clk: imx: composite-7ulp: Check the PCC present bit

When some module is disabled by fuse, its PCC PR bit is default 0 and
PCC is not operational. Any write to this PCC will cause SError.

Fixes: b40ba80 ("clk: imx: Update the compsite driver to support imx8ulp")
Reviewed-by: Peng Fan <[email protected]>
Signed-off-by: Ye Li <[email protected]>
Signed-off-by: Peng Fan <[email protected]>
Reviewed-by: Abel Vesa <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Abel Vesa <[email protected]>

Author: Ye Li

drivers/clk/imx/clk-composite-7ulp.c

@@ -14,6 +14,7 @@
 #include "../clk-fractional-divider.h"
 #include "clk.h"
 
+#define PCG_PR_MASK		BIT(31)
 #define PCG_PCS_SHIFT	24
 #define PCG_PCS_MASK	0x7
 #define PCG_CGC_SHIFT	30
@@ -78,6 +79,12 @@ static struct clk_hw *imx_ulp_clk_hw_composite(const char *name,
 	struct clk_hw *hw;
 	u32 val;
 
+	val = readl(reg);
+	if (!(val & PCG_PR_MASK)) {
+		pr_info("PCC PR is 0 for clk:%s, bypass\n", name);
+		return 0;
+	}
+
 	if (mux_present) {
 		mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 		if (!mux)