--- /dev/null
+/**
+ * IIO driver for the MiraMEMS DA311 3-axis accelerometer
+ *
+ * Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
+ * Copyright (c) 2011-2013 MiraMEMS Sensing Technology Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/byteorder/generic.h>
+
+#define DA311_CHIP_ID 0x13
+
+/*
+ * Note register addressed go from 0 - 0x3f and then wrap.
+ * For some reason there are 2 banks with 0 - 0x3f addresses,
+ * rather then a single 0-0x7f bank.
+ */
+
+/* Bank 0 regs */
+#define DA311_REG_BANK 0x0000
+#define DA311_REG_LDO_REG 0x0006
+#define DA311_REG_CHIP_ID 0x000f
+#define DA311_REG_TEMP_CFG_REG 0x001f
+#define DA311_REG_CTRL_REG1 0x0020
+#define DA311_REG_CTRL_REG3 0x0022
+#define DA311_REG_CTRL_REG4 0x0023
+#define DA311_REG_CTRL_REG5 0x0024
+#define DA311_REG_CTRL_REG6 0x0025
+#define DA311_REG_STATUS_REG 0x0027
+#define DA311_REG_OUT_X_L 0x0028
+#define DA311_REG_OUT_X_H 0x0029
+#define DA311_REG_OUT_Y_L 0x002a
+#define DA311_REG_OUT_Y_H 0x002b
+#define DA311_REG_OUT_Z_L 0x002c
+#define DA311_REG_OUT_Z_H 0x002d
+#define DA311_REG_INT1_CFG 0x0030
+#define DA311_REG_INT1_SRC 0x0031
+#define DA311_REG_INT1_THS 0x0032
+#define DA311_REG_INT1_DURATION 0x0033
+#define DA311_REG_INT2_CFG 0x0034
+#define DA311_REG_INT2_SRC 0x0035
+#define DA311_REG_INT2_THS 0x0036
+#define DA311_REG_INT2_DURATION 0x0037
+#define DA311_REG_CLICK_CFG 0x0038
+#define DA311_REG_CLICK_SRC 0x0039
+#define DA311_REG_CLICK_THS 0x003a
+#define DA311_REG_TIME_LIMIT 0x003b
+#define DA311_REG_TIME_LATENCY 0x003c
+#define DA311_REG_TIME_WINDOW 0x003d
+
+/* Bank 1 regs */
+#define DA311_REG_SOFT_RESET 0x0105
+#define DA311_REG_OTP_XOFF_L 0x0110
+#define DA311_REG_OTP_XOFF_H 0x0111
+#define DA311_REG_OTP_YOFF_L 0x0112
+#define DA311_REG_OTP_YOFF_H 0x0113
+#define DA311_REG_OTP_ZOFF_L 0x0114
+#define DA311_REG_OTP_ZOFF_H 0x0115
+#define DA311_REG_OTP_XSO 0x0116
+#define DA311_REG_OTP_YSO 0x0117
+#define DA311_REG_OTP_ZSO 0x0118
+#define DA311_REG_OTP_TRIM_OSC 0x011b
+#define DA311_REG_LPF_ABSOLUTE 0x011c
+#define DA311_REG_TEMP_OFF1 0x0127
+#define DA311_REG_TEMP_OFF2 0x0128
+#define DA311_REG_TEMP_OFF3 0x0129
+#define DA311_REG_OTP_TRIM_THERM_H 0x011a
+
+/*
+ * a value of + or -1024 corresponds to + or - 1G
+ * scale = 9.81 / 1024 = 0.009580078
+ */
+
+static const int da311_nscale = 9580078;
+
+#define DA311_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 da311_channels[] = {
+ /* | 0x80 comes from the android driver */
+ DA311_CHANNEL(DA311_REG_OUT_X_L | 0x80, X),
+ DA311_CHANNEL(DA311_REG_OUT_Y_L | 0x80, Y),
+ DA311_CHANNEL(DA311_REG_OUT_Z_L | 0x80, Z),
+};
+
+struct da311_data {
+ struct i2c_client *client;
+};
+
+static int da311_register_mask_write(struct i2c_client *client, u16 addr,
+ u8 mask, u8 data)
+{
+ int ret;
+ u8 tmp_data = 0;
+
+ if (addr & 0xff00) {
+ /* Select bank 1 */
+ ret = i2c_smbus_write_byte_data(client, DA311_REG_BANK, 0x01);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (mask != 0xff) {
+ ret = i2c_smbus_read_byte_data(client, addr);
+ if (ret < 0)
+ return ret;
+ tmp_data = ret;
+ }
+
+ tmp_data &= ~mask;
+ tmp_data |= data & mask;
+ ret = i2c_smbus_write_byte_data(client, addr & 0xff, tmp_data);
+ if (ret < 0)
+ return ret;
+
+ if (addr & 0xff00) {
+ /* Back to bank 0 */
+ ret = i2c_smbus_write_byte_data(client, DA311_REG_BANK, 0x00);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+/* Init sequence taken from the android driver */
+static int da311_reset(struct i2c_client *client)
