On 09/07/15 21:16, Dmitry Torokhov wrote: > On Thu, Jul 09, 2015 at 11:32:11AM +0300, Roger Quadros wrote: >> Dmitry, >> >> On 08/07/15 18:08, Dmitry Torokhov wrote: >>> On Wed, Jul 08, 2015 at 10:59:04AM +0300, Roger Quadros wrote: >>>> Dmitry, >>>> >>>> On 07/07/15 19:25, Dmitry Torokhov wrote: >>>>> Hi Roger, >>>>> >>>>> On Tue, Jul 07, 2015 at 12:37:31PM +0300, Roger Quadros wrote: >>>>>> Hi Dmitry, >>>>>> >>>>>> On 07/07/15 03:27, Dmitry Torokhov wrote: >>>>>>> The binding specification says that "touchscreen-size-x" and "-y" specify >>>>>>> horizontal and vertical resolution of the touchscreen and therefore maximum >>>>>>> absolute coordinates should be reduced by 1 since we are starting with 0. >>>>>>> >>>>>>> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> >>>>>>> --- >>>>>>> drivers/input/touchscreen/of_touchscreen.c | 10 ++++++---- >>>>>>> 1 file changed, 6 insertions(+), 4 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/input/touchscreen/of_touchscreen.c b/drivers/input/touchscreen/of_touchscreen.c >>>>>>> index 759cf4b..50bc0f2 100644 >>>>>>> --- a/drivers/input/touchscreen/of_touchscreen.c >>>>>>> +++ b/drivers/input/touchscreen/of_touchscreen.c >>>>>>> @@ -71,23 +71,25 @@ void touchscreen_parse_of_params(struct input_dev *dev, bool multitouch) >>>>>>> >>>>>>> axis = multitouch ? ABS_MT_POSITION_X : ABS_X; >>>>>>> data_present = touchscreen_get_prop_u32(np, "touchscreen-size-x", >>>>>>> - input_abs_get_max(dev, axis), >>>>>>> + input_abs_get_max(dev, >>>>>>> + axis) + 1, >>>>>> >>>>>> Why do we need to pass default_value to touchscreen_get_prop_u32()? >>>>>> If the property doesn't exist we are not updating the parameter >>>>>> anyway right? >>>>> >>>>> The binding can specify max, fuzz, both, or neither. If only one is >>>>> specified we do not want to "undo" whatever the driver did (for example >>>> >>>> why not? At least that is not what touchscreen_parse_properties() does. >>>> It will update the touchscreen params if any one of the DT property >>>> is present. >>> >>> Yes, but while keeping the old properties (max, fuzz) intact if they >>> have not been specified in dts. That is why we are passing default value >>> to touchscreen_get_prop_u32. >>> >>>> >>>>> tsc2005 sets up the default maximums before trying to parse OF), so we >>>>> fetch the current value and pass it on as default one. >>>> >>>> This is what would happen in tsc2005 case >>>> >>>> -driver first sets ABS_X_max to 0xfff and ABS_Y_max to 0xfff. >>>> -calls touchscreen_parse_properties() >>>> -which calls touchscreen_get_prop_u32(dev, "touchscreen-size-x", >>>> 0xfff+1, &maximum) >>>> -if DT properties are missing, touchscreen_get_prop_u32() changes >>>> ABS_X_max to 0x1000 and returns false. >>>> - as data_present is false we don't do a -1 and so we have ABS_X_max >>>> changed to 0x1000. >>> >>> If data_present is false we do not call input_set_abs_params() at all >>> ans so nothing changes in input device settings. Now, if fuzz would be >> >> You are right. I missed the fact that we don't call input_set_abs_params() >> in data_present is false case hence my confusion. >> >>> set up (but size was not) we would be calling input_set_abs_params(), >>> but given that we subtract 1 from maximum returned by >>> touchscreen_get_prop_u32() we'd be setting input_set_abs_params(input, >>> ABS_X, 0, 0x1000 - 1, fuzz) thus preserving 0xfff value set by the >>> driver. >>> >>>> >>>> This doesn't look right. >>>> >>>> So IMO default_value parameter can be removed from >>>> touchscreen_get_prop_u32() to make things simpler. >>>> >>>> If the property doesn't exist it will not change *value and return false. >>> >>> But it will change if one of the properties set. For example, if you set >>> fuzz but not size. >> >> Yes. Thanks for explaining :). > > No problem. Can I put you down as "reviewed-by" on the of_touchscreen > changes then? Yes please. For all 3 patches. Reviewed-by: Roger Quadros <rogerq@xxxxxx> cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
