Re: [PATCH v3] video: da8xx-fb: reset LCDC only if functional clock changes with DVFS

[Florian Tobias Schandinat <FlorianSchandinat@gmx.de>]

On 01/03/2012 12:40 PM, Manjunathappa, Prakash 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 as its functional clock does
> not change with DVFS.
> 
> 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 <prakash.pm@ti.com>

Applied.


Thanks,

Florian Tobias Schandinat

> ---
> Since v2:
> Fix, update lcd_fck_rate with current LCD functional clock rate.
> Since v1:
> Fixed the commit message.
> 
>  drivers/video/da8xx-fb.c |   16 +++++++++++-----
>  1 files changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
> index 6b27751..dee1918 100644
> --- a/drivers/video/da8xx-fb.c
> +++ b/drivers/video/da8xx-fb.c
> @@ -163,6 +163,7 @@ 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);
>  };
> @@ -895,11 +896,13 @@ 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)) {
> +			par->lcd_fck_rate = clk_get_rate(par->lcdc_clk);
> +			lcd_disable_raster();
> +			lcd_calc_clk_divider(par);
> +			lcd_enable_raster();
> +		}
>  	}
>  
>  	return 0;
> @@ -1192,6 +1195,9 @@ static int __devinit fb_probe(struct platform_device *device)
>  
>  	par = da8xx_fb_info->par;
>  	par->lcdc_clk = fb_clk;
> +#ifdef CONFIG_CPU_FREQ
> +	par->lcd_fck_rate = clk_get_rate(fb_clk);
> +#endif
>  	par->pxl_clk = lcdc_info->pxl_clk;
>  	if (fb_pdata->panel_power_ctrl) {
>  		par->panel_power_ctrl = fb_pdata->panel_power_ctrl;