[PATCH] video:da8xx-fb: calculate pixel clock period for the panel

From: Manjunathappa, Prakash
Date: Thu Feb 09 2012 - 00:20:57 EST


Patch calculates pixel clock period in pico seconds and updates
the same in variable screen information structure. fbset utility
uses this information.

Signed-off-by: Manjunathappa, Prakash <prakash.pm@xxxxxx>
---
drivers/video/da8xx-fb.c | 21 ++++++++++++++++++++-
1 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
index f360d62..8b0a174 100644
--- a/drivers/video/da8xx-fb.c
+++ b/drivers/video/da8xx-fb.c
@@ -32,6 +32,7 @@
#include <linux/console.h>
#include <linux/slab.h>
#include <video/da8xx-fb.h>
+#include <asm/div64.h>

#define DRIVER_NAME "da8xx_lcdc"

@@ -174,7 +175,6 @@ static struct fb_var_screeninfo da8xx_fb_var __devinitdata = {
.activate = 0,
.height = -1,
.width = -1,
- .pixclock = 46666, /* 46us - AUO display */
.accel_flags = 0,
.left_margin = LEFT_MARGIN,
.right_margin = RIGHT_MARGIN,
@@ -1048,6 +1048,24 @@ static struct fb_ops da8xx_fb_ops = {
.fb_blank = cfb_blank,
};

+/*
+ * Calculate and return pixel clock period in pico secods
+ */
+static unsigned int da8xxfb_pixel_clk_period(struct da8xx_fb_par *par)
+{
+ unsigned int lcd_clk, div;
+ unsigned int configured_pix_clk;
+ unsigned long long pix_clk_period_picosec = 1000000000000ULL;
+
+ lcd_clk = clk_get_rate(par->lcdc_clk);
+ div = lcd_clk / par->pxl_clk;
+ configured_pix_clk = (lcd_clk / div);
+
+ do_div(pix_clk_period_picosec, configured_pix_clk);
+
+ return pix_clk_period_picosec;
+}
+
static int __devinit fb_probe(struct platform_device *device)
{
struct da8xx_lcdc_platform_data *fb_pdata =
@@ -1209,6 +1227,7 @@ static int __devinit fb_probe(struct platform_device *device)

da8xx_fb_var.hsync_len = lcdc_info->hsw;
da8xx_fb_var.vsync_len = lcdc_info->vsw;
+ da8xx_fb_var.pixclock = da8xxfb_pixel_clk_period(par);

/* Initialize fbinfo */
da8xx_fb_info->flags = FBINFO_FLAG_DEFAULT;
--
1.7.1

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