linux-kernel - [PATCH 4/5] Revert "drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested"

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Date:   Tue, 10 Dec 2019 15:24:46 +0200
From:   Claudiu Beznea <claudiu.beznea@...rochip.com>
To:     <sam@...nborg.org>, <bbrezillon@...nel.org>, <airlied@...ux.ie>,
        <daniel@...ll.ch>, <nicolas.ferre@...rochip.com>,
        <alexandre.belloni@...tlin.com>, <ludovic.desroches@...rochip.com>,
        <lee.jones@...aro.org>
CC:     <dri-devel@...ts.freedesktop.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Peter Rosin <peda@...ntia.se>
Subject: [PATCH 4/5] Revert "drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested"

This reverts commit f6f7ad3234613f6f7f27c25036aaf078de07e9b0.
("drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested")
because allowing selecting a higher pixel clock may overclock
LCD devices, not all of them being capable of this.

Cc: Peter Rosin <peda@...ntia.se>
Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
index 721fa88bf71d..1a70dff1a417 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
@@ -117,18 +117,6 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
 		div = DIV_ROUND_UP(prate, mode_rate);
 		if (ATMEL_HLCDC_CLKDIV(div) & ~ATMEL_HLCDC_CLKDIV_MASK)
 			div = ATMEL_HLCDC_CLKDIV_MASK;
-	} else {
-		int div_low = prate / mode_rate;
-
-		if (div_low >= 2 &&
-		    ((prate / div_low - mode_rate) <
-		     10 * (mode_rate - prate / div)))
-			/*
-			 * At least 10 times better when using a higher
-			 * frequency than requested, instead of a lower.
-			 * So, go with that.
-			 */
-			div = div_low;
 	}
 
 	cfg |= ATMEL_HLCDC_CLKDIV(div);
-- 
2.7.4