clk: add clock-indices support

Add a property called clock-indices to allow clock-output-names
to be used where the index used to lookup a clock is not a 1:1
mapping to the array position in the clock-output-names

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
(cherry picked from commit 7a0fc1a3df82d29e00b4c9f88a6b37450d6711f1)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt
index 7c52c29..700e7aa 100644 (file)
--- a/Documentation/devicetree/bindings/clock/clock-bindings.txt
+++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt
@@ -44,6 +44,23 @@ For example:
   clocks by index. The names should reflect the clock output signal
   names for the device.
 
+clock-indices:    If the identifyng number for the clocks in the node
+                  is not linear from zero, then the this mapping allows
+                  the mapping of identifiers into the clock-output-names
+                  array.
+
+For example, if we have two clocks <&oscillator 1> and <&oscillator 3>:
+
+       oscillator {
+               compatible = "myclocktype";
+               #clock-cells = <1>;
+               clock-indices = <1>, <3>;
+               clock-output-names = "clka", "clkb";
+       }
+
+       This ensures we do not have any empty nodes in clock-output-names
+
+
 ==Clock consumers==
 
 Required properties:

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f9c4632..4ea3c06 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2501,8 +2501,12 @@ EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
 const char *of_clk_get_parent_name(struct device_node *np, int index)
 {
        struct of_phandle_args clkspec;
+       struct property *prop;
        const char *clk_name;
+       const __be32 *vp;
+       u32 pv;
        int rc;
+       int count;
 
        if (index < 0)
                return NULL;
@@ -2512,8 +2516,22 @@ const char *of_clk_get_parent_name(struct device_node *np, int index)
        if (rc)
                return NULL;
 
+       index = clkspec.args_count ? clkspec.args[0] : 0;
+       count = 0;
+
+       /* if there is an indices property, use it to transfer the index
+        * specified into an array offset for the clock-output-names property.
+        */
+       of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
+               if (index == pv) {
+                       index = count;
+                       break;
+               }
+               count++;
+       }
+
        if (of_property_read_string_index(clkspec.np, "clock-output-names",
-                                         clkspec.args_count ? clkspec.args[0] : 0,
+                                         index,
                                          &clk_name) < 0)
                clk_name = clkspec.np->name;