6 files changed, 388 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt
new file mode 100644
index 000000000000..eb65d417f8c4
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt
@@ -0,0 +1,117 @@
+This binding is a work-in-progress, and are based on some experimental
+work by benh[1].
+
+Sources of clock signal can be represented by any node in the device
+tree.  Those nodes are designated as clock providers.  Clock consumer
+nodes use a phandle and clock specifier pair to connect clock provider
+outputs to clock inputs.  Similar to the gpio specifiers, a clock
+specifier is an array of one more more cells identifying the clock
+output on a device.  The length of a clock specifier is defined by the
+value of a #clock-cells property in the clock provider node.
+
+[1] http://patchwork.ozlabs.org/patch/31551/
+
+==Clock providers==
+
+Required properties:
+#clock-cells:      Number of cells in a clock specifier; Typically 0 for nodes
+                   with a single clock output and 1 for nodes with multiple
+                   clock outputs.
+
+Optional properties:
+clock-output-names: Recommended to be a list of strings of clock output signal
+                    names indexed by the first cell in the clock specifier.
+                    However, the meaning of clock-output-names is domain
+                    specific to the clock provider, and is only provided to
+                    encourage using the same meaning for the majority of clock
+                    providers.  This format may not work for clock providers
+                    using a complex clock specifier format.  In those cases it
+                    is recommended to omit this property and create a binding
+                    specific names property.
+
+                    Clock consumer nodes must never directly reference
+                    the provider's clock-output-names property.
+
+For example:
+
+    oscillator {
+        #clock-cells = <1>;
+        clock-output-names = "ckil", "ckih";
+    };
+
+- this node defines a device with two clock outputs, the first named
+  "ckil" and the second named "ckih".  Consumer nodes always reference
+  clocks by index. The names should reflect the clock output signal
+  names for the device.
+
+==Clock consumers==
+
+Required properties:
+clocks:         List of phandle and clock specifier pairs, one pair
+                for each clock input to the device.  Note: if the
+                clock provider specifies '0' for #clock-cells, then
+                only the phandle portion of the pair will appear.
+
+Optional properties:
+clock-names:    List of clock input name strings sorted in the same
+                order as the clocks property.  Consumers drivers
+                will use clock-names to match clock input names
+                with clocks specifiers.
+clock-ranges:   Empty property indicating that child nodes can inherit named
+                clocks from this node. Useful for bus nodes to provide a
+                clock to their children.
+
+For example:
+
+    device {
+        clocks = <&osc 1>, <&ref 0>;
+        clock-names = "baud", "register";
+    };
+
+
+This represents a device with two clock inputs, named "baud" and "register".
+The baud clock is connected to output 1 of the &osc device, and the register
+clock is connected to output 0 of the &ref.
+
+==Example==
+
+    /* external oscillator */
+    osc: oscillator {
+        compatible = "fixed-clock";
+        #clock-cells = <1>;
+        clock-frequency  = <32678>;
+        clock-output-names = "osc";
+    };
+
+    /* phase-locked-loop device, generates a higher frequency clock
+     * from the external oscillator reference */
+    pll: pll@4c000 {
+        compatible = "vendor,some-pll-interface"
+        #clock-cells = <1>;
+        clocks = <&osc 0>;
+        clock-names = "ref";
+        reg = <0x4c000 0x1000>;
+        clock-output-names = "pll", "pll-switched";
+    };
+
+    /* UART, using the low frequency oscillator for the baud clock,
+     * and the high frequency switched PLL output for register
+     * clocking */
+    uart@a000 {
+        compatible = "fsl,imx-uart";
+        reg = <0xa000 0x1000>;
+        interrupts = <33>;
+        clocks = <&osc 0>, <&pll 1>;
+        clock-names = "baud", "register";
+    };
+
+This DT fragment defines three devices: an external oscillator to provide a
+low-frequency reference clock, a PLL device to generate a higher frequency
+clock signal, and a UART.
+
+* The oscillator is fixed-frequency, and provides one clock output, named "osc".
+* The PLL is both a clock provider and a clock consumer. It uses the clock
+  signal generated by the external oscillator, and provides two output signals
+  ("pll" and "pll-switched").
+* The UART has its baud clock connected the external oscillator and its
+  register clock connected to the PLL clock (the "pll-switched" signal)
diff --git a/Documentation/devicetree/bindings/clock/fixed-clock.txt b/Documentation/devicetree/bindings/clock/fixed-clock.txt
new file mode 100644
index 000000000000..0b1fe7824093
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/fixed-clock.txt
@@ -0,0 +1,21 @@
+Binding for simple fixed-rate clock sources.
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : shall be "fixed-clock".
+- #clock-cells : from common clock binding; shall be set to 0.
+- clock-frequency : frequency of clock in Hz. Should be a single cell.
+
+Optional properties:
+- gpios : From common gpio binding; gpio connection to clock enable pin.
+- clock-output-names : From common clock binding.
+
+Example:
+        clock {
+                compatible = "fixed-clock";
+                #clock-cells = <0>;
+                clock-frequency = <1000000000>;
+        };
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 46317cbc088f..c87fdd710560 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -16,6 +16,7 @@
 #include <linux/err.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 static DEFINE_SPINLOCK(enable_lock);
 static DEFINE_MUTEX(prepare_lock);
@@ -1550,3 +1551,142 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
         return ret;
 }
 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
+
+#ifdef CONFIG_OF
+/**
+ * struct of_clk_provider - Clock provider registration structure
+ * @link: Entry in global list of clock providers
+ * @node: Pointer to device tree node of clock provider
+ * @get: Get clock callback.  Returns NULL or a struct clk for the
+ *       given clock specifier
+ * @data: context pointer to be passed into @get callback
+ */
+struct of_clk_provider {
+        struct list_head link;
+
+        struct device_node *node;
+        struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
+        void *data;
+};
+
+static LIST_HEAD(of_clk_providers);
+static DEFINE_MUTEX(of_clk_lock);