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From: Andreas Kemnade <andreas@kemnade.info>
To: Sven Van Asbroeck <thesven73@gmail.com>
Cc: Discussions about the Letux Kernel <letux-kernel@openphoenux.org>,
	"H. Nikolaus Schaller" <hns@goldelico.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Mark Brown <broonie@kernel.org>,
	kernel list <linux-kernel@vger.kernel.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: [Letux-kernel] [BUG] SPI broken for SPI based panel drivers
Date: Tue, 1 Dec 2020 17:44:33 +0100	[thread overview]
Message-ID: <20201201174433.2000c8a3@aktux> (raw)
In-Reply-To: <CAGngYiUG76Q-cb_HdDKMia5yXzv_mS+5NPeaBquK3_4b3tr-4Q@mail.gmail.com>

On Tue, 1 Dec 2020 11:10:49 -0500
Sven Van Asbroeck <thesven73@gmail.com> wrote:

> Nikolaus,
> 
> On Tue, Dec 1, 2020 at 9:38 AM H. Nikolaus Schaller <hns@goldelico.com> wrote:
> >
> > Let's work on a fix for the fix now.
> >  
> 
> Are you quite sure the chip-select of the tpo,td028ttec1 panel
> is active-high? A quick google produced a datasheet which
> seems to indicate that XCS is active-low?
> 
Schematics is here:
https://projects.goldelico.com/p/gta04-main/downloads/48/

The display connector P204-LCD indicates some inversion at the XCS and
XRES pins.

This patch fixes things for a boot where the display was not
touched by the bootloader
diff --git a/arch/arm/boot/dts/omap3-gta04.dtsi b/arch/arm/boot/dts/omap3-gta04.dtsi
index c8745bc800f7..003202d12990 100644
--- a/arch/arm/boot/dts/omap3-gta04.dtsi
+++ b/arch/arm/boot/dts/omap3-gta04.dtsi
@@ -124,7 +124,6 @@
                        spi-max-frequency = <100000>;
                        spi-cpol;
                        spi-cpha;
-                       spi-cs-high;
 
                        backlight= <&backlight>;
                        label = "lcd";

So if that one is really active-low, why did it ever work?!

Regards,
Andreas

  parent reply	other threads:[~2020-12-01 16:45 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-30 19:03 [BUG] SPI broken for SPI based panel drivers H. Nikolaus Schaller
2020-11-30 20:13 ` Sven Van Asbroeck
2020-11-30 20:22   ` Sven Van Asbroeck
2020-12-01  8:59   ` H. Nikolaus Schaller
2020-12-01 12:16     ` Mark Brown
2020-12-01 14:05       ` H. Nikolaus Schaller
2020-12-01 14:20         ` Linus Walleij
2020-12-01 14:34           ` Sven Van Asbroeck
2020-12-01 14:35           ` H. Nikolaus Schaller
2020-12-01 15:52             ` Sven Van Asbroeck
2020-12-01 16:46               ` H. Nikolaus Schaller
2020-12-01 16:10             ` Sven Van Asbroeck
2020-12-01 16:39               ` H. Nikolaus Schaller
2020-12-01 16:53                 ` Sven Van Asbroeck
2020-12-01 17:10                   ` H. Nikolaus Schaller
2020-12-01 18:43                     ` Sven Van Asbroeck
2020-12-02 12:19                       ` Mark Brown
2020-12-04 10:08                       ` H. Nikolaus Schaller
2020-12-04 13:46                         ` Sven Van Asbroeck
2020-12-04 16:49                           ` H. Nikolaus Schaller
2020-12-04 19:19                             ` Sven Van Asbroeck
2020-12-04 21:31                               ` H. Nikolaus Schaller
2020-12-05  0:25                             ` Linus Walleij
2020-12-05  7:04                               ` H. Nikolaus Schaller
2020-12-09  8:04                                 ` Andreas Kemnade
2020-12-09  8:40                                   ` H. Nikolaus Schaller
2020-12-09  8:38                                 ` Linus Walleij
2020-12-09  8:45                                   ` H. Nikolaus Schaller
2020-12-01 22:51                     ` Linus Walleij
2020-12-01 16:44               ` Andreas Kemnade [this message]
2020-12-01 16:51                 ` [Letux-kernel] " H. Nikolaus Schaller
2020-12-01 16:52                 ` H. Nikolaus Schaller
2020-12-01 16:55                 ` Sven Van Asbroeck
2020-12-01 16:20           ` Mark Brown
2020-12-01 16:41             ` H. Nikolaus Schaller
2020-12-01 17:11               ` Mark Brown
2020-12-01 12:41     ` Sven Van Asbroeck
2020-12-01 13:32       ` H. Nikolaus Schaller
2020-12-01 14:08         ` Sven Van Asbroeck
2020-12-01 15:33           ` Mark Brown
2020-12-05 20:57   ` Pavel Machek
2020-12-07 13:43     ` Mark Brown

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