Re: [PATCH v5 2/6] drm/vc4: hdmi: Move clock calculation into its own function

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jan 27, 2022 at 03:10:17PM +0100, Maxime Ripard wrote:
> The code to compute our clock rate for a given setup will be called in
> multiple places in the next patches, so let's create a separate function
> for it.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
>  drivers/gpu/drm/vc4/vc4_hdmi.c | 49 +++++++++++++++++++++++-----------
>  1 file changed, 34 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 105911644b02..a1fa37ad350d 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -1274,6 +1274,35 @@ vc4_hdmi_encoder_clock_valid(const struct vc4_hdmi *vc4_hdmi,
>  	return MODE_OK;
>  }
>  
> +static unsigned long long
> +vc4_hdmi_encoder_compute_mode_clock(const struct drm_display_mode *mode,
> +				    unsigned int bpc)
> +{
> +	unsigned long long clock = mode->clock * 1000;
> +
> +	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
> +		clock = clock * 2;
> +
> +	return clock * bpc / 8;

div_u64()/etc.?

> +}
> +
> +static int
> +vc4_hdmi_encoder_compute_clock(const struct vc4_hdmi *vc4_hdmi,
> +			       struct vc4_hdmi_connector_state *vc4_state,
> +			       const struct drm_display_mode *mode,
> +			       unsigned int bpc)
> +{
> +	unsigned long long clock;
> +
> +	clock = vc4_hdmi_encoder_compute_mode_clock(mode, bpc);
> +	if (vc4_hdmi_encoder_clock_valid(vc4_hdmi, clock) != MODE_OK)
> +		return -EINVAL;
> +
> +	vc4_state->pixel_rate = clock;

This thing seems a bit confused between pixels vs. TMDS characters.
Either that or some/all of the pixel_clock/rate things are just
misnamed?

> +
> +	return 0;
> +}
> +
>  #define WIFI_2_4GHz_CH1_MIN_FREQ	2400000000ULL
>  #define WIFI_2_4GHz_CH1_MAX_FREQ	2422000000ULL
>  
> @@ -1286,6 +1315,7 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
>  	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
>  	unsigned long long pixel_rate = mode->clock * 1000;
>  	unsigned long long tmds_rate;
> +	int ret;
>  
>  	if (vc4_hdmi->variant->unsupported_odd_h_timings &&
>  	    ((mode->hdisplay % 2) || (mode->hsync_start % 2) ||
> @@ -1306,21 +1336,10 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
>  		pixel_rate = mode->clock * 1000;
>  	}
>  
> -	if (conn_state->max_bpc == 12) {
> -		pixel_rate = pixel_rate * 150;
> -		do_div(pixel_rate, 100);
> -	} else if (conn_state->max_bpc == 10) {
> -		pixel_rate = pixel_rate * 125;
> -		do_div(pixel_rate, 100);
> -	}
> -
> -	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
> -		pixel_rate = pixel_rate * 2;
> -
> -	if (vc4_hdmi_encoder_clock_valid(vc4_hdmi, pixel_rate) != MODE_OK)
> -		return -EINVAL;
> -
> -	vc4_state->pixel_rate = pixel_rate;
> +	ret = vc4_hdmi_encoder_compute_clock(vc4_hdmi, vc4_state, mode,
> +					     conn_state->max_bpc);
> +	if (ret)
> +		return ret;
>  
>  	return 0;
>  }
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel