> Add support for Freescale MMA7455L 3-axis in 10-bit mode with both
> I2C and SPI bus support. This is a rather simple driver that
> currently doesn't support all the hardware features of MMA7455L.
please add a link to the datasheet
comments below
> Tested on Embedded Artists' LPC4357 Dev Kit using I2C bus.
>
> Signed-off-by: Joachim Eastwood <manabian@xxxxxxxxx>
> ---
>
> drivers/iio/accel/Kconfig | 14 ++
> drivers/iio/accel/Makefile | 1 +
> drivers/iio/accel/mma7455.c | 424 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 439 insertions(+)
> create mode 100644 drivers/iio/accel/mma7455.c
>
> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> index a59047d7657e..8ccb3de85484 100644
> --- a/drivers/iio/accel/Kconfig
> +++ b/drivers/iio/accel/Kconfig
> @@ -99,6 +99,20 @@ config KXCJK1013
> To compile this driver as a module, choose M here: the module will
> be called kxcjk-1013.
>
> +config MMA7455
> + tristate "Freescale MMA7455L Accelerometer Driver"
> + depends on I2C || SPI_MASTER
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + select REGMAP_I2C if I2C
> + select REGMAP_SPI if SPI_MASTER
> + help
> + Say yes here to build support for the Freescale MMA7455L 3-axis
> + accelerometer.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called mma7455.
> +
> config MMA8452
> tristate "Freescale MMA8452Q Accelerometer Driver"
> depends on I2C
> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> index ebd2675b2a02..6ac9382761f8 100644
> --- a/drivers/iio/accel/Makefile
> +++ b/drivers/iio/accel/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel.o
> obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
> obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
> obj-$(CONFIG_KXSD9) += kxsd9.o
> +obj-$(CONFIG_MMA7455) += mma7455.o
> obj-$(CONFIG_MMA8452) += mma8452.o
>
> obj-$(CONFIG_MMA9551_CORE) += mma9551_core.o
> diff --git a/drivers/iio/accel/mma7455.c b/drivers/iio/accel/mma7455.c
> new file mode 100644
> index 000000000000..fa62f2bcb54a
> --- /dev/null
> +++ b/drivers/iio/accel/mma7455.c
> @@ -0,0 +1,424 @@
> +/*
> + * mma7455.c - Support for Freescale MMA7455L 3-axis 10-bit accelerometer
> + * Copyright 2015 Joachim Eastwood <manabian@xxxxxxxxx>
> + *
> + * Based on MMA8452Q IIO driver
> + * Copyright 2014 Peter Meerwald <pmeerw@xxxxxxxxxx>
> + *
> + * 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/i2c.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 <linux/spi/spi.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)
whitespace inconsistencies
> +#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 = 10;
> + 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(s16) * 3);
use le16 to hint which endianness the device registers have
> + 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 = 0;
initialization not needed
> + 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->scan_index * 2,
it would be clearer to use chan->address instead of computing the register
instead of s16 I suggest to use le16
using regmap_bulk_read(), there is no endianness conversion; the driver
will only work when chip endianness equals CPU endianness
> + ®, sizeof(s16));
> + if (ret)
> + return ret;
> +
> + *val = sign_extend32(reg, 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;
> +
> + if (iio_buffer_enabled(indio_dev))
> + return -EBUSY;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_SAMP_FREQ:
check val2 == 0
> + if (val == 250)
> + i = MMA7455_CTL1_DFBW_125HZ;
> + else if (val == 125)
> + 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 ssize_t mma7455_show_samp_freq_avail(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return scnprintf(buf, PAGE_SIZE, "125 250\n");
> +}
> +
