lkml.org 
[lkml]   [2009]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 09/10] lis3: Scale output values to mg
Date
Report output values as 1/1000 of earth gravity.

Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
---
drivers/hwmon/lis3lv02d.c | 31 ++++++++++++++++++++++++++++---
drivers/hwmon/lis3lv02d.h | 4 ++++
2 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/drivers/hwmon/lis3lv02d.c b/drivers/hwmon/lis3lv02d.c
index be2eb97..7e72836 100644
--- a/drivers/hwmon/lis3lv02d.c
+++ b/drivers/hwmon/lis3lv02d.c
@@ -53,6 +53,19 @@
#define LIS3_PWRON_DELAY_WAI_12B (5000)
#define LIS3_PWRON_DELAY_WAI_8B (3000)

+/*
+ * LIS3LV02D spec says 1024 LSBs corresponds 1 G -> 1LSB is 1000/1024 mG
+ * LIS302D spec says: 18 mG / digit
+ * SCALING_ACCURACY is used to increase accuracy of the intermediate
+ * calculation results.
+ */
+#define LIS3_SCALING_ACCURACY 1024
+#define LIS3_2G2G_SENSITIVITY_WAI_12B ((LIS3_SCALING_ACCURACY * 1000) / 1024)
+#define LIS3_2G2G_SENSITIVITY_WAI_8B (18 * LIS3_SCALING_ACCURACY)
+
+#define LIS3_DEFAULT_FUZZ 3
+#define LIS3_DEFAULT_FLAT 3
+
struct lis3lv02d lis3_dev = {
.misc_wait = __WAIT_QUEUE_HEAD_INITIALIZER(lis3_dev.misc_wait),
};
@@ -105,11 +118,16 @@ static inline int lis3lv02d_get_axis(s8 axis, int hw_values[3])
static void lis3lv02d_get_xyz(struct lis3lv02d *lis3, int *x, int *y, int *z)
{
int position[3];
+ int i;

position[0] = lis3->read_data(lis3, OUTX);
position[1] = lis3->read_data(lis3, OUTY);
position[2] = lis3->read_data(lis3, OUTZ);

+ for (i = 0; i < 3; i++)
+ position[i] = (position[i] * lis3->scale) /
+ LIS3_SCALING_ACCURACY;
+
*x = lis3lv02d_get_axis(lis3->ac.x, position);
*y = lis3lv02d_get_axis(lis3->ac.y, position);
*z = lis3lv02d_get_axis(lis3->ac.z, position);
@@ -385,6 +403,7 @@ int lis3lv02d_joystick_enable(void)
{
struct input_dev *input_dev;
int err;
+ int max_val, fuzz, flat;

if (lis3_dev.idev)
return -EINVAL;
@@ -404,9 +423,13 @@ int lis3lv02d_joystick_enable(void)
input_dev->dev.parent = &lis3_dev.pdev->dev;

set_bit(EV_ABS, input_dev->evbit);
- input_set_abs_params(input_dev, ABS_X, -lis3_dev.mdps_max_val, lis3_dev.mdps_max_val, 3, 3);
- input_set_abs_params(input_dev, ABS_Y, -lis3_dev.mdps_max_val, lis3_dev.mdps_max_val, 3, 3);
- input_set_abs_params(input_dev, ABS_Z, -lis3_dev.mdps_max_val, lis3_dev.mdps_max_val, 3, 3);
+ max_val = (lis3_dev.mdps_max_val * lis3_dev.scale)
+ / LIS3_SCALING_ACCURACY;
+ fuzz = (LIS3_DEFAULT_FUZZ * lis3_dev.scale) / LIS3_SCALING_ACCURACY;
+ flat = (LIS3_DEFAULT_FLAT * lis3_dev.scale) / LIS3_SCALING_ACCURACY;
+ input_set_abs_params(input_dev, ABS_X, -max_val, max_val, fuzz, flat);
+ input_set_abs_params(input_dev, ABS_Y, -max_val, max_val, fuzz, flat);
+ input_set_abs_params(input_dev, ABS_Z, -max_val, max_val, fuzz, flat);

err = input_register_polled_device(lis3_dev.idev);
if (err) {
@@ -521,12 +544,14 @@ int lis3lv02d_init_device(struct lis3lv02d *dev)
dev->read_data = lis3lv02d_read_12;
dev->mdps_max_val = 2048;
dev->pwron_delay = LIS3_PWRON_DELAY_WAI_12B;
+ dev->scale = LIS3_2G2G_SENSITIVITY_WAI_12B;
break;
case WAI_8B:
printk(KERN_INFO DRIVER_NAME ": 8 bits sensor found\n");
dev->read_data = lis3lv02d_read_8;
dev->mdps_max_val = 128;
dev->pwron_delay = LIS3_PWRON_DELAY_WAI_8B;
+ dev->scale = LIS3_2G2G_SENSITIVITY_WAI_8B;
break;
default:
printk(KERN_ERR DRIVER_NAME
diff --git a/drivers/hwmon/lis3lv02d.h b/drivers/hwmon/lis3lv02d.h
index a692116..42618b8 100644
--- a/drivers/hwmon/lis3lv02d.h
+++ b/drivers/hwmon/lis3lv02d.h
@@ -212,6 +212,10 @@ struct lis3lv02d {
s16 (*read_data) (struct lis3lv02d *lis3, int reg);
int mdps_max_val;
int pwron_delay;
+ int scale; /*
+ * relationship between 1 LBS and mG
+ * (1/1000th of earth gravity)
+ */

struct input_polled_dev *idev; /* input device */
struct platform_device *pdev; /* platform device */
--
1.5.6.3


\
 
 \ /
  Last update: 2009-11-10 13:47    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site