linux-kernel - Re: [PATCH RFC v2 5/8] drm/bridge: dw-hdmi: support dynamically get input/out color info

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Message-ID: <1690671.DkqnqcUgQk@avalon>
Date:   Wed, 19 Dec 2018 09:50:41 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Andrzej Hajda <a.hajda@...sung.com>
Cc:     Neil Armstrong <narmstrong@...libre.com>, architt@...eaurora.org,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Sandy Huang <hjc@...k-chips.com>,
        Heiko Stübner <heiko@...ech.de>,
        maxime.ripard@...tlin.com, Zheng Yang <zhengyang@...k-chips.com>,
        dri-devel@...ts.freedesktop.org, linux-amlogic@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC v2 5/8] drm/bridge: dw-hdmi: support dynamically get input/out color info

Hello,

On Wednesday, 19 December 2018 09:26:08 EET Andrzej Hajda wrote:
> On 30.11.2018 14:42, Neil Armstrong wrote:
> > From: Zheng Yang <zhengyang@...k-chips.com>
> > 
> > To get input/output bus_format/enc_format dynamically, this patch
> > 
> > introduce following funstion in plat_data:
> > 	- get_input_bus_format
> > 	- get_output_bus_format
> > 	- get_enc_in_encoding
> > 	- get_enc_out_encoding
> 
> It seems fishy. On one side description says about dynamic resolution of
> formats and encodings.
> 
> On the other side these functions as only argument takes platform_data
> which should be rather static.
> 
> Where is this "dynamic" thing? The only usage of these callbacks I have
> found in next patches is also not dynamic, the functions just return
> some static value.
> 
> Moreover function takes void* argument, which is again something
> suspicious, why cannot you pass know structure?
> 
> And finally encoding usually should depend on display mode, it should
> not depend only static data.
> 
> 
> What kind of problems do you want to solve here?

I would add that this doesn't seem to be specific to dw-hdmi in any way. I'd 
prefer an API at the drm_bridge level to handle this.

> > Signed-off-by: Zheng Yang <zhengyang@...k-chips.com>
> > Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
> > ---
> > 
> >  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 28 +++++++++++++++++------
> >  include/drm/bridge/dw_hdmi.h              |  5 ++++
> >  2 files changed, 26 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index
> > 4a9a24e854db..bd564ffdf18b 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > @@ -1810,6 +1810,7 @@ static void hdmi_disable_overflow_interrupts(struct
> > dw_hdmi *hdmi)> 
> >  static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode
> >  *mode) {
> >  
> >  	int ret;
> > 
> > +	void *data = hdmi->plat_data->phy_data;
> > 
> >  	hdmi_disable_overflow_interrupts(hdmi);
> > 
> > @@ -1821,10 +1822,13 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi,
> > struct drm_display_mode *mode)> 
> >  		dev_dbg(hdmi->dev, "CEA mode used vic=%d\n", hdmi->vic);
> >  	
> >  	}
> > 
> > -	if ((hdmi->vic == 6) || (hdmi->vic == 7) ||
> > -	    (hdmi->vic == 21) || (hdmi->vic == 22) ||
> > -	    (hdmi->vic == 2) || (hdmi->vic == 3) ||
> > -	    (hdmi->vic == 17) || (hdmi->vic == 18))
> > +	if (hdmi->plat_data->get_enc_out_encoding)
> > +		hdmi->hdmi_data.enc_out_encoding =
> > +			hdmi->plat_data->get_enc_out_encoding(data);
> > +	else if ((hdmi->vic == 6) || (hdmi->vic == 7) ||
> > +		 (hdmi->vic == 21) || (hdmi->vic == 22) ||
> > +		 (hdmi->vic == 2) || (hdmi->vic == 3) ||
> > +		 (hdmi->vic == 17) || (hdmi->vic == 18))
> > 
> >  		hdmi->hdmi_data.enc_out_encoding = V4L2_YCBCR_ENC_601;
> >  	
> >  	else
> >  	
> >  		hdmi->hdmi_data.enc_out_encoding = V4L2_YCBCR_ENC_709;
> > 
> > @@ -1833,21 +1837,31 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi,
> > struct drm_display_mode *mode)> 
> >  	hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0;
> >  	
> >  	/* TOFIX: Get input format from plat data or fallback to RGB888 */
> > 
> > -	if (hdmi->plat_data->input_bus_format)
> > +	if (hdmi->plat_data->get_input_bus_format)
> > +		hdmi->hdmi_data.enc_in_bus_format =
> > +			hdmi->plat_data->get_input_bus_format(data);
> > +	else if (hdmi->plat_data->input_bus_format)
> > 
> >  		hdmi->hdmi_data.enc_in_bus_format =
> >  		
> >  			hdmi->plat_data->input_bus_format;
> >  	
> >  	else
> >  	
> >  		hdmi->hdmi_data.enc_in_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> >  	
> >  	/* TOFIX: Get input encoding from plat data or fallback to none */
> > 
> > -	if (hdmi->plat_data->input_bus_encoding)
> > +	if (hdmi->plat_data->get_enc_in_encoding)
> > +		hdmi->hdmi_data.enc_in_encoding =
> > +			hdmi->plat_data->get_enc_in_encoding(data);
> > +	else if (hdmi->plat_data->input_bus_encoding)
> > 
> >  		hdmi->hdmi_data.enc_in_encoding =
> >  		
> >  			hdmi->plat_data->input_bus_encoding;
> >  	
> >  	else
> >  	
> >  		hdmi->hdmi_data.enc_in_encoding = V4L2_YCBCR_ENC_DEFAULT;
> >  	
> >  	/* TOFIX: Default to RGB888 output format */
> > 
> > -	hdmi->hdmi_data.enc_out_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> > +	if (hdmi->plat_data->get_output_bus_format)
> > +		hdmi->hdmi_data.enc_out_bus_format =
> > +			hdmi->plat_data->get_output_bus_format(data);
> > +	else
> > +		hdmi->hdmi_data.enc_out_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> > 
> >  	hdmi->hdmi_data.pix_repet_factor = 0;
> >  	hdmi->hdmi_data.hdcp_enable = 0;
> > 
> > diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
> > index 7a02744ce0bc..2e797f782c51 100644
> > --- a/include/drm/bridge/dw_hdmi.h
> > +++ b/include/drm/bridge/dw_hdmi.h
> > @@ -142,6 +142,11 @@ struct dw_hdmi_plat_data {
> > 
> >  	int (*configure_phy)(struct dw_hdmi *hdmi,
> >  	
> >  			     const struct dw_hdmi_plat_data *pdata,
> >  			     unsigned long mpixelclock);
> > 
> > +
> > +	unsigned long (*get_input_bus_format)(void *data);
> > +	unsigned long (*get_output_bus_format)(void *data);
> > +	unsigned long (*get_enc_in_encoding)(void *data);
> > +	unsigned long (*get_enc_out_encoding)(void *data);
> > 
> >  };
> >  
> >  struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,


-- 
Regards,

Laurent Pinchart