+{
+ const struct {
+ u16 addr;
+ u8 mask;
+ u8 data;
+ } init_data[] = {
+ { DA311_REG_TEMP_CFG_REG, 0xff, 0x08 },
+ { DA311_REG_CTRL_REG5, 0xff, 0x80 },
+ { DA311_REG_CTRL_REG4, 0x30, 0x00 },
+ { DA311_REG_CTRL_REG1, 0xff, 0x6f },
+ { DA311_REG_TEMP_CFG_REG, 0xff, 0x88 },
+ { DA311_REG_LDO_REG, 0xff, 0x02 },
+ { DA311_REG_OTP_TRIM_OSC, 0xff, 0x27 },
+ { DA311_REG_LPF_ABSOLUTE, 0xff, 0x30 },
+ { DA311_REG_TEMP_OFF1, 0xff, 0x3f },
+ { DA311_REG_TEMP_OFF2, 0xff, 0xff },
+ { DA311_REG_TEMP_OFF3, 0xff, 0x0f },
+ };
+ int i, ret;
+
+ /* Reset */
+ ret = da311_register_mask_write(client, DA311_REG_SOFT_RESET,
+ 0xff, 0xaa);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < ARRAY_SIZE(init_data); i++) {
+ ret = da311_register_mask_write(client,
+ init_data[i].addr,
+ init_data[i].mask,
+ init_data[i].data);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int da311_enable(struct i2c_client *client, bool enable)
+{
+ u8 data = enable ? 0x00 : 0x20;
+
+ return da311_register_mask_write(client, DA311_REG_TEMP_CFG_REG,
+ 0x20, data);
+}
+
+static int da311_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct da311_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = i2c_smbus_read_word_data(data->client, chan->address);
+ if (ret < 0)
+ return ret;
+ /*
+ * Values are 12 bits, stored as 16 bits with the 4
+ * least significant bits always 0.
+ */
+ *val = (short)ret >> 4;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = da311_nscale;
+ return IIO_VAL_INT_PLUS_NANO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info da311_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = da311_read_raw,
+};
+
+static int da311_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct da311_data *data;
+
+ ret = i2c_smbus_read_byte_data(client, DA311_REG_CHIP_ID);
+ if (ret != DA311_CHIP_ID)
+ return (ret < 0) ? ret : -ENODEV;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ data->client = client;
+ i2c_set_clientdata(client, indio_dev);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &da311_info;
+ indio_dev->name = "da311";
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = da311_channels;
+ indio_dev->num_channels = ARRAY_SIZE(da311_channels);
+
+ ret = da311_reset(client);
+ if (ret < 0)
+ return ret;
+
+ ret = da311_enable(client, true);
+ if (ret < 0)
+ return ret;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(&client->dev, "device_register failed\n");
+ da311_enable(client, false);
+ }
+
+ return ret;
+}
+
+static int da311_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+ iio_device_unregister(indio_dev);
+
+ return da311_enable(client, false);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int da311_suspend(struct device *dev)
+{
+ return da311_enable(to_i2c_client(dev), false);
+}
+
+static int da311_resume(struct device *dev)
+{
+ return da311_enable(to_i2c_client(dev), true);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(da311_pm_ops, da311_suspend, da311_resume);
+
+static const struct i2c_device_id da311_i2c_id[] = {
+ {"da311", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, da311_i2c_id);
+
+static struct i2c_driver da311_driver = {
+ .driver = {
+ .name = "da311",
+ .pm = &da311_pm_ops,
+ },
+ .probe = da311_probe,
+ .remove = da311_remove,
+ .id_table = da311_i2c_id,
+};
+
+module_i2c_driver(da311_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("MiraMEMS DA311 3-Axis Accelerometer driver");
+MODULE_LICENSE("GPL v2");