Re: [PATCH v2 5/5] OMAPDSS: HDMI: Add support to dump clocks through

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

On Fri, 2011-09-23 at 11:22 +0530, K, Mythri P wrote:

> > - What is dcofreq? Looking at the code, it tells if the pixel clock is >
> > 1000MHz. Why is such a field needed, can't the HDMI driver manage that
> > itself? And if it's needed, why is it called dcofreq, the name doesn't
> > make much sense to me.
> It is DCO frequency, It suggest the frequency selector range ,

The field is not DCO frequency, it's a boolean, 0 or 1. That's why the
name doesn't really make sense to me.

> HDMI_PLL_CONFIGURATION2 (3:1) has to be set accordingly by the driver
> depending on whether the CLKOUTLDO is greater than or less than
> 1000Mhz, but anyways the decision is taken by the driver.

But can't it be done in the ti_hdmi driver, at the same time when
programming the registers? Why do we need to set the boolean beforehand.

> Also the name is as suggested by TRM .

I couldn't find boolean dcofreq in the TRM.

> > - We are doing HDMI PLL calculations in the omapdss drivers hdmi.c file.
> > The PLL calculations are PLL specific, and thus should be in the
> > specific HDMI implementation file, right?
> >
> >> +     seq_printf(s, "DISPC clock source %s (%s)\t(%s)\n",
> >> +                     dss_get_generic_clk_source_name(dispc_clk_src),
> >> +                     dss_feat_get_clk_source_name(dispc_clk_src),
> >> +                     dispc_clk_src == OMAP_DSS_CLK_SRC_FCK ?
> >> +                     "off" : "on");
> >
> > Why do you print DISPC clock source? How is that part of HDMI clock
> > configuration?
> Reason is to check whether the DISPC clock source is PRCM / DSI PLL,
> Because DSI PLL might not be sufficient.

But it's already printed by the DISPC section, and it's not part of
HDMI, so I don't quite see the need.

What do you mean DSI PLL might not be sufficient? We can get higher
DISPC clocks with DSI PLL than with PRCM.

 Tomi