topic Re: PRE in devicetree in i.MX Processors

PRE in devicetree

jotes — Thu, 09 Aug 2018 08:22:50 GMT

Hello,

I would like to connect 2 PREs to one IPU (as shown in the diagram below). I am using fb0 and fb1 (overlay). As I understand, the both framebuffers can be connected to separate PRE. Could you please guide me how to add a proper entry in devicetree?

When I write:

&mxcfb1 { /* fb0 and fb1 */
prefetch;
};

only the fb0 is using PRE.

Regards!

Re: PRE in devicetree

Bio_TICFSL — Fri, 17 Aug 2018 16:26:34 GMT

Hi jotes,

Kernel config:

CONFIG_MXC_IPU_V3_PRE=y

CONFIG_MXC_IPU_V3_PRG=y

DTS File:

memory: memory {

reg = <0x10000000 0xefffffff>;

};

&mxcfb1 {

prefetch;

};

&pre1 {

status = "okay";

};

&pre2 {

status = "okay";

};

&prg1 {

memory-region = <&memory>;

status = "okay";

};

&prg2 {

memory-region = <&memory>;

status = "okay";

};

There is one PRG per IPU and each PRG can handshake between 1 to 3 PRE and one IPU. Please see the image below:

PRE-0 is dedicated to IPU-1, PRE-3 is dedicated to IPU-2, PRE-1 and PRE-2 can be configured to be used together with either IPU-1 or IPU-2.

Regards

Re: PRE in devicetree

jotes — Mon, 03 Sep 2018 09:35:47 GMT

Hello,

Thanks for your answer, but is it possible to configure the devicetree to use 2 PRE for one display? Or should I modify the driver?

Regards