First 5 patches are bugfixes or small enhancements found during
tests with a real platform.
The last patch adds compensation for raw values allowing proper
calibration for Android compass apps.
Changes since v1:
* fixed nits reported by Peter
* few whitespaces and spelling erorrs
* added MMC35240_ prefix to some macro's
Daniel Baluta (6):
iio: magnetometer: mmc35240: i2c device name should be lower case
iio: magnetometer: mmc35240: NULL terminate attribute array
iio: magnetometer: mmc35240: Fix broken processed value
iio: magnetometer: mmc35240: Use a smaller sleep value
iio: magnetometer: mmc35240: Fix sensitivity on z-axis
iio: magnetometer: mmc35240: Add compensation for raw values
drivers/iio/magnetometer/mmc35240.c | 113 ++++++++++++++++++++++++++++--------
1 file changed, 90 insertions(+), 23 deletions(-)
--
1.9.1
This is the standard convention for i2c device name and
also this is the name used in some Intel platforms DT
files.
Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/iio/magnetometer/mmc35240.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index aa6e25d..417eca1 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -490,7 +490,7 @@ static const struct acpi_device_id mmc35240_acpi_match[] = {
MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
static const struct i2c_device_id mmc35240_id[] = {
- {"MMC35240", 0},
+ {"mmc35240", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, mmc35240_id);
--
1.9.1
This avoid nasty crashes when registering the IIO device.
Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/iio/magnetometer/mmc35240.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 417eca1..9d62c53 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -125,6 +125,7 @@ static const struct iio_chan_spec mmc35240_channels[] = {
static struct attribute *mmc35240_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+ NULL
};
static const struct attribute_group mmc35240_attribute_group = {
--
1.9.1
The current computation for fractional part of the magnetic
field is broken. This patch fixes it by taking a different
approach. We expose the raw reading in milli Gauss (to avoid
rounding errors) with a scale of 0.001.
Thus the final computation is done in userspace where floating
point operation are more relaxed.
Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/iio/magnetometer/mmc35240.c | 43 +++++++++++++++++++++++--------------
1 file changed, 27 insertions(+), 16 deletions(-)
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 9d62c53..7fff38e 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -113,8 +113,9 @@ static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666");
.modified = 1, \
.channel2 = IIO_MOD_ ## _axis, \
.address = AXIS_ ## _axis, \
- .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
- .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec mmc35240_channels[] = {
@@ -241,9 +242,19 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
3 * sizeof(__le16));
}
-static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,
- __le16 buf[],
- int *val, int *val2)
+/**
+ * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
+ compensation for output value.
+ *
+ * @data: device private data
+ * @index: axis index for which we want the conversion
+ * @buf: raw data to be converted, 2 bytes in little endian format
+ * @val: compensated output reading (unit is milli gauss)
+ *
+ * Returns: 0 in case of success, -EINVAL when @index is not valid
+ */
+static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
+ __le16 buf[], int *val)
{
int raw_x, raw_y, raw_z;
int sens_x, sens_y, sens_z;
@@ -261,18 +272,15 @@ static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,
switch (index) {
case AXIS_X:
- *val = (raw_x - nfo) / sens_x;
- *val2 = ((raw_x - nfo) % sens_x) * 1000000;
+ *val = (raw_x - nfo) * 1000 / sens_x;
break;
case AXIS_Y:
- *val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z;
- *val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z))
- * 1000000;
+ *val = (raw_y - nfo) * 1000 / sens_y -
+ (raw_z - nfo) * 1000 / sens_z;
break;
case AXIS_Z:
- *val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z;
- *val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z))
- * 1000000;
+ *val = (raw_y - nfo) * 1000 / sens_y +
+ (raw_z - nfo) * 1000 / sens_z;
break;
default:
return -EINVAL;
@@ -290,16 +298,19 @@ static int mmc35240_read_raw(struct iio_dev *indio_dev,
__le16 buf[3];
switch (mask) {
- case IIO_CHAN_INFO_PROCESSED:
+ case IIO_CHAN_INFO_RAW:
mutex_lock(&data->mutex);
ret = mmc35240_read_measurement(data, buf);
mutex_unlock(&data->mutex);
if (ret < 0)
return ret;
- ret = mmc35240_raw_to_gauss(data, chan->address,
- buf, val, val2);
+ ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
if (ret < 0)
return ret;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = 0;
+ *val2 = 1000;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
mutex_lock(&data->mutex);
--
1.9.1
According to datasheet, Page 8, minimum wait time to complete
measurement is 10ms. Adjusting this value will increase the
userspace polling rate.
Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/iio/magnetometer/mmc35240.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 7fff38e..7bc72b3 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -219,7 +219,8 @@ static int mmc35240_take_measurement(struct mmc35240_data *data)
return ret;
if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
break;
- msleep(20);
+ /* minimum wait time to complete measurement is 10 ms */
+ usleep_range(10000, 11000);
}
if (tries < 0) {
--
1.9.1
Datasheet says (Page 2) that typical value for sensitivity
for 16 bits mode on Z-axis is 770. Anyhow, looking at the
input driver provided by Memsic the value for MMC35240 is
1024.
Also, testing shows that using 1024 for Z-axis senzitivity
offers better results.
Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/iio/magnetometer/mmc35240.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 7bc72b3..73fa111 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -77,7 +77,7 @@ static const struct {
} mmc35240_props_table[] = {
/* 16 bits, 100Hz ODR */
{
- {1024, 1024, 770},
+ {1024, 1024, 1024},
32768,
},
/* 16 bits, 200Hz ODR */
--
1.9.1
This patch adds compensation formula to raw readings, borrowed
from Memsic's input driver.
Signed-off-by: Daniel Baluta <[email protected]>
---
drivers/iio/magnetometer/mmc35240.c | 62 ++++++++++++++++++++++++++++++++++---
1 file changed, 58 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 73fa111..7540bbf 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -58,6 +58,31 @@
#define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
#define MMC53240_WAIT_SET_RESET 1000 /* us */
+/*
+ * Memsic OTP process code piece is put here for reference:
+ *
+ * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
+ * 1) For X axis, the COEFFICIENT is always 1.
+ * 2) For Y axis, the COEFFICIENT is as below:
+ * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
+ * (reg_data[2] >> 4)) + 1.0;
+ * 3) For Z axis, the COEFFICIENT is as below:
+ * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
+ * We implemented the OTP logic into driver.
+ */
+
+/* scale = 1000 here for Y otp */
+#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
+
+/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
+#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
+
+#define MMC35240_X_COEFF(x) (x)
+#define MMC35240_Y_COEFF(y) (y + 1000)
+#define MMC35240_Z_COEFF(z) (z + 13500)
+
+#define MMC35240_OTP_START_ADDR 0x1B
+
enum mmc35240_resolution {
MMC35240_16_BITS_SLOW = 0, /* 100 Hz */
MMC35240_16_BITS_FAST, /* 200 Hz */
@@ -102,6 +127,10 @@ struct mmc35240_data {
struct mutex mutex;
struct regmap *regmap;
enum mmc35240_resolution res;
+
+ /* OTP compensation */
+ int axis_coef[3];
+ int axis_scale[3];
};
static const int mmc35240_samp_freq[] = {100, 200, 333, 666};
@@ -172,8 +201,9 @@ static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
static int mmc35240_init(struct mmc35240_data *data)
{
- int ret;
+ int ret, y_convert, z_convert;
unsigned int reg_id;
+ u8 otp_data[6];
ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id);
if (ret < 0) {
@@ -197,9 +227,30 @@ static int mmc35240_init(struct mmc35240_data *data)
return ret;
/* set default sampling frequency */
- return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
- MMC35240_CTRL1_BW_MASK,
- data->res << MMC35240_CTRL1_BW_SHIFT);
+ ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
+ MMC35240_CTRL1_BW_MASK,
+ data->res << MMC35240_CTRL1_BW_SHIFT);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
+ (u8 *)otp_data, sizeof(otp_data));
+ if (ret < 0)
+ return ret;
+
+ y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
+ (otp_data[2] >> 4));
+ z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
+
+ data->axis_coef[0] = MMC35240_X_COEFF(1);
+ data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
+ data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
+
+ data->axis_scale[0] = 1;
+ data->axis_scale[1] = 1000;
+ data->axis_scale[2] = 10000;
+
+ return 0;
}
static int mmc35240_take_measurement(struct mmc35240_data *data)
@@ -286,6 +337,9 @@ static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
default:
return -EINVAL;
}
+ /* apply OTP compensation */
+ *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
+
return 0;
}
--
1.9.1
On 05/06/15 12:03, Daniel Baluta wrote:
> This is the standard convention for i2c device name and
> also this is the name used in some Intel platforms DT
> files.
>
> Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
> Signed-off-by: Daniel Baluta <[email protected]>
applied to the togreg branch of iio.git
Thanks,
> ---
> drivers/iio/magnetometer/mmc35240.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> index aa6e25d..417eca1 100644
> --- a/drivers/iio/magnetometer/mmc35240.c
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -490,7 +490,7 @@ static const struct acpi_device_id mmc35240_acpi_match[] = {
> MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
>
> static const struct i2c_device_id mmc35240_id[] = {
> - {"MMC35240", 0},
> + {"mmc35240", 0},
> {}
> };
> MODULE_DEVICE_TABLE(i2c, mmc35240_id);
>
On 05/06/15 12:03, Daniel Baluta wrote:
> This avoid nasty crashes when registering the IIO device.
