[PATCHv4 16/33] CLK: OMAP: DPLL: do not of_iomap NULL autoidle register

[Tero Kristo]

AM33xx series SoCs do not have autoidle support, and for these the
autoidle register is marked as NULL. Check against a NULL pointer and
do not attempt to of_iomap in this case, as this just creates a bogus
pointer and causes a kernel crash during boot.

Signed-off-by: Tero Kristo <t-kristo at ti.com>
---
 drivers/clk/omap/dpll.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/omap/dpll.c b/drivers/clk/omap/dpll.c
index 1d24feada..d8a958a 100644
--- a/drivers/clk/omap/dpll.c
+++ b/drivers/clk/omap/dpll.c
@@ -162,6 +162,7 @@ static void __init of_omap_dpll_setup(struct device_node *node,
 	u32 max_multiplier = 2047;
 	u32 max_divider = 128;
 	u32 min_divider = 1;
+	u32 val;
 	int i;
 
 	dd = kzalloc(sizeof(struct dpll_data), GFP_KERNEL);
@@ -210,7 +211,14 @@ static void __init of_omap_dpll_setup(struct device_node *node,
 
 	dd->control_reg = of_iomap(node, 0);
 	dd->idlest_reg = of_iomap(node, 1);
-	dd->autoidle_reg = of_iomap(node, 2);
+	/*
+	 * AM33xx DPLLs have no autoidle support, and the autoidle reg
+	 * for these is NULL. Do not attempt to of_iomap in this case,
+	 * as this just creates a bogus pointer and crashes the kernel.
+	 */
+	of_property_read_u32_index(node, "reg", 2 * 2, &val);
+	if (val)
+		dd->autoidle_reg = of_iomap(node, 2);
 	dd->mult_div1_reg = of_iomap(node, 3);
 
 	dd->idlest_mask = idlest_mask;
-- 
1.7.9.5