[PATCH] joydev.c automatic re-calibration

From: Renato Golin
Date: Tue May 22 2007 - 20:33:26 EST


This small patch adds the automatic recalibration feature without
spoiling previously calibrated devices. It's a fix for those joysticks
that report faulty range, specially Saitek Cyborg Evo Force.

File: drivers/input/joydev.c
Fix:
- extracted code from joydev_connect to method
joydev_calculate_correction to be able to call it from both
joydev_event upon recalibration and joydev_connect during first
connection.
- on joydev_connect check ranges and zero calibration if found out of range
- on joydev_event, every time found out of range, update min/max and
recalculate the correction

Patch below and attached.

cheers,
--renato

== PATCH BEGIN ==

--- joydev.c.original 2007-05-22 22:23:43.000000000 +0100
+++ joydev.c 2007-05-23 01:24:04.000000000 +0100
@@ -53,6 +53,8 @@
__u8 absmap[ABS_MAX + 1];
__u8 abspam[ABS_MAX + 1];
__s16 abs[ABS_MAX + 1];
+ __s16 absmin[ABS_MAX + 1];
+ __s16 absmax[ABS_MAX + 1];
};

struct joydev_list {
@@ -67,6 +69,19 @@

static struct joydev *joydev_table[JOYDEV_MINORS];

+static void joydev_calculate_correction(int min, int max, int axis,
struct joydev *joydev)
+{
+ int t, j = joydev->abspam[axis];
+ int flat = joydev->handle.dev->absflat[j];
+
+ joydev->corr[axis].coef[0] = (max + min) / 2 - flat;
+ joydev->corr[axis].coef[1] = (max + min) / 2 + flat;
+ if (!(t = ((max - min) / 2 - 2 * flat)))
+ return;
+ joydev->corr[axis].coef[2] = (1 << 29) / t;
+ joydev->corr[axis].coef[3] = (1 << 29) / t;
+}
+
static int joydev_correct(int value, struct js_corr *corr)
{
switch (corr->type) {
@@ -103,6 +118,14 @@
case EV_ABS:
event.type = JS_EVENT_AXIS;
event.number = joydev->absmap[code];
+ /* recalibration if needed */
+ if (value < joydev->absmin[code]) {
+ joydev->absmin[code] = value;
+ joydev_calculate_correction(value,
joydev->absmax[code], code, joydev);
+ } else if (value > joydev->absmax[code]) {
+ joydev->absmax[code] = value;
+
joydev_calculate_correction(joydev->absmin[code], value, code,
joydev);
+ }
event.value = joydev_correct(value,
joydev->corr + event.number);
if (event.value == joydev->abs[event.number])
return;
@@ -470,7 +493,7 @@
{
struct joydev *joydev;
struct class_device *cdev;
- int i, j, t, minor;
+ int i, j, minor;

for (minor = 0; minor < JOYDEV_MINORS && joydev_table[minor]; minor++);
if (minor == JOYDEV_MINORS) {
@@ -515,19 +538,21 @@

for (i = 0; i < joydev->nabs; i++) {
j = joydev->abspam[i];
- if (dev->absmax[j] == dev->absmin[j]) {
+ joydev->absmin[i] = dev->absmin[j];
+ joydev->absmax[i] = dev->absmax[j];
+ if (joydev->absmax[i] == joydev->absmin[i]) {
joydev->corr[i].type = JS_CORR_NONE;
joydev->abs[i] = dev->abs[j];
continue;
}
joydev->corr[i].type = JS_CORR_BROKEN;
joydev->corr[i].prec = dev->absfuzz[j];
- joydev->corr[i].coef[0] = (dev->absmax[j] +
dev->absmin[j]) / 2 - dev->absflat[j];
- joydev->corr[i].coef[1] = (dev->absmax[j] +
dev->absmin[j]) / 2 + dev->absflat[j];
- if (!(t = ((dev->absmax[j] - dev->absmin[j]) / 2 - 2 *
dev->absflat[j])))
- continue;
- joydev->corr[i].coef[2] = (1 << 29) / t;
- joydev->corr[i].coef[3] = (1 << 29) / t;
+
+ if (dev->abs[j] > joydev->absmax[i] || dev->abs[j] <
joydev->absmin[i]) {
+ printk("Joydev: Bad axis range, recalibrating
automatically\n");
+ joydev_calculate_correction(0, 0, i, joydev);
+ } else
+ joydev_calculate_correction(joydev->absmin[i],
joydev->absmax[i], i, joydev);

