Messages in this thread | | | Date | Tue, 3 Mar 2015 16:37:13 -0800 | From | Arun Ramamurthy <> | Subject | Re: [PATCH] video: ARM CLCD: Added dt support to set tim2 register |
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On 15-03-03 02:22 AM, Pawel Moll wrote: > On Tue, 2015-03-03 at 10:02 +0000, Pawel Moll wrote: >> On Mon, 2015-03-02 at 19:09 +0000, Arun Ramamurthy wrote: >>>> The existing bindings intentionally avoided quoting internal registers - >>>> they are supposed to describe how the hardware is wired up... >>>> >>>> So how about something like "arm,pl11x,tft-invert-clac"? Then the driver >>>> sets the bit or not, depending on the property existance? >>>> >>> Sure, I can change it to two properties called arm,pl11x,tft-invert-clac >>> and arm,pl11x,tft-clksel. Would that be acceptable? >> >> That would be fine by me :-) > > Or (after having a look at the TRM) I should rather say: the invert-clac > is fine by me :-) but the tft-clksel doesn't work, I afraid. > > If I'm not mistaken, there are two problems with it. > > Number one: it's not TFT-specific, is it? So it certainly should not > have the "tft-" bit. > > Number two: setting this bit says "do not use CLCDCLK for the logic; use > HCLK instead", correct? If so, have a look at the clock properties. They > say: > > - clock-names: should contain "clcdclk" and "apb_pclk" > > - clocks: contains phandle and clock specifier pairs for the entries > in the clock-names property. See > > So if your hardware has the reference clock wired to HCLK, and you > defining the clocks as "clcdclk", you are (no offence meant ;-) > lying :-) > No offense taken :) > So how about solving the problem by extending the clock-names definition > like this (feel free to use own wording): > > - clock-names: should contain two clocks, either "clcdclk" or "hclk" > (depending on which input is to be used as a reference > clock by the controller logic) and "apb_pclk" > > That way you're precisely describing the way the hardware is wired up. > And the driver simply tries to get clcdclk first, if it's defined - > cool, set clksel to 1, if not - try hclk and set clksel to 0. If neither > of them is present - bail out. > > Does this make any sense? > This makes sense to me, thank you for the suggestions. I will fix it all up in V2 > Pawel >
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