On 29 June 2016 at 17:35, Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote: > On 2016년 06월 30일 03:48, Stephen Boyd wrote: >> Quoting Chanwoo Choi (2016-06-28 23:25:57) >>> On 2016년 06월 29일 06:59, Stephen Boyd wrote: >>>> Quoting Chanwoo Choi (2016-06-28 05:06:48) >>>>> 2016-06-28 4:11 GMT+09:00 Stephen Boyd <stephen.boyd@xxxxxxxxxx>: >>>>>> Quoting Chanwoo Choi (2016-06-26 04:20:43) >>>>>>> 2016-06-26 14:56 GMT+09:00 Stephen Boyd <stephen.boyd@xxxxxxxxxx>: >>>>>>>> +PROPERTIES >>>>>>>> + >>>>>>>> +- compatible: >>>>>>>> + Usage: required >>>>>>>> + Value type: <string> >>>>>>>> + Definition: Should contain "qcom,pm8941-misc"; >>>>>>>> + >>>>>>>> +- reg: >>>>>>>> + Usage: required >>>>>>>> + Value type: <u32> >>>>>>>> + Definition: Should contain the offset to the misc address space >>>>>>> >>>>>>> 'reg' property is used on extcon-qcom-spmi-misc.c? >>>>>>> I think that you don't need to include this property. >>>>>> >>>>>> No it isn't used in the driver right now, but there is a register offset >>>>>> for this module and there are registers that can be read/written in this >>>>>> module. I'd like to keep it as required so we can easily read the >>>>>> registers in the future if needed. >>>>> >>>>> OK. >>>>> But, If you want to remain the reg property, you should add the code to get >>>>> the register offset by using OF functions. This patch don't include the OF >>>>> function to handle it. >>>>> >>>> >>>> Sorry I don't follow the argument. I've put the reg property here for >>>> future proofing so that the binding doesn't have to change in backwards >>>> incompatible ways in the future if we do need to get the property later. >>> >>> I don't mention that 'reg' property should be removed. >> >> Ok good. We need to keep reg property as this device is on a bus that >> uses reg property for addressing. >> >>> Just if you want to remain it, you should add some codes as following: >>> For exmaple, >>> - of_get_address() to get the address information from device-tree. >>> >>> If documentation include the some properties, you should add the handling code >>> in device driver. When you add the code to get the offset from device-tree, >>> it doesn't influence the some behavior in the future. >> >> Sorry I don't understand that argument. We can put properties into >> bindings and not use them in drivers if there isn't any immediate need >> to use them. >> >> From what I can tell you're suggesting we call of_get_address() in the >> driver and then do nothing with the value of the property? Is that just >> to check that the node is compliant with the binding and actually has a >> reg property? We don't add code in the kernel to check dts compliance, >> so I'm not inclined to do anything more here. > > I don't agree. > > When he DT binding document include the 'reg' property. > But, the device driver don't include any code to handle the 'reg' property > (just to get the offset). It is obviously wrong. > > It is just basic principle to write the Device-tree binding document. > > Other developer who don' know the history about 'reg' property > would be embarrassed. Why don't extcon driver include the code to > handle the 'reg' property? There is no method to explain it. > Perhaps Rob can explain why having a reg property is required for a bus that has #address-cells=<1> even though the device driver isn't using the reg property. -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