>
> Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
> Signed-off-by: Daniel Baluta <[email protected]>
Applied to the togreg branch of iio.git
> ---
> drivers/iio/magnetometer/mmc35240.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> index 417eca1..9d62c53 100644
> --- a/drivers/iio/magnetometer/mmc35240.c
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -125,6 +125,7 @@ static const struct iio_chan_spec mmc35240_channels[] = {
>
> static struct attribute *mmc35240_attributes[] = {
> &iio_const_attr_sampling_frequency_available.dev_attr.attr,
> + NULL
> };
>
> static const struct attribute_group mmc35240_attribute_group = {
>
On 05/06/15 12:03, Daniel Baluta wrote:
> The current computation for fractional part of the magnetic
> field is broken. This patch fixes it by taking a different
> approach. We expose the raw reading in milli Gauss (to avoid
> rounding errors) with a scale of 0.001.
>
> Thus the final computation is done in userspace where floating
> point operation are more relaxed.
>
> Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
> Signed-off-by: Daniel Baluta <[email protected]>
Applied to the togreg branch of iio.git.
Thanks
> ---
> drivers/iio/magnetometer/mmc35240.c | 43 +++++++++++++++++++++++--------------
> 1 file changed, 27 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> index 9d62c53..7fff38e 100644
> --- a/drivers/iio/magnetometer/mmc35240.c
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -113,8 +113,9 @@ static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666");
> .modified = 1, \
> .channel2 = IIO_MOD_ ## _axis, \
> .address = AXIS_ ## _axis, \
> - .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> - .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
> + BIT(IIO_CHAN_INFO_SCALE), \
> }
>
> static const struct iio_chan_spec mmc35240_channels[] = {
> @@ -241,9 +242,19 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
> 3 * sizeof(__le16));
> }
>
> -static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,
> - __le16 buf[],
> - int *val, int *val2)
> +/**
> + * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
> + compensation for output value.
> + *
> + * @data: device private data
> + * @index: axis index for which we want the conversion
> + * @buf: raw data to be converted, 2 bytes in little endian format
> + * @val: compensated output reading (unit is milli gauss)
> + *
> + * Returns: 0 in case of success, -EINVAL when @index is not valid
> + */
> +static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
> + __le16 buf[], int *val)
> {
> int raw_x, raw_y, raw_z;
> int sens_x, sens_y, sens_z;
> @@ -261,18 +272,15 @@ static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,
>
> switch (index) {
> case AXIS_X:
> - *val = (raw_x - nfo) / sens_x;
> - *val2 = ((raw_x - nfo) % sens_x) * 1000000;
> + *val = (raw_x - nfo) * 1000 / sens_x;
> break;
> case AXIS_Y:
> - *val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z;
> - *val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z))
> - * 1000000;
> + *val = (raw_y - nfo) * 1000 / sens_y -
> + (raw_z - nfo) * 1000 / sens_z;
> break;
> case AXIS_Z:
> - *val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z;
> - *val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z))
> - * 1000000;
> + *val = (raw_y - nfo) * 1000 / sens_y +
> + (raw_z - nfo) * 1000 / sens_z;
> break;
> default:
> return -EINVAL;
> @@ -290,16 +298,19 @@ static int mmc35240_read_raw(struct iio_dev *indio_dev,
> __le16 buf[3];
>
> switch (mask) {
> - case IIO_CHAN_INFO_PROCESSED:
> + case IIO_CHAN_INFO_RAW:
> mutex_lock(&data->mutex);
> ret = mmc35240_read_measurement(data, buf);
> mutex_unlock(&data->mutex);
> if (ret < 0)
> return ret;
> - ret = mmc35240_raw_to_gauss(data, chan->address,
> - buf, val, val2);
> + ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
> if (ret < 0)
> return ret;
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + *val = 0;
> + *val2 = 1000;
> return IIO_VAL_INT_PLUS_MICRO;
> case IIO_CHAN_INFO_SAMP_FREQ:
> mutex_lock(&data->mutex);
>
On 05/06/15 12:03, Daniel Baluta wrote:
> According to datasheet, Page 8, minimum wait time to complete
> measurement is 10ms. Adjusting this value will increase the
> userspace polling rate.
>
> Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
> Signed-off-by: Daniel Baluta <[email protected]>
Applied to the togreg branch of iio.git.
