linux-kernel - Re: [PATCH V2 1/5] soc: imx: imx8m-blk-ctrl: Fix imx8mm mipi reset

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Message-ID: <CAJ+vNU3sCk2r2TX0=-N76wWxWNna7qnYnruxVxPTGD8L6yVtug@mail.gmail.com>
Date:   Fri, 19 Nov 2021 15:51:42 -0800
From:   Tim Harvey <tharvey@...eworks.com>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     Adam Ford <aford173@...il.com>,
        Linux ARM Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Schrempf Frieder <frieder.schrempf@...tron.de>,
        linux-media <linux-media@...r.kernel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Adam Ford-BE <aford@...conembedded.com>,
        cstevens@...conembedded.com, Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Peng Fan <peng.fan@....com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Device Tree Mailing List <devicetree@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        Marek Vasut <marex@...x.de>
Subject: Re: [PATCH V2 1/5] soc: imx: imx8m-blk-ctrl: Fix imx8mm mipi reset

On Thu, Nov 11, 2021 at 10:55 PM Jagan Teki <jagan@...rulasolutions.com> wrote:
>
> On Sat, Nov 6, 2021 at 9:24 PM Adam Ford <aford173@...il.com> wrote:
> >
> > Most of the blk-ctrl reset bits are found in one register, however
> > there are two bits in offset 8 for pulling the MIPI DPHY out of reset
> > and these need to be set when IMX8MM_DISPBLK_PD_MIPI_CSI is brought
> > out of reset or the MIPI_CSI hangs.
> >
> > Fixes: 926e57c065df ("soc: imx: imx8m-blk-ctrl: add DISP blk-ctrl")
> > Signed-off-by: Adam Ford <aford173@...il.com>
> > ---
> >
> > V2:  Make a note that the extra register is only for Mini/Nano DISPLAY_BLK_CTRL
> >      Rename the new register to mipi_phy_rst_mask
> >      Encapsulate the edits to this register with an if-statement
>
> This is DPHY reset mask, not sure we can handle this via blk-ctrl.
> Marek has similar patch to support this [1]. we need to phandle the
> phy in host node in order to work this.
>
> However this current patch change seems directly handling dphy reset
> which indeed fine me as well.
>
> >
> >  drivers/soc/imx/imx8m-blk-ctrl.c | 18 ++++++++++++++++++
> >  1 file changed, 18 insertions(+)
> >
> > diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
> > index 519b3651d1d9..581eb4bc7f7d 100644
> > --- a/drivers/soc/imx/imx8m-blk-ctrl.c
> > +++ b/drivers/soc/imx/imx8m-blk-ctrl.c
> > @@ -17,6 +17,7 @@
> >
> >  #define BLK_SFT_RSTN   0x0
> >  #define BLK_CLK_EN     0x4
> > +#define BLK_MIPI_RESET_DIV     0x8 /* Mini/Nano DISPLAY_BLK_CTRL only */
> >
> >  struct imx8m_blk_ctrl_domain;
> >
> > @@ -36,6 +37,15 @@ struct imx8m_blk_ctrl_domain_data {
> >         const char *gpc_name;
> >         u32 rst_mask;
> >         u32 clk_mask;
> > +
> > +       /*
> > +        * i.MX8M Mini and Nano have a third DISPLAY_BLK_CTRL register
> > +        * which is used to control the reset for the MIPI Phy.
> > +        * Since it's only present in certain circumstances,
> > +        * an if-statement should be used before setting and clearing this
> > +        * register.
> > +        */
> > +       u32 mipi_phy_rst_mask;
>
> May be dphy_rst_mask (above comment may not be required, as it
> understand directly with commit message).
>
> >  };
> >
> >  #define DOMAIN_MAX_CLKS 3
> > @@ -78,6 +88,8 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
> >
> >         /* put devices into reset */
> >         regmap_clear_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> > +       if (data->mipi_phy_rst_mask)
> > +               regmap_clear_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
> >
> >         /* enable upstream and blk-ctrl clocks to allow reset to propagate */
> >         ret = clk_bulk_prepare_enable(data->num_clks, domain->clks);
> > @@ -99,6 +111,8 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
> >
> >         /* release reset */
> >         regmap_set_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> > +       if (data->mipi_phy_rst_mask)
> > +               regmap_set_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
> >
> >         /* disable upstream clocks */
> >         clk_bulk_disable_unprepare(data->num_clks, domain->clks);
> > @@ -120,6 +134,9 @@ static int imx8m_blk_ctrl_power_off(struct generic_pm_domain *genpd)
> >         struct imx8m_blk_ctrl *bc = domain->bc;
> >
> >         /* put devices into reset and disable clocks */
> > +       if (data->mipi_phy_rst_mask)
> > +               regmap_clear_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
> > +
> >         regmap_clear_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> >         regmap_clear_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
> >
> > @@ -488,6 +505,7 @@ static const struct imx8m_blk_ctrl_domain_data imx8mm_disp_blk_ctl_domain_data[]
> >                 .gpc_name = "mipi-csi",
> >                 .rst_mask = BIT(3) | BIT(4),
> >                 .clk_mask = BIT(10) | BIT(11),
> > +               .mipi_phy_rst_mask = BIT(16) | BIT(17),
>
> DPHY has BIT(17) for Master reset and BIT(16) for Slave reset. I think
> we just need master reset to enable. I've tested only BIT(17) on
> mipi-dsi gpc and it is working.
>

Jagan,

In my testing I had to use BIT(16) | BIT(17) in order to capture via CSI.

Best regards,

Tim