Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161516AbbKSUjy (ORCPT ); Thu, 19 Nov 2015 15:39:54 -0500 Received: from mail-ob0-f178.google.com ([209.85.214.178]:36399 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161497AbbKSUjw (ORCPT ); Thu, 19 Nov 2015 15:39:52 -0500 MIME-Version: 1.0 In-Reply-To: <2241755.f72hngpPkv@avalon> References: <1447958344-836-1-git-send-email-geert+renesas@glider.be> <1447958344-836-2-git-send-email-geert+renesas@glider.be> <1756365.Ijac5ApxcA@avalon> <2241755.f72hngpPkv@avalon> Date: Thu, 19 Nov 2015 21:39:50 +0100 X-Google-Sender-Auth: sUD3MqowhdWlQ5EUr6tKDK2oPGE Message-ID: Subject: Re: [PATCH 01/25] serial: sh-sci: Update DT binding documentation for external clock input From: Geert Uytterhoeven To: Laurent Pinchart Cc: Geert Uytterhoeven , Greg Kroah-Hartman , Simon Horman , Magnus Damm , Yoshinori Sato , Laurent Pinchart , "linux-serial@vger.kernel.org" , Linux-sh list , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2283 Lines: 53 On Thu, Nov 19, 2015 at 9:27 PM, Laurent Pinchart wrote: > On Thursday 19 November 2015 22:19:14 Laurent Pinchart wrote: >> On Thursday 19 November 2015 19:38:40 Geert Uytterhoeven wrote: >> > Amend the DT bindings to include the optional external clock on >> > (H)SCI(F) and some SCIFA, where this pin can serve as a clock input, >> > depending on board wiring. >> > --- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt >> > +++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt >> > >> > @@ -43,6 +43,9 @@ Required properties: >> > - clocks: Must contain a phandle and clock-specifier pair for each >> > entry >> > >> > in clock-names. >> > >> > - clock-names: Must contain "fck" for the SCIx UART functional clock. >> > >> > + On (H)SCI(F) and some SCIFA, an additional clock may be specified: >> Could you list the SCIFA variants that support external clocks ? >> >> > + - "hsck" for the optional external clock input (on HSCIF), >> > + - "sck" for the optional external clock input (on other variants). > > Additionally, those clocks are used as inputs to the baud rate generator for > external clocks, as the ones listed in patch 02/25 in this series. I'd merge > the two patches and clarify the wording. "SCK" predates the BRG, it even exists on SCI in H8/300. That SCK is used as input to the BRG is just an artefact of how the BRG was added to the SCIF. The BRG is just muxed with the existing SCK to form a clock input, which is muxed with the BRR clock through the SCSCR.CKEx bits. And the BRG itself can choose between SCIF_CLK and INT_CLK. Hence that's why I split it in two parts. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/