limited to 'drivers/iio/accel/mma7455_core.c')
| -rw-r--r-- | drivers/iio/accel/mma7455_core.c | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/drivers/iio/accel/mma7455_core.c b/drivers/iio/accel/mma7455_core.c new file mode 100644 index 000000000..c633cc2c0 --- /dev/null +++ b/drivers/iio/accel/mma7455_core.c @@ -0,0 +1,311 @@ +/* + * IIO accel core driver for Freescale MMA7455L 3-axis 10-bit accelerometer + * Copyright 2015 Joachim Eastwood <manabian@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * UNSUPPORTED hardware features: + * - 8-bit mode with different scales + * - INT1/INT2 interrupts + * - Offset calibration + * - Events + */ + +#include <linux/delay.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/module.h> +#include <linux/regmap.h> + +#include "mma7455.h" + +#define MMA7455_REG_XOUTL 0x00 +#define MMA7455_REG_XOUTH 0x01 +#define MMA7455_REG_YOUTL 0x02 +#define MMA7455_REG_YOUTH 0x03 +#define MMA7455_REG_ZOUTL 0x04 +#define MMA7455_REG_ZOUTH 0x05 +#define MMA7455_REG_STATUS 0x09 +#define MMA7455_STATUS_DRDY BIT(0) +#define MMA7455_REG_WHOAMI 0x0f +#define MMA7455_WHOAMI_ID 0x55 +#define MMA7455_REG_MCTL 0x16 +#define MMA7455_MCTL_MODE_STANDBY 0x00 +#define MMA7455_MCTL_MODE_MEASURE 0x01 +#define MMA7455_REG_CTL1 0x18 +#define MMA7455_CTL1_DFBW_MASK BIT(7) +#define MMA7455_CTL1_DFBW_125HZ BIT(7) +#define MMA7455_CTL1_DFBW_62_5HZ 0 +#define MMA7455_REG_TW 0x1e + +/* + * When MMA7455 is used in 10-bit it has a fullscale of -8g + * corresponding to raw value -512. The userspace interface + * uses m/s^2 and we declare micro units. + * So scale factor is given by: + * g * 8 * 1e6 / 512 = 153228.90625, with g = 9.80665 + */ +#define MMA7455_10BIT_SCALE 153229 + +struct mma7455_data { + struct regmap *regmap; + struct device *dev; +}; + +static int mma7455_drdy(struct mma7455_data *mma7455) +{ + unsigned int reg; + int tries = 3; + int ret; + + while (tries-- > 0) { + ret = regmap_read(mma7455->regmap, MMA7455_REG_STATUS, ®); + if (ret) + return ret; + + if (reg & MMA7455_STATUS_DRDY) + return 0; + + msleep(20); + } + + dev_warn(mma7455->dev, "data not ready\n"); + + return -EIO; +} + +static irqreturn_t mma7455_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct mma7455_data *mma7455 = iio_priv(indio_dev); + u8 buf[16]; /* 3 x 16-bit channels + padding + ts */ + int ret; + + ret = mma7455_drdy(mma7455); + if (ret) + goto done; + + ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf, + sizeof(__le16) * 3); + if (ret) + goto done; + + iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns()); + +done: + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static int mma7455_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mma7455_data *mma7455 = iio_priv(indio_dev); + unsigned int reg; + __le16 data; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (iio_buffer_enabled(indio_dev)) + return -EBUSY; + + ret = mma7455_drdy(mma7455); + if (ret) + return ret; + + ret = regmap_bulk_read(mma7455->regmap, chan->address, &data, + sizeof(data)); + if (ret) + return ret; + + *val = sign_extend32(le16_to_cpu(data), 9); + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + *val = 0; + *val2 = MMA7455_10BIT_SCALE; + + return IIO_VAL_INT_PLUS_MICRO; + + case IIO_CHAN_INFO_SAMP_FREQ: + ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, ®); + if (ret) + return ret; + + if (reg & MMA7455_CTL1_DFBW_MASK) + *val = 250; + else + *val = 125; + + return IIO_VAL_INT; + } + + return -EINVAL; +} + +static int mma7455_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct mma7455_data *mma7455 = iio_priv(indio_dev); + int i; + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + if (val == 250 && val2 == 0) + i = MMA7455_CTL1_DFBW_125HZ; + else if (val == 125 && val2 == 0) + i = MMA7455_CTL1_DFBW_62_5HZ; + else + return -EINVAL; + + return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1, + MMA7455_CTL1_DFBW_MASK, i); + + case IIO_CHAN_INFO_SCALE: + /* In 10-bit mode there is only one scale available */ + if (val == 0 && val2 == MMA7455_10BIT_SCALE) + return 0; + break; + } + + return -EINVAL; +} + +static IIO_CONST_ATTR(sampling_frequency_available, "125 250"); + +static struct attribute *mma7455_attributes[] = { + &iio_const_attr_sampling_frequency_available.dev_attr.attr, + NULL +}; + +static const struct attribute_group mma7455_group = { + .attrs = mma7455_attributes, +}; + +static const struct iio_info mma7455_info = { + .attrs = &mma7455_group, + .read_raw = mma7455_read_raw, + .write_raw = mma7455_write_raw, + .driver_module = THIS_MODULE, +}; + +#define MMA7455_CHANNEL(axis, idx) { \ + .type = IIO_ACCEL, \ + .modified = 1, \ + .address = MMA7455_REG_##axis##OUTL,\ + .channel2 = IIO_MOD_##axis, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ + BIT(IIO_CHAN_INFO_SCALE), \ + .scan_index = idx, \ + .scan_type = { \ + .sign = 's', \ + .realbits = 10, \ + .storagebits = 16, \ + .endianness = IIO_LE, \ + }, \ +} + +static const struct iio_chan_spec mma7455_channels[] = { + MMA7455_CHANNEL(X, 0), + MMA7455_CHANNEL(Y, 1), + MMA7455_CHANNEL(Z, 2), + IIO_CHAN_SOFT_TIMESTAMP(3), +}; + +static const unsigned long mma7455_scan_masks[] = {0x7, 0}; + +const struct regmap_config mma7455_core_regmap = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MMA7455_REG_TW, +}; +EXPORT_SYMBOL_GPL(mma7455_core_regmap); + +int mma7455_core_probe(struct device *dev, struct regmap *regmap, + const char *name) +{ + struct mma7455_data *mma7455; + struct iio_dev *indio_dev; + unsigned int reg; + int ret; + + ret = regmap_read(regmap, MMA7455_REG_WHOAMI, ®); + if (ret) { + dev_err(dev, "unable to read reg\n"); + return ret; + } + + if (reg != MMA7455_WHOAMI_ID) { + dev_err(dev, "device id mismatch\n"); + return -ENODEV; + } + + indio_dev = devm_iio_device_alloc(dev, sizeof(*mma7455)); + if (!indio_dev) + return -ENOMEM; + + dev_set_drvdata(dev, indio_dev); + mma7455 = iio_priv(indio_dev); + mma7455->regmap = regmap; + mma7455->dev = dev; + + indio_dev->info = &mma7455_info; + indio_dev->name = name; + indio_dev->dev.parent = dev; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = mma7455_channels; + indio_dev->num_channels = ARRAY_SIZE(mma7455_channels); + indio_dev->available_scan_masks = mma7455_scan_masks; + + regmap_write(mma7455->regmap, MMA7455_REG_MCTL, + MMA7455_MCTL_MODE_MEASURE); + + ret = iio_triggered_buffer_setup(indio_dev, NULL, + mma7455_trigger_handler, NULL); + if (ret) { + dev_err(dev, "unable to setup triggered buffer\n"); + return ret; + } + + ret = iio_device_register(indio_dev); + if (ret) { + dev_err(dev, "unable to register device\n"); + iio_triggered_buffer_cleanup(indio_dev); + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(mma7455_core_probe); + +int mma7455_core_remove(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct mma7455_data *mma7455 = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + iio_triggered_buffer_cleanup(indio_dev); + + regmap_write(mma7455->regmap, MMA7455_REG_MCTL, + MMA7455_MCTL_MODE_STANDBY); + + return 0; +} +EXPORT_SYMBOL_GPL(mma7455_core_remove); + +MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>"); +MODULE_DESCRIPTION("Freescale MMA7455L core accelerometer driver"); +MODULE_LICENSE("GPL v2"); |