On 14/08/2023 05:39, Yinbo Zhu wrote: > > > 在 2023/8/11 下午10:25, Bartosz Golaszewski 写道: >> On Thu, Aug 10, 2023 at 8:19 AM Yinbo Zhu <zhuyinbo@xxxxxxxxxxx> wrote: >>> >>> >>> >>> 在 2023/8/9 下午11:39, Conor Dooley 写道: >>>> On Wed, Aug 09, 2023 at 03:47:55PM +0800, Yinbo Zhu wrote: >>>>> 在 2023/8/8 下午8:05, Conor Dooley 写道: >>>>>> On Mon, Aug 07, 2023 at 03:40:42PM +0800, Yinbo Zhu wrote: >>>> >>>>>>> + loongson,gpio-ctrl-mode: >>>>>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>>>>> + description: >>>>>>> + This option indicate this GPIO control mode, where '0' represents >>>>>>> + bit control mode and '1' represents byte control mode. >>>>>> >>>>>> How is one supposed to know which of these modes to use? >>>>> >>>>> >>>>> Byte mode is to access by byte, such as gpio3, the base address of the >>>>> gpio controller is offset by 3 bytes as the access address of gpio3. >>>>> >>>>> The bit mode is the normal mode that like other platform gpio and it is >>>>> to access by bit. >>>>> >>>>> If both modes are supported, it is recommended to prioritize using byte >>>>> mode that according to spec. >>>> >>>> So, sounds like this property should instead be a boolean that notes >>>> whether the hardware supports the mode or not, rather than the current >>>> enum used to determine software policy. >>> >>> >>> okay, I got it, I will use boolean, >>> >> >> Why do you want to put it into device-tree so badly? This is not the >> first driver that would have of_match_data for different variants >> where you can have a structure that would keep offsets for different >> models. It's not like you will have hundreds of "compatible" chips >> anyway, most likely just a few? > > > Using this ways that put offset property into device-tree that can be > compatible with future GPIO chips without the need to modify drivers, That's not an argument for putting into DT. > such as more 2K chips in the future, but use of_match_data and data > field of_device_id, which every time a new SoC is released, the GPIO > driver needs to be modified once, which is not friendly to us. Sorry, "friendly" is again hardly an argument what should or should not be in DT. Best regards, Krzysztof
