[PATCH v2 2/4] clk: keystone: don't cache clock rate

Michael Walle
2025-12-23T12:48:00Z

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 <mwalle@kernel.org>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Randolph Sapp <rs@ti.com>
---
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