Re: [DO NOT MERGE v6 08/37] clocksource: sh_tmu: CLOCKSOURCE support.

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-sh@vger.kernel.org, "Damien Le Moal" <dlemoal@kernel.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jiri Slaby" <jirislaby@kernel.org>,
	"Magnus Damm" <magnus.damm@gmail.com>,
	"Daniel Lezcano" <daniel.lezcano@linaro.org>,
	"Rich Felker" <dalias@libc.org>,
	"John Paul Adrian Glaubitz" <glaubitz@physik.fu-berlin.de>,
	"Lee Jones" <lee@kernel.org>, "Helge Deller" <deller@gmx.de>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Jernej Skrabec" <jernej.skrabec@gmail.com>,
	"Chris Morgan" <macromorgan@hotmail.com>,
	"Yang Xiwen" <forbidden405@foxmail.com>,
	"Sebastian Reichel" <sre@kernel.org>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Hyeonggon Yoo" <42.hyeyoo@gmail.com>,
	"David Rientjes" <rientjes@google.com>,
	"Baoquan He" <bhe@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Guenter Roeck" <linux@roeck-us.net>,
	"Stephen Rothwell" <sfr@canb.auug.org.au>,
	"Azeem Shaikh" <azeemshaikh38@gmail.com>,
	"Javier Martinez Canillas" <javierm@redhat.com>,
	"Max Filippov" <jcmvbkbc@gmail.com>,
	"Palmer Dabbelt" <palmer@rivosinc.com>,
	"Bin Meng" <bmeng@tinylab.org>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Jacky Huang" <ychuang3@nuvoton.com>,
	"Lukas Bulwahn" <lukas.bulwahn@gmail.com>,
	"Biju Das" <biju.das.jz@bp.renesas.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	"Sergey Shtylyov" <s.shtylyov@omp.ru>,
	"Michael Karcher" <kernel@mkarcher.dialup.fu-berlin.de>,
	"Laurent Pinchart" <laurent.pinchart+renesas@ideasonboard.com>,
	linux-ide@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-clk@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-pci@vger.kernel.org, linux-serial@vger.kernel.org,
	linux-fbdev@vger.kernel.org
Subject: Re: [DO NOT MERGE v6 08/37] clocksource: sh_tmu: CLOCKSOURCE support.
Date: Mon, 26 Feb 2024 17:54:43 +0100	[thread overview]
Message-ID: <CAMuHMdXOaasX9Dv-Kv=VOO0dhnp8ObQC6-YqsFZT0Q-VeqPg+Q@mail.gmail.com> (raw)
In-Reply-To: <f7a504fc42486f4f3f75ca7ac8cd57c084407da0.1704788539.git.ysato@users.sourceforge.jp>

Hi Saton-san,

Thanks for your patch!

Please drop the period at the end of the one-line summary.

On Tue, Jan 9, 2024 at 9:23 AM Yoshinori Sato
<ysato@users.sourceforge.jp> wrote:
> Allows initialization as CLOCKSOURCE.

Please explain why this is needed. E.g.

    Add support for early registration using TIMER_OF_DECLARE(),
    so the timer can be used as a clocksource on SoCs that do not
    have any other suitable timer.

>
> Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>

> --- a/drivers/clocksource/sh_tmu.c
> +++ b/drivers/clocksource/sh_tmu.c

> @@ -148,8 +151,8 @@ static int __sh_tmu_enable(struct sh_tmu_channel *ch)
>         /* enable clock */
>         ret = clk_enable(ch->tmu->clk);
>         if (ret) {
> -               dev_err(&ch->tmu->pdev->dev, "ch%u: cannot enable clock\n",
> -                       ch->index);
> +               pr_err("%s ch%u: cannot enable clock\n",
> +                      ch->tmu->name, ch->index);

Please wrap the line after, not before, "ch->tmu->name,".

>                 return ret;
>         }
>

> @@ -324,14 +332,14 @@ static int sh_tmu_register_clocksource(struct sh_tmu_channel *ch,
>         cs->mask = CLOCKSOURCE_MASK(32);
>         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
>
> -       dev_info(&ch->tmu->pdev->dev, "ch%u: used as clock source\n",
> -                ch->index);
> +       pr_info("%s ch%u: used as clock source\n",
> +               ch->tmu->name, ch->index);

No need to wrap this line at all.

