Re: [PATCH 01/16] iio: hid-sensors: Convert units and exponent

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

[-- Attachment #1: Type: text/plain, Size: 9844 bytes --]

Hi Jonathan,

I have just sent you one patch, which can be applied to iio git tree on 
top of the currently applied patches.

Thanks,
Srinivas

On 05/04/2014 07:56 AM, Jonathan Cameron wrote:
> Cool. I will hold them for now then. Had a bored moment and not much 
> else pending so jumped the gun!
>
> On May 4, 2014 3:49:38 PM GMT+01:00, Srinivas Pandruvada 
> <srinivas.pandruvada@linux.intel.com> wrote:
>
>     Hi Jonathan,
>
>     Somebody pointed me some error in magnetometer calculation, I have a
>     correction,
>     I will submit as another patch. I was about to push second version of
>     these patches.
>
>     Thanks,
>     Srinivas
>
>     On 05/03/2014 12:24 PM, Jonathan Cameron wrote:
>
>         On 26/04/14 20:34, Srinivas Pandruvada wrote:
>
>             On 04/25/2014 11:30 AM, Jonathan Cameron wrote:
>
>                 On 19/04/14 00:22, Srinivas Pandruvada wrote:
>
>                     HID sensor hub specify a default unit and
>                     alternative units. This along with unit exponent
>                     can be used adjust scale. This change change HID
>                     sensor data units to IIO defined units for each
>                     sensor type. So in this way user space can use a
>                     simply use: "(data + offset) * scale" to get final
>                     result. Signed-off-by: Srinivas Pandruvada
>                     <srinivas.pandruvada@linux.intel.com> 
>
>                 see inline. 
>
>         Applied to the togreg branch of iio.git with a tweaks to
>         comments as mentioned (please check I didn't mess them up!)
>
>                     ---
>                     .../iio/common/hid-sensors/hid-sensor-attributes.c
>                     | 114 +++++++++++++++++++++
>                     include/linux/hid-sensor-hub.h | 4 + 2 files
>                     changed, 118 insertions(+) diff --git
>                     a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
>                     b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
>                     index 75b5473..451a95b 100644 ---
>                     a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
>                     +++
>                     b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
>                     @@ -26,6 +26,40 @@ #include <linux/iio/iio.h>
>                     #include <linux/iio/sysfs.h> +struct { + u32
>                     usage_id; + int unit; /* 0 for default others from
>                     HID sensor spec */ + int scale_val0; /* scale,
>                     whole number */ + int scale_val1; /* scale,
>                     fraction in micros */ +} unit_conversion[] = { +
>                     {HID_USAGE_SENSOR_ACCEL_3D, 0, 9, 806650}, +
>                     {HID_USAGE_SENSOR_ACCEL_3D, +
>                     HID_USAGE_SENSOR_UNITS_METERS_PER_SEC_SQRD, 1, 0},
>                     + {HID_USAGE_SENSOR_ACCEL_3D, +
>                     HID_USAGE_SENSOR_UNITS_G, 9, 806650}, + +
>                     {HID_USAGE_SENSOR_GYRO_3D, 0, 0, 17453}, +
>                     {HID_USAGE_SENSOR_GYRO_3D, +
>                     HID_USAGE_SENSOR_UNITS_RADIANS_PER_SECOND, 1, 0},
>                     + {HID_USAGE_SENSOR_GYRO_3D, +
>                     HID_USAGE_SENSOR_UNITS_DEGREES_PER_SECOND, 0,
>                     17453}, + + {HID_USAGE_SENSOR_COMPASS_3D, 0, 1000,
>                     0}, + {HID_USAGE_SENSOR_COMPASS_3D,
>                     HID_USAGE_SENSOR_UNITS_GAUSS, 1, 0}, + +
>                     {HID_USAGE_SENSOR_INCLINOMETER_3D, 0, 17453, 0}, +
>                     {HID_USAGE_SENSOR_INCLINOMETER_3D, +
>                     HID_USAGE_SENSOR_UNITS_DEGREES, 0, 17453}, +
>                     {HID_USAGE_SENSOR_INCLINOMETER_3D, +
>                     HID_USAGE_SENSOR_UNITS_RADIANS, 1, 0}, + +
>                     {HID_USAGE_SENSOR_ALS, 0, 1, 0}, +
>                     {HID_USAGE_SENSOR_ALS, HID_USAGE_SENSOR_UNITS_LUX,
>                     1, 0}, + + {HID_USAGE_SENSOR_PRESSURE, 0, 100000,
>                     0}, + {HID_USAGE_SENSOR_PRESSURE,
>                     HID_USAGE_SENSOR_UNITS_PASCAL, 1, 0}, +}; + static
>                     int pow_10(unsigned power) { int i; @@ -209,6
>                     +243,86 @@ int
>                     hid_sensor_write_raw_hyst_value(struct
>                     hid_sensor_common *st, }
>                     EXPORT_SYMBOL(hid_sensor_write_raw_hyst_value);
>                     +/* + * This fuction applies the unit exponent to
>                     the scale. + * For example: 
>
>                 Function
>
>                     + * 9.806650 ->exp:2-> val0[980]val1[6650] + *
>                     9.000806 ->exp:2-> val0[900]val1[806] + * 0.174535
>                     ->exp:2-> val0[17]val1[4535] + * 1.001745
>                     ->exp:0-> val0[1]val1[1745] + * 1.001745 ->exp:2->