joydev->abs[i] = joydev_correct(dev->abs[j], joydev->corr + i);
}

== PATCH END == --- joydev.c.original 2007-05-22 22:23:43.000000000 +0100
+++ joydev.c 2007-05-23 01:24:04.000000000 +0100
@@ -53,6 +53,8 @@
__u8 absmap[ABS_MAX + 1];
__u8 abspam[ABS_MAX + 1];
__s16 abs[ABS_MAX + 1];
+ __s16 absmin[ABS_MAX + 1];
+ __s16 absmax[ABS_MAX + 1];
};

struct joydev_list {
@@ -67,6 +69,19 @@

static struct joydev *joydev_table[JOYDEV_MINORS];

+static void joydev_calculate_correction(int min, int max, int axis, struct joydev *joydev)
+{
+ int t, j = joydev->abspam[axis];
+ int flat = joydev->handle.dev->absflat[j];
+
+ joydev->corr[axis].coef[0] = (max + min) / 2 - flat;
+ joydev->corr[axis].coef[1] = (max + min) / 2 + flat;
+ if (!(t = ((max - min) / 2 - 2 * flat)))
+ return;
+ joydev->corr[axis].coef[2] = (1 << 29) / t;
+ joydev->corr[axis].coef[3] = (1 << 29) / t;
+}
+
static int joydev_correct(int value, struct js_corr *corr)
{
switch (corr->type) {
@@ -103,6 +118,14 @@
case EV_ABS:
event.type = JS_EVENT_AXIS;
event.number = joydev->absmap[code];
+ /* recalibration if needed */
+ if (value < joydev->absmin[code]) {
+ joydev->absmin[code] = value;
+ joydev_calculate_correction(value, joydev->absmax[code], code, joydev);
+ } else if (value > joydev->absmax[code]) {
+ joydev->absmax[code] = value;
+ joydev_calculate_correction(joydev->absmin[code], value, code, joydev);
+ }
event.value = joydev_correct(value, joydev->corr + event.number);
if (event.value == joydev->abs[event.number])
return;
@@ -470,7 +493,7 @@
{
struct joydev *joydev;
struct class_device *cdev;
- int i, j, t, minor;
+ int i, j, minor;

for (minor = 0; minor < JOYDEV_MINORS && joydev_table[minor]; minor++);
if (minor == JOYDEV_MINORS) {
@@ -515,19 +538,21 @@

for (i = 0; i < joydev->nabs; i++) {
j = joydev->abspam[i];
- if (dev->absmax[j] == dev->absmin[j]) {
+ joydev->absmin[i] = dev->absmin[j];
+ joydev->absmax[i] = dev->absmax[j];
+ if (joydev->absmax[i] == joydev->absmin[i]) {
joydev->corr[i].type = JS_CORR_NONE;
joydev->abs[i] = dev->abs[j];
continue;
}
joydev->corr[i].type = JS_CORR_BROKEN;
joydev->corr[i].prec = dev->absfuzz[j];
- joydev->corr[i].coef[0] = (dev->absmax[j] + dev->absmin[j]) / 2 - dev->absflat[j];
- joydev->corr[i].coef[1] = (dev->absmax[j] + dev->absmin[j]) / 2 + dev->absflat[j];
- if (!(t = ((dev->absmax[j] - dev->absmin[j]) / 2 - 2 * dev->absflat[j])))
- continue;
- joydev->corr[i].coef[2] = (1 << 29) / t;
- joydev->corr[i].coef[3] = (1 << 29) / t;
+
+ if (dev->abs[j] > joydev->absmax[i] || dev->abs[j] < joydev->absmin[i]) {
+ printk("Joydev: Bad axis range, recalibrating automatically\n");
+ joydev_calculate_correction(0, 0, i, joydev);
+ } else
+ joydev_calculate_correction(joydev->absmin[i], joydev->absmax[i], i, joydev);

joydev->abs[i] = joydev_correct(dev->abs[j], joydev->corr + i);
}