Thanks,
> ---
> drivers/iio/magnetometer/mmc35240.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> index 7fff38e..7bc72b3 100644
> --- a/drivers/iio/magnetometer/mmc35240.c
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -219,7 +219,8 @@ static int mmc35240_take_measurement(struct mmc35240_data *data)
> return ret;
> if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
> break;
> - msleep(20);
> + /* minimum wait time to complete measurement is 10 ms */
> + usleep_range(10000, 11000);
> }
>
> if (tries < 0) {
>
On 05/06/15 12:03, Daniel Baluta wrote:
> Datasheet says (Page 2) that typical value for sensitivity
> for 16 bits mode on Z-axis is 770. Anyhow, looking at the
> input driver provided by Memsic the value for MMC35240 is
> 1024.
>
> Also, testing shows that using 1024 for Z-axis senzitivity
> offers better results.
>
> Fixes: abeb6b1e7b ("iio: magnetometer: Add support for MEMSIC MMC35240")
> Signed-off-by: Daniel Baluta <[email protected]>
applied
> ---
> drivers/iio/magnetometer/mmc35240.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> index 7bc72b3..73fa111 100644
> --- a/drivers/iio/magnetometer/mmc35240.c
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -77,7 +77,7 @@ static const struct {
> } mmc35240_props_table[] = {
> /* 16 bits, 100Hz ODR */
> {
> - {1024, 1024, 770},
> + {1024, 1024, 1024},
> 32768,
> },
> /* 16 bits, 200Hz ODR */
>
On 05/06/15 12:03, Daniel Baluta wrote:
> This patch adds compensation formula to raw readings, borrowed
> from Memsic's input driver.
>
> Signed-off-by: Daniel Baluta <[email protected]>
Applied to the togreg branch of iio.git, pushed out shortly as testing.
Thanks,
Jonathan
> ---
> drivers/iio/magnetometer/mmc35240.c | 62 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 58 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
> index 73fa111..7540bbf 100644
> --- a/drivers/iio/magnetometer/mmc35240.c
> +++ b/drivers/iio/magnetometer/mmc35240.c
> @@ -58,6 +58,31 @@
> #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
> #define MMC53240_WAIT_SET_RESET 1000 /* us */
>
> +/*
> + * Memsic OTP process code piece is put here for reference:
> + *
> + * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
> + * 1) For X axis, the COEFFICIENT is always 1.
> + * 2) For Y axis, the COEFFICIENT is as below:
> + * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
> + * (reg_data[2] >> 4)) + 1.0;
> + * 3) For Z axis, the COEFFICIENT is as below:
> + * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
> + * We implemented the OTP logic into driver.
> + */
> +
> +/* scale = 1000 here for Y otp */
> +#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
> +
> +/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
> +#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
> +
> +#define MMC35240_X_COEFF(x) (x)
> +#define MMC35240_Y_COEFF(y) (y + 1000)
> +#define MMC35240_Z_COEFF(z) (z + 13500)
> +
> +#define MMC35240_OTP_START_ADDR 0x1B
> +
> enum mmc35240_resolution {
> MMC35240_16_BITS_SLOW = 0, /* 100 Hz */
> MMC35240_16_BITS_FAST, /* 200 Hz */
> @@ -102,6 +127,10 @@ struct mmc35240_data {
> struct mutex mutex;
> struct regmap *regmap;
> enum mmc35240_resolution res;
> +
> + /* OTP compensation */
> + int axis_coef[3];
> + int axis_scale[3];
> };
>
> static const int mmc35240_samp_freq[] = {100, 200, 333, 666};
> @@ -172,8 +201,9 @@ static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
>
> static int mmc35240_init(struct mmc35240_data *data)
> {
> - int ret;
> + int ret, y_convert, z_convert;
> unsigned int reg_id;
> + u8 otp_data[6];
>
> ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id);
> if (ret < 0) {
> @@ -197,9 +227,30 @@ static int mmc35240_init(struct mmc35240_data *data)
> return ret;
>
> /* set default sampling frequency */
> - return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
> - MMC35240_CTRL1_BW_MASK,
> - data->res << MMC35240_CTRL1_BW_SHIFT);
> + ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
> + MMC35240_CTRL1_BW_MASK,
> + data->res << MMC35240_CTRL1_BW_SHIFT);
> + if (ret < 0)
> + return ret;
> +
> + ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
> + (u8 *)otp_data, sizeof(otp_data));
> + if (ret < 0)
> + return ret;
> +
> + y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
> + (otp_data[2] >> 4));
> + z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
> +
> + data->axis_coef[0] = MMC35240_X_COEFF(1);
> + data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
> + data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
> +
> + data->axis_scale[0] = 1;
> + data->axis_scale[1] = 1000;
> + data->axis_scale[2] = 10000;
> +
> + return 0;
> }
>
> static int mmc35240_take_measurement(struct mmc35240_data *data)
> @@ -286,6 +337,9 @@ static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
> default:
> return -EINVAL;
> }
> + /* apply OTP compensation */
> + *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
> +
> return 0;
> }
>
>