Em Mon, 15 Apr 2013 12:19:23 +0200 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> escreveu: > Hi Mauro, > > On Sunday 14 April 2013 16:59:58 Mauro Carvalho Chehab wrote: > > Em Fri, 12 Apr 2013 11:13:06 +0200 Laurent Pinchart escreveu: > > > Hi Mauro, > > > > > > The following changes since commit > 81e096c8ac6a064854c2157e0bf802dc4906678c: > > > [media] budget: Add support for Philips Semi Sylt PCI ref. design > > > > > > (2013-04-08 07:28:01 -0300) > > > > > > are available in the git repository at: > > > git://linuxtv.org/pinchartl/media.git sensors/next > > > > > > for you to fetch changes up to c890926a06339944790c5c265e21e8547aa55e49: > > > mt9p031: Use the common clock framework (2013-04-12 11:07:07 +0200) > > > > > > ---------------------------------------------------------------- > > > > > > Laurent Pinchart (5): > > > mt9m032: Fix PLL setup > > > mt9m032: Define MT9M032_READ_MODE1 bits > > > mt9p031: Use devm_* managed helpers > > > mt9p031: Add support for regulators > > > mt9p031: Use the common clock framework > > > > Hmm... It seems ugly to have regulators and clock framework and other SoC > > calls inside an i2c driver that can be used by a device that doesn't have > > regulators. > > > > I'm not sure what's the best solution for it, so, I'll be adding those two > > patches, but it seems that we'll need to restrict the usage of those calls > > only if the caller driver is a platform driver. > > The MT9P031 needs power supplies and a clock on all platforms, regardless of > the bridge bus type. Well, all digital devices require clock and power. If power is either a simple electric circuit, a battery or a regulator, that depends on the board. > I suppose the use case that mostly concerns you here is > USB webcams Yes. > where the power supplies and the clock are controlled > automatically by the device. Or could be not controlled at all. It could be a simple XTAL attached to the sensor or a clock signal provided by the bridge obtained from a fixed XTAL, and a resistor bridge or a Zenner diode providing the needed power voltage. > If we ever need to support such a device in the > future we can of course revisit the driver then, and one possible solution > would be to register fixed voltage regulators and a fixed clock. That is an overkill: devices were the power supply/xtal clock can't be controlled should not require extra software that pretend to control it. Regards, Mauro -- 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
