Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751868AbbGMHYy (ORCPT ); Mon, 13 Jul 2015 03:24:54 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:33962 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751438AbbGMHYx (ORCPT ); Mon, 13 Jul 2015 03:24:53 -0400 Message-ID: <55A367BE.6040103@linaro.org> Date: Mon, 13 Jul 2015 12:54:46 +0530 From: Vaibhav Hiremath User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org CC: devicetree@vger.kernel.org, sameo@linux.intel.com, linux-kernel@vger.kernel.org, robh+dt@kernel.org, lee.jones@linaro.org Subject: Re: [PATCH 3/6] mfd: devicetree: bindings: 88pm800: Add DT property for 32KHz output enable References: <1436442431-3471-1-git-send-email-vaibhav.hiremath@linaro.org> <1436442431-3471-4-git-send-email-vaibhav.hiremath@linaro.org> <55A0C1B8.4030402@samsung.com> In-Reply-To: <55A0C1B8.4030402@samsung.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2002 Lines: 54 On Saturday 11 July 2015 12:41 PM, Krzysztof Kozlowski wrote: > W dniu 09.07.2015 o 20:47, Vaibhav Hiremath pisze: >> 88PM800 family of device supports output of 32KHz clock (low jitter) >> on CLK32K2/3 pin which can be supplied to other peripherals on the board. >> >> This patch adds the devicetree binding to enable this feature. >> >> Signed-off-by: Vaibhav Hiremath >> --- >> Documentation/devicetree/bindings/mfd/88pm800.txt | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/mfd/88pm800.txt b/Documentation/devicetree/bindings/mfd/88pm800.txt >> index dec842f..ae1311c 100644 >> --- a/Documentation/devicetree/bindings/mfd/88pm800.txt >> +++ b/Documentation/devicetree/bindings/mfd/88pm800.txt >> @@ -9,6 +9,12 @@ Required parent device properties: >> - #interrupt-cells : should be 1. >> The cell is the 88pm80x local IRQ number >> >> +Optional properties : >> + - marvell,88pm800-32khz-xolj-out-en : If set, driver will enable low jitter >> + version of 32Khz clock output on > > I am not sure if I understand it correctly. The hardware always has such > clocks and you only want to enable/disable it in DT? Any reasons why > these should not be enabled always? > Small amount of Power savings... Although currently I do not have power numbers to justify this. As per spec, (it only talks about power consumption in power down state) Power-down State => VSYS > 2.8 => 4.5 μA CLK32K2 = 0 => 18 μW > Enabling it in DT does not look like a job for DT. Maybe you there > should be just a clock driver (clock provider)? > It's init time (and one time) settings, wouldn't clock-provider be overkill for this? Thanks, Vaibhav -- 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/