diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt
index f2ea53832ac63e..d9a783c35c5a1f 100644
--- a/Documentation/devicetree/bindings/clock/clock-bindings.txt
+++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt
@@ -169,6 +169,22 @@ a shared clock is forbidden.
 Configuration of common clocks, which affect multiple consumer devices can
 be similarly specified in the clock provider node.
 
+==Critical clocks==
+
+Some platforms require clock to be always running, e.g. because those clock
+supply devices which are not otherwise attached to the system. One example
+is a system where the SoC serves as a crystal oscillator replacement for a
+programmable logic device. The critical-clock property of a clock controller
+allows listing clock which must never be turned off.
+
+   clock-controller@a000f000 {
+        compatible = "vendor,clk95;
+        reg = <0xa000f000 0x1000>
+        #clocks-cells = <1>;
+        ...
+        critical-clocks = <UART3_CLK>, <SPI5_CLK>;
+   };
+
 ==Protected clocks==
 
 Some platforms or firmwares may not fully expose all the clocks to the OS, such
diff --git a/drivers/clk/clk-bd718x7.c b/drivers/clk/clk-bd718x7.c
index ac40b669d60b74..90b81a35f503f9 100644
--- a/drivers/clk/clk-bd718x7.c
+++ b/drivers/clk/clk-bd718x7.c
@@ -70,10 +70,25 @@ static int bd71837_clk_is_enabled(struct clk_hw *hw)
 	return enabled & c->mask;
 }
 
+static int bd71837_match_clkspec(struct clk_hw *hw, struct of_phandle_args *clkspec)
+{
+	struct bd718xx_clk *c = container_of(hw, struct bd718xx_clk, hw);
+
+	/*
+	 * if (clk_hw == clkspec)
+	 *   return 0;
+	 * else
+	 *   return 1;
+	 */
+
+	return 0;
+}
+
 static const struct clk_ops bd71837_clk_ops = {
 	.prepare = &bd71837_clk_enable,
 	.unprepare = &bd71837_clk_disable,
 	.is_prepared = &bd71837_clk_is_enabled,
+	.match_clkspec = &bd71837_match_clkspec,
 };
 
 static int bd71837_clk_probe(struct platform_device *pdev)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f467d63bbf1eef..fa8e9ea446158f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3849,6 +3849,31 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
 	core->max_rate = ULONG_MAX;
 	hw->core = core;
 
+	struct of_phandle_args clkspec;
+	u32 clksize, clktotal;
+	int i, index;
+
+	if (np && core->ops->match_clkspec && !of_property_read_u32(np, "#clock-cells", &clksize)) {
+		if (clksize == 0) {
+			if (of_property_read_bool(np, "critical-clocks"))
+				core->flags |= CLK_IS_CRITICAL;
+			clktotal = 0;
+		} else {
+			clkspec.np = np;
+			clktotal = of_property_count_u32_elems(np, "critical-clocks");
+			clktotal /= clksize;
+			for (index = 0; index < clktotal; index++) {
+				for (i = 0; i < clksize; i++) {
+					ret = of_property_read_u32_index(np, "critical-clocks",
+									 (index * clksize) + i,
+									 &(clkspec.args[i]));
+				}
+				if (!core->ops->match_clkspec(hw, &clkspec))
+					core->flags |= CLK_IS_CRITICAL;
+			}
+		}
+	}
+
 	ret = clk_core_populate_parent_map(core, init);
 	if (ret)
 		goto fail_parents;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index f59c875271a0ee..766e93efb23c55 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -205,6 +205,7 @@ struct clk_duty {
  *		directory is provided as an argument.  Called with
  *		prepare_lock held.  Returns 0 on success, -EERROR otherwise.
  *
+ * @match_clkspec: Check whether clk_hw matches DT clock specifier
  *
  * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
  * implementations to split any work between atomic (enable) and sleepable
@@ -252,6 +253,7 @@ struct clk_ops {
 	int		(*init)(struct clk_hw *hw);
 	void		(*terminate)(struct clk_hw *hw);
 	void		(*debug_init)(struct clk_hw *hw, struct dentry *dentry);
+	int		(*match_clkspec)(struct clk_hw *hw, struct of_phandle_args *clkspec);
 };
 
 /**