> +static ssize_t mma7455_show_scale_avail(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return scnprintf(buf, PAGE_SIZE, "0.%u\n", MMA7455_10BIT_SCALE);
> +}
> +
> +static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma7455_show_samp_freq_avail);
> +static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
> + mma7455_show_scale_avail, NULL, 0);
> +
> +static struct attribute *mma7455_attributes[] = {
> + &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
> + &iio_dev_attr_in_accel_scale_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, \
> + .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, \
> + .shift = 0, \
> + .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};
> +
> +static int mma7455_probe(struct device *dev, struct regmap *regmap)
> +{
> + 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 = "mma7455l";
> + 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;
> +}
> +
> +static int mma7455_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;
> +}
> +
> +static const struct regmap_config mma7455_regmap = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .max_register = MMA7455_REG_TW,
> +};
> +
> +#if IS_ENABLED(CONFIG_SPI_MASTER)
> +static int mma7455_spi_probe(struct spi_device *spi)
> +{
> + struct regmap *regmap;
> +
> + regmap = devm_regmap_init_spi(spi, &mma7455_regmap);
> + if (IS_ERR(regmap))
> + return PTR_ERR(regmap);
> +
> + return mma7455_probe(&spi->dev, regmap);
> +}
> +
> +static int mma7455_spi_remove(struct spi_device *spi)
> +{
> + return mma7455_remove(&spi->dev);
> +}
> +
> +static const struct spi_device_id mma7455_spi_id[] = {
> + { "mma7455", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(spi, mma7455_spi_id);
> +
> +static struct spi_driver mma7455_spi_driver = {
> + .probe = mma7455_spi_probe,
> + .remove = mma7455_spi_remove,
> + .id_table = mma7455_spi_id,
> + .driver = {
> + .name = "mma7455-spi",
> + },
> +};
> +#endif
> +
> +#if IS_ENABLED(CONFIG_I2C)
> +static int mma7455_i2c_probe(struct i2c_client *i2c,
> + const struct i2c_device_id *id)
> +{
> + struct regmap *regmap;
> +
> + regmap = devm_regmap_init_i2c(i2c, &mma7455_regmap);
> + if (IS_ERR(regmap))
> + return PTR_ERR(regmap);
> +
> + return mma7455_probe(&i2c->dev, regmap);
> +}
> +
> +static int mma7455_i2c_remove(struct i2c_client *i2c)
> +{
> + return mma7455_remove(&i2c->dev);
> +}
> +
> +static const struct i2c_device_id mma7455_i2c_id[] = {
> + { "mma7455", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, mma7455_i2c_id);
> +
> +static struct i2c_driver mma7455_i2c_driver = {
> + .probe = mma7455_i2c_probe,
> + .remove = mma7455_i2c_remove,
> + .id_table = mma7455_i2c_id,
> + .driver = {
> + .name = "mma7455-i2c",
> + },
> +};
> +#endif
> +
> +static int __init mma7455_modinit(void)
> +{
> + int ret;
> +#if IS_ENABLED(CONFIG_I2C)
> + ret = i2c_add_driver(&mma7455_i2c_driver);
> + if (ret)
> + pr_err("failed to register MMA7455L I2C driver: %d\n", ret);
> +#endif
> +#if IS_ENABLED(CONFIG_SPI_MASTER)
> + ret = spi_register_driver(&mma7455_spi_driver);
> + if (ret)
> + pr_err("failed to register MMA7455L SPI driver: %d\n", ret);
> +#endif
> + return ret;
> +}
> +module_init(mma7455_modinit);
> +
> +static void __exit mma7455_exit(void)
> +{
> +#if IS_ENABLED(CONFIG_I2C)
> + i2c_del_driver(&mma7455_i2c_driver);
> +#endif
> +#if IS_ENABLED(CONFIG_SPI_MASTER)
> + spi_unregister_driver(&mma7455_spi_driver);
> +#endif
> +}
> +module_exit(mma7455_exit);
> +
> +MODULE_AUTHOR("Joachim Eastwood <manabian@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Freescale MMA7455L I2C/SPI accelerometer driver");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald
+43-664-2444418 (mobile)
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