Hi Sam,
On Sun, 12 Aug 2018 20:41:52 +0200 Sam Ravnborg sam@ravnborg.org wrote:
New DRM based driver for at91sam9 SOC's that uses the Atmel LCDC IP core.
First of all, thanks for this contribution.
This is first version of a patch set that adds drivers for the Atmel LCDC IP core. Posted for review as the basics works now.
The LCDC IP core contains two devices:
- a PWM often used for backlight
- a LCD display controller
Both devices are supported today by the atmel_lcdfb driver. For this new set of drivers the compatible strings was selected to avoid clash with the existing compatible strings used for the atmel_lcdfb driver to allow them to co-exist.
Hm, I think Rob commented on that already, but we usually try to stay compatible with the exisiting/old bindings when introducing a new one. Don't know how feasible this is in this particular case though.
This patchset implements three drivers.
- A MFD driver that include the generic parts.
- A PWM driver.
- A DRM display controller driver.
This is the same split as used for the Atmel hlcdc IP.
The hlcdc and lcdc has only a few things in common and trying to share the code for them was not a viable solution.
The DRM implementation has a few shortcomings compared to the existing fbdev based driver: - STN displays are not supported Binding support is missing but most of the STN specific functionality is otherwise ported from the fbdev driver. I assume the info should come from the panel but as I lack HW I have not looked too much into what is required. - gamma support is missing The driver utilises drm_simple_kms_helper and this helper lacks support for setting up gamma. If this is useful please let me know and I will extend drm_simple_kms_helper to support this and update the driver.
I guess you can skip that for now.
- modesetting is not checked (see TODO in file) Is this required for such a simple setup?
Well, that's always better if you can check that the requested display mode is supported before trying to apply it.
- support for extra modes as applicable (and lcd-wiring-mode)
Peter already suggested something I think.
- support for AVR32 (is it relevant?)
It is, AVR32 is no longer supported in mainline.
The first patch renames .../drm/atmel-hlcdc to .../drm/atmel to have a nice home for both drivers.
Sounds good.
Regards,
Boris