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SubjectRe: [PATCH v11 4/7] drm/sun4i: dsi: Handle bus clock explicitly
On Thu, Nov 28, 2019 at 11:21 PM Maxime Ripard <maxime@cerno.tech> wrote:
>
> On Sat, Nov 23, 2019 at 01:20:21AM +0530, Jagan Teki wrote:
> > > > Please have a look at this snippet, I have used your second
> > > > suggestions. let me know if you have any comments?
> > > >
> > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > > b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > > index 8fa90cfc2ac8..91c95e56d870 100644
> > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > > > @@ -1109,24 +1109,36 @@ 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 = regmap_init_mmio(dev, base, &sun6i_dsi_regmap_config);
> > >
> > > You should use the devm variant here
> >
> > Sure.
> >
> > >
> > > > + 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, NULL);
> > >
> > > I guess you still need to pass 'bus' here?
> >
> > But the idea here is not to specify clock name explicitly to support
> > A64. otherwise A64 would fail as we are not specifying the clock-names
> > explicitly on dsi node.
>
> Right. But you have no guarantee that the bus clock is going to be the
> first one on the other SoCs either.
>
> What about something like that instead:
>
> char *clk_name = NULL;
> if (dsi->has_mod_clk)
> clk_name = "bus";
>
> clk = devm_clk_get(dev, clk_name);
> if (IS_ERR(clk))
> return PTR_ERR(clk));
>
> regmap_mmio_attach_clk(regmap, clk);

This makes sense, thanks for your input. I have tested in A33, A64.

>
> >
> > dsi: dsi@1ca0000 {
> > compatible = "allwinner,sun50i-a64-mipi-dsi";
> > reg = <0x01ca0000 0x1000>;
> > interrupts = <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
> > clocks = <&ccu CLK_BUS_MIPI_DSI>;
> > resets = <&ccu RST_BUS_MIPI_DSI>;
> > phys = <&dphy>;
> > phy-names = "dphy";
> > .....
> > };
> >
> > >
> > > > + 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 {
> > > > + printk("Jagan.. Got the BUS clock\n");
> > > > + ret = regmap_mmio_attach_clk(dsi->regs, dsi->bus_clk);
> > > > + if (ret)
> > > > + goto err_bus_clk;
> > > > + }
> > > > +
> > > > if (dsi->variant->has_mod_clk) {
> > > > 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;
> > > > }
> > > > }
> > > >
> > > > @@ -1167,6 +1179,14 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > > > err_unprotect_clk:
> > > > if (dsi->variant->has_mod_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);
> > > > +err_regmap:
> > > > + regmap_exit(dsi->regs);
> > > > return ret;
> > > > }
> > > >
> > > > @@ -1181,6 +1201,13 @@ static int sun6i_dsi_remove(struct platform_device *pdev)
> > > > if (dsi->variant->has_mod_clk)
> > > > clk_rate_exclusive_put(dsi->mod_clk);
> > > >
> > > > + if (!IS_ERR(dsi->bus_clk)) {
> > > > + regmap_mmio_detach_clk(dsi->regs);
> > > > + clk_put(dsi->bus_clk);
> > >
> > > This will trigger a warning, you put down the reference twice
> >
> > You mean regmap_mmio_detach_clk will put the clk?
>
> No, devm_clk_get will.

Got it. Will update and send v12.

Jagan.

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