ARM: tegra: clock: Add shared bus clock type

Some clocks may have multiple downstream users that need to request a
higher clock rate.  Shared bus clocks provide a unique shared_bus_user
clock to each user.  The frequency of the bus is set to the highest
enabled shared_bus_user clock, with a minimum value set by the
shared bus.  Drivers can use clk_enable and clk_disable to enable
or disable their requirement, and clk_set_rate to set the minimum rate.

Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Colin Cross <ccross@android.com>
diff --git a/arch/arm/mach-tegra/clock.h b/arch/arm/mach-tegra/clock.h
index a63dbf9..bb755c2 100644
--- a/arch/arm/mach-tegra/clock.h
+++ b/arch/arm/mach-tegra/clock.h
@@ -85,6 +85,7 @@
 	struct clk_ops		*ops;
 	unsigned long		rate;
 	unsigned long		max_rate;
+	unsigned long		min_rate;
 	u32			flags;
 	const char		*name;
 
@@ -98,6 +99,8 @@
 	u32				reg;
 	u32				reg_shift;
 
+	struct list_head		shared_bus_list;
+
 	union {
 		struct {
 			unsigned int			clk_num;
@@ -120,6 +123,11 @@
 			struct clk			*main;
 			struct clk			*backup;
 		} cpu;
+		struct {
+			struct list_head		node;
+			bool				enabled;
+			unsigned long			rate;
+		} shared_bus_user;
 	} u;
 
 	spinlock_t spinlock;