linux-kernel - Re: [PATCH v13 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver

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Message-ID: <20200522122717.GB1634618@smile.fi.intel.com>
Date:   Fri, 22 May 2020 15:27:17 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Tali Perry <tali.perry1@...il.com>
Cc:     ofery@...gle.com, brendanhiggins@...gle.com,
        avifishman70@...il.com, tmaimon77@...il.com, kfting@...oton.com,
        venture@...gle.com, yuenn@...gle.com, benjaminfair@...gle.com,
        robh+dt@...nel.org, wsa@...-dreams.de,
        linux-arm-kernel@...ts.infradead.org, linux-i2c@...r.kernel.org,
        openbmc@...ts.ozlabs.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v13 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller
 driver

On Fri, May 22, 2020 at 02:33:11PM +0300, Tali Perry wrote:
> Add Nuvoton NPCM BMC I2C controller driver.

I thought we are waiting for Wolfram finishing his review...


In any case see couple of comments below.

...


> +#ifdef CONFIG_DEBUG_FS

Now, do we need the rest of DEBUG_FS guards?

> +	if (status) {
> +		if (bus->rec_fail_cnt == ULLONG_MAX) {
> +			dev_dbg(bus->dev, "rec_fail_cnt reach max, reset to 0");

> +			bus->rec_fail_cnt = 0;

It's redundant, since we will anyway roll over when incrementing.
https://stackoverflow.com/q/18195715/2511795

> +		}
> +		bus->rec_fail_cnt++;
> +	} else {
> +		if (bus->rec_succ_cnt == ULLONG_MAX) {
> +			dev_dbg(bus->dev, "rec_succ_cnt reach max, reset to 0");

> +			bus->rec_succ_cnt = 0;

Ditto.

> +		}
> +		bus->rec_succ_cnt++;
> +	}
> +#endif

...

> +static int npcm_i2c_remove_bus(struct platform_device *pdev)
> +{
> +	unsigned long lock_flags;
> +	struct npcm_i2c *bus = platform_get_drvdata(pdev);
> +
> +	spin_lock_irqsave(&bus->lock, lock_flags);
> +	npcm_i2c_disable(bus);
> +	spin_unlock_irqrestore(&bus->lock, lock_flags);
> +	i2c_del_adapter(&bus->adap);

> +	debugfs_remove_recursive(bus->debugfs);

This should be in reversed order, i.e. you inited last in ->probe(), thus
should remove first in ->remove().

> +	return 0;
> +}

...

> +static int __init npcm_i2c_init(void)
> +{
> +	struct dentry *dir;
> +
> +	dir = debugfs_create_dir("i2c", NULL);

> +	if (IS_ERR_OR_NULL(dir))

IS_ERR() is redundant. And NULL already being checked inside i2c_init_debugfs()
or how do you call it?

> +		return 0;
> +
> +	npcm_i2c_debugfs_dir = dir;
> +	return 0;
> +}
> +
> +static void __exit npcm_i2c_exit(void)
> +{
> +	debugfs_remove_recursive(npcm_i2c_debugfs_dir);
> +}

> +
> +module_init(npcm_i2c_init);
> +module_exit(npcm_i2c_exit);

Slightly better to attach to the respective function, like other macros above
do.

-- 
With Best Regards,
Andy Shevchenko