Hallo, > > On 19/12/2024 01:58, Sebastian Reichel wrote: > > Hi, > > > > On Mon, Dec 16, 2024 at 08:30:45AM +0100, Krzysztof Kozlowski wrote: > >> On 13/12/2024 11:28, Stefan Raufhake wrote: > >>> Hallo Krzysztof, > >>> > >>>> > >>>> On Tue, Dec 10, 2024 at 09:23:43AM +0000, Stefan Raufhake wrote: > >>>>> From: Stefan Raufhake <s.raufhake@xxxxxxxxxxx> > >>>>> > >>>>> Some GPIO-controlled power supplies can be turned off (charging disabled). > >>>>> Support changing the charging state by setting charge_type to > >>>>> POWER_SUPPLY_CHARGE_TYPE_STANDARD and disabling charging by setting > >>>>> charge_type to POWER_SUPPLY_CHARGE_TYPE_NONE. One potential use case for > >>>>> this is disabling battery backup on a UPS. > >>>>> > >>>>> Signed-off-by: Stefan Raufhake <s.raufhake@xxxxxxxxxxx> > >>>>> --- > >>>>> .../bindings/power/supply/gpio-charger.yaml | 6 +++ > >>>>> drivers/power/supply/gpio-charger.c | 43 +++++++++++++++++++ > >>>>> 2 files changed, 49 insertions(+) > >>>>> > >>>> > >>>> <form letter> > >>>> This is a friendly reminder during the review process. > >>>> > >>>> It seems my or other reviewer's previous comments were not fully > >>>> addressed. Maybe the feedback got lost between the quotes, maybe you > >>>> just forgot to apply it. Please go back to the previous discussion and > >>>> either implement all requested changes or keep discussing them. > >>>> > >>>> Thank you. > >>>> </form letter> > >>> > >>> Sorry, it seems I made a mistake during the patch review process. > >>> Should I reply to your email about version 1 of the patch or only about > >>> version 2? I don't want to make another mistake and open two discussions > >>> at the same time. > >>> I hope to do better in the future. > >>> > >>>> > >>>>> diff --git a/Documentation/devicetree/bindings/power/supply/gpio-charger.yaml b/Documentation/devicetree/bindings/power/supply/gpio-charger.yaml > >>>>> index 89f8e2bcb2d7..084520bfc040 100644 > >>>>> --- a/Documentation/devicetree/bindings/power/supply/gpio-charger.yaml > >>>>> +++ b/Documentation/devicetree/bindings/power/supply/gpio-charger.yaml > >>>>> @@ -44,6 +44,10 @@ properties: > >>>>> maxItems: 32 > >>>>> description: GPIOs used for current limiting > >>>>> > >>>>> + enable-gpios: > >>>>> + maxItems: 1 > >>>>> + description: GPIO is used to enable/disable the charger > >>>>> + > >>>> > >>>> You did not respond to my comments, nothing improved. Without > >>>> explanation based on hardware - which I asked - this is still a no. > >>>> > >>>> Implement and respond fully to previous feedback. > >>>> > >>>> Best regards, > >>>> Krzysztof > >>>> > >>> > >>> > >>> Sorry, I'm new to this and don't really know what exactly you want for the > >>> hardware description and how best to represent our hardware in dts. > >>> For the gpio power supply, it can basically be any circuit that implements > >>> a "fully charged" GPIO and a "disable ups" GPIO. > >>> > >>> We're using a circuit built around the LTC3350 (super capacitor ups chip): > >>> We use this pin to indicate that our UPS is fully charged (once the input > >>> is gone, it's not fully charged anymore): > >>> PFO (pin 38): Power-Fail Status Output. This open-drain output is pulled > >>> low when a power failure has occurred. > >>> > >>> For the "disable ups" GPIO, we have some external circuitry around the > >>> LTC3350. I can't share the schematic, but it boils down to "disable usage > >>> of ups" so that the device shuts down immediately when power is lost. > >>> > >>> We've implemented this in many of our devices, but first we're looking > >>> at [1] and [2], which we also want to upstream the device trees for. > >>> [1] https://www.beckhoff.com/en-en/products/ipc/embedded-pcs/cx9240-arm-r-cortex-r-a53/cx9240.html > >>> [2] https://www.beckhoff.com/en-en/products/ipc/embedded-pcs/cx8200-arm-r-cortex-r-a53/cx8200.html > >>> > >>> For the LTC3350, there is a separate driver posted to the Linux kernel > >>> mail list [3] by another devolper that we would like to use in the future, > >>> but without this gpio, our circuit won't work. > >>> [3] https://lore.kernel.org/all/?q=power%3A+supply%3A+ltc3350-charger > >> > >> This does not address my concerns at all. Read the previous comments - > >> you are duplicating existing property. > > > > I think there is some misunderstanding. IIUIC you (Krzysztof) are > > referencing the following existing gpios property without any > > prefix? > > > >> gpios: > >> maxItems: 1 > >> description: GPIO indicating the charger presence > > > > This informs the operating system, that the charger has been plugged > > in (so the GPIO is an input from operating system point of view). > > > > The work from Stefan is not about presence detection, but > > controlling if the charging should happen at all (so the GPIO is an > > output from operating system point of view). So that's two very > > different things. > > So the gpios and charging status are input GPIOs and this is an output? > If so this seems right, indeed. > Yes, Krzysztof, you see it right. Sebastian described the problem correctly from my point of view. > > > > Technically there is some overlap with another existing property: > > charge-current-limit-gpios. I suppose a charger device limited to > > 0 Microampere is effectively off. But I think its fair to have a > > dedicated GPIO for explicit disabling. > > > > If my analysis of the situation is correct, the documentation seems > > to be bad. Please suggest better wording :) Which part of the documentation is being referred to: the binding, the commit message, or another section? Once clarified, I can suggest a better wording in this part of the documentation. > > P.S.: binding and driver should be send in separate patches. > In the next version, I will split the binding and driver into two separate patches. > Yeah, still all my comments should be addressed. > Krzysztof, in the bindings for 'gpio-charger.yaml' (Documentation/devicetree/bindings/power/supply/gpio-charger.yaml), is the property name 'enable-gpios' suitable for you, or should I rename it? If a rename is needed, which name makes the most sense to you for this function? > > Best regards, > Krzysztof Best regards, Stefan
