Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751788Ab3JUVHS (ORCPT ); Mon, 21 Oct 2013 17:07:18 -0400 Received: from mail-oa0-f49.google.com ([209.85.219.49]:55845 "EHLO mail-oa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751287Ab3JUVHO (ORCPT ); Mon, 21 Oct 2013 17:07:14 -0400 MIME-Version: 1.0 In-Reply-To: <20131017140542.GE24056@e106331-lin.cambridge.arm.com> References: <1381960030-1640-1-git-send-email-tim.kryger@linaro.org> <1381960030-1640-5-git-send-email-tim.kryger@linaro.org> <20131017140542.GE24056@e106331-lin.cambridge.arm.com> Date: Mon, 21 Oct 2013 14:07:14 -0700 Message-ID: Subject: Re: [RESEND PATCH v2 4/6] clocksource: kona: Add basic use of external clock From: Tim Kryger To: Mark Rutland Cc: Christian Daudt , "rob.herring@calxeda.com" , Pawel Moll , Stephen Warren , Ian Campbell , Daniel Lezcano , Thomas Gleixner , Chris Ball , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mmc@vger.kernel.org" , "patches@linaro.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3088 Lines: 80 On Thu, Oct 17, 2013 at 7:05 AM, Mark Rutland wrote: > On Wed, Oct 16, 2013 at 10:47:08PM +0100, Tim Kryger wrote: >> When an clock handle is specified in the device tree, enable it and use >> it to determine the external clock frequency. > > I'd drop handle here and just say "When a clock is specified". > > This will need a binding document update. Can you be more specific about what you are looking for here? Shall I just say that the frequency property is now deprecated since it actually belongs to the external clock whose association with a kona timer instance might be declared in the DT using the common clock bindings but could also be declared through other means? >> Signed-off-by: Tim Kryger >> Reviewed-by: Markus Mayer >> Reviewed-by: Matt Porter >> --- >> drivers/clocksource/bcm_kona_timer.c | 14 +++++++++++--- >> 1 file changed, 11 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c >> index 0d7d8c3..fd11f96 100644 >> --- a/drivers/clocksource/bcm_kona_timer.c >> +++ b/drivers/clocksource/bcm_kona_timer.c >> @@ -17,6 +17,7 @@ >> #include >> #include >> #include >> +#include >> >> #include >> #include >> @@ -107,11 +108,18 @@ static const struct of_device_id bcm_timer_ids[] __initconst = { >> static void __init kona_timers_init(struct device_node *node) >> { >> u32 freq; >> + struct clk *external_clk; >> >> - if (!of_property_read_u32(node, "clock-frequency", &freq)) >> + external_clk = of_clk_get_by_name(node, NULL); > > Is there only a single external clock input to the kona timer, or is > only one relevant here? > > Are there any other inputs currently not modelled (e.g. regulators)? The timer block relies upon a single clock and does not use any regulators. >> + >> + if (!IS_ERR(external_clk)) { >> + arch_timer_rate = clk_get_rate(external_clk); >> + clk_prepare_enable(external_clk); >> + } else if (!of_property_read_u32(node, "clock-frequency", &freq)) { >> arch_timer_rate = freq; >> - else >> - panic("clock-frequency not set in the .dts file"); >> + } else { >> + panic("neither clock-frequency or clocks handle in .dts file"); > > Nit: it's not a handle, it's a phandle+args pair. > > Why not just "Unable to determine clock frequency"? Sure that sounds fine. > > Do we need to panic here? Might a system have other clocks it could use > to continue? I completely agree that this driver could be improved. However, this is unrelated to the topic of this series so I will address it later in a separate patch. -- 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/