[RFC] clk: Add clk_hw based provider enable/disable API

[Abel Vesa <abel.vesa@linaro.org>]

Sometimes, a clock needs to be enabled or disabled by the provider,
without actually touching the enable count. For example, a clock
provider driver might choose to disable some unused clocks on sync state
callback rather than on the default clk_disable_unused. Such clocks are
usually enabled by bootloader and need to stay ungated until some driver
built as module probes. So add clk_hw enable/disable to allow the clock
provider drivers to disable such clocks on sync state callback.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
---
 drivers/clk/clk.c            | 25 +++++++++++++++++++++++++
 include/linux/clk-provider.h |  2 ++
 2 files changed, 27 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f00d4c1158d7..a727cffb6bba 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1011,6 +1011,17 @@ void clk_disable(struct clk *clk)
 }
 EXPORT_SYMBOL_GPL(clk_disable);
 
+void clk_hw_disable(const struct clk_hw *hw)
+{
+	struct clk_core *core = hw->core;
+
+	trace_clk_disable(core);
+	if (core->ops->disable)
+		core->ops->disable(core->hw);
+	trace_clk_disable_complete(core);
+}
+EXPORT_SYMBOL_GPL(clk_hw_disable);
+
 static int clk_core_enable(struct clk_core *core)
 {
 	int ret = 0;
@@ -1176,6 +1187,20 @@ int clk_enable(struct clk *clk)
 }
 EXPORT_SYMBOL_GPL(clk_enable);
 
+int clk_hw_enable(const struct clk_hw *hw)
+{
+	struct clk_core *core = hw->core;
+	int ret = 0;
+
+	trace_clk_enable(core);
+	if (core->ops->enable)
+		ret = core->ops->enable(core->hw);
+	trace_clk_enable_complete(core);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_hw_enable);
+
 /**
  * clk_is_enabled_when_prepared - indicate if preparing a clock also enables it.
  * @clk: clock source
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index c10dc4c659e2..0f9968a7a6d2 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1212,6 +1212,8 @@ unsigned long clk_hw_get_flags(const struct clk_hw *hw);
 bool clk_hw_is_prepared(const struct clk_hw *hw);
 bool clk_hw_rate_is_protected(const struct clk_hw *hw);
 bool clk_hw_is_enabled(const struct clk_hw *hw);
+int clk_hw_enable(const struct clk_hw *hw);
+void clk_hw_disable(const struct clk_hw *hw);
 bool __clk_is_enabled(struct clk *clk);
 struct clk *__clk_lookup(const char *name);
 int __clk_mux_determine_rate(struct clk_hw *hw,
-- 
2.34.3