On Wed, Oct 22, 2014 at 10:02:41PM +0300, Grygorii Strashko wrote:

On 10/22/2014 08:38 PM, Dmitry Torokhov wrote:

quoted

On Mon, Oct 20, 2014 at 03:56:02PM +0300, Grygorii Strashko wrote:

quoted

From: Geert Uytterhoeven <geert+renesas@glider.be>

The existing pm_clk_add() allows to pass a clock by con_id. However,
when referring to a specific clock from DT, no con_id is available.

Add pm_clk_add_clk(), which allows to specify the struct clk * directly.

Reviewed-by: Kevin Hilman <redacted>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---

 Pay attantion pls, that there is another series of patches
 which have been posted already and which depends from this patch
   "[PATCH v4 0/3] ARM: rk3288 : Add PM Domain support"
   https://lkml.org/lkml/2014/10/20/105

 drivers/base/power/clock_ops.c | 41 +++++++++++++++++++++++++++++++----------
 include/linux/pm_clock.h       |  8 ++++++++
 2 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
index 7836930..f14b767 100644
--- a/drivers/base/power/clock_ops.c
+++ b/drivers/base/power/clock_ops.c

@@ -53,7 +53,8 @@ static inline int __pm_clk_enable(struct device *dev, struct clk *clk)
  */
 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
 {
-	ce->clk = clk_get(dev, ce->con_id);
+	if (!ce->clk)
+		ce->clk = clk_get(dev, ce->con_id);
 	if (IS_ERR(ce->clk)) {
 		ce->status = PCE_STATUS_ERROR;
 	} else {

@@ -63,15 +64,8 @@ static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
 	}
 }

-/**
- * pm_clk_add - Start using a device clock for power management.
- * @dev: Device whose clock is going to be used for power management.
- * @con_id: Connection ID of the clock.
- *
- * Add the clock represented by @con_id to the list of clocks used for
- * the power management of @dev.
- */
-int pm_clk_add(struct device *dev, const char *con_id)
+static int __pm_clk_add(struct device *dev, const char *con_id,
+			struct clk *clk)
 {
 	struct pm_subsys_data *psd = dev_to_psd(dev);
 	struct pm_clock_entry *ce;

@@ -93,6 +87,8 @@ int pm_clk_add(struct device *dev, const char *con_id)
 			kfree(ce);
 			return -ENOMEM;
 		}
+	} else {
+		ce->clk = clk;
 	}

 	pm_clk_acquire(dev, ce);

@@ -104,6 +100,31 @@ int pm_clk_add(struct device *dev, const char *con_id)
 }

 /**
+ * pm_clk_add - Start using a device clock for power management.
+ * @dev: Device whose clock is going to be used for power management.
+ * @con_id: Connection ID of the clock.
+ *
+ * Add the clock represented by @con_id to the list of clocks used for
+ * the power management of @dev.
+ */
+int pm_clk_add(struct device *dev, const char *con_id)
+{
+	return __pm_clk_add(dev, con_id, NULL);

Bikeshedding: why do we need __pm_clk_add() and not simply have
"canonical" pm_clk_add_clk() and then do:

int pm_clk_add(struct device *dev, const char *con_id)
{
struct clk *clk;

clk = clk_get(dev, con_id);
...
return pm_clk_add_clk(dev, clk);
}

Hm. I did fast look at code and:
1) agree - there is a lot of thing which can be optimized ;)
2) in my strong opinion, this patch is the fastest and simplest
way to introduce new API (take a look on pm_clock_entry->con_id
management code) and It is exactly what we need as of now.

Yeah, I guess. We are lucky we do not crash when we are tryign to print
NULL strings (see pm_clk_acquire).

BTW, what is the point of doing pm_clk_add(dev, NULL)? We add clock
entry with status PCE_STATUS_ERROR and then have to handle it
everywhere? Can we just return -EINVAL if someone triies to pass NULL
ass con_id?

Thanks.

-- 
Dmitry