Re: [PATCH] iio: adc: ade9000: fix NULL pointer dereference in clkout registration

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Wed, Aug 26, 2026 at 10:24:18AM +0800, Linmao Li wrote:
> 
> 在 2026/8/24 23:08, Andy Shevchenko 写道:
> > On Mon, Aug 24, 2026 at 08:52:10PM +0800, Linmao Li wrote:
> > > ade9000_setup_clkout() passes NULL as the register address when
> > > registering a divider clock. During clock registration, the common
> > > clock framework calls clk_divider_recalc_rate(), which dereferences
> > > the address through readl(). As a result, probing an ADE9000 configured
> > > as a clock provider with an external input clock crashes.
> > > 
> > > CLKOUT passes CLKIN through without changing its rate. Register it as
> > > a 1:1 fixed-factor clock, which does not require register access.
> > Do you have HW to test? What will be the result for the internal clock case?
> No, unfortunately I do not have access to the hardware, so this is
> based on code inspection only.
> 
> For the crystal oscillator case, the device tree does not provide a
> clocks property. devm_clk_get_optional_enabled() therefore returns
> NULL, and ade9000_setup_clkout() returns here:
> 
>         if (!device_property_present(dev, "#clock-cells") || !st->clkin)
>                 return 0;
> 
> No clock provider is registered in that case. This behavior is
> unchanged by the patch. The modified registration path is reached only
> when an external input clock is present and the device is configured as
> a clock provider.

Then add a sentence to summarise this, something like "this change doesn't
affect the configuration with the internal clock".

-- 
With Best Regards,
Andy Shevchenko