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Date: Fri, 24 May 2024 12:41:18 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Jayesh Choudhary <j-choudhary@ti.com>
Cc: linux-kernel@vger.kernel.org, andrzej.hajda@intel.com, 
	neil.armstrong@linaro.org, rfoss@kernel.org, Laurent.pinchart@ideasonboard.com, 
	sam@ravnborg.org, mripard@kernel.org, dri-devel@lists.freedesktop.org, 
	jonas@kwiboo.se, jernej.skrabec@gmail.com, maarten.lankhorst@linux.intel.com, 
	tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch, a-bhatia1@ti.com
Subject: Re: [PATCH v3 1/2] drm/bridge: sii902x: Fix mode_valid hook
Message-ID: <y6ersd72tp2d6k4i2hja7bg37lahnvye2qion67urxeakw6rju@dher7oomt2ks>
References: <20240524093509.127189-1-j-choudhary@ti.com>
 <20240524093509.127189-2-j-choudhary@ti.com>
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In-Reply-To: <20240524093509.127189-2-j-choudhary@ti.com>

On Fri, May 24, 2024 at 03:05:08PM +0530, Jayesh Choudhary wrote:
> Currently, mode_valid hook returns all mode as valid and it is
> defined only in drm_connector_helper_funcs. With the introduction of
> 'DRM_BRIDGE_ATTACH_NO_CONNECTOR', connector is not initialized in
> bridge_attach call for cases when the encoder has this flag enabled.
> So add the mode_valid hook in drm_bridge_funcs as well with proper
> clock checks for maximum and minimum pixel clock supported by the
> bridge.
> 
> Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
> ---
>  drivers/gpu/drm/bridge/sii902x.c | 37 ++++++++++++++++++++++++++++++--
>  1 file changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
> index 2fbeda9025bf..bae551e107f9 100644
> --- a/drivers/gpu/drm/bridge/sii902x.c
> +++ b/drivers/gpu/drm/bridge/sii902x.c
> @@ -163,6 +163,14 @@
>  
>  #define SII902X_AUDIO_PORT_INDEX		3
>  
> +/*
> + * The maximum resolution supported by the HDMI bridge is 1080p@60Hz
> + * and 1920x1200 requiring a pixel clock of 165MHz and the minimum
> + * resolution supported is 480p@60Hz requiring a pixel clock of 25MHz
> + */
> +#define SII902X_MIN_PIXEL_CLOCK_KHZ		25000
> +#define SII902X_MAX_PIXEL_CLOCK_KHZ		165000
> +
>  struct sii902x {
>  	struct i2c_client *i2c;
>  	struct regmap *regmap;
> @@ -310,12 +318,26 @@ static int sii902x_get_modes(struct drm_connector *connector)
>  	return num;
>  }
>  
> +static enum
> +drm_mode_status sii902x_validate(struct sii902x *sii902x,
> +				 const struct drm_display_mode *mode)
> +{
> +	if (mode->clock < SII902X_MIN_PIXEL_CLOCK_KHZ)
> +		return MODE_CLOCK_LOW;
> +
> +	if (mode->clock > SII902X_MAX_PIXEL_CLOCK_KHZ)
> +		return MODE_CLOCK_HIGH;
> +
> +	return MODE_OK;
> +}
> +
>  static enum drm_mode_status sii902x_mode_valid(struct drm_connector *connector,
>  					       struct drm_display_mode *mode)
>  {
> -	/* TODO: check mode */
> +	struct sii902x *sii902x = connector_to_sii902x(connector);
> +	const struct drm_display_mode *mod = mode;
>  
> -	return MODE_OK;
> +	return sii902x_validate(sii902x, mod);

There is no need to. The drm_bridge_chain_mode_valid() should take care
of calling bridge's mode_valid callback and rejecting the mode if it is
not accepted.

>  }
>  
>  static const struct drm_connector_helper_funcs sii902x_connector_helper_funcs = {
> @@ -504,6 +526,16 @@ static int sii902x_bridge_atomic_check(struct drm_bridge *bridge,
>  	return 0;
>  }
>  
> +static enum drm_mode_status
> +sii902x_bridge_mode_valid(struct drm_bridge *bridge,
> +			  const struct drm_display_info *info,
> +			  const struct drm_display_mode *mode)
> +{
> +	struct sii902x *sii902x = bridge_to_sii902x(bridge);
> +
> +	return sii902x_validate(sii902x, mode);
> +}
> +
>  static const struct drm_bridge_funcs sii902x_bridge_funcs = {
>  	.attach = sii902x_bridge_attach,
>  	.mode_set = sii902x_bridge_mode_set,
> @@ -516,6 +548,7 @@ static const struct drm_bridge_funcs sii902x_bridge_funcs = {
>  	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>  	.atomic_get_input_bus_fmts = sii902x_bridge_atomic_get_input_bus_fmts,
>  	.atomic_check = sii902x_bridge_atomic_check,
> +	.mode_valid = sii902x_bridge_mode_valid,
>  };
>  
>  static int sii902x_mute(struct sii902x *sii902x, bool mute)
> -- 
> 2.25.1
> 

-- 
With best wishes
Dmitry