linux-kernel - Re: [PATCH v11 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver

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Message-ID: <20200520102452.GP1634618@smile.fi.intel.com>
Date:   Wed, 20 May 2020 13:24:52 +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 v11 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller
 driver

On Wed, May 20, 2020 at 12:51:12PM +0300, Tali Perry wrote:
> Add Nuvoton NPCM BMC I2C controller driver.

...

> +#ifdef CONFIG_DEBUG_FS

Why?!

> +#include <linux/debugfs.h>
> +#endif


...

> +/* Status of one I2C module */
> +struct npcm_i2c {
> +	struct i2c_adapter adap;

> +	struct device *dev;

Isn't it adap.dev->parent?

> +};

...

> +static void npcm_i2c_master_abort(struct npcm_i2c *bus)
> +{
> +	/* Only current master is allowed to issue a stop condition */

> +	if (npcm_i2c_is_master(bus)) {

	if (!npcm_i2c_is_master(bus))
		return;

?

> +		npcm_i2c_eob_int(bus, true);
> +		npcm_i2c_master_stop(bus);
> +		npcm_i2c_clear_master_status(bus);
> +	}
> +}

...

> +/* SDA status is set - TX or RX, master */
> +static void npcm_i2c_irq_handle_sda(struct npcm_i2c *bus, u8 i2cst)
> +{
> +	u8 fif_cts;

> +	if (bus->state == I2C_IDLE) {
> +		if (npcm_i2c_is_master(bus)) {

	if (a) {
		if (b) {
			...
		}
	}

==

	if (a && b) {
		...
	}

Check whole code for such pattern.

> +		}
> +
> +	/* SDA interrupt, after start\restart */
> +	} else {
> +		if (NPCM_I2CST_XMIT & i2cst) {
> +			bus->operation = I2C_WRITE_OPER;
> +			npcm_i2c_irq_master_handler_write(bus);
> +		} else {
> +			bus->operation = I2C_READ_OPER;
> +			npcm_i2c_irq_master_handler_read(bus);
> +		}
> +	}
> +}

...


> +	}
> +

+ /* 1MHz */ ?

> +	else if (bus_freq_hz <= I2C_MAX_FAST_MODE_PLUS_FREQ) {

> +	}
> +
> +	/* Frequency larger than 1 MHZ is not supported */
> +	else
> +		return -EINVAL;

...

> +	// master and slave modes share a single irq.

It's again being inconsistent with comment style. Choose one and fix all
comments accordingly (SPDX is another story, though)

...

> +static int i2c_debugfs_get(void *data, u64 *val)
> +{
> +	*val = *(u64 *)(data);
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(i2c_debugfs_ops, i2c_debugfs_get, NULL, "0x%02llx\n");

Why not to use debugfs_create_u64(), or how is it called?

> +static void i2c_init_debugfs(struct platform_device *pdev, struct npcm_i2c *bus)
> +{
> +	if (!npcm_i2c_debugfs_dir)
> +		return;
> +

> +	if (!pdev || !bus)
> +		return;

How is it possible?

> +	bus->debugfs = debugfs_create_dir(dev_name(&pdev->dev),
> +					  npcm_i2c_debugfs_dir);
> +	if (IS_ERR_OR_NULL(bus->debugfs)) {
> +		bus->debugfs = NULL;
> +		return;
> +	}

	struct dentry *d;

	d = create(...);
	if (IS_ERR_OR_NULL(d))
		return;

	bus->... = d;

> +
> +	debugfs_create_file("ber_count", 0444, bus->debugfs,
> +			    &bus->ber_count,
> +			    &i2c_debugfs_ops);
> +
> +	debugfs_create_file("rec_succ_count", 0444, bus->debugfs,
> +			    &bus->rec_succ_count,
> +			    &i2c_debugfs_ops);
> +
> +	debugfs_create_file("rec_fail_count", 0444, bus->debugfs,
> +			    &bus->rec_fail_count,
> +			    &i2c_debugfs_ops);
> +
> +	debugfs_create_file("nack_count", 0444, bus->debugfs,
> +			    &bus->nack_count,
> +			    &i2c_debugfs_ops);
> +
> +	debugfs_create_file("timeout_count", 0444, bus->debugfs,
> +			    &bus->timeout_count,
> +			    &i2c_debugfs_ops);
> +}

...

> +#ifdef CONFIG_DEBUG_FS

Why?!

> +	i2c_init_debugfs(pdev, bus);
> +#endif

...

> +#ifdef CONFIG_DEBUG_FS

Ditto.

> +	debugfs_remove_recursive(bus->debugfs);
> +#endif

> +static int __init npcm_i2c_init(void)
> +{

> +	npcm_i2c_debugfs_dir = debugfs_create_dir("i2c", NULL);

You didn't compile this with !CONFIG_DEBUG_FS?

> +	if (IS_ERR_OR_NULL(npcm_i2c_debugfs_dir)) {
> +		pr_warn("i2c init of debugfs failed\n");
> +		npcm_i2c_debugfs_dir = NULL;
> +	}

See above for the better pattern. Why do you need noisy warning? What does it
say to user? Can they use device or not?

> +	return 0;
> +}

-- 
With Best Regards,
Andy Shevchenko