The TISCI firmware will return 0 if the clock or consumer is not enabled although there is a stored value in the firmware. IOW a call to set rate will work but at get rate will always return 0 if the clock is disabled. The clk framework will try to cache the clock rate when it's requested by a consumer. If the clock or consumer is not enabled at that point, the cached value is 0, which is wrong. Thus, disable the cache altogether.
Signed-off-by: Michael Walle <[email protected]> Reviewed-by: Kevin Hilman <[email protected]> Reviewed-by: Randolph Sapp <[email protected]> --- drivers/clk/keystone/sci-clk.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c index 9d5071223f4c..0a1565fdbb3b 100644 --- a/drivers/clk/keystone/sci-clk.c +++ b/drivers/clk/keystone/sci-clk.c @@ -333,6 +333,14 @@ static int _sci_clk_build(struct sci_clk_provider *provider, init.ops = &sci_clk_ops; init.num_parents = sci_clk->num_parents; + + /* + * A clock rate query to the SCI firmware will return 0 if either the + * clock itself is disabled or the attached device/consumer is disabled. + * This makes it inherently unsuitable for the caching of the clk + * framework. + */ + init.flags = CLK_GET_RATE_NOCACHE; sci_clk->hw.init = &init; ret = devm_clk_hw_register(provider->dev, &sci_clk->hw); -- 2.47.3
