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

From: Andy Shevchenko
Date: Wed May 20 2020 - 06:24:55 EST


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