Re: [PATCH 2/6] hwmon: (pmbus/max20830): add support for enable GPIO

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing delay between asserting the enable GPIO and initiating I2C communication.
--

commit a97eed13d5037d1e7850e1b18fc5fc3222705d55
Author: Alexis Czezar Torreno <alexisczezar.torreno@analog.com>

hwmon: (pmbus/max20830): add support for enable GPIO

This commit adds support for a GPIO-controlled EN pin. The EN pin is
asserted high to allow the device to operate.

> diff --git a/drivers/hwmon/pmbus/max20830.c b/drivers/hwmon/pmbus/max20830.c
> index cb2c23672166d..cb3a39d747ede 100644
> --- a/drivers/hwmon/pmbus/max20830.c
> +++ b/drivers/hwmon/pmbus/max20830.c
[ ... ]
> @@ -29,8 +30,14 @@ static struct pmbus_driver_info max20830_info = {
>  static int max20830_probe(struct i2c_client *client)
>  {
>  	u8 buf[I2C_SMBUS_BLOCK_MAX + 1] = {};
> +	struct gpio_desc *enable_gpio;
>  	int ret;
>  
> +	enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(enable_gpio))
> +		return dev_err_probe(&client->dev, PTR_ERR(enable_gpio),
> +				     "Failed to get enable GPIO\n");
> +

[Severity: High]
Will this cause the probe to fail if the device was previously unpowered?

When the enable GPIO is asserted high using devm_gpiod_get_optional() with
GPIOD_OUT_HIGH, the device initiates its power-on reset and internal 
initialization sequence. 

Because there is no explicit delay between asserting the enable pin and the 
subsequent I2C communication in max20830_probe(), is it possible the first
I2C transaction will fail with a NACK because the hardware hasn't finished
initializing?

Should there be a short delay here after pulling the enable pin high to
give the device time to be ready for I2C communication?

>  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BLOCK_DATA) &&
>  	    !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
>  		return -ENODEV;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260630-dev-max20830c-v1-0-a02786bde470@analog.com?part=2