evdev: Support the "Calibration" string option.

Originally based on a patch from Daniel Stone, this commit allows for
the calibration factors to be set either from Xorg.conf or via HAL.

Previously the only way was via the properties interface.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

man/evdev.man

@@ -150,6 +150,14 @@ be set in the configuration.
 Number of reopen attempts after a read error occurs on the device (e.g. after
 waking up from suspend). In between each attempt is a 100ms wait. Default: 10.
 .TP 7
+.BI "Option \*qCalibration\*q \*q" "min-x max-x min-y max-y" \*q
+Calibrates the X and Y axes for devices that need to scale to a different
+coordinate system than reported to the X server. This feature is required
+for devices that need to scale to a different coordinate system than
+originally reported by the kernel (e.g. touchscreens). The scaling to the
+custom coordinate system is done in-driver and the X server is unaware of
+the transformation. Property: "Evdev Axis Calibration".
+.TP 7
 .BI "Option \*qSwapAxes\*q \*q" Bool \*q
 Swap x/y axes. Default: off. Property: "Evdev Axes Swap".
 .TP 7
@@ -178,9 +186,7 @@ driver.
 .TP 7
 .BI "Evdev Axis Calibration"
 4 32-bit values, order min-x, max-x, min-y, max-y or 0 values to disable
-run-time axis calibration. This feature is required for devices that need to
-scale to a different coordinate system than originally reported to the X
-server, such as touchscreens that require run-time calibration.
+in-driver axis calibration.
 .TP 7
 .BI "Evdev Axis Inversion"
 2 boolean values (8 bit, 0 or 1), order X, Y. 1 inverts the axis.

src/evdev.c

@@ -1950,12 +1950,32 @@ EvdevProbe(InputInfoPtr pInfo)
     return 0;
 }
 
+static void
+EvdevSetCalibration(InputInfoPtr pInfo, int num_calibration, int calibration[4])
+{
+    EvdevPtr pEvdev = pInfo->private;
+
+    if (num_calibration == 0) {
+        pEvdev->flags &= ~EVDEV_CALIBRATED;
+        pEvdev->calibration.min_x = 0;
+        pEvdev->calibration.max_x = 0;
+        pEvdev->calibration.min_y = 0;
+        pEvdev->calibration.max_y = 0;
+    } else if (num_calibration == 4) {
+        pEvdev->flags |= EVDEV_CALIBRATED;
+        pEvdev->calibration.min_x = calibration[0];
+        pEvdev->calibration.max_x = calibration[1];
+        pEvdev->calibration.min_y = calibration[2];
+        pEvdev->calibration.max_y = calibration[3];
+    }
+}
 
 static InputInfoPtr
 EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
 {
     InputInfoPtr pInfo;
-    const char *device;
+    const char *device, *str;
+    int num_calibration = 0, calibration[4] = { 0, 0, 0, 0 };
     EvdevPtr pEvdev;
 
     if (!(pInfo = xf86AllocateInput(drv, 0)))
@@ -2028,6 +2048,19 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
     pEvdev->invert_y = xf86SetBoolOption(pInfo->options, "InvertY", FALSE);
     pEvdev->swap_axes = xf86SetBoolOption(pInfo->options, "SwapAxes", FALSE);
 
+    str = xf86CheckStrOption(pInfo->options, "Calibration", NULL);
+    if (str) {
+        num_calibration = sscanf(str, "%d %d %d %d",
+                                 &calibration[0], &calibration[1],
+                                 &calibration[2], &calibration[3]);
+        if (num_calibration == 4)
+            EvdevSetCalibration(pInfo, num_calibration, calibration);
+        else
+            xf86Msg(X_ERROR,
+                    "%s: Insufficient calibration factors (%d). Ignoring calibration\n",
+                    pInfo->name, num_calibration);
+    }
+
     /* Grabbing the event device stops in-kernel event forwarding. In other
        words, it disables rfkill and the "Macintosh mouse button emulation".
        Note that this needs a server that sets the console to RAW mode. */
@@ -2503,25 +2536,7 @@ EvdevSetProperty(DeviceIntPtr dev, Atom atom, XIPropertyValuePtr val,
             return BadMatch;
 
         if (!checkonly)
-        {
-            if (val->size == 0)
-            {
-                pEvdev->flags &= ~EVDEV_CALIBRATED;
-                pEvdev->calibration.min_x = 0;
-                pEvdev->calibration.max_x = 0;
-                pEvdev->calibration.min_y = 0;
-                pEvdev->calibration.max_y = 0;
-            } else if (val->size == 4)
-            {
-                CARD32 *vals = (CARD32*)val->data;
-
-                pEvdev->flags |= EVDEV_CALIBRATED;
-                pEvdev->calibration.min_x = vals[0];
-                pEvdev->calibration.max_x = vals[1];
-                pEvdev->calibration.min_y = vals[2];
-                pEvdev->calibration.max_y = vals[3];
-            }
-        }
+            EvdevSetCalibration(pInfo, val->size, val->data);
     } else if (atom == prop_swap)
     {
         if (val->format != 8 || val->type != XA_INTEGER || val->size != 1)