From mboxrd@z Thu Jan 1 00:00:00 1970 From: hdegoede@redhat.com (Hans de Goede) Date: Fri, 31 Jul 2015 10:31:30 +0200 Subject: [linux-sunxi] [PATCH 6/8] ARM: dts: axp209: Add usb_power_supply child node to the ax209 node In-Reply-To: <20150731083541.5f2c683a@pluto.restena.lu> References: <1433885881-19809-1-git-send-email-hdegoede@redhat.com> <1433885881-19809-7-git-send-email-hdegoede@redhat.com> <20150731075104.48c467e6@pluto.restena.lu> <20150731083541.5f2c683a@pluto.restena.lu> Message-ID: <55BB3262.5000403@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 31-07-15 08:35, Bruno Pr?mont wrote: > On Fri, 31 Jul 2015 14:14:28 +0800 Chen-Yu Tsai wrote: >> On Fri, Jul 31, 2015 at 1:51 PM, Bruno Pr?mont wrote: >>> Hi ChenYu, >>> >>> On Fri, 31 Jul 2015 13:31:53 +0800 Chen-Yu Tsai wrote: >>>> Hi Hans, >>>> >>>> On Wed, Jun 10, 2015 at 5:37 AM, Hans de Goede wrote: >>>>> Add a node representing the usb power supply part of the axp209 pmic, note >>>>> that the usb power supply and the (to be added later) ac power supply will >>>>> each have their own child-node, so that they can be separately specified >>>>> as power-supply for other nodes using a power-supply property with a >>>>> phandle pointing to the right axp209 child-node. >>>>> >>>>> Signed-off-by: Hans de Goede >>>>> --- >>>>> arch/arm/boot/dts/axp209.dtsi | 5 +++++ >>>>> 1 file changed, 5 insertions(+) >>>>> >>>>> diff --git a/arch/arm/boot/dts/axp209.dtsi b/arch/arm/boot/dts/axp209.dtsi >>>>> index 24c935c..051ab3b 100644 >>>>> --- a/arch/arm/boot/dts/axp209.dtsi >>>>> +++ b/arch/arm/boot/dts/axp209.dtsi >>>>> @@ -89,4 +89,9 @@ >>>>> regulator-name = "ldo5"; >>>>> }; >>>>> }; >>>>> + >>>>> + usb_power_supply: usb_power_supply { >>>>> + compatible = "x-powers,axp202-usb-power-supply"; >>>>> + status = "disabled"; >>>> >>>> Is there any reason to have this disabled by default? >>>> AFAIK this is not something configurable in hardware, >>>> and the driver just gives readouts and status updates. >>> >>> There are some devices that only have 'AC-IN' instead of usb/otg power >>> (set-top boxes) so having the devices tell what power sources they >>> have makes sense (otherwise those that have ac-in instead of otg would >>> have to disable usb_power_supply) and avoids confusion by explicitly >>> stating presence in device dts. >> >> That's true. But this is a bit of hardware inside the AXP. >> If it's power isn't routed, it should report it, shouldn't it? > > If the device does not use the input there are two cases: > - ac-in and usb/otg in short-circuited (there is a bit in AXP registers > to provide this indication) > - the unused one is just not connected/connectable > > In either case the voltage of the unused/unusable branch is not really > useful, nor is it useful to have it show up in sysfs. Exactly my thinking on this, +1 . >> And normal users would probably expect to read the input >> voltage/current/status through sysfs (or maybe hwmon?), >> instead of not finding the device and having to look through >> the DTS. > > Only those supplies effectively present (in-use or with connectors > to eventually use them) should be visible in sysfs. > Having more of them will just confuse the users, they would be searching > how they can connect the supply while there is no means to do so > except soldering to the tiny AXP pins. +1 Regards, Hans