On Thu, Mar 20, 2025 at 05:59:58PM +0200, Tomi Valkeinen wrote:
> At the moment the driver just sets the clock rate with clk_set_rate(),
> and if the resulting rate is not the same as requested, prints a debug
> print, but nothing else.
>
> Add mode_fixup(), in which the clk_round_rate() is used to get the
> "rounded" rate, and set that to the adjusted_mode.
>
> In practice, with the current K3 SoCs, the display PLL is capable of
> producing very exact clocks, so most likely the rounded rate is the same
> as the original one.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/tidss/tidss_crtc.c | 22 ++++++++++++++++++++++
> drivers/gpu/drm/tidss/tidss_dispc.c | 6 ++++++
> drivers/gpu/drm/tidss/tidss_dispc.h | 2 ++
> 3 files changed, 30 insertions(+)
>
> diff --git a/drivers/gpu/drm/tidss/tidss_crtc.c b/drivers/gpu/drm/tidss/tidss_crtc.c
> index 1604eca265ef..b3338dac25bc 100644
> --- a/drivers/gpu/drm/tidss/tidss_crtc.c
> +++ b/drivers/gpu/drm/tidss/tidss_crtc.c
> @@ -309,7 +309,29 @@ enum drm_mode_status tidss_crtc_mode_valid(struct drm_crtc *crtc,
> return dispc_vp_mode_valid(tidss->dispc, tcrtc->hw_videoport, mode);
> }
>
> +static bool tidss_crtc_mode_fixup(struct drm_crtc *crtc,
> + const struct drm_display_mode *mode,
> + struct drm_display_mode *adjusted_mode)
> +{
> + struct tidss_crtc *tcrtc = to_tidss_crtc(crtc);
> + struct drm_device *ddev = crtc->dev;
> + struct tidss_device *tidss = to_tidss(ddev);
> + long rate;
> +
> + rate = dispc_vp_round_clk_rate(tidss->dispc, tcrtc->hw_videoport,
> + adjusted_mode->clock * 1000);
> + if (rate < 0)
> + return false;
> +
> + adjusted_mode->clock = rate / 1000;
> +
> + drm_mode_set_crtcinfo(adjusted_mode, 0);
> +
> + return true;
> +}
mode_fixup is deprecated in favor of atomic_check. If you can't use it
for some reason, it should be documented one way or another.
Maxime
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