Re: [PATCH 3/6] dt-bindings: hwmon: (pmbus/max20830): add VOUT feedback resistor properties

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing initialization delay after asserting the enable GPIO causes probe failure if the device was previously powered off.
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commit a97eed13d5037d1e7850e1b18fc5fc3222705d55
Author: Alexis Czezar Torreno <alexisczezar.torreno@analog.com>

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

Add support for the GPIO controlled EN pin. The EN pin is asserted high
for 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]
Could this cause a regression where the driver fails to probe due to a missing
hardware boot-up delay?

When the enable GPIO is configured in the device tree and the device was
previously powered off, asserting it with GPIOD_OUT_HIGH will power up the
device. However, the driver proceeds to call i2c_smbus_read_block_data()
shortly after without any settling time.

If the regulator requires a delay to boot up before it can acknowledge i2c
packets, this immediate read might receive a nack and cause the driver
probe to abort.

>  	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;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260630-dev-max20830c-v1-0-a02786bde470@analog.com?part=3