From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tero Kristo Subject: Re: [PATCH v2 4/5] ARM: dts: omap5: describe control for ckobuffer Date: Wed, 27 Apr 2016 15:31:03 +0300 Message-ID: <5720B107.4000907@ti.com> References: <20160426172710.GI5995@atomide.com> <70572DA1-BEB4-4681-BA6C-2E1C9002D730@goldelico.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <70572DA1-BEB4-4681-BA6C-2E1C9002D730@goldelico.com> Sender: linux-kernel-owner@vger.kernel.org To: "H. Nikolaus Schaller" , Tony Lindgren , "Ujfalusi, Peter" Cc: =?UTF-8?Q?Beno=c3=aet_Cousson?= , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King , ldewangan@nvidia.com, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, marek@goldelico.com, kernel@pyra-handheld.com, letux-kernel@openphoenux.org List-Id: linux-omap@vger.kernel.org On 27/04/16 09:04, H. Nikolaus Schaller wrote: > >> Am 26.04.2016 um 19:27 schrieb Tony Lindgren : >> >> Tero, >> >> * H. Nikolaus Schaller [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 >>> --- >>> 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 >>> >