From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Ellero Date: Wed, 18 Mar 2015 09:26:47 +0100 Subject: [U-Boot] iMX6 IPU configuration by EDID In-Reply-To: <55083951.2030301@boundarydevices.com> References: <5507FC48.3010302@brickedbrain.com> <55083951.2030301@boundarydevices.com> Message-ID: <550936C7.1010709@brickedbrain.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 17/03/2015 15:25, Eric Nelson wrote: > Hi Luca, > > On 03/17/2015 03:04 AM, Luca Ellero wrote: >> Hi all, >> >> I'm trying to configure IPU on a iMX6 based platform by reading EDID >> from the external monitor. >> >> Everything seem to work fine except for the pixelclock. In particular my >> monitor has a standard resolution of 1280x1024 at 60 (108 MHz pixelclock). >> >> When the function ipu_init_sync_panel (file ipu_disp.c) is called it >> correctly receive 108 MHz as pixelclock. but during the execution of >> this function it gets rounded to 130 MHz. >> >> I can see that the function calls clk_round_rate to round the clock to >> 130 MHz but it's not clear for me how it works. >> > > It's been a while since I've looked at this, but I believe there's > a hidden fixed clock somewhere in the IPU driver. > > http://lists.denx.de/pipermail/u-boot/2014-January/thread.html#170363 > >> Can someone please tell me how to get the exact pixelclock I would like >> to achieve? I've carefully read the iMX6 manual but it's not very useful >> in this case. >> >> Another doubt that I have regards the field "ext_clk" of parameter >> "ipu_di_signal_cfg_t sig". In this case, is it better to set it or not? >> > > I believe this is supposed to be set for HDMI, such that the IPU > clock is derived from the HDMI PHY clock and it's best to use > the Linux driver as a guide. > Hi Eric, thank you for your reply. I'll try to investigate the Linux driver then. Kind regards Luca -- Luca Ellero E-mail: luca.ellero at brickedbrain.com Internet: www.brickedbrain.com