From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from devils.ext.ti.com ([198.47.26.153]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1X0EY6-000867-Gp for linux-mtd@lists.infradead.org; Thu, 26 Jun 2014 18:37:34 +0000 Message-ID: <53AC67FC.4050103@ti.com> Date: Thu, 26 Jun 2014 13:35:40 -0500 From: Darren Etheridge MIME-Version: 1.0 To: =?ISO-8859-1?Q?Guido_Mart=EDnez?= , Pekon Gupta Subject: Re: [PATCH v1 3/3] ARM: dts: am335x-bone: add support for beaglebone LCD4 cape References: <1403612666-31197-1-git-send-email-pekon@ti.com> <1403612666-31197-4-git-send-email-pekon@ti.com> <20140626154052.GB15648@fox> In-Reply-To: <20140626154052.GB15648@fox> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 8bit Cc: Tony Lindgren , Jason Kridner , linux-omap , linux-mtd , Robert Nelson List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Guido, Pekon, On 06/26/2014 10:40 AM, Guido Martínez wrote: > Hi Pekon, > > I had some issues with this patch. Booting linux-next on a BeagleBone > Black with this exact LCD left me with an unusable white screen. Please > see below for some details. > > On Tue, Jun 24, 2014 at 05:54:26PM +0530, Pekon Gupta wrote: >> This patch adds support for LCD4 cape as advertised on >> http://elinux.org/CircuitCo:BeagleBone_LCD4 >> >> This cape has: >> * 480x272 TFT-LCD panel >> - LCD panel datasheet and timing information are sourced from [1] >> - LCD backlight is connected to 'EHRPWM1A' on cape board, but its used for >> enabling backlight power-supply. So 'gpio-backlight' driver is used instead >> of 'pwm-backlight' driver (Kconfig: BACKLIGHT_GPIO=y). >> >> * 4-wire resistive Touchscreen >> >> *Known constrains* >> As LCD panel pins (lcd_data, hsync, vsync, pclk) are shared with on-board >> NXP HDMI framer, so either HDMI or LCD-cape can be used at time. Thus while >> using this cape 'hdmi' DT node needs to be disabled in am335x-boneblack.dts >> >> [1] www.newhavendisplay.com/specs/NHD-4.3-480272MF-ATXI-T-1.pdf >> www.newhavendisplay.com/app_notes/OTA5180A.pdf >> >> Signed-off-by: Pekon Gupta >> --- >> + >> + panel { >> + status = "disabled"; >> + compatible = "ti,tilcdc,panel"; >> + pinctrl-names = "default"; >> + pinctrl-0 = <&bbcape_lcd_pins>; >> + panel-info { >> + ac-bias = <255>; >> + ac-bias-intrpt = <0>; >> + dma-burst-sz = <16>; >> + bpp = <16>; >> + fdd = <0x80>; >> + sync-edge = <0>; >> + sync-ctrl = <0>; > I had to set this to <1>. Does that make sense? > >> + raster-order = <0>; >> + fifo-th = <0>; >> + }; >> + display-timings { >> + native-mode = <&timing0>; >> + /* www.newhavendisplay.com/app_notes/OTA5180A.pdf */ >> + timing0: 480x272 { >> + clock-frequency = <30000000>; >> + hactive = <480>; >> + vactive = <272>; >> + hfront-porch = <8>; >> + hback-porch = <47>; >> + hsync-len = <41>; >> + vback-porch = <2>; >> + vfront-porch = <3>; >> + vsync-len = <10>; >> + hsync-active = <0>; >> + vsync-active = <0>; >> + de-active = <1>; >> + pixelclk-active = <0>; > Are you sure these timings are ok? When enabling the sync control I get > an usable display, but it looks a bit funny. For example an all black > display looks very clear and has a dotted pattern. > > I tried to take a picture of it but it doesn't show. These timings look wrong to me, for instance this sets a clock frequency of 30MHz where as the linked app-note says 9MHz. I think the LCD4 cape uses the same LCD panel as is used on the AM335x EVMSK. Therefore the display timings from my DT patch for the EVMSK should work: https://patchwork.kernel.org/patch/4144801/ Darren > > Also I'm just guessing about the timings, maybe it's something else? > >> + }; >> + }; >> + }; >> +}; >> diff --git a/arch/arm/boot/dts/am335x-bone.dts b/arch/arm/boot/dts/am335x-bone.dts >> index f16bfcf..41439dc 100644 >> --- a/arch/arm/boot/dts/am335x-bone.dts >> +++ b/arch/arm/boot/dts/am335x-bone.dts >> @@ -10,6 +10,7 @@ >> #include "am33xx.dtsi" >> #include "am335x-bone-common.dtsi" >> #include "am335x-bone-memory-cape.dts" >> +#include "am335x-bone-display-cape.dts" >> >> &ldo3_reg { >> regulator-min-microvolt = <1800000>; >> diff --git a/arch/arm/boot/dts/am335x-boneblack.dts b/arch/arm/boot/dts/am335x-boneblack.dts >> index e6d7e54..03232c7 100644 >> --- a/arch/arm/boot/dts/am335x-boneblack.dts >> +++ b/arch/arm/boot/dts/am335x-boneblack.dts >> @@ -10,6 +10,7 @@ >> #include "am33xx.dtsi" >> #include "am335x-bone-common.dtsi" >> #include "am335x-bone-memory-cape.dts" >> +#include "am335x-bone-display-cape.dts" >> >> &ldo3_reg { >> regulator-min-microvolt = <1800000>; >> -- >> 1.8.5.1.163.gd7aced9 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-omap" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >