diff mbox series

[v2,1/5] iio: accel: bma400: Fix the scale min and max macro values

Message ID 20220326194146.15549-2-jagathjog1996@gmail.com (mailing list archive)
State Changes Requested
Headers show
Series iio: accel: bma400: Add support for buffer and step | expand

Commit Message

Jagath Jog J March 26, 2022, 7:41 p.m. UTC
Changing the scale macro values to match the bma400 sensitivity
for 1 LSB of all the available ranges.

Signed-off-by: Jagath Jog J <jagathjog1996@gmail.com>
---
 drivers/iio/accel/bma400.h | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

Comments

Jonathan Cameron March 27, 2022, 4:31 p.m. UTC | #1
On Sun, 27 Mar 2022 01:11:42 +0530
Jagath Jog J <jagathjog1996@gmail.com> wrote:

> Changing the scale macro values to match the bma400 sensitivity
> for 1 LSB of all the available ranges.
> 
> Signed-off-by: Jagath Jog J <jagathjog1996@gmail.com>
Hi Jagath,

> ---
>  drivers/iio/accel/bma400.h | 22 ++++++++++++++++++++--
>  1 file changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/accel/bma400.h b/drivers/iio/accel/bma400.h
> index c4c8d74155c2..190366debdb3 100644
> --- a/drivers/iio/accel/bma400.h
> +++ b/drivers/iio/accel/bma400.h
> @@ -83,8 +83,26 @@
>  #define BMA400_ACC_ODR_MIN_WHOLE_HZ 25
>  #define BMA400_ACC_ODR_MIN_HZ       12
>  
> -#define BMA400_SCALE_MIN            38357
> -#define BMA400_SCALE_MAX            306864
> +/* BMA400_SCALE_MIN macro value represents m/s^2 for 1 LSB before
Multiline comment syntax in IIO is
/*
 * BMA400....

> + * converting to micro values for +-2g range.
> + *
> + * For +-2g - 1 LSB = 0.976562 milli g = 0.009576 m/s^2
> + * For +-4g - 1 LSB = 1.953125 milli g = 0.019153 m/s^2
> + * For +-16g - 1 LSB = 7.8125 milli g = 0.076614 m/s^2
> + *
> + * The raw value which is used to select the different ranges is determined
> + * by the first bit set position from the scale value, so BMA400_SCALE_MIN
> + * should be odd.
> + *
> + * Scale values for +-2g, +-4g, +-8g and +-16g is populated into bma400_scales
> + * array by left shifting BMA400_SCALE_MIN.
> + * eg:
> + * To select +-2g = 9577 << 0 = raw value to write is 0.
> + * To select +-8g = 9577 << 2 = raw value to write is 2.
> + * To select +-16g = 9677 << 3 = raw value to write is 3.

9667?

> + */
> +#define BMA400_SCALE_MIN            9577
> +#define BMA400_SCALE_MAX            76617
>  
>  #define BMA400_NUM_REGULATORS       2
>  #define BMA400_VDD_REGULATOR        0
diff mbox series

Patch

diff --git a/drivers/iio/accel/bma400.h b/drivers/iio/accel/bma400.h
index c4c8d74155c2..190366debdb3 100644
--- a/drivers/iio/accel/bma400.h
+++ b/drivers/iio/accel/bma400.h
@@ -83,8 +83,26 @@ 
 #define BMA400_ACC_ODR_MIN_WHOLE_HZ 25
 #define BMA400_ACC_ODR_MIN_HZ       12
 
-#define BMA400_SCALE_MIN            38357
-#define BMA400_SCALE_MAX            306864
+/* BMA400_SCALE_MIN macro value represents m/s^2 for 1 LSB before
+ * converting to micro values for +-2g range.
+ *
+ * For +-2g - 1 LSB = 0.976562 milli g = 0.009576 m/s^2
+ * For +-4g - 1 LSB = 1.953125 milli g = 0.019153 m/s^2
+ * For +-16g - 1 LSB = 7.8125 milli g = 0.076614 m/s^2
+ *
+ * The raw value which is used to select the different ranges is determined
+ * by the first bit set position from the scale value, so BMA400_SCALE_MIN
+ * should be odd.
+ *
+ * Scale values for +-2g, +-4g, +-8g and +-16g is populated into bma400_scales
+ * array by left shifting BMA400_SCALE_MIN.
+ * eg:
+ * To select +-2g = 9577 << 0 = raw value to write is 0.
+ * To select +-8g = 9577 << 2 = raw value to write is 2.
+ * To select +-16g = 9677 << 3 = raw value to write is 3.
+ */
+#define BMA400_SCALE_MIN            9577
+#define BMA400_SCALE_MAX            76617
 
 #define BMA400_NUM_REGULATORS       2
 #define BMA400_VDD_REGULATOR        0