Re: [PATCH] video: da8xx-fb: reset LCDC only if functional clock
flat view
From: Madhvapathi Sriram <hidden>
Date: 2011-12-21 10:59:01
Prakash, On Wed, Dec 21, 2011 at 12:57 PM, Manjunathappa, Prakash [off-list ref] wrote:
LCDC functional clock may or may not be derived from CPU/MPU DPLL, For example, AM335x => Separate independent DPLL for LCDC Davinci => Same DPLL as MPU So, on platforms where LCDC functional clock is not derived from CPU/MPU PLL it is not required to reset LCDC module, if CPU frequency does not change with DVFS.
Is it not the case that the CPU frequency always changes during DVFS? This sentence does not strike me straight. Did you mean that if the frequency of the PLL (from which LCDC derives) does not change with DVFS, then LCDC module is not required to be reset?
quoted hunk ↗ jump to hunk
This patch adds check to do reset only if functional clock changes between pre and post notifier callbacks with DVFS. Signed-off-by: Manjunathappa, Prakash <redacted> --- drivers/video/da8xx-fb.c | 13 ++++++++----- 1 files changed, 8 insertions(+), 5 deletions(-)diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c index 29577bf..1334a68 100644 --- a/drivers/video/da8xx-fb.c +++ b/drivers/video/da8xx-fb.c@@ -161,6 +161,7 @@ struct da8xx_fb_par {int vsync_timeout; #ifdef CONFIG_CPU_FREQ struct notifier_block freq_transition; + unsigned int lcd_fck_rate; #endif void (*panel_power_ctrl)(int); };@@ -840,11 +841,12 @@ static int lcd_da8xx_cpufreq_transition(struct notifier_block *nb,struct da8xx_fb_par *par; par = container_of(nb, struct da8xx_fb_par, freq_transition); - if (val = CPUFREQ_PRECHANGE) { - lcd_disable_raster(); - } else if (val = CPUFREQ_POSTCHANGE) { - lcd_calc_clk_divider(par); - lcd_enable_raster(); + if (val = CPUFREQ_POSTCHANGE) { + if (par->lcd_fck_rate != clk_get_rate(par->lcdc_clk)) { + lcd_disable_raster(); + lcd_calc_clk_divider(par); + lcd_enable_raster(); + } } return 0;@@ -1137,6 +1139,7 @@ static int __devinit fb_probe(struct platform_device *device)par = da8xx_fb_info->par; par->lcdc_clk = fb_clk; + par->lcd_fck_rate = clk_get_rate(fb_clk); par->pxl_clk = lcdc_info->pxl_clk; if (fb_pdata->panel_power_ctrl) { par->panel_power_ctrl = fb_pdata->panel_power_ctrl; -- 1.7.1 _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source