From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:58646 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498Ab3IWKec convert rfc822-to-8bit (ORCPT ); Mon, 23 Sep 2013 06:34:32 -0400 From: =?iso-8859-1?q?J=FCrgen_Beisert?= To: linux-arm-kernel@lists.infradead.org Subject: Re: [PATCHv5] staging/iio/adc: change the MXS touchscreen driver implementation Date: Mon, 23 Sep 2013 12:35:56 +0200 Cc: Marek Vasut , linux-iio@vger.kernel.org, devel@driverdev.osuosl.org, fabio.estevam@freescale.com, jic23@cam.ac.uk, Lothar =?iso-8859-1?q?Wa=DFmann?= References: <1379593369-22010-1-git-send-email-jbe@pengutronix.de> <201309230155.04914.marex@denx.de> <201309230955.58828.jbe@pengutronix.de> In-Reply-To: <201309230955.58828.jbe@pengutronix.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Message-Id: <201309231235.56309.jbe@pengutronix.de> Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org Hi Marek, On Monday 23 September 2013 09:55:58 Jürgen Beisert wrote: > On Monday 23 September 2013 01:55:04 Marek Vasut wrote: > > > The following series replaces the current busy loop touchscreen > > > implementation for i.MX28/i.MX23 SoCs by a fully interrupt driven > > > implementation. > > > > > > Since i.MX23 and i.MX28 silicon differs, the existing implementation > > > can be used for the i.MX28 SoC only. > > > > > > So, the first two patches of this series move the i.MX28 specific > > > definitions out of the way. The third patch simplifies the register > > > access to make it easier to add the i.MX23 support. Then the i.MX23 > > > specific definitions are added, also the code to distinguish both SoCs > > > at run-time. Up to here the existing touchscreen driver will now run on > > > an i.MX23 Soc as well. > > > > > > When the i.MX23 SoC is running from battery it seems not to be a good > > > idea to run a busy loop to detect touches and their location. The > > > fourth patch adds a fully interrupt driven implementation which makes > > > use of the built-in delay and multiple sample features of the > > > touchscreen controller. This will reduce the interrupt load to a > > > minimum. > > > > > > The next to last patch in this series just removes the existing busy > > > loop implementation. > > > > > > The last patch adds a devicetree bindings proposal (to be discussed). > > > > > > Some restrictions/questions: > > > > > > - the touchscreen part is yet tested on i.MX23 SoC only > > > - has someone a good idea how to implement a reliable pressure > > > measurement if the resistances of the touchscreen's plates are unknown? > > > > > > Changes since v4: > > > > > > - honor Jonathan's comments about function names > > > - honor Dmitry's comments about workqueue canceling and interrupts > > > - adding devicetree bindings proposal > > > > > > Changes since v3: > > > > > > - split adding register access functions and i.MX23 support into two > > > patches > > > > > > Changes since v2: > > > > > > - useless debug output removed > > > > > > Changes since v1: > > > > > > - adding register access functions to make the existing code more > > > readable - adding some functions to distinguish the SoCs at run-time to > > > avoid if-else contructs whenever differences in the register layout > > > between i.MX23 and i.MX28 must be handled > > > > Just tested this on M28EVK, the touchscreen is dead. I do not get any > > touch events when I use ts_calibrate and when I hd /dev/input/eventX , I > > get nothing either. > > > > Right now, I'm somehow on a tight schedule, but I'd like to see this > > resolved ASAP. Do you have any hint for me ? > > Seems the very first touch detection does not work. A colleague just told > me, we have an i.MX28 based hardware here and maybe a touchscreen from a > different platform which maybe can be used with the i.MX28 platform. Stay > tuned... I also found an MX28EVK with a touchscreen here and: yes it does not work with the modified driver. But now I'm confused, because of Lothar's statement about the TX28 platform. @Lothar: What kernel revision did you use? I had to go back to 3.9 to get a working kernel on the MX28EVK. More recent vanilla kernels stop working (MMC and network fail here). Regards, Juergen -- Pengutronix e.K.                              | Juergen Beisert             | Linux Solutions for Science and Industry      | http://www.pengutronix.de/ |