From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752672AbcD0Mbt (ORCPT ); Wed, 27 Apr 2016 08:31:49 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:39514 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752385AbcD0Mbq (ORCPT ); Wed, 27 Apr 2016 08:31:46 -0400 Subject: Re: [PATCH v2 4/5] ARM: dts: omap5: describe control for ckobuffer To: "H. Nikolaus Schaller" , Tony Lindgren , "Ujfalusi, Peter" References: <20160426172710.GI5995@atomide.com> <70572DA1-BEB4-4681-BA6C-2E1C9002D730@goldelico.com> CC: =?UTF-8?Q?Beno=c3=aet_Cousson?= , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King , , , , , , , From: Tero Kristo Message-ID: <5720B107.4000907@ti.com> Date: Wed, 27 Apr 2016 15:31:03 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <70572DA1-BEB4-4681-BA6C-2E1C9002D730@goldelico.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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 >>> >