5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jay Buddhabhatti jay.buddhabhatti@amd.com
[ Upstream commit b782921ddd7f84f524723090377903f399fdbbcb ]
Currently zynqmp clock driver is not calculating closest mux rate and because of that Linux is not setting proper frequency for CPU and not able to set given frequency for dynamic frequency scaling.
E.g., In current logic initial acpu clock parent and frequency as below apll1 0 0 0 2199999978 0 0 50000 Y acpu0_mux 0 0 0 2199999978 0 0 50000 Y acpu0_idiv1 0 0 0 2199999978 0 0 50000 Y acpu0 0 0 0 2199999978 0 0 50000 Y
After changing acpu frequency to 549999994 Hz using CPU freq scaling its selecting incorrect parent which is not closest frequency. rpll_to_xpd 0 0 0 1599999984 0 0 50000 Y acpu0_mux 0 0 0 1599999984 0 0 50000 Y acpu0_div1 0 0 0 533333328 0 0 50000 Y acpu0 0 0 0 533333328 0 0 50000 Y
Parent should remain same since 549999994 = 2199999978 / 4.
So use __clk_mux_determine_rate_closest() generic function to calculate closest rate for mux clock. After this change its selecting correct parent and correct clock rate. apll1 0 0 0 2199999978 0 0 50000 Y acpu0_mux 0 0 0 2199999978 0 0 50000 Y acpu0_div1 0 0 0 549999995 0 0 50000 Y acpu0 0 0 0 549999995 0 0 50000 Y
Fixes: 3fde0e16d016 ("drivers: clk: Add ZynqMP clock driver") Signed-off-by: Jay Buddhabhatti jay.buddhabhatti@amd.com Link: https://lore.kernel.org/r/20231129112916.23125-2-jay.buddhabhatti@amd.com Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/zynqmp/clk-mux-zynqmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c index 0af8f74c5fa5..880ea34c0038 100644 --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c @@ -85,7 +85,7 @@ static int zynqmp_clk_mux_set_parent(struct clk_hw *hw, u8 index) static const struct clk_ops zynqmp_clk_mux_ops = { .get_parent = zynqmp_clk_mux_get_parent, .set_parent = zynqmp_clk_mux_set_parent, - .determine_rate = __clk_mux_determine_rate, + .determine_rate = __clk_mux_determine_rate_closest, };
static const struct clk_ops zynqmp_clk_mux_ro_ops = {