clk: keystone: don't cache clock rate

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>
Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Antonios Christidis <a-christidis@ti.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Link: https://patch.msgid.link/20260507-clk-sci-v2-1-38f59b48777a@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>

diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
index 9d5071223f4cb31bbca41694fde724757785514e..0a1565fdbb3b990c76b01de2e307b22866fd8db1 100644 (file)
--- 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);