Commit 2d814828 authored Nov 09, 2017 by Stefan Agner Committed by Bartlomiej Zolnierkiewicz Nov 09, 2017

video: fbdev: mxsfb: fix pixelclock polarity



The PIXDATA flags of the display_flags enum are controller centric,
e.g. NEGEDGE means the controller shall drive the data signals on
pixelclocks negative edge. However, the drivers flag is display
centric: Sample the data on negative (falling) edge.

Therefore, change the if statement to check for the POSEDGE flag
(which is typically not set):
Drive on positive edge => sample on negative edge

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Liu Ying <Ying.Liu@freescale.com>
Cc: Lothar Waßmann <LW@KARO-electronics.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Max Krummenacher <max.krummenacher@toradex.com>
Cc: Mauro Salvini <mauro.salvini@smigroup.net>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

parent ab798b90

drivers/video/fbdev/mxsfb.c

+11 −2

Original line number	Diff line number	Diff line
		@@ -150,7 +150,7 @@
		#define STMLCDIF_24BIT 3 /** pixel data bus to the display is of 24 bit width */

		#define MXSFB_SYNC_DATA_ENABLE_HIGH_ACT (1 << 6)
		#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negtive edge sampling */
		#define MXSFB_SYNC_DOTCLK_FALLING_ACT (1 << 7) /* negative edge sampling */

		enum mxsfb_devtype {
		MXSFB_V3,
		@@ -788,7 +788,16 @@ static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host,

		if (vm.flags & DISPLAY_FLAGS_DE_HIGH)
		host->sync \|= MXSFB_SYNC_DATA_ENABLE_HIGH_ACT;
		if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)

		/*
		* The PIXDATA flags of the display_flags enum are controller
		* centric, e.g. NEGEDGE means drive data on negative edge.
		* However, the drivers flag is display centric: Sample the
		* data on negative (falling) edge. Therefore, check for the
		* POSEDGE flag:
		* drive on positive edge => sample on negative edge
		*/
		if (vm.flags & DISPLAY_FLAGS_PIXDATA_POSEDGE)
		host->sync \|= MXSFB_SYNC_DOTCLK_FALLING_ACT;

		put_display_node:

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