Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753240AbbFVURN (ORCPT ); Mon, 22 Jun 2015 16:17:13 -0400 Received: from mail-oi0-f48.google.com ([209.85.218.48]:36834 "EHLO mail-oi0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752844AbbFVURE (ORCPT ); Mon, 22 Jun 2015 16:17:04 -0400 MIME-Version: 1.0 In-Reply-To: <20150622200549.9112.2411@quantum> References: <1432839219-475-1-git-send-email-geert+renesas@glider.be> <1432839219-475-14-git-send-email-geert+renesas@glider.be> <20150622200549.9112.2411@quantum> Date: Mon, 22 Jun 2015 22:17:03 +0200 X-Google-Sender-Auth: Y-LxEUWB4Ac6DTSKAEQbcMZ69HI Message-ID: Subject: Re: [PATCH v2 13/14] clk: shmobile: mstp: Consider "zb_clk" suitable for power management From: Geert Uytterhoeven To: Michael Turquette Cc: Geert Uytterhoeven , Stephen Boyd , Simon Horman , Magnus Damm , Laurent Pinchart , "Rafael J. Wysocki" , Kevin Hilman , Ulf Hansson , linux-clk@vger.kernel.org, Linux PM list , Linux-sh list , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-kernel@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: 2738 Lines: 74 Hi Mike, On Mon, Jun 22, 2015 at 10:05 PM, Michael Turquette wrote: Still sending email from Linaro, which will cause me to receive an autoreply? > Quoting Geert Uytterhoeven (2015-05-28 11:53:38) >> Currently the CPG Clock Domain code looks for MSTP clocks to power >> manage a device. >> >> Unfortunately, on R-Mobile APE6 (r8a73a4) and SH-Mobile AG5 (sh73a0), >> the Bus State Controller (BSC) is not power-managed by an MSTP clock, >> but by a plain CPG clock (zb_clk). Add a special case to handle this, >> so the clock is properly managed, and devices connected to the BSC work >> as expected. >> >> Signed-off-by: Geert Uytterhoeven >> --- >> v2: >> - New. >> --- >> drivers/clk/shmobile/clk-mstp.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/clk/shmobile/clk-mstp.c b/drivers/clk/shmobile/clk-mstp.c >> index 619f3eccefd4884f..19e2b11953383587 100644 >> --- a/drivers/clk/shmobile/clk-mstp.c >> +++ b/drivers/clk/shmobile/clk-mstp.c >> @@ -258,6 +258,10 @@ int cpg_mstp_attach_dev(struct generic_pm_domain *domain, struct device *dev) >> "renesas,cpg-mstp-clocks")) >> goto found; >> >> + /* BSC on r8a73a4/sh73a0 uses zb_clk instead of an mstp clock*/ >> + if (!strcmp(clkspec.np->name, "zb_clk")) >> + goto found; > > Hello Geert, > > Is the driver the right place to handle this corner case? What do you > think about linking zb_clk up to the bsc devicetree node for > r8a73a4/sh73a0? It already is linked: bsc: bus@fec10000 { compatible = "renesas,bsc-r8a73a4", "renesas,bsc", "simple-pm-bus"; #address-cells = <1>; #size-cells = <1>; ranges = <0 0 0 0x20000000>; reg = <0 0xfec10000 0 0x400>; clocks = <&zb_clk>; power-domains = <&pd_c4>; }; https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/r8a73a4.dtsi#n446 But without this hack in clk-mstp, the clock domain controller doesn't know it can use this clock for power management like an ordinary mstp clock. 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 Please read the FAQ at http://www.tux.org/lkml/