From mboxrd@z Thu Jan 1 00:00:00 1970 From: vaibhav.hiremath@linaro.org (Vaibhav Hiremath) Date: Mon, 13 Jul 2015 12:54:46 +0530 Subject: [PATCH 3/6] mfd: devicetree: bindings: 88pm800: Add DT property for 32KHz output enable In-Reply-To: <55A0C1B8.4030402@samsung.com> 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> Message-ID: <55A367BE.6040103@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 ?A CLK32K2 = 0 => 18 ?W > 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