On 06/05/2014 09:33 PM, Srinivas Pandruvada wrote:
[...]
+
+#define AK09911_RAW_TO_GAUSS(asa) ((((asa) + 128) * 6000) / 256)
Instead of doing the conversion in kernel, how about specifing offset and
scale attributes?
+
'...]
+static int ak09911_verify_chip_id(struct i2c_client *client)
+{
+ u8 wia_val[2];
+ int ret;
+
+ ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_WIA1,
+ 2, wia_val);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error reading WIA\n");
+ return ret;
+ }
+
+ dev_dbg(&client->dev, "WIA %02x %02x\n", wia_val[0], wia_val[1]);
+
+ if (wia_val[0] != AK09911_WIA1_VALUE ||
+ wia_val[1] != AK09911_WIA2_VALUE) {
strange alignment here
+ dev_err(&client->dev, "Device ak09911 not found\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
[...]
+static int ak09911_read_axis(struct iio_dev *indio_dev, int index, int *val)
+{
+ struct ak09911_data *data = iio_priv(indio_dev);
+ struct i2c_client *client = data->client;
+ int ret;
+
+ mutex_lock(&data->lock);
+
+ ret = ak09911_set_mode(client, AK09911_MODE_SNG_MEASURE);
+ if (ret < 0)
+ goto fn_exit;
+
+ ret = wait_conversion_complete_polled(data);
+ if (ret < 0)
+ goto fn_exit;
+
+ /* Read data */
+ ret = i2c_smbus_read_word_data(client, ak09911_index_to_reg[index]);
+ if (ret < 0) {
+ dev_err(&client->dev, "Read axis data fails\n");
+ goto fn_exit;
+ }
+
+ mutex_unlock(&data->lock);
+
+ /* Clamp to valid range. */
+ *val = clamp_t(s16, ret, -8192, 8191);
how about usign sign_extend32 here?
extra space between val and =
+
+ return IIO_VAL_INT;
+
+fn_exit:
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int ak09911_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2,
+ long mask)
+{
+ struct ak09911_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ return ak09911_read_axis(indio_dev, chan->address, val);
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = data->raw_to_gauss[chan->address];
+ return IIO_VAL_INT_PLUS_MICRO;
+ }
+
+ return -EINVAL;
+}
+
+#define AK09911_CHANNEL(axis, index) \
+ { \
+ .type = IIO_MAGN, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_##axis, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .address = index, \
+ }
+
+static const struct iio_chan_spec ak09911_channels[] = {
+ AK09911_CHANNEL(X, 0), AK09911_CHANNEL(Y, 1), AK09911_CHANNEL(Z, 2),
+};
+
+static const struct iio_info ak09911_info = {
+ .read_raw = &ak09911_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static const struct acpi_device_id ak_acpi_match[] = {
+ {"AK009911", 0},
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
+
+static int ak09911_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct ak09911_data *data;
+ char *name;
+ int ret;
+
+ ret = ak09911_verify_chip_id(client);
+ if (ret) {
+ dev_err(&client->dev, "AK00911 not detected\n");
+ return -ENODEV;
+ }
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+
+ data->client = client;
+ mutex_init(&data->lock);
+
+ ret = ak09911_get_asa(client);
+ if (ret)
+ return ret;
+
+ if (id)
+ name = (char *) id->name;
+ else if (ACPI_HANDLE(&client->dev))
+ name = (char *)dev_name(&client->dev);
Don't cast the const of the string away. Rather make your name const char *
+ else
+ return -ENODEV;
+
+ dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->channels = ak09911_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ak09911_channels);
+ indio_dev->info = &ak09911_info;
+ indio_dev->name = id->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->name = name;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
[...]
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