>                     val0[100]val1[1745] + * 1.001745 ->exp:4->
>                     val0[10017]val1[45] + * 9.806650 ->exp:-2->
>                     val0[0]val1[98066] 
>
>                 It took me a while to get what you meant here, perhaps
>                 for the examples it is worth showing the actual value
>                 directly as well. Maybe. 9.806650 exp:2->980.6650 ->
>                 val0[980]val1[665000] (note the above is I think
>                 incorrect due to lack of trailing zeros on val1.
>
>                     + */ +static void adjust_exponent_micro(int *val0,
>                     int *val1, int scale0, + int scale1, int exp) +{ +
>                     int i; + int x; + int res; + int rem; + + if (exp
>                     > 0) { + *val0 = scale0 * pow_10(exp); + res = 0;
>                     + if (exp > 6) { + *val1 = 0; + return; + } 
>
>                 so if example 1 above.. val0 = 900 as desired. i = 0;
>                 sca1e1 = 806650 x = 806650/100000 = 8; res = 80;
>                 scale1 = 06650 i = 1 x = 06650/10000 = 0; res = 80; so
>                 980. Good.
>
>                     + for (i = 0; i < exp; ++i) { + x = scale1 /
>                     pow_10(5 - i); + res += (pow_10(exp - 1 - i) * x);
>                     + scale1 = scale1 % pow_10(5 - i); + } + *val0 +=
>                     res; + *val1 = scale1 * pow_10(exp); 
>
>                 val1 = 665000 which is correct with the trailing zeros
>                 in val2. So your code is good but examples need those
>                 zeros! 
>
>             Impressive, Absolutely great review. I will correct
>             comments in the next version. 
>
>         Given this was the only issue in the patch set I'll just fix
>         it up as I merge it. It's been a couple of weeks an noone else
>         has chipped in on this series, so I'm taking it now.
>
>             Thanks, Srinivas
>
>                     + } else if (exp < 0) { + exp = abs(exp); + if
>                     (exp > 6) { + *val0 = *val1 = 0; + return; + } +
>                     *val0 = scale0 / pow_10(exp); + rem = scale0 %
>                     pow_10(exp); + res = 0; + for (i = 0; i < (6 -
>                     exp); ++i) { + x = scale1 / pow_10(5 - i); + res
>                     += (pow_10(5 - exp - i) * x); + scale1 = scale1 %
>                     pow_10(5 - i); + } + *val1 = rem * pow_10(6 - exp)
>                     + res; + } else { + *val0 = scale0; + *val1 =
>                     scale1; + } +} + +int hid_sensor_format_scale(u32
>                     usage_id, + struct hid_sensor_hub_attribute_info
>                     *attr_info, + int *val0, int *val1) +{ + int i; +
>                     int exp; + + *val0 = 1; + *val1 = 0; + + for (i =
>                     0; ARRAY_SIZE(unit_conversion); ++i) { + if
>                     (unit_conversion[i].usage_id == usage_id && +
>                     unit_conversion[i].unit == attr_info->units) { +
>                     exp = hid_sensor_convert_exponent( +
>                     attr_info->unit_expo); +
>                     adjust_exponent_micro(val0, val1, +
>                     unit_conversion[i].scale_val0, +
>                     unit_conversion[i].scale_val1, exp); + break; + }
>                     + } + + return IIO_VAL_INT_PLUS_MICRO; +}
>                     +EXPORT_SYMBOL(hid_sensor_format_scale); + int
>                     hid_sensor_parse_common_attributes(struct
>                     hid_sensor_hub_device *hsdev, u32 usage_id, struct
>                     hid_sensor_common *st) diff --git
>                     a/include/linux/hid-sensor-hub.h
>                     b/include/linux/hid-sensor-hub.h index
>                     b70cfd7..89626b2 100644 ---
>                     a/include/linux/hid-sensor-hub.h +++
>                     b/include/linux/hid-sensor-hub.h @@ -223,4 +223,8
>                     @@ int hid_sensor_read_samp_freq_value(struct
>                     hid_sensor_common *st, int
>                     hid_sensor_get_usage_index(struct
>                     hid_sensor_hub_device *hsdev, u32 report_id, int
>                     field_index, u32 usage_id); +int
>                     hid_sensor_format_scale(u32 usage_id, + struct
>                     hid_sensor_hub_attribute_info *attr_info, + int
>                     *val0, int *val1); + #endif
>
>                 -- To unsubscribe from this list: send the line
>                 "unsubscribe linux-iio" in the body of a message to
>                 majordomo@vger.kernel.org More majordomo info at
>                 http://vger.kernel.org/majordomo-info.html
>
>
>
>     --
>     To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>     the body of a message to majordomo@vger.kernel.org
>     More majordomo info athttp://vger.kernel.org/majordomo-info.html
>
>
> -- 
> Sent from my Android phone with K-9 Mail. Please excuse my brevity. 


[-- Attachment #2: Type: text/html, Size: 10805 bytes --]