Re: [PATCH 5/7] media: meson-ir-tx: Ensure clock is disabled on unbind

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:

New issues:
- [Low] The commit message refers to non-existent clock API functions.

Pre-existing issues:
- [High] The driver masks `-EPROBE_DEFER` and other error codes by unconditionally returning `-ENODEV` when `devm_clk_get_enabled()` or `platform_get_irq()` fails, breaking probe deferral.
- [High] The `rc_dev` structure allocated during probe is permanently leaked on driver unbind due to the use of `rc_allocate_device()` without ensuring a corresponding `rc_free_device()` call.
--

--- Patch [5]: [PATCH 5/7] media: meson-ir-tx: Ensure clock is disabled on unbind ---
commit e95895078113495fea5b981fafe002c5ff1f56c1
Author: Sean Young <sean@mess.org>

media: meson-ir-tx: Ensure clock is disabled on unbind

This patch changes the clock acquisition in the meson-ir-tx driver to use
the devres managed devm_clk_get_enabled(). This ensures the clock is
automatically disabled and unprepared when the driver unbinds.

> clk_prepare_enabled() needs a call to clk_disable_prepare() on
> driver unbind. Make it devm managed.

[Severity: Low]
This isn't a bug, but there are typos in the function names mentioned here.
Should they be clk_prepare_enable() and clk_disable_unprepare() instead?

> diff --git a/drivers/media/rc/meson-ir-tx.c b/drivers/media/rc/meson-ir-tx.c
> index fded2c256f2a6..e7bb107e6a843 100644
> --- a/drivers/media/rc/meson-ir-tx.c
> +++ b/drivers/media/rc/meson-ir-tx.c
> @@ -288,8 +288,8 @@ static int meson_irtx_mod_clock_probe(struct meson_irtx *ir,
>  	if (!np)
>  		return -ENODEV;
>  
> -	clock = devm_clk_get(ir->dev, "xtal");
> -	if (IS_ERR(clock) || clk_prepare_enable(clock))
> +	clock = devm_clk_get_enabled(ir->dev, "xtal");
> +	if (IS_ERR(clock))
>  		return -ENODEV;

[Severity: High]
This is a pre-existing issue, but does this incorrectly mask -EPROBE_DEFER?

If devm_clk_get_enabled() returns -EPROBE_DEFER, returning a hardcoded
-ENODEV will permanently fail the probe instead of allowing it to defer.
Would it be better to return PTR_ERR(clock) here?

The same issue appears to happen with platform_get_irq() in
meson_irtx_probe():

drivers/media/rc/meson-ir-tx.c:meson_irtx_probe() {
    ...
    irq = platform_get_irq(pdev, 0);
    if (irq < 0)
        return -ENODEV;
    ...
}

Would it be better to propagate these error codes directly?


[Severity: High]
This is another pre-existing issue, but does this driver permanently leak
the rc_dev structure on unbind?

The driver allocates the structure manually in meson_irtx_probe():

drivers/media/rc/meson-ir-tx.c:meson_irtx_probe() {
    ...
    rc = rc_allocate_device(RC_DRIVER_IR_RAW_TX);
    ...
    ret = devm_rc_register_device(dev, rc);
    ...
}

Since devm_rc_register_device() only ties rc_unregister_device() to the
devres cleanup, and there is no matching rc_free_device() call or use of
devm_rc_allocate_device(), does the initial reference count remain
un-dropped when the driver is unbound?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1783673420.git.sean@mess.org?part=5

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