On Sun, Jun 09, 2013 at 10:53:35PM +0300, Andy Shevchenko wrote: > Please, try to avoid top posting in the future emails. > > On Fri, Jun 7, 2013 at 12:26 AM, Bin Gao <bin.gao@xxxxxxxxxxxxxxx> wrote: > > With v4l2, the camera sensor i2c devices are taken over by v4l2 master > > driver, i.e. ISP driver, and are not expected to be accessed from > > user sapce by ioctl. So ISP driver has to register them by itself to > > get all related information for further communication. Please check > > v4l2_i2c_new_subdev_board() in drivers/media/video/v4l2-common.c for details. > > Yes, this is legacy approach for non-DT/non-ACPI5 platforms. So what's the new approach for DT/ACPI5 platforms? > > > The platform code can definitely disallow calling i2c_register_board_info() > > to register them but keep the i2c devices list and then let ISP driver register > > them. But, problems come when a single kernel is going to run on two platforms > > - one platform has ACPI5 and the other has SFI. > > You have to forget about SFI. Your ISP subdevices use plain platform > data anyway. Why have to forget about SFI which is supported by upstream kernel? > In ACPI 5 case v4l2 framework must be extended to cover that case. To extend v4l2 framework is one of the options, but this helper is also one option. > > The dynamic unregister and then > > register based on this new helper will not have dependency on firmware interface - > > the same platform code will work for all platforms. > > It's not a care of the ISP driver. I think you have to talk to Sakari > about your issues. We have to do it in the ISP driver if we want one binary kernel supporting multiple platforms. > > On Thu, Jun 06, 2013 at 11:32:06PM +0300, Andy Shevchenko wrote: > >> On Thu, Jun 6, 2013 at 9:33 PM, Bin Gao <bin.gao@xxxxxxxxxxxxxxx> wrote: > >> > There is a requirement to get the i2c_client pointer dynamically without > >> > knowing the bus and slave address. But we do know the client name, > >> > i.e. the name in the i2c_board_info. This patch is to fit this requirement. > >> > > >> > A good example is that an ISP(Imaging Signal Processor) driver needs > >> > register i2c camera sensor devices via v4l2, so it has to unregister > >> > all i2c clients that were previously registered by calling > >> > i2c_register_board_info(), and then re-register. For this case we > >> > can use this helper to get i2c_client by passing the client name. > >> > >> Why ISP driver would like to register sensor drivers in the first place? > >> That seems the task of platform code, or DT, or ACPI5 > >> > >> Why do you need to re-register them at run time? > > -- > With Best Regards, > Andy Shevchenko -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
