[PATCH] drm/panel: Fix ARM Versatile panel clocks

Eric Anholt eric at anholt.net
Thu Feb 8 10:50:58 UTC 2018


Linus Walleij <linus.walleij at linaro.org> writes:

> These clocks are in kHz not in Hz, oops. Fix it so my
> new bandwidth calculations patch starts working with these
> panels.
>
> Cc: Eric Anholt <eric at anholt.net>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
>  drivers/gpu/drm/panel/panel-arm-versatile.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-arm-versatile.c b/drivers/gpu/drm/panel/panel-arm-versatile.c
> index 3930b4925b15..35707d0ae6b0 100644
> --- a/drivers/gpu/drm/panel/panel-arm-versatile.c
> +++ b/drivers/gpu/drm/panel/panel-arm-versatile.c
> @@ -132,7 +132,7 @@ static const struct versatile_panel_type versatile_panels[] = {
>  		.width_mm = 79,
>  		.height_mm = 54,
>  		.mode = {
> -			.clock = 10000000,
> +			.clock = 10000,
>  			.hdisplay = 320,
>  			.hsync_start = 320 + 6,
>  			.hsync_end = 320 + 6 + 6,
> @@ -156,7 +156,7 @@ static const struct versatile_panel_type versatile_panels[] = {
>  		.width_mm = 171,
>  		.height_mm = 130,
>  		.mode = {
> -			.clock = 25000000,
> +			.clock = 25000,
>  			.hdisplay = 640,
>  			.hsync_start = 640 + 24,
>  			.hsync_end = 640 + 24 + 96,
> @@ -179,7 +179,7 @@ static const struct versatile_panel_type versatile_panels[] = {
>  		.width_mm = 34,
>  		.height_mm = 45,
>  		.mode = {
> -			.clock = 625000000,
> +			.clock = 625000,

625000kHz still seems really suspicious.  The fbdev driver does:

	clk_set_rate(fb->clk, (1000000000 / regs.pixclock) * 1000);

which seems really strange to me -- set the clock rate lower as pixclock
increases?  What's going on here?
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