>
>         clocksource_register_hz(cs, ch->tmu->rate);
>         return 0;
>  }
>
> -static struct sh_tmu_channel *ced_to_sh_tmu(struct clock_event_device *ced)
> +static inline struct sh_tmu_channel *ced_to_sh_tmu(struct clock_event_device *ced)
>  {
>         return container_of(ced, struct sh_tmu_channel, ced);
>  }
> @@ -364,8 +372,8 @@ static int sh_tmu_clock_event_set_state(struct clock_event_device *ced,
>         if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
>                 sh_tmu_disable(ch);
>
> -       dev_info(&ch->tmu->pdev->dev, "ch%u: used for %s clock events\n",
> -                ch->index, periodic ? "periodic" : "oneshot");
> +       pr_info("%s ch%u: used for %s clock events\n",
> +               ch->tmu->name, ch->index, periodic ? "periodic" : "oneshot");

Please wrap the line after, not before, "ch->tmu->name,".

>         sh_tmu_clock_event_start(ch, periodic);
>         return 0;
>  }
> @@ -403,7 +411,8 @@ static void sh_tmu_clock_event_resume(struct clock_event_device *ced)
>  }
>
>  static void sh_tmu_register_clockevent(struct sh_tmu_channel *ch,
> -                                      const char *name)
> +                                      const char *name,
> +                                      struct device_node *np)

"np" is unused in this function, hence this change is unneeded.
(Hey, I already said that in my review of v3)

>  {
>         struct clock_event_device *ced = &ch->ced;
>         int ret;
> @@ -417,30 +426,32 @@ static void sh_tmu_register_clockevent(struct sh_tmu_channel *ch,
>         ced->set_state_shutdown = sh_tmu_clock_event_shutdown;
>         ced->set_state_periodic = sh_tmu_clock_event_set_periodic;
>         ced->set_state_oneshot = sh_tmu_clock_event_set_oneshot;
> -       ced->suspend = sh_tmu_clock_event_suspend;
> -       ced->resume = sh_tmu_clock_event_resume;
> -
> -       dev_info(&ch->tmu->pdev->dev, "ch%u: used for clock events\n",
> -                ch->index);
> +       if (ch->tmu->pdev) {
> +               ced->suspend = sh_tmu_clock_event_suspend;
> +               ced->resume = sh_tmu_clock_event_resume;
> +       }
> +       pr_info("%s ch%u: used for clock events\n",
> +               ch->tmu->name, ch->index);

No need to wrap this line at all.

>
>         clockevents_config_and_register(ced, ch->tmu->rate, 0x300, 0xffffffff);
>
>         ret = request_irq(ch->irq, sh_tmu_interrupt,
>                           IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
> -                         dev_name(&ch->tmu->pdev->dev), ch);
> +                         ch->tmu->name, ch);
>         if (ret) {
> -               dev_err(&ch->tmu->pdev->dev, "ch%u: failed to request irq %d\n",
> -                       ch->index, ch->irq);
> +               pr_err("%s ch%u: failed to request irq %d\n",
> +                      ch->tmu->name, ch->index, ch->irq);

Please wrap the line after, not before, "ch->tmu->name,".

>                 return;
>         }
>  }
>
>  static int sh_tmu_register(struct sh_tmu_channel *ch, const char *name,
> +                          struct device_node *np,

np is unneeded.

>                            bool clockevent, bool clocksource)
>  {
>         if (clockevent) {
>                 ch->tmu->has_clockevent = true;
> -               sh_tmu_register_clockevent(ch, name);
> +               sh_tmu_register_clockevent(ch, name, np);
>         } else if (clocksource) {
>                 ch->tmu->has_clocksource = true;
>                 sh_tmu_register_clocksource(ch, name);

> @@ -465,53 +477,59 @@ static int sh_tmu_channel_setup(struct sh_tmu_channel *ch, unsigned int index,
>         else
>                 ch->base = tmu->mapbase + 8 + ch->index * 12;
>
> -       ch->irq = platform_get_irq(tmu->pdev, index);
> +       if (tmu->pdev)
> +               ch->irq = platform_get_irq(tmu->pdev, index);
> +       else
> +               ch->irq = of_irq_get(np, index);

You can use of_irq_get() unconditionally.

>         if (ch->irq < 0)
>                 return ch->irq;
>
>         ch->cs_enabled = false;
>         ch->enable_count = 0;
>
> -       return sh_tmu_register(ch, dev_name(&tmu->pdev->dev),
> +       return sh_tmu_register(ch, tmu->name, np,

No need to pass np.

