From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH resend v2 1/2] Input: touchscreen DT binding - add touchscreen-min-x and -min-y properties References: <20180731111958.20043-1-hdegoede@redhat.com> <20180731111958.20043-2-hdegoede@redhat.com> <20180803003101.GA118981@dtor-ws> From: Hans de Goede Message-ID: <6f1b0575-87e7-3443-9080-5abfd8e6c726@redhat.com> Date: Thu, 20 Sep 2018 19:31:43 +0200 MIME-Version: 1.0 In-Reply-To: <20180803003101.GA118981@dtor-ws> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit To: Dmitry Torokhov Cc: Benjamin Tissoires , robh@kernel.org, devicetree@vger.kernel.org, linux-input@vger.kernel.org List-ID: Hi, I completely missed this mail earlier, sorry. Thank you Benjamin for pointing this out to me. On 03-08-18 02:31, Dmitry Torokhov wrote: > Hi Hans, > > On Tue, Jul 31, 2018 at 01:19:57PM +0200, Hans de Goede wrote: >> Some touchscreens, depending on the firmware and/or the digitizer report >> coordinates which never reach 0 along one or both of their axis. >> >> This has been seen for example on the Silead touchscreens on a Onda V891w >> and a Point of View mobii TAB-P800w(v2.0). >> >> This commits documents 2 new touchscreen properties for communicating >> the minimum reported values to the OS: touchscreen-min-x and -min-y. >> >> This commit also drop the (in pixels) comment from the documentation >> of the touchscreen-size-x and touchscreen-size-y properties. This comment >> suggests that there is a relation between the range of reported >> coordinates and the display resolution, which is only true for some >> devices. The (in pixels) comment is replaced with "(maximum x coordinate >> reported + 1)" to mirror the language describing the new touchscreen-min-x >> and -min-y properties. > > I am concerned that people will not read the documentation carefully and > will treat it as true size, since it is what in the name. Maybe we > should say that it is size of usable area, in device units, and that > maximum reported coordinate is "touchscreen-min-x + touchscreen-size-x - > 1"? Not sure what you mean with "true size" but in the implementation from this series, the maximum coordinated reported is (touchscreen-size-x - 1) not (touchscreen-min-x + touchscreen-size-x - 1) as you suggest. Basically what this series does is set: input_absinfo.minimum to the new touchscreen-min-x value (or 0 if not specified) input_absinfo.maximum to touchscreen-size-x - 1 as we've always done. So the usable range / the range mapping from one screen edge to the other is: touchscreen-min-x - (touchscreen-size-x - 1) Which matches with the dt bindings doc after this patch, which reads after this patch: - touchscreen-min-x : minimum x coordinate reported (0 if not set) - touchscreen-min-y : minimum y coordinate reported (0 if not set) - touchscreen-size-x : horizontal resolution of touchscreen (maximum x coordinate reported + 1) - touchscreen-size-y : vertical resolution of touchscreen (maximum y coordinate reported + 1) I hope this clarifies things and if you want to change anything let me know. Regards, Hans