[PATCH v3 1/2] drm/bridge: Add Cadence DSI driver

[Boris Brezillon]

On Tue, 19 Sep 2017 15:59:20 +0300
Tomi Valkeinen <tomi.valkeinen at ti.com> wrote:

> Hi Boris,
> 
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 
> On 31/08/17 18:55, Boris Brezillon wrote:
> > Add a driver for Cadence DPI -> DSI bridge.
> > 
> > This driver only support a subset of Cadence DSI bridge capabilities.
> > 
> > Here is a non-exhaustive list of missing features:
> >  * burst mode
> >  * dynamic configuration of the DPHY based on the
> >  * support for additional input interfaces (SDI input)
> > 
> > Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>  
> 
> <snip>
> 
> > +	dsi->pclk = devm_clk_get(&pdev->dev, "pclk");
> > +	if (IS_ERR(dsi->pclk))
> > +		return PTR_ERR(dsi->pclk);  
> 
> What's the purpose of pclk? Isn't that normally dealt with the normal
> modesetting, enabled with the video stream? How could it even be enabled
> here, without anyone setting the rate?

It's the peripheral clock, not the pixel clock, and AFAIU it has to be
enabled before accessing DSI registers.