Messages in this thread | | | Subject | Re: [PATCH v2 4/5] ARM: dts: omap5: describe control for ckobuffer | From | Tero Kristo <> | Date | Wed, 27 Apr 2016 15:31:03 +0300 |
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On 27/04/16 09:04, H. Nikolaus Schaller wrote: > >> Am 26.04.2016 um 19:27 schrieb Tony Lindgren <tony@atomide.com>: >> >> Tero, >> >> * H. Nikolaus Schaller <hns@goldelico.com> [160418 11:23]: >>> OMAP5 has a register to control if the ckobuffer is enabled >>> and defines the polarity. ckobuffer is required to drive a twl6040 >>> with the system clock. Hence, add the pinctrl,single to the >>> OMAP5 SoC description so that omap5-board-common can >>> set up the ckobuffer as required. >> >> Is this really a mux or should it be a mux clock? > > It is a pinmux setting for the clock out buffer to choose what signal > (and polarity) is presented on the fref_xtal_clk pad. > > The register is part of the CTRL_MODULE_WKUP. > The clock signal is the xtal master clock of the whole SoC. > > Although there is a bit to choose an alternate clock, there is no > alternate in the OMAP5 silicon. > > Therefore I would say it is about padconf and not clock or clock mux > related. > > It just happens to be a clock signal which can be routed to this > pad.
The two could very well be implemented as clock nodes, a mux and a gate. This would describe the hardware functionality better imo, if the assumptions made here are correct. Implementing the control as pinctrl hacks looks rather weird to me.
I could not find any documentation related to the ckobuffer usage though, maybe Peter can provide some insight? I think you spent some considerable time bringing up twl6040 a few years back...
-Tero
> > BR, > Nikolaus > >> >> Regards, >> >> Tony >> >>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> >>> --- >>> arch/arm/boot/dts/omap5.dtsi | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/arch/arm/boot/dts/omap5.dtsi b/arch/arm/boot/dts/omap5.dtsi >>> index 120b6b8..1d9050f 100644 >>> --- a/arch/arm/boot/dts/omap5.dtsi >>> +++ b/arch/arm/boot/dts/omap5.dtsi >>> @@ -277,6 +277,16 @@ >>> pinctrl-single,register-width = <16>; >>> pinctrl-single,function-mask = <0x7fff>; >>> }; >>> + >>> + omap5_control_ckobuffer: pinmux@cdb4 { >>> + compatible = "ti,omap5-padconf", >>> + "pinctrl-single"; >>> + reg = <0xcdb4 4>; >>> + #address-cells = <1>; >>> + #size-cells = <0>; >>> + pinctrl-single,register-width = <32>; >>> + pinctrl-single,function-mask = <0xf0000000>; >>> + }; >>> }; >>> >>> ocmcram: ocmcram@40300000 { >>> -- >>> 2.7.3 >>> >
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