Re: [PATCH 2/2] iio: accel: Add support for Domintech DMARD06 accelerometer

This patch add support for Domintech DMARD06 accelerometer.

comments below
 

typo: accelerometer

'error' is a bit pessimistic, how about 'ret'? :-)

+

can't use i2c_smbus_read_byte_data()?

+	error = i2c_master_send(client, &reg, 1);
+	if (unlikely(error < 0))
+		return error;
+
+	error = i2c_master_recv(client, buf, 1);
+	if (unlikely(error < 0))
+		return error;

not sure if it is worth to annotate unlikely() here -- i2c is slooow
locking is needed if you really need two i2c_master calls

+	return 0;
+}
+
+static int dmard06_read_chip_id(struct dmard06_data *dmard06)
+{
+	u8 buf;
+	u8 chip_id;
+	int error;
+
+	error = dmard06_i2c_read(dmard06->client, DMARD06_CHIP_ID_REG, &buf);
+	if (error) {
+		dev_err(&dmard06->client->dev, "Failed to read chip id: %d\n",
+			error);
+		return error;
+	}
+
+	chip_id = (buf & 0x00ff);

why? buf is u8 anyways

+	if (chip_id != DMARD06_CHIP_ID) {
+		dev_err(&dmard06->client->dev, "Invalid chip id: %02x\n",
+			chip_id);
+		return -EINVAL;

often ENODEV is used for this case

+	}
+
+	dev_info(&dmard06->client->dev, "Found DMARD%02x chip\n", chip_id);

we prefer silent probing of the driver, please don't clutter the log

+
+	return 0;
+}
+
+static int dmard06_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct dmard06_data *dmard06 = iio_priv(indio_dev);
+	u8 buf;
+	bool reversed;
+	int error;
+	int tmp;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		error = dmard06_i2c_read(dmard06->client, chan->address, &buf);
+		if (error) {
+			dev_err(&dmard06->client->dev,
+				"Failed to read data %d\n", error);
+			return error;
+		}
+
+		reversed = (buf >> 7) & 1;
+		tmp = (int)((buf & 0x7f) >> 1);

+
+		switch (chan->type) {
+		case IIO_ACCEL:

wouldn't sign_extend32(buf >> 1, 6) do the job?

+			*val = reversed ? (tmp - DMARD06_AXIS_MAX_VAL) : tmp;
+			return IIO_VAL_INT;
+		case IIO_TEMP:
+			*val = reversed ? -tmp : tmp;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_OFFSET:
+		switch (chan->type) {
+		case IIO_TEMP:
+			*val = DMARD06_TEMP_CENTER_VAL;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_ACCEL:
+			*val = 0;
+			*val2 = DMARD06_AXIS_SCALE_VAL;
+			return IIO_VAL_INT_PLUS_MICRO;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info dmard06_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= dmard06_read_raw,
+};
+
+#define DMARD06_ACCEL_CHANNEL(_axis, reg) {			\

maybe rename reg to _reg

+	.type = IIO_ACCEL,					\
+	.address = reg,						\
+	.channel2 = IIO_MOD_##_axis,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.modified = 1,						\
+}
+
+#define DMARD06_TEMP_CHANNEL(reg) {				\
+	.type = IIO_TEMP,					\
+	.address = reg,						\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			      BIT(IIO_CHAN_INFO_OFFSET),	\
+}
+
+static const struct iio_chan_spec dmard06_channels[] = {
+	DMARD06_ACCEL_CHANNEL(X, DMARD06_XOUT_REG),
+	DMARD06_ACCEL_CHANNEL(Y, DMARD06_YOUT_REG),
+	DMARD06_ACCEL_CHANNEL(Z, DMARD06_ZOUT_REG),
+	DMARD06_TEMP_CHANNEL(DMARD06_TOUT_REG),
+};
+
+static int dmard06_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	int error;
+	struct iio_dev *indio_dev;
+	struct dmard06_data *dmard06;
+
+	dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);

not needed

+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev, "I2C check functionality failed\n");
+		return -ENXIO;
+	}
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dmard06));
+	if (!indio_dev) {
+		dev_err(&client->dev, "Failed to allocate iio device\n");
+		return -ENOMEM;
+	}
+
+	dmard06 = iio_priv(indio_dev);
+	dmard06->client = client;
+
+	error = dmard06_read_chip_id(dmard06);
+	if (error)
+		return error;
+
+	i2c_set_clientdata(client, indio_dev);
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->name = DMARD06_DRV_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = dmard06_channels;
+	indio_dev->num_channels = ARRAY_SIZE(dmard06_channels);
+	indio_dev->info = &dmard06_info;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id dmard06_id[] = {
+	{ "dmard06", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, dmard06_id);
+
+static const struct of_device_id dmard06_of_match[] = {
+	{ .compatible = "domintech,dmard06" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, dmard06_of_match);
+
+static struct i2c_driver dmard06_driver = {
+	.probe = dmard06_probe,
+	.id_table = dmard06_id,
+	.driver = {
+		.name = DMARD06_DRV_NAME,
+		.of_match_table = of_match_ptr(dmard06_of_match),
+	},
+};
+module_i2c_driver(dmard06_driver);
+
+MODULE_AUTHOR("Aleksei Mamlin [off-list ref]");
+MODULE_DESCRIPTION("Domintech DMARD06 accelerometer driver");
+MODULE_LICENSE("GPL v2");

-- 

Peter Meerwald-Stadler
+43-664-2444418 (mobile)