>                                clockevent, clocksource);
>  }
>
> -static int sh_tmu_map_memory(struct sh_tmu_device *tmu)
> +static int sh_tmu_map_memory(struct sh_tmu_device *tmu, struct device_node *np)
>  {
>         struct resource *res;
>
> -       res = platform_get_resource(tmu->pdev, IORESOURCE_MEM, 0);
> -       if (!res) {
> -               dev_err(&tmu->pdev->dev, "failed to get I/O memory\n");
> -               return -ENXIO;
> -       }
> +       if (tmu->pdev) {
> +               res = platform_get_resource(tmu->pdev, IORESOURCE_MEM, 0);
> +               if (!res) {
> +                       pr_err("sh_tmu failed to get I/O memory\n");
> +                       return -ENXIO;
> +               }
> +
> +               tmu->mapbase = ioremap(res->start, resource_size(res));
> +       } else
> +               tmu->mapbase = of_iomap(np, 0);

You can use of_iomap() unconditionally.

>
> -       tmu->mapbase = ioremap(res->start, resource_size(res));
>         if (tmu->mapbase == NULL)
>                 return -ENXIO;
>
>         return 0;
>  }
>
> -static int sh_tmu_parse_dt(struct sh_tmu_device *tmu)
> +static int sh_tmu_parse_dt(struct sh_tmu_device *tmu, struct device_node *np)
>  {
> -       struct device_node *np = tmu->pdev->dev.of_node;
> -
>         tmu->model = SH_TMU;
>         tmu->num_channels = 3;
>
>         of_property_read_u32(np, "#renesas,channels", &tmu->num_channels);
>
>         if (tmu->num_channels != 2 && tmu->num_channels != 3) {
> -               dev_err(&tmu->pdev->dev, "invalid number of channels %u\n",
> -                       tmu->num_channels);
> +               pr_err("%s: invalid number of channels %u\n",
> +                      tmu->name, tmu->num_channels);

Please wrap the line after, not before, "ch->tmu->name,".

>                 return -EINVAL;
>         }
>
>         return 0;
>  }
>
> -static int sh_tmu_setup(struct sh_tmu_device *tmu, struct platform_device *pdev)
> +static int sh_tmu_setup(struct sh_tmu_device *tmu,
> +                       struct platform_device *pdev, struct device_node *np)
>  {
>         unsigned int i;
>         int ret;

> @@ -531,14 +554,17 @@ static int sh_tmu_setup(struct sh_tmu_device *tmu, struct platform_device *pdev)
>                 tmu->model = id->driver_data;
>                 tmu->num_channels = hweight8(cfg->channels_mask);
>         } else {
> -               dev_err(&tmu->pdev->dev, "missing platform data\n");
> +               pr_err("%s missing platform data\n", tmu->name);
>                 return -ENXIO;
>         }
>
>         /* Get hold of clock. */
> -       tmu->clk = clk_get(&tmu->pdev->dev, "fck");
> +       if (pdev)
> +               tmu->clk = clk_get(&tmu->pdev->dev, "fck");
> +       else
> +               tmu->clk = of_clk_get(np, 0);

You can use of_clk_get() unconditionally.

>         if (IS_ERR(tmu->clk)) {
> -               dev_err(&tmu->pdev->dev, "cannot get clock\n");
> +               pr_err("%s: cannot get clock\n", tmu->name);
>                 return PTR_ERR(tmu->clk);
>         }
>

> @@ -665,12 +711,17 @@ static void __exit sh_tmu_exit(void)
>         platform_driver_unregister(&sh_tmu_device_driver);
>  }
>
> +subsys_initcall(sh_tmu_init);
> +module_exit(sh_tmu_exit);
> +#endif
> +
>  #ifdef CONFIG_SUPERH
> +#ifdef CONFIG_SH_DEVICE_TREE
> +TIMER_OF_DECLARE(sh_tmu, "renesas,tmu", sh_tmu_of_register);

Probably this TIMER_OF_DECLARE() should be done unconditionally,
like is done in drivers/clocksource/renesas-ostm.c.

I gave that a try on R-Mobile A1, which also has TMU, but it didn't
seem to work (timer not firing?). So I suspect there are some missing
clk_enable() calls.  In the case of the platform driver, these are
handled using pm_runtime_get_sync().

> +#else
>  sh_early_platform_init("earlytimer", &sh_tmu_device_driver);
>  #endif
> -
> -subsys_initcall(sh_tmu_init);
> -module_exit(sh_tmu_exit);
> +#endif
>
>  MODULE_AUTHOR("Magnus Damm");
>  MODULE_DESCRIPTION("SuperH TMU Timer Driver");

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds