Re: [PATCH v3 6/9] i2c: of-prober: Defer regulator_disable() on successful probe in simple helper

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Unconditional 100ms boot delay during cleanup when no I2C component is found.
--

--- Patch [6]: [PATCH v3 6/9] i2c: of-prober: Defer regulator_disable() on successful probe in simple helper ---
commit ea6b3a85720b084309159275d4c96f6a15c76ff3
Author: Chen-Yu Tsai <wenst@chromium.org>

i2c: of-prober: Defer regulator_disable() on successful probe in simple helper

This commit introduces a 100ms delay before disabling the regulator during
cleanup. This allows async drivers time to probe and increment the
regulator enable count, avoiding hardware re-initialization delays.

> diff --git a/drivers/i2c/i2c-core-of-prober.c b/drivers/i2c/i2c-core-of-prober.c
> --- a/drivers/i2c/i2c-core-of-prober.c
> +++ b/drivers/i2c/i2c-core-of-prober.c

[ ... ]

> @@ -235,11 +235,23 @@ static int i2c_of_probe_simple_enable_regulator(struct device *dev, struct i2c_o
>  	return 0;
>  }
>  
> -static void i2c_of_probe_simple_disable_regulator(struct device *dev, struct i2c_of_probe_simple_ctx *ctx)
> +static void i2c_of_probe_simple_disable_regulator(struct device *dev,
> +						  struct i2c_of_probe_simple_ctx *ctx,
> +						  bool defer_disable)
>  {
>  	if (!ctx->supply)
>  		return;
>  
> +	/*
> +	 * Wait a bit of time for async drivers to probe and increase the
> +	 * regulator enable count. This allows the drivers to check and
> +	 * skip waiting for re-initialization.
> +	 */
> +	if (defer_disable) {
> +		dev_dbg(dev, "Deferring regulator disable\n");
> +		msleep(100);
> +	}
> +
>  	dev_dbg(dev, "Disabling regulator supply \"%s\"\n", ctx->opts->supply_name);
>  
>  	regulator_disable(ctx->supply);

[ ... ]

> @@ -401,7 +413,7 @@ void i2c_of_probe_simple_cleanup(struct device *dev, void *data)
>  	i2c_of_probe_simple_disable_gpio(dev, ctx);
>  	i2c_of_probe_simple_put_gpiod(ctx);
>  
> -	i2c_of_probe_simple_disable_regulator(dev, ctx);
> +	i2c_of_probe_simple_disable_regulator(dev, ctx, true);

[Severity: Medium]
Will this cause an unconditional 100ms boot delay if no I2C component is
found?

When i2c_of_probe_component() finishes its scan without finding a
responding component, it still unconditionally calls ops->cleanup():

drivers/i2c/i2c-core-of-prober.c:i2c_of_probe_component() {
    ...
    if (ops->cleanup)
        ops->cleanup(dev, ctx);
    ...
}

This invokes i2c_of_probe_simple_cleanup(), which now passes
defer_disable = true, triggering the msleep(100) even when nothing was
probed.

Could this delay be skipped if no component was actually found?

>  	i2c_of_probe_simple_put_supply(ctx);
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260721075226.2347933-1-wenst@chromium.org?part=6