--- /dev/null
+/*
+ * 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");
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