Message-ID: <20191221160203.sokdonzswd6as4ed@gilmour.lan>
Date:   Sat, 21 Dec 2019 17:02:03 +0100
From:   Maxime Ripard <mripard@...nel.org>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     Chen-Yu Tsai <wens@...e.org>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Michael Trimarchi <michael@...rulasolutions.com>,
        Icenowy Zheng <icenowy@...c.io>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-amarula <linux-amarula@...rulasolutions.com>
Subject: Re: [PATCH v13 4/7] drm/sun4i: dsi: Handle bus clock via
 regmap_mmio_attach_clk

On Sat, Dec 21, 2019 at 05:11:00PM +0530, Jagan Teki wrote:
> On Thu, Dec 19, 2019 at 3:35 AM Maxime Ripard <mripard@...nel.org> wrote:
> >
> > On Thu, Dec 19, 2019 at 12:40:14AM +0530, Jagan Teki wrote:
> > > regmap has special API to enable the controller bus clock while
> > > initializing register space, and current driver is using
> > > devm_regmap_init_mmio_clk which require to specify bus
> > > clk_id argument as "bus"
> > >
> > > But, the usage of clocks are varies between different Allwinner
> > > DSI controllers. Clocking in A33 would need bus and mod clocks
> > > where as A64 would need only bus clock.
> > >
> > > Since A64 support only single bus clock, it is optional to
> > > specify the clock-names on the controller device tree node.
> > > So using NULL on clk_id would get the attached clock.
> > >
> > > To support clk_id as "bus" and "NULL" during clock enablement
> > > between controllers, this patch add generic code to handle
> > > the bus clock using regmap_mmio_attach_clk with associated
> > > regmap APIs.
> > >
> > > Signed-off-by: Jagan Teki <jagan@...rulasolutions.com>
> > > ---
> > > Changes for v13:
> > > - update the changes since has_mod_clk is dropped in previous patch
> > >
> > >  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 45 +++++++++++++++++++++-----
> > >  1 file changed, 37 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > index 68b88a3dc4c5..de8955fbeb00 100644
> > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > @@ -1081,6 +1081,7 @@ static const struct component_ops sun6i_dsi_ops = {
> > >  static int sun6i_dsi_probe(struct platform_device *pdev)
> > >  {
> > >       struct device *dev = &pdev->dev;
> > > +     const char *bus_clk_name = NULL;
> > >       struct sun6i_dsi *dsi;
> > >       struct resource *res;
> > >       void __iomem *base;
> > > @@ -1094,6 +1095,10 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > >       dsi->host.ops = &sun6i_dsi_host_ops;
> > >       dsi->host.dev = dev;
> > >
> > > +     if (of_device_is_compatible(dev->of_node,
> > > +                                 "allwinner,sun6i-a31-mipi-dsi"))
> > > +             bus_clk_name = "bus";
> > > +
> > >       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > >       base = devm_ioremap_resource(dev, res);
> > >       if (IS_ERR(base)) {
> > > @@ -1107,25 +1112,36 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > >               return PTR_ERR(dsi->regulator);
> > >       }
> > >
> > > -     dsi->regs = devm_regmap_init_mmio_clk(dev, "bus", base,
> > > -                                           &sun6i_dsi_regmap_config);
> > > -     if (IS_ERR(dsi->regs)) {
> > > -             dev_err(dev, "Couldn't create the DSI encoder regmap\n");
> > > -             return PTR_ERR(dsi->regs);
> > > -     }
> > > -
> > >       dsi->reset = devm_reset_control_get_shared(dev, NULL);
> > >       if (IS_ERR(dsi->reset)) {
> > >               dev_err(dev, "Couldn't get our reset line\n");
> > >               return PTR_ERR(dsi->reset);
> > >       }
> > >
> > > +     dsi->regs = devm_regmap_init_mmio(dev, base, &sun6i_dsi_regmap_config);
> > > +     if (IS_ERR(dsi->regs)) {
> > > +             dev_err(dev, "Couldn't init regmap\n");
> > > +             return PTR_ERR(dsi->regs);
> > > +     }
> > > +
> > > +     dsi->bus_clk = devm_clk_get(dev, bus_clk_name);
> > > +     if (IS_ERR(dsi->bus_clk)) {
> > > +             dev_err(dev, "Couldn't get the DSI bus clock\n");
> > > +             ret = PTR_ERR(dsi->bus_clk);
> > > +             goto err_regmap;
> > > +     } else {
> > > +             ret = regmap_mmio_attach_clk(dsi->regs, dsi->bus_clk);
> > > +             if (ret)
> > > +                     goto err_bus_clk;
> > > +     }
> > > +
> > >       if (of_device_is_compatible(dev->of_node,
> > >                                   "allwinner,sun6i-a31-mipi-dsi")) {
> > >               dsi->mod_clk = devm_clk_get(dev, "mod");
> > >               if (IS_ERR(dsi->mod_clk)) {
> > >                       dev_err(dev, "Couldn't get the DSI mod clock\n");
> > > -                     return PTR_ERR(dsi->mod_clk);
> > > +                     ret = PTR_ERR(dsi->mod_clk);
> > > +                     goto err_attach_clk;
> > >               }
> > >       }
> > >
> > > @@ -1164,6 +1180,14 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > >       pm_runtime_disable(dev);
> > >  err_unprotect_clk:
> > >       clk_rate_exclusive_put(dsi->mod_clk);
> > > +err_attach_clk:
> > > +     if (!IS_ERR(dsi->bus_clk))
> > > +             regmap_mmio_detach_clk(dsi->regs);
> > > +err_bus_clk:
> > > +     if (!IS_ERR(dsi->bus_clk))
> > > +             clk_put(dsi->bus_clk);
> >
> > You still have an unbalanced clk_get / clk_put here
>
> You mean it is not needed right since devm_clk_get has release call
> via devres_alloc?

Yes

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