Re: [EXT] Re: [PATCH 2/3] pmdomain: imx8mp-blk-ctrl: imx8mp_blk: Add fdcc clock to hdmimix domain

[Adam Ford]

On Sun, Jan 28, 2024 at 7:39 PM Sandor Yu <sandor.yu@xxxxxxx> wrote:
>
>
>
> > -----Original Message-----
> > From: Adam Ford <aford173@xxxxxxxxx>
> > Sent: 2024年1月28日 2:20
> > To: linux-pm@xxxxxxxxxxxxxxx
> > Cc: Sandor Yu <sandor.yu@xxxxxxx>; Jacky Bai <ping.bai@xxxxxxx>; Rob
> > Herring <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski
> > <krzysztof.kozlowski+dt@xxxxxxxxxx>; Conor Dooley <conor+dt@xxxxxxxxxx>;
> > Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha Hauer
> > <s.hauer@xxxxxxxxxxxxxx>; Pengutronix Kernel Team
> > <kernel@xxxxxxxxxxxxxx>; Fabio Estevam <festevam@xxxxxxxxx>;
> > dl-linux-imx <linux-imx@xxxxxxx>; Ulf Hansson <ulf.hansson@xxxxxxxxxx>;
> > Lucas Stach <l.stach@xxxxxxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx;
> > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Marek
> > Vasut <marex@xxxxxxx>; Peng Fan (OSS) <peng.fan@xxxxxxxxxxx>
> > Subject: [EXT] Re: [PATCH 2/3] pmdomain: imx8mp-blk-ctrl: imx8mp_blk: Add
> > fdcc clock to hdmimix domain
> >
> > Caution: This is an external email. Please take care when clicking links or
> > opening attachments. When in doubt, report the message using the 'Report
> > this email' button
> >
> >
> > On Sat, Jan 6, 2024 at 4:40 PM Adam Ford <aford173@xxxxxxxxx> wrote:
> > >
> > > According to i.MX8MP RM and HDMI ADD, the fdcc clock is part of hdmi
> > > rx verification IP that should not enable for HDMI TX.
> > > But actually if the clock is disabled before HDMI/LCDIF probe, LCDIF
> > > will not get pixel clock from HDMI PHY and print the error
> > > logs:
> > >
> > > [CRTC:39:crtc-2] vblank wait timed out
> > > WARNING: CPU: 2 PID: 9 at drivers/gpu/drm/drm_atomic_helper.c:1634
> > > drm_atomic_helper_wait_for_vblanks.part.0+0x23c/0x260
> > >
> > > Add fdcc clock to LCDIF and HDMI TX power domains to fix the issue.
> >
> > Peng (or anyone from NXP),
> >
> > I borrowed this patch from the NXP down-stream kernel for two reasons:
> >  It's in NXP's branch to address an error & move the fdcc clock out of the
> > HDMI-tx driver due to questions/feedback that Lucas got on that driver.
> >
> > The FDCC clock isn't well documented, and it seems like it's necessary for the
> > HDMI-TX, but I'd like to make sure this is the proper solution, and I haven't
> > received any additional feedback.
> > Can someone from NXP confirm that really is the proper solution?
> >
> > thank you,
> >
> > adam
>
> Hi Adam,
>

Sandor,

> In NXP internal document, the clock HDMI_FDCC_TST_CLK_ROOT was for internal use only for future NXP development IP.
> It should not be exposed to customer in document but unfortunately it have to be enabled for HDMITX.
>
> I submitted a request ticket to the design team several months ago,
> Generally, tickets of this didn't get the priority in design team and I haven’t received any valuable feedback.
> Once design team confirmed, I think the document will update to add the fdcc clock.

Thank you for your response.   Do you have any objections to having
the FDCC clock added to the power domain driver?  I know there are
several of us who would really like to see the HDMI-TX driver applied,
and I think this patch gets us one step closer.

thanks,

adam
>
> B.R
> Sandor
>
> >
> > >
> > > Signed-off-by: Sandor Yu <Sandor.yu@xxxxxxx>
> > > Reviewed-by: Jacky Bai <ping.bai@xxxxxxx>
> > > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> > > ---
> > > The original work was from Sandor on the NXP Down-stream kernel
> > >
> > > diff --git a/drivers/pmdomain/imx/imx8mp-blk-ctrl.c
> > > b/drivers/pmdomain/imx/imx8mp-blk-ctrl.c
> > > index e3203eb6a022..a56f7f92d091 100644
> > > --- a/drivers/pmdomain/imx/imx8mp-blk-ctrl.c
> > > +++ b/drivers/pmdomain/imx/imx8mp-blk-ctrl.c
> > > @@ -55,7 +55,7 @@ struct imx8mp_blk_ctrl_domain_data {
> > >         const char *gpc_name;
> > >  };
> > >
> > > -#define DOMAIN_MAX_CLKS 2
> > > +#define DOMAIN_MAX_CLKS 3
> > >  #define DOMAIN_MAX_PATHS 3
> > >
> > >  struct imx8mp_blk_ctrl_domain {
> > > @@ -457,8 +457,8 @@ static const struct imx8mp_blk_ctrl_domain_data
> > imx8mp_hdmi_domain_data[] = {
> > >         },
> > >         [IMX8MP_HDMIBLK_PD_LCDIF] = {
> > >                 .name = "hdmiblk-lcdif",
> > > -               .clk_names = (const char *[]){ "axi", "apb" },
> > > -               .num_clks = 2,
> > > +               .clk_names = (const char *[]){ "axi", "apb", "fdcc" },
> > > +               .num_clks = 3,
> > >                 .gpc_name = "lcdif",
> > >                 .path_names = (const char *[]){"lcdif-hdmi"},
> > >                 .num_paths = 1,
> > > @@ -483,8 +483,8 @@ static const struct imx8mp_blk_ctrl_domain_data
> > imx8mp_hdmi_domain_data[] = {
> > >         },
> > >         [IMX8MP_HDMIBLK_PD_HDMI_TX] = {
> > >                 .name = "hdmiblk-hdmi-tx",
> > > -               .clk_names = (const char *[]){ "apb", "ref_266m" },
> > > -               .num_clks = 2,
> > > +               .clk_names = (const char *[]){ "apb", "ref_266m",
> > "fdcc" },
> > > +               .num_clks = 3,
> > >                 .gpc_name = "hdmi-tx",
> > >         },
> > >         [IMX8MP_HDMIBLK_PD_HDMI_TX_PHY] = {
> > > --
> > > 2.43.0
> > >