linux-kernel - [PATCH] atmel_lcdfb: fix pixclok divider calculation

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Message-ID: <48209708.3020807@atmel.com>
Date:	Tue, 06 May 2008 19:36:08 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	linux-fbdev-devel@...ts.sourceforge.net, adaplas@...il.com
CC:	Per Hedblom <per.hedblom@...m.se>, Roel Kluin <12o3l@...cali.nl>,
	Jan Weber <jw022609@...-greifswald.de>,
	Andrew Victor <linux@...im.org.za>,
	Haavard Skinnemoen <hskinnemoen@...el.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] atmel_lcdfb: fix pixclok divider calculation

Fix divider calculation and allow CLKVAL = 0 (divisor 2)

It was not possible to get the clock value 0 (divisor 2) because 
the test "<=0" force the BYPASS bit to be activated instead.

Signed-off-by: Nicolas Ferre <nicolas.ferre@...el.com>
---
Thanks a lot to Jan, Per, Roel and Haavard for sending me
similar patches.

 drivers/video/atmel_lcdfb.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
--- a/drivers/video/atmel_lcdfb.c
+++ b/drivers/video/atmel_lcdfb.c
@@ -441,13 +441,12 @@ static int atmel_lcdfb_set_par(struct fb_info *info)
 
 	value = DIV_ROUND_UP(clk_value_khz, PICOS2KHZ(info->var.pixclock));
 
-	value = (value / 2) - 1;
-	dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", value);
-
-	if (value <= 0) {
+	if (value < 2) {
 		dev_notice(info->device, "Bypassing pixel clock divider\n");
 		lcdc_writel(sinfo, ATMEL_LCDC_LCDCON1, ATMEL_LCDC_BYPASS);
 	} else {
+		value = (value / 2) - 1;
+		dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", value);
 		lcdc_writel(sinfo, ATMEL_LCDC_LCDCON1, value << ATMEL_LCDC_CLKVAL_OFFSET);
 		info->var.pixclock = KHZ2PICOS(clk_value_khz / (2 * (value + 1)));
 		dev_dbg(info->device, "  updated pixclk:     %lu KHz\n",

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