Re: [PATCH v13 3/4] clk: validate spread spectrum configuration

[Peng Fan <peng.fan@oss.nxp.com>]

On Thu, Sep 03, 2026 at 05:32:15PM +0200, Dario Binacchi wrote:
>The spread spectrum configuration is passed to the provider's
>set_spread_spectrum() callback without any validation, as clk-conf.c
>only skips all-zero triplets from "assigned-clock-sscs". An invalid
>device tree can hand providers a zero modulation frequency or a spread
>ratio above 100%, and each provider would have to add the same checks
>to protect e.g. divisions in its rate computations.
>
>The KUnit test data for assigned-clock-sscs uses spread values of 30000
>and 40000 permyriad (300% and 400%), which the new check rejects, as
>reported by Sashiko, so fix them to 300 and 400 (3% and 4%). Also use
>a realistic 6% value for the initial settings of the skip tests, for
>consistency.
>
>Fixes: c86814e70390 ("clk: Introduce clk_hw_set_spread_spectrum")
>Reported-by: Sashiko <sashiko-bot@kernel.org>
>Closes: https://lore.kernel.org/r/20260901155657.6A5981F00A3A@smtp.kernel.org
>Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
>

Reviewed-by: Peng Fan <peng.fan@nxp.com>