This patch adds the clk constraint type.

The constraint is set by enabling the clk for the device. Once the
device is probed, the clk is disabled and the constraint is removed.

We may want to do clk_set_rate() from here, but lets wait for some real
users that really want it.

Tested-by: Rajendra Nayak <redacted>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/boot_constraints/Makefile |  2 +-
 drivers/boot_constraints/clk.c    | 70 +++++++++++++++++++++++++++++++++++++++
 drivers/boot_constraints/core.c   |  4 +++
 drivers/boot_constraints/core.h   |  3 ++
 include/linux/boot_constraint.h   |  5 +++
 5 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 drivers/boot_constraints/clk.c

diff --git a/drivers/boot_constraints/Makefile b/drivers/boot_constraints/Makefile
index a45616f0c3b0..3424379fd1e4 100644
--- a/drivers/boot_constraints/Makefile
+++ b/drivers/boot_constraints/Makefile

@@ -1,3 +1,3 @@
 # Makefile for device boot constraints
 
-obj-y := core.o supply.o
+obj-y := clk.o core.o supply.o

diff --git a/drivers/boot_constraints/clk.c b/drivers/boot_constraints/clk.c
new file mode 100644
index 000000000000..b5b1d63c3e76
--- /dev/null
+++ b/drivers/boot_constraints/clk.c

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2017 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#define pr_fmt(fmt) "Clock Boot Constraints: " fmt