Re: [PATCH] arm64: dts: imx8m: add syscon node for display_blk_ctrl module regs

From: Tommaso Merciai
Date: Tue Nov 02 2021 - 11:47:54 EST

On Tue, Nov 02, 2021 at 07:23:06AM -0500, Adam Ford wrote:
> The upcoming 5.16 kernel will have a new blk-ctrl driver which will
> work in conjunction with the GPC. You can see it in linux-next [1],
> and I would expect it to be present in 5.16-rc1 once the merge is
> done.
>
> In [1], Look for :
>
> disp_blk_ctrl: blk-ctrl@32e28000 {
> compatible = "fsl,imx8mm-disp-blk-ctrl", "syscon";
>
> It creates a bunch of virtual power domains which are effectively the
> resets for the VPU, CSI, DSI, and LCDIF [2].
>
> Basically, to pull the respective device out of reset, you'd reference
> them using power-domains. I have an RFC patch for the CSI located [3]
> which should bring the GPC power domain up, then take the CSI bridge
> and MIPI_CSI out of reset using the blk-ctrl. A few of us are still
> investigating the CSI bridge and mipi_csi drivers to determine what's
> going wrong, but inside that patch, you'll see that we reference
> "power-domains = <&disp_blk_ctrl IMX8MM_DISPBLK_PD_CSI_BRIDGE>;" and
> "power-domains = <&disp_blk_ctrl IMX8MM_DISPBLK_PD_MIPI_CSI>;" which
> are part of the new blk-ctrl driver @32e2800. Other peripherals like
> LCD, DSI, and the VPU's should be able to reference their respective
> power domains to activate the corresponding resets after enabling the
> proper GPC power domain.

Hi Adam,
Then is all done right. Using this this new driver/dts node eLCDIF/mipi_dsi
module are out of reset. Thanks for the tips. I'm trying to get eLCDIF/mipi_dsi
work on mainline. I try to get work

- eLCDIF using: mxsfb_drv.c
- mipi_dsi using: nwl-dsi.c

What do you think about? You think that can be a good way ( taking
imx8mq as reference )?

Let me know.
Thanks,

Tommaso
>
>
> [1] - https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm64/boot/dts/freescale/imx8mm.dtsi?h=next-20211102
> [2] - https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/include/dt-bindings/power/imx8mm-power.h?h=next-20211102
> [3] - https://patchwork.kernel.org/project/linux-arm-kernel/patch/20211023203457.1217821-2-aford173@xxxxxxxxx/
>
> On Tue, Nov 2, 2021 at 6:59 AM Tommaso Merciai <tomm.merciai@xxxxxxxxx> wrote:
> >
> > On Mon, Nov 01, 2021 at 11:22:21PM -0500, Adam Ford wrote:
> > > On Mon, Nov 1, 2021 at 5:58 PM Tommaso Merciai <tomm.merciai@xxxxxxxxx> wrote:
> > > >
> > > > On Mon, Nov 01, 2021 at 11:35:49PM +0100, Ahmad Fatoum wrote:
> > > > > Hello Tommaso,
> > > > >
> > > > > On 01.11.21 23:28, Tommaso Merciai wrote:
> > > > > > Add system controller node for registers of module Display Block Control
> > > > > > (DISPLAY_BLK_CTRL, base address: 0x32e28000).
> > > > > > The DISPLAY_BLK_CTRL module contains general purpose registers (GPRs),
> > > > > > which control varied features of the associated peripherals.
> > > > > > Reference: IMX8MMRM Rev. 3, 11/2020, p 3897
> > > > > > ---
> > > > > > arch/arm64/boot/dts/freescale/imx8mm.dtsi | 5 +++++
> > > > > > 1 file changed, 5 insertions(+)
> > > > > >
> > > > > > diff --git a/arch/arm64/boot/dts/freescale/imx8mm.dtsi b/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > > > > > index 2f632e8ca388..3e496b457e1a 100644
> > > > > > --- a/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > > > > > +++ b/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > > > > > @@ -961,6 +961,11 @@ aips4: bus@32c00000 {
> > > > > > #size-cells = <1>;
> > > > > > ranges = <0x32c00000 0x32c00000 0x400000>;
> > > > > >
> > > > > > + dispmix_gpr: display-gpr@32e28000 {
> > > > > > + compatible = "fsl, imx8mm-iomuxc-gpr", "syscon";
> > > > >
> > > > > Please read vendor patches before submitting them. The space
> > > > > is out-of-place in the compatible and the compatible is wrong:
> > > > > This doesn't look like a i.MX8MM pin controller.
> > > > >
> > > > > Cheers,
> > > > > Ahmad
> > > >
> > > > Hi Ahmad,
> > > > Thanks for your review. Do you think this is correct?
> > > >
> > > > compatible = "fsl,imx8mm-dispmix-gpr", "syscon";
> > > >
> > > > Let me know.
> > >
> > > There was already a driver created for the blk-ctrl stuff and it has a
> > > device tree binding at 32e28000. It's tied into the power-domain
> > > system, so if you want to enable the csi, dsi, or lcd, etc. you can
> > > just reference the blt-ctrl power domain index, and it enables the
> > > device's gpc power domain and takes the corresponding device out of
> > > reset.
> >
> > Hi Adam,
> > You mean using the gpcv2.c driver?
> >
> > drivers/soc/imx/gpcv2.c
> >
> > With the following node, to put out of reset eLCDIF and mipi_dsi:
> >
> > gpc: gpc@303a0000 {
> > compatible = "fsl,imx8mm-gpc";
> > reg = <0x303a0000 0x10000>;
> > interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
> > interrupt-parent = <&gic>;
> > interrupt-controller;
> > #interrupt-cells = <3>;
> >
> > pgc {
> >
> > #address-cells = <1>;
> > #size-cells = <0>;
> > pgc_mipi: power-domain@0 {
> > #power-domain-cells = <0>;
> > reg = <IMX8M_POWER_DOMAIN_MIPI>;
> > };
> >
> > pgc_disp: power-domain@7 {
> > #power-domain-cells = <0>;
> > reg = <IMX8M_POWER_DOMAIN_DISP>;
> > };
> > };
> > };
> >
> > Let me know.
> >
> > Thanks,
> > Tommaso
> >
> > >
> > > adam
> > > >
> > > > Thanks,
> > > > Tommaso
> > > >
> > > > >
> > > > > > + reg = <0x32e28000 0x100>;
> > > > > > + };
> > > > > > +
> > > > > > usbotg1: usb@32e40000 {
> > > > > > compatible = "fsl,imx8mm-usb", "fsl,imx7d-usb";
> > > > > > reg = <0x32e40000 0x200>;
> > > > > >
> > > > >
> > > > >
> > > > > --
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