On Thu, Mar 02, 2017 at 03:38:07PM +0000, Chris Brandt wrote:
> Hello Guenter,
>
> Thank you for your review!
>
>
> On Thursday, March 02, 2017, Guenter Roeck wrote:
> > > +/*
> > > + * Renesas RZ/A Series WDT Driver
> > > + *
> > > + * Copyright (C) 2017 Renesas Electronics America, Inc.
> > > + * Copyright (C) 2017 Chris Brandt
> > > + *
> > > + * This file is subject to the terms and conditions of the GNU
> > > +General Public
> > > + * License. See the file "COPYING" in the main directory of this
> > > +archive
> > > + * for more details.
> > > + *
> > > + *
> >
> > The above two lines are unnecessary.
>
> OK.
>
> #I'll assume you mean take out just the last sentence (2 lines), not both
> sentences (all 3 lines).
>
The two empty lines.
>
> > > +/* Watchdog Timer Registers */
> > > +#define WTCSR 0
> > > +#define WTCSR_MAGIC 0xA500
> > > +#define WTSCR_WT (1<<6)
> > > +#define WTSCR_TME (1<<5)
> >
> > BIT()
>
> OK.
>
> > > +#define WTSCR_CKS(i) i
> >
> > (i)
>
> OK.
>
>
> > > +#define WRCSR_CLEAR_WOVF 0xA500 /* special value */
> >
> > Please use
> > #define SOMETHING<tab>value
> > throughout and make sure value is aligned.
>
> OK.
>
> > > + rate = clk_get_rate(priv->clk);
> > > + if (!rate)
> > > + return -ENOENT;
> > > +
> > > + /* Assume slowest clock rate possible (CKS=7) */
> > > + rate /= 16384;
> > > +
> >
> > The rate check should probably be here to avoid situations where rate <
> > 16384.
>
> Do I need that if it's technically not possible to have a 'rate' less than 25MHz?
>
> These watchdogs HW are always feed directly from the peripheral clock and there
> is no such thing as a 16kHz peripheral block an any Renesas SoC.
>
Following that line of argument, can clk_get_rate() ever return 0 ?
>
> > > + priv->wdev.info = &rza_wdt_ident,
> > > + priv->wdev.ops = &rza_wdt_ops,
> > > + priv->wdev.parent = &pdev->dev;
> > > +
> > > + /*
> > > + * Since the max possible timeout of our 8-bit count register is
> > less
> > > + * than a second, we must use max_hw_heartbeat_ms.
> > > + */
> > > + priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX)/rate;
> >
> > space before and after /
>
> OK.
> #Funny because checkpatch.pl said it didn't like a space on one side but
> not the other, so I choose no spaces and it was happy. I'm way below 80
> characters for that line so it doesn't matter to me.
>
That would be a bug in checkpatch. coding style, chapter 3.1, still applies.
Or at least I hope so.
>
> > > + dev_info(&pdev->dev, "max hw timeout of %dms\n",
> > > + priv->wdev.max_hw_heartbeat_ms);
> >
> > dev_dbg ?
>
> OK.
> #I guess we don't need to see that info on every boot.
>
>
> > > +
> > > + priv->wdev.min_timeout = 1;
> > > + priv->wdev.timeout = DEFAULT_TIMEOUT;
> > > +
> >
> > Add watchdog_init_timeout(&priv->wdev, 0, &pdev->dev); to optionally get
> > the timeout from dt ?
>
> OK. Good idea.
>
> > > + platform_set_drvdata(pdev, priv);
> > > + watchdog_set_drvdata(&priv->wdev, priv);
> > > +
> > > + ret = watchdog_register_device(&priv->wdev);
> >
> > devm_watchdog_register_device()
>
> OK.
>
>
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + return 0;
Also just
return ret;
> > > +}
> > > +
> > > +static int rza_wdt_remove(struct platform_device *pdev) {
> > > + struct rza_wdt *priv = platform_get_drvdata(pdev);
> > > +
> > > + watchdog_unregister_device(&priv->wdev);
> > > + iounmap(priv->base);
> >
> > iounmap is unnecessary (and wrong).
>
> Anything mapped with devm_ioremap_resource() automatically gets unmapped
> when the drive gets unloaded?
That is the point of devm_ functions. It also means that you won't need
a remove function if you also use devm_watchdog_register_device().
Guenter
