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? Thanks. -- Dmitry -- 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
