--- /dev/null
+/**
+ * Freescale MMA7660FC 3-Axis Accelerometer
+ *
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.
+ */
+
+#include <linux/acpi.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define MMA7660_DRIVER_NAME "mma7660"
+
+#define MMA7660_REG_XOUT 0x00
+#define MMA7660_REG_YOUT 0x01
+#define MMA7660_REG_ZOUT 0x02
+#define MMA7660_REG_OUT_BIT_ALERT BIT(6)
+
+#define MMA7660_REG_MODE 0x07
+#define MMA7660_REG_MODE_BIT_MODE BIT(0)
+#define MMA7660_REG_MODE_BIT_TON BIT(2)
+
+#define MMA7660_I2C_READ_RETRIES 5
+
+/*
+ * The accelerometer has one measurement range:
+ *
+ * -1.5g - +1.5g (6-bit, signed)
+ *
+ * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1) = 0.467142857
+ */
+
+#define MMA7660_SCALE_AVAIL "0.467142857"
+
+const int mma7660_nscale = 467142857;
+
+#define MMA7660_CHANNEL(reg, axis) { \
+ .type = IIO_ACCEL, \
+ .address = reg, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_##axis, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+}
+
+static const struct iio_chan_spec mma7660_channels[] = {
+ MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
+ MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
+ MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
+};
+
+enum mma7660_mode {
+ MMA7660_MODE_STANDBY,
+ MMA7660_MODE_ACTIVE
+};
+
+struct mma7660_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ enum mma7660_mode mode;
+};
+
+static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);
+
+static struct attribute *mma7660_attributes[] = {
+ &iio_const_attr_in_accel_scale_available.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group mma7660_attribute_group = {
+ .attrs = mma7660_attributes
+};
+
+static int mma7660_set_mode(struct mma7660_data *data,
+ enum mma7660_mode mode)
+{
+ int ret;
+ struct i2c_client *client = data->client;
+
+ if (mode == data->mode)
+ return 0;
+
+ ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to read sensor mode\n");
+ return ret;
+ }
+
+ if (mode == MMA7660_MODE_ACTIVE) {
+ ret &= ~MMA7660_REG_MODE_BIT_TON;
+ ret |= MMA7660_REG_MODE_BIT_MODE;
+ } else {
+ ret &= ~MMA7660_REG_MODE_BIT_TON;
+ ret &= ~MMA7660_REG_MODE_BIT_MODE;
+ }
+
+ ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to change sensor mode\n");
+ return ret;
+ }
+
+ data->mode = mode;
+
+ return ret;
+}
+
+static int mma7660_read_accel(struct mma7660_data *data, u8 address)
+{
+ int ret, retries = MMA7660_I2C_READ_RETRIES;
+ struct i2c_client *client = data->client;
+
+ /*
+ * Read data. If the Alert bit is set, the register was read at
+ * the same time as the device was attempting to update the content.
+ * The solution is to read the register again. Do this only
+ * MMA7660_I2C_READ_RETRIES times to avoid spending too much time
+ * in the kernel.
+ */
+ do {
+ ret = i2c_smbus_read_byte_data(client, address);
+ if (ret < 0) {
+ dev_err(&client->dev, "register read failed\n");
+ return ret;
+ }
+ } while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);
+
+ if (ret & MMA7660_REG_OUT_BIT_ALERT) {
+ dev_err(&client->dev, "all register read retries failed\n");
+ return -ETIMEDOUT;
+ }
+
+ return ret;
+}
+
+static int mma7660_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct mma7660_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&data->lock);
+ ret = mma7660_read_accel(data, chan->address);
+ mutex_unlock(&data->lock);
+ if (ret < 0)
+ return ret;
+ *val = sign_extend32(ret, 5);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = mma7660_nscale;
+ return IIO_VAL_INT_PLUS_NANO;
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info mma7660_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = mma7660_read_raw,
+ .attrs = &mma7660_attribute_group,
+};
+
+static int mma7660_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct mma7660_data *data;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev) {
+ dev_err(&client->dev, "iio allocation failed!\n");
+ return -ENOMEM;
+ }
+
+ data = iio_priv(indio_dev);
+ data->client = client;
+ i2c_set_clientdata(client, indio_dev);
+ mutex_init(&data->lock);
+ data->mode = MMA7660_MODE_STANDBY;
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &mma7660_info;
+ indio_dev->name = MMA7660_DRIVER_NAME;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mma7660_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);
+
+ ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
+ if (ret < 0)
+ return ret;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(&client->dev, "device_register failed\n");
+ mma7660_set_mode(data, MMA7660_MODE_STANDBY);
+ }
+
+ return ret;
+}
+
+static int mma7660_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+ iio_device_unregister(indio_dev);
+
+ return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mma7660_suspend(struct device *dev)
+{
+ struct mma7660_data *data;
+
+ data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+
+ return mma7660_set_mode(data, MMA7660_MODE_STANDBY);
+}
+
+static int mma7660_resume(struct device *dev)
+{
+ struct mma7660_data *data;
+
+ data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
+
+ return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
+}
+
+static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume);
+
+#define MMA7660_PM_OPS (&mma7660_pm_ops)
+#else
+#define MMA7660_PM_OPS NULL
+#endif
+
+static const struct i2c_device_id mma7660_i2c_id[] = {
+ {"mma7660", 0},
+ {}
+};
+
+static const struct acpi_device_id mma7660_acpi_id[] = {
+ {"MMA7660", 0},
+ {}
+};
+
+MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);
+
+static struct i2c_driver mma7660_driver = {
+ .driver = {
+ .name = "mma7660",
+ .pm = MMA7660_PM_OPS,
+ .acpi_match_table = ACPI_PTR(mma7660_acpi_id),
+ },
+ .probe = mma7660_probe,
+ .remove = mma7660_remove,
+ .id_table = mma7660_i2c_id,
+};
+
+module_i2c_driver(mma7660_driver);
+
+MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");
+MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-rpi.git / commitdiff