default-rate property can now be used to set initial rates for clocks.
This is added by default for all clocks which get initialized through
of_clk_init().

Signed-off-by: Tero Kristo <t-kri...@ti.com>
---
 .../devicetree/bindings/clock/clock-bindings.txt   |    9 ++
 drivers/clk/clk.c                                  |   86 ++++++++++++++++++++
 include/linux/clk-provider.h                       |    2 +
 3 files changed, 97 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt 
b/Documentation/devicetree/bindings/clock/clock-bindings.txt
index 7c52c29..d676112 100644
--- a/Documentation/devicetree/bindings/clock/clock-bindings.txt
+++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt
@@ -44,6 +44,15 @@ For example:
   clocks by index. The names should reflect the clock output signal
   names for the device.
 
+default-rate:  Sets the rate of the clock during boot to the provided
+               rate.
+
+For example:
+
+    clk-divider {
+        default-rate = <1000000>;
+    };
+
 ==Clock consumers==
 
 Required properties:
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 5517944..cb144e4 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2526,6 +2526,89 @@ const char *of_clk_get_parent_name(struct device_node 
*np, int index)
 }
 EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
 
+static LIST_HEAD(clk_init_info_list);
+
+struct clk_init_info {
+       struct device_node *node;
+       struct clk *clk;
+       u32 rate;
+       struct list_head link;
+       struct list_head sort_link;
+};
+
+int __init of_clk_parse_init_rate(struct device_node *node, struct clk *clk)
+{
+       u32 rate;
+       struct clk_init_info *cinfo;
+
+       if (of_property_read_u32(node, "default-rate", &rate))
+               return 0;
+
+       cinfo = kzalloc(sizeof(*cinfo), GFP_KERNEL);
+       if (!cinfo)
+               return -ENOMEM;
+
+       cinfo->node = node;
+       cinfo->clk = clk;
+       cinfo->rate = rate;
+       list_add(&cinfo->link, &clk_init_info_list);
+       INIT_LIST_HEAD(&cinfo->sort_link);
+
+       return 0;
+}
+
+int __init of_clk_set_init_rates(void)
+{
+       struct clk_init_info *cinfo, *tmp;
+       struct of_phandle_args clkspec;
+       int ret = 0;
+       struct list_head sorted_list;
+       struct clk *clk;
+
+       INIT_LIST_HEAD(&sorted_list);
+
+       list_for_each_entry(cinfo, &clk_init_info_list, link) {
+               /* Get missing clk pointers */
+               if (!cinfo->clk) {
+                       clkspec.np = cinfo->node;
+                       cinfo->clk = of_clk_get_from_provider(&clkspec);
+               }
+
+               /* Check if we are the parent of any of the sorted clocks */
+               list_for_each_entry(tmp, &sorted_list, sort_link) {
+                       clk = tmp->clk;
+                       while (clk && clk != cinfo->clk)
+                               clk = clk->parent;
+
+                       if (clk == cinfo->clk) {
+                               /* Add us before this node in the list */
+                               list_add_tail(&cinfo->sort_link,
+                                             &tmp->sort_link);
+                               break;
+                       }
+               }
+
+               if (list_empty(&cinfo->sort_link))
+                       list_add_tail(&cinfo->sort_link, &sorted_list);
+       }
+
+       /* Process sorted list and set clk rates */
+       list_for_each_entry_safe(cinfo, tmp, &sorted_list, sort_link) {
+               int r = clk_set_rate(cinfo->clk, cinfo->rate);
+               if (r) {
+                       pr_err("%s: clk_set_rate for %s failed: %d\n", __func__,
+                              cinfo->node->name, ret);
+                       ret = r;
+               }
+
+               /* Clean up the static list */
+               list_del(&cinfo->link);
+               kfree(cinfo);
+       }
+
+       return ret;
+}
+
 /**
  * of_clk_init() - Scan and init clock providers from the DT
  * @matches: array of compatible values and init functions for providers.
@@ -2544,6 +2627,9 @@ void __init of_clk_init(const struct of_device_id 
*matches)
        for_each_matching_node_and_match(np, matches, &match) {
                of_clk_init_cb_t clk_init_cb = match->data;
                clk_init_cb(np);
+               of_clk_parse_init_rate(np, NULL);
        }
+
+       of_clk_set_init_rates();
 }
 #endif
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 939533d..1bbd194 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -506,6 +506,8 @@ struct clk *of_clk_src_simple_get(struct of_phandle_args 
*clkspec,
 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void 
*data);
 int of_clk_get_parent_count(struct device_node *np);
 const char *of_clk_get_parent_name(struct device_node *np, int index);
+int of_clk_parse_init_rate(struct device_node *node, struct clk *clk);
+int of_clk_set_init_rates(void);
 
 void of_clk_init(const struct of_device_id *matches);
 
-- 
1.7.9.5

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