On 08/19/2011 06:16 PM, Sakari Ailus wrote: > Sylwester Nawrocki wrote: >> On 08/18/2011 09:02 PM, Sakari Ailus wrote: >>>>>>> >>>>>>> He-h, I guess you are not going to apply this one. >>>>>>> The patch breaks init logic of the device. If we have no ->power(), we >>>>>>> still need to bring the device to the known state. I have no good idea >>>>>>> how to do this. >>>>>> >>>>>> I don't think it breaks anything actually. Albeit in practice one is still >>>>>> likely to put the adp1653 reset line to the board since that lowers its power >>>>>> consumption significantly. >>>>> Yeah, even in practice we might see various ways of a chip connection. >>>>> >>>>>> Instead of being in power-up state after opening the flash subdev, it will >>>>>> reach this state already when the system is powered up. At subdev open all >>>>>> the relevant registers are written to anyway, so I don't see an issue here. >>>>> You mean at first writing to the V4L2 value, do you? Because ->open() >>>>> uses set_power() which will be skipped in case of no ->power method >>>>> defined. >>>>> >>>>>> I think either this one, or one should check in probe() that the power() >>>>>> callback is non-NULL. >>>>>> The board code is going away in the near future so this callback will >>>>>> disappear eventually anyway. >>>>> So, it's up to you to include or not my last patch. >>>>> >>>>>> The gpio code in the board file should likely >>>>>> be moved to the driver itself. >>>>> The line could be different, the hw could be used in environment w/o >>>>> gpio, but with (for example) external gate, and so on. I think current >>>>> generic driver is pretty okay. >>>> >>>> Would it make sense to use the regulator API in place of the platform_data >>>> callback? If there is only one GPIO then it's easy to create a 'fixed voltage >>>> regulator' for this. >>> >>> I don't know the regulator framework very well, but do you mean creating a new >>> regulator which just controls a gpio? It would be preferable that this wouldn't >>> create a new driver nor add any board core. >> >> I'm afraid your requirements are too demanding :) >> Yes, I meant creating a new regulator. In case the ADP1635 voltage regulator >> is inhibited through a GPIO at a host processor such regulator would in fact >> be only flipping a GPIO (and its driver would request the GPIO and set it into >> a default inactive state during its initialization). But the LDO for ADP1635 > > Thinking about this again, I think we'd need a regulator and reset gpio. > The reset line probably can't be really modelled as a power supply, as > the voltage provided to the chip is different from the reset line. Both > may exist on some boards. > > The regulator might be a dummy one, too, as well as the reset line. Yes, this would make the driver most complete I guess. And the gpio API seems a natural choice for the reset signal. If there is some 'non-standard' circuit to drive the ADP1635 pin possibly it can be handled by some existing or dedicated gpio driver. -- Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
