Hi Olof, On 2 January 2012 12:18, Olof Johansson <olof@xxxxxxxxx> wrote: > Hi, > > On Sun, Jan 1, 2012 at 9:54 PM, Thomas Abraham > <thomas.abraham@xxxxxxxxxx> wrote: >> The platform-lcd driver depends on platform-specific callbacks to setup the >> lcd panel. These callbacks are supplied using driver's platform data. But >> for adding device tree support for platform-lcd driver, providing such >> callbacks is not possible (without using auxdata). >> >> Since the callbacks are usually lcd panel specific, it is possible to include >> the lcd panel specific setup and control functionality in the platform-lcd >> driver itself, thereby eliminating the need for supplying platform specific >> callbacks to the driver. The platform-lcd driver can include support for >> multiple lcd panels. >> >> This patchset removes the need for platform data for platform-lcd driver and >> adds support which can be used to implement lcd panel specific functionality >> in the driver. As an example, the support for Hydis hv070wsa lcd panel is added >> to the platform-lcd driver which is then used on the Exynos4 based Origen board. >> This currently breaks build for other users of platform-lcd driver. Those can be >> fixed if this approach is acceptable. > > I think it would be a better idea to provide a generic binding for the > simple LCD panels that just need one or two power GPIOs to be turned > on (some tend to need one to activate and one for power control -- > second might in some cases be handled through a regulator I suppose). > I'm sure there will be exceptions to this; panels that have quirks or > requirements on various things that will either require an expanded > binding, or custom probe functions. A majority of the existing users of the platform-lcd driver are using a single gpio to enable or disable the display. As you mentioned, a generic binding can be added for such lcd panels. There are other implementations that use one or more gpios but requires toggling those gpios in a panel specific way (usually with some delay). Such implementations will require custom panel support included in the platfrom-lcd driver. I will prepare a patch for these cases. > > Especially in the case you are providing -- that lcd driver is only > using a single gpio, and it would be much more valuable to have a > trivial binding for this that uses shared code for this. Otherwise > every single simple panel will need to be added over time. Yes. I agree. It is better to have a common binding and there are many panels that can use this generic binding. I will make these changes. Thanks for your review. Regards, Thomas. > > > -Olof -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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