[PATCH 3/7] bus: add bus driver for accessing Allwinner A64 DE2

On Sat, Apr 14, 2018 at 4:16 PM, Jagan Teki [off-list ref] wrote:

On Sat, Apr 14, 2018 at 4:00 PM, Chen-Yu Tsai [off-list ref] wrote:

quoted

On Sat, Apr 14, 2018 at 6:25 PM, Jagan Teki [off-list ref] wrote:

quoted

On Fri, Mar 16, 2018 at 11:23 PM, Icenowy Zheng [off-list ref] wrote:

quoted

The "Display Engine 2.0" (usually called DE2) on the Allwinner A64 SoC
is different from the ones on other Allwinner SoCs. It requires a SRAM
region to be claimed, otherwise all DE2 subblocks won't be accessible.

Add a bus driver for the Allwinner A64 DE2 part which claims the SRAM
region when probing.

Along with this bus driver, we also need
drivers/gpu/drm/sun4i/sun4i_drv.c which can usually drive the
pipelines like mixer0 and 1 are the cases for A64?

I imagine that's the next part to be sent out, after the hardware
representation in the device tree has been decided on.

Yeah, this hardware representation along with separate bus driver
going like in another direction especially if we add pipelines support
to it, may be we can add sram stuff to platdata of existinf
sun4i_drv.c

Look like SRAM init during sun4i_drv is unable to claim or map the
memory? do we have any suggestion on adding 'allwinner,pipelines' ? is
it ok to add one more de which is compatible with sun4i_drv.c like
this.

de: display-engine {
                compatible = "allwinner,sun8i-a64-display-engine",
"allwinner,sun8i-h3-display-engine";
                allwinner,pipelines = <&mixer0>;
};

Jagan.

-- 
Jagan Teki
Senior Linux Kernel Engineer | Amarula Solutions
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.