From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?TXlsw6huZQ==?= Josserand Subject: Re: [PATCH v6 0/2] Input: Add Cypress Gen5 Touchscreen driver Date: Tue, 24 Jul 2018 15:00:46 +0200 Message-ID: <20180724150046.7d70786c@dell-desktop.home> References: <20180703094309.18514-1-mylene.josserand@bootlin.com> <20180704162158.euiw2v3hyv3hzofn@penguin> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <20180704162158.euiw2v3hyv3hzofn@penguin> Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Torokhov Cc: robh+dt@kernel.org, mark.rutland@arm.com, mylene.josserand@free-electrons.com, thomas.petazzoni@free-electrons.com, maxime.ripard@free-electrons.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org Hello Dmitry, On Wed, 4 Jul 2018 16:21:58 +0000 Dmitry Torokhov wrote: > Hi Mylène, > > On Tue, Jul 03, 2018 at 11:43:07AM +0200, Mylène Josserand wrote: > > Hello, > > > > Here is a V6 series to add the driver of the touchscreen Cypress, > > TrueTouch Generation 5. > > Based on v4.18-rc3. > > > > This patch series has already been posted in several iterations: > > - v1: Sent on 2017/05/29 > > - v2: Sent on 2017/08/18 > > - v3: Sent on 2017/09/27 > > - v4: Sent on 2017/12/01 > > - v5: Sent on 2017/12/20 > > > > I did not have any comments the last 4 versions. > > And no reviews on my v5 during 6 months. Could I have any updates > > or feedback on my series to know why it is not merged (to be able to > > correct what is wrong)? > > Sorry, I must have missed the v5, sorry about that. > > I probably asked this question before, but just to make sure - I see > references to HID in the patch - the device is really not HID > compatible? Is there any hope it could be made work with i2c-hid + > hid-multitouch? > > Thanks. > I have checked and, for what I have seen, all the HID descriptor stuff is HID compliant. We could definitely use i2c-hid and hid-multitouch (there is the "hid-cypress" driver that exists also). The only problem is that this touchscreen has two modes: a bootloader mode and an application mode (which is the one where we can send HID commands). After a power-on-reset, it is always in "bootloader" mode so we need to send some commands (called "bootloader commands") to switch to application mode. These commands are not HID-compliant as the datasheet indicates: "Bootloader commands are not HID-over-I2C compliant." I think that if the touchscreen would start directly in "application" mode, we could directly use i2c-hid and hid-cypress drivers. Unfortunately, this is not the case. In bootloader mode, the ProductID is 0xc101 and in application mode, it is 0xc001 (already available in hid-ids.h: USB_DEVICE_ID_CYPRESS_TRUETOUCH but not handled) What would be the better approach here? Should I add a new product ID to detect the bootloader mode in hid-cypress driver and send non-HID commands to switch to "application" mode in this driver? Anyway, I guess that I will drop this cyttsp5 driver and update the existing one, right? Let me know what you think about it. Thank you in advance, Best regards, -- Mylène Josserand, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com