On 10/25/2013 12:33 PM, Laurent Pinchart wrote: > On Thursday 24 October 2013 23:06:18 Stephen Warren wrote: >> On 10/24/2013 12:20 PM, Laurent Pinchart wrote: ... >>> The case I'm mostly concerned about would be two different compatibility >>> strings to select whether the device should be handled by a KMS or V4L >>> driver. I don't think that's a good idea. >> >> I wouldn't think of the two compatible values as selecting different >> specific Linux drivers, but rather they simply describe the HW in >> different levels of detail. The fact that if we know a certain level of >> detail about the HW means that Linux can and does create a KMS driver >> rather than a V4L2 driver seems like a detail that's completely hidden >> inside the OS. > > I expect the same level of details to be needed on both the KMS and V4L sides. > Taking the example of the ADV7511 HDMI transmitter, the only change in the DT > bindings between KMS and V4L would be the compatible string. "adi,adv7511-v4l" > and "adi,adv7511-kms" is an option that I don't really like. Renaming -v4l and > -kms to different names wouldn't fundamentally change the problem. Yes, two compatible values such as "adi,adv7511-v4l" and "adi,adv7511-kms" sounds like a bad idea. Rather, shouldn't we have just "adi,adv7511", and the driver for that should register itself in a way that allows either/both the top-level DRM or top-level V4L drivers to find it, and make use of its services. There are plenty of drivers in the kernel already that export services through two different subsystems, e.g. a GPIO HW module that registers as both a struct gpio_chip and a struct irq_chip, or both a struct gpio_chip and a pinctrl device. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
