On Sat, Nov 15, 2008 at 4:08 PM, Vojtech Pavlik <vojtech@xxxxxxx> wrote:
> On Fri, Nov 14, 2008 at 04:46:08PM -0500, Dan Streetman wrote:
>> Ok - I'll update the patch to invert Y before reporting.
>>
>> On the issue of whether to use a module param to send raw coordinates
>> or hw-calibrated coordinates, or to just change the code to report the
>> hw-calibrated coordinates instead of the raw coordinates, what do you
>> think?
>
> I'm in favor for the option, because of:
>
> * backwards compatibility
> * the Linux input standard is unprocessed coordinate data
> (but after compensating for all hardware quirks)
> * most touchscreens can't do HW calibration anyway, and we
> benefit from common SW calibration code, eg in tslib
>
> Actually, I don't see much value in the hw-calibrated data, but I see it
> could be useful in some cases, so I'm still fine with adding the
> possibility to use that mode.
Just to point it out again because I think it's important...userspace can treat
the hardware-calibrated coordinates *exactly the same* as the raw coordinates if
using software calibration such as tslib. So like I said there is not really a
benefit there of using the raw coordinates, except for one-time backwards
compatibility. This is why I don't see the point in reporting the raw
coordinates by default instead of the hw-calibrated coordinates - I think the
module parameter is fine to let the user pick which one they want, but it should
default to the hw-calibrated coordinates.
But, that's just my opinion :) So here is the updated patch with the Y
inversion and normal non-inverted Y min/max, the module parameter permissions
set to 0644, and default to raw.
This patch adds a module parameter to report either the raw coordinate data or
the hardware-calibrated coordinate data. The default is set to the raw
coordinates for backwards compatibilty.
Signed-off-by: Dan Streetman <ddstreet@xxxxxxxx>
--- a/drivers/input/touchscreen/usbtouchscreen.c 2008-11-17 10:51:30.000000000 -0500
+++ b/drivers/input/touchscreen/usbtouchscreen.c 2008-11-17 10:51:45.000000000 -0500
@@ -60,6 +60,10 @@ static int swap_xy;
module_param(swap_xy, bool, 0644);
MODULE_PARM_DESC(swap_xy, "If set X and Y axes are swapped.");
+static int hwcalib_xy = 0;
+module_param(hwcalib_xy, bool, 0644);
+MODULE_PARM_DESC(hwcalib_xy, "If set hw-calibrated X/Y are used if available");
+
/* device specifc data/functions */
struct usbtouch_usb;
struct usbtouch_device_info {
@@ -260,8 +264,13 @@ static int panjit_read_data(struct usbto
static int mtouch_read_data(struct usbtouch_usb *dev, unsigned char *pkt)
{
- dev->x = (pkt[8] << 8) | pkt[7];
- dev->y = (pkt[10] << 8) | pkt[9];
+ if (hwcalib_xy) {
+ dev->x = (pkt[4] << 8) | pkt[3];
+ dev->y = 0xffff - ((pkt[6] << 8) | pkt[5]); // Invert Y
+ } else {
+ dev->x = (pkt[8] << 8) | pkt[7];
+ dev->y = (pkt[10] << 8) | pkt[9];
+ }
dev->touch = (pkt[2] & 0x40) ? 1 : 0;
return 1;
@@ -294,6 +303,12 @@ static int mtouch_init(struct usbtouch_u
return ret;
}
+ // Default min/max xy are the raw values, override if using hw-calib
+ if (hwcalib_xy) {
+ input_set_abs_params(usbtouch->input, ABS_X, 0, 0xffff, 0, 0);
+ input_set_abs_params(usbtouch->input, ABS_Y, 0, 0xffff, 0, 0);
+ }
+
return 0;
}
#endif
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