Re: [PATCH v1 4/4] clk: scpi: register scpi-cpufreq once and clear on failure

[Sudeep Holla <sudeep.holla@kernel.org>]

On Mon, Jul 27, 2026 at 10:19:15AM +0800, Xixin Liu wrote:
> scpi_clk_probe() walks clock children and, for each DVFS provider, calls
> platform_device_register_simple("scpi-cpufreq"). Two related bugs:
> 
The function named above appears to be scpi_clocks_probe(), not
scpi_clk_probe(). Fix that.

> 1) Multiple DVFS children each spawned another virtual cpufreq device.
>    If cpufreq_dev is already set, continue and skip a second register.
> 

The registration uses id -1, so every device must be named "scpi-cpufreq".
A second device_add() cannot register that name and must return -EEXIST;
platform_device_register_full() then drops the second pdev.

So the above information could be misleading.

Can you state it as each additional DVFS child attempts a duplicate
registration and overwrites the first valid pointer with ERR_PTR(-EEXIST),
rather than saying that each child spawns another device?

> 2) On IS_ERR, the pointer still held ERR_PTR (e.g. -ENOMEM). remove()
>    treats any non-NULL cpufreq_dev as live and would call
>    platform_device_unregister() on the error pointer (oops). Clear
>    cpufreq_dev to NULL after the failure warn so remove() skips it.
>

This also fixes bugs introduced by the original virtual device support and
by moving registration inside the child loop. So

Fixes: 9490f01e2471 ("clk: scpi: add support for cpufreq virtual device")
Fixes: 67bcc2c5f1da ("clk: scpi: don't add cpufreq device if the scpi dvfs node is disabled")

-- 
Regards,
Sudeep