RE: [PATCH V3 3/4] clk: imx: Add support for i.MX8MN clock driver

[Anson Huang]

Hi, Stephen

> -----Original Message-----
> From: Stephen Boyd <sboyd@xxxxxxxxxx>
> Sent: Monday, June 10, 2019 11:14 PM
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> shawnguo@xxxxxxxxxx; will.deacon@xxxxxxx; Abel Vesa
> <abel.vesa@xxxxxxx>; Aisheng Dong <aisheng.dong@xxxxxxx>; Anson
> Huang <anson.huang@xxxxxxx>; Jacky Bai <ping.bai@xxxxxxx>; Leonard
> Crestez <leonard.crestez@xxxxxxx>
> Cc: dl-linux-imx <linux-imx@xxxxxxx>
> Subject: RE: [PATCH V3 3/4] clk: imx: Add support for i.MX8MN clock driver
> 
> Quoting Anson Huang (2019-06-08 02:58:18)
> > Hi, Stephen
> >
> > > -----Original Message-----
> > > From: Stephen Boyd <sboyd@xxxxxxxxxx>
> > > Sent: Saturday, June 8, 2019 2:01 AM
> > > To: bjorn.andersson@xxxxxxxxxx; catalin.marinas@xxxxxxx;
> > > devicetree@xxxxxxxxxxxxxxx; dinguyen@xxxxxxxxxx;
> > > enric.balletbo@xxxxxxxxxxxxx; festevam@xxxxxxxxx;
> > > horms+renesas@xxxxxxxxxxxx; jagan@xxxxxxxxxxxxxxxxxxxx;
> > > kernel@xxxxxxxxxxxxxx; l.stach@xxxxxxxxxxxxxx; linux-arm-
> > > kernel@xxxxxxxxxxxxxxxxxxx; linux-clk@xxxxxxxxxxxxxxx; linux-
> > > kernel@xxxxxxxxxxxxxxx; mark.rutland@xxxxxxx;
> > > maxime.ripard@xxxxxxxxxxx; mturquette@xxxxxxxxxxxx; olof@xxxxxxxxx;
> > > robh+dt@xxxxxxxxxx; s.hauer@pengutronix .de
> > > robh+<s.hauer@xxxxxxxxxxxxxx>;
> > > shawnguo@xxxxxxxxxx; will.deacon@xxxxxxx; Abel Vesa
> > > <abel.vesa@xxxxxxx>; Aisheng Dong <aisheng.dong@xxxxxxx>; Anson
> > > Huang <anson.huang@xxxxxxx>; Jacky Bai <ping.bai@xxxxxxx>;
> Leonard
> > > Crestez <leonard.crestez@xxxxxxx>
> > > Cc: dl-linux-imx <linux-imx@xxxxxxx>
> > > Subject: RE: [PATCH V3 3/4] clk: imx: Add support for i.MX8MN clock
> > > driver
> > >
> > > Quoting Anson Huang (2019-06-06 17:50:28)
> > > >
> > > > I will use devm_platform_ioremap_resource() instead of ioremap(),
> > > > and can you be more specific about devmified clk registration?
> > > >
> > >
> > > I mean using things like devm_clk_hw_register().
> >
> > Sorry, I am still a little confused, all the clock
> > register(clk_register()) are via each different clock types like
> > imx_clk_gate4/imx_clk_pll14xx, if using clk_hw_register, means we need
> > to re-write the clock driver using different clk register method, that
> > will make the driver completely different from i.mx8mq/i.mx8mm, they
> > are actually same series of SoC as i.mx8mn, it will introduce many
> confusion, is my understanding correct? And is it OK to just keep what it is
> and make them all aligned?
> >
> 
> Ok, the problem I'm trying to point out is that clk registrations need to be
> undone, i.e. clk_unregister() needs to be called, when the driver fails to
> probe. devm_*() is one way to do this, but if you have other ways of
> removing all the registered clks then that works too. Makes sense?

Yes, it makes sense. Do you think it is OK to add an imx_unregister_clocks() API, then
call it in every place of returning failure in .probe function? If yes, I will add it and also
fix it in i.MX8MQ driver which uses platform driver model but does NOT handle this case. 

        base = devm_platform_ioremap_resource(pdev, 0);
-       if (WARN_ON(IS_ERR(base)))
-               return PTR_ERR(base);
+       if (WARN_ON(IS_ERR(base))) {
+               ret = PTR_ERR(base);
+               goto unregister_clks;
+       }

                pr_err("failed to register clks for i.MX8MN\n");
-               return -EINVAL;
+               goto unregister_clks;
        }

        return 0;
+
+unregister_clks:
+       imx_unregister_clocks(clks, ARRAY_SIZE(clks));
+
+       return ret;

+void imx_unregister_clocks(struct clk *clks[], unsigned int count)
+{
+       unsigned i;
+
+       for (i = 0; i < count; i++)
+               clk_unregister(clks[i]);
+}
+

Thanks,
Anson.