On 06/06/2014 02:16 AM, Lars-Peter Clausen wrote:
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?
This value is going to be returned via scale attribute. The "asa" is not
the measured axis value but sensitivity adjustment value. Spec
defines a formula using "asa", which needs to be multiplied with the
measures flux value to get the real flux.
Thanks,
Srinivas
+
'...]
+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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