[PATCH 0/3] Introduce devm_clk_register()

[PATCH 0/3] Introduce devm_clk_register()

[Stephen Boyd]

The first patch in this series fixes error checking in the wm831x clock
driver and is here to prevent context conflicts in the third patch.
I split it out in case it needed to merge sooner rather than later.

The goal of this series is to add devm_clk_register() so I can use it in
some MSM clock code I'm sending out in the near future. The second 
patch adds the API and the third patch moves over an existing user of
clk_unregister() to the devm API.

Stephen Boyd (3):
  clk: wm831x: Fix clk_register() error code checking
  clk: Add devm_clk_{register,unregister}()
  clk: wm831x: Use devm_clk_register() to simplify code

 drivers/clk/clk-wm831x.c     |  34 ++++---------
 drivers/clk/clk.c            | 111 +++++++++++++++++++++++++++++++++++--------
 include/linux/clk-provider.h |   2 +
 3 files changed, 101 insertions(+), 46 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCH 1/3] clk: wm831x: Fix clk_register() error code checking

[Stephen Boyd]

clk_register() returns an ERR_PTR upon failure, not NULL. Fix
these error paths.

Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/clk/clk-wm831x.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/clk-wm831x.c b/drivers/clk/clk-wm831x.c
index e7b7765..eb1afaf 100644
--- a/drivers/clk/clk-wm831x.c
+++ b/drivers/clk/clk-wm831x.c
@@ -371,20 +371,20 @@ static __devinit int wm831x_clk_probe(struct platform_device *pdev)
 
 	clkdata->xtal_hw.init = &wm831x_xtal_init;
 	clkdata->xtal = clk_register(&pdev->dev, &clkdata->xtal_hw);
-	if (!clkdata->xtal)
-		return -EINVAL;
+	if (IS_ERR(clkdata->xtal))
+		return PTR_ERR(clkdata->xtal);
 
 	clkdata->fll_hw.init = &wm831x_fll_init;
 	clkdata->fll = clk_register(&pdev->dev, &clkdata->fll_hw);
-	if (!clkdata->fll) {
-		ret = -EINVAL;
+	if (IS_ERR(clkdata->fll)) {
+		ret = PTR_ERR(clkdata->fll);
 		goto err_xtal;
 	}
 
 	clkdata->clkout_hw.init = &wm831x_clkout_init;
 	clkdata->clkout = clk_register(&pdev->dev, &clkdata->clkout_hw);
-	if (!clkdata->clkout) {
-		ret = -EINVAL;
+	if (IS_ERR(clkdata->clkout)) {
+		ret = PTR_ERR(clkdata->clkout);
 		goto err_fll;
 	}
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCH 1/3] clk: wm831x: Fix clk_register() error code checking

[Mark Brown]

On Tue, Sep 18, 2012 at 11:05:28PM -0700, Stephen Boyd wrote:
> clk_register() returns an ERR_PTR upon failure, not NULL. Fix
> these error paths.

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

this is an API change since the driver was sent which the driver didn't
get updatd for.

[PATCH 2/3] clk: Add devm_clk_{register,unregister}()

[Stephen Boyd]

Some clock drivers can be simplified if devres takes care of
unregistering any registered clocks along error paths. Introduce
devm_clk_register() so that clock drivers get unregistration for
free along with simplified error paths.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/clk/clk.c            | 111 +++++++++++++++++++++++++++++++++++--------
 include/linux/clk-provider.h |   2 +
 2 files changed, 92 insertions(+), 21 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 56e4495e..6852809 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -17,6 +17,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/device.h>
 
 static DEFINE_SPINLOCK(enable_lock);
 static DEFINE_MUTEX(prepare_lock);
@@ -1361,28 +1362,9 @@ struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
 }
 EXPORT_SYMBOL_GPL(__clk_register);
 
-/**
- * clk_register - allocate a new clock, register it and return an opaque cookie
- * @dev: device that is registering this clock
- * @hw: link to hardware-specific clock data
- *
- * clk_register is the primary interface for populating the clock tree with new
- * clock nodes.  It returns a pointer to the newly allocated struct clk which
- * cannot be dereferenced by driver code but may be used in conjuction with the
- * rest of the clock API.  In the event of an error clk_register will return an
- * error code; drivers must test for an error code after calling clk_register.
- */
-struct clk *clk_register(struct device *dev, struct clk_hw *hw)
+static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
 {
 	int i, ret;
-	struct clk *clk;
-
-	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
-	if (!clk) {
-		pr_err("%s: could not allocate clk\n", __func__);
-		ret = -ENOMEM;
-		goto fail_out;
-	}
 
 	clk->name = kstrdup(hw->init->name, GFP_KERNEL);
 	if (!clk->name) {
@@ -1420,7 +1402,7 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
 
 	ret = __clk_init(dev, clk);
 	if (!ret)
-		return clk;
+		return 0;
 
 fail_parent_names_copy:
 	while (--i >= 0)
@@ -1429,6 +1411,36 @@ fail_parent_names_copy:
 fail_parent_names:
 	kfree(clk->name);
 fail_name:
+	return ret;
+}
+
+/**
+ * clk_register - allocate a new clock, register it and return an opaque cookie
+ * @dev: device that is registering this clock
+ * @hw: link to hardware-specific clock data
+ *
+ * clk_register is the primary interface for populating the clock tree with new
+ * clock nodes.  It returns a pointer to the newly allocated struct clk which
+ * cannot be dereferenced by driver code but may be used in conjuction with the
+ * rest of the clock API.  In the event of an error clk_register will return an
+ * error code; drivers must test for an error code after calling clk_register.
+ */
+struct clk *clk_register(struct device *dev, struct clk_hw *hw)
+{
+	int ret;
+	struct clk *clk;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk) {
+		pr_err("%s: could not allocate clk\n", __func__);
+		ret = -ENOMEM;
+		goto fail_out;
+	}
+
+	ret = _clk_register(dev, hw, clk);
+	if (!ret)
+		return clk;
+
 	kfree(clk);
 fail_out:
 	return ERR_PTR(ret);
@@ -1444,6 +1456,63 @@ EXPORT_SYMBOL_GPL(clk_register);
 void clk_unregister(struct clk *clk) {}
 EXPORT_SYMBOL_GPL(clk_unregister);
 
+static void devm_clk_release(struct device *dev, void *res)
+{
+	clk_unregister(res);
+}
+
+/**
+ * devm_clk_register - resource managed clk_register()
+ * @dev: device that is registering this clock
+ * @hw: link to hardware-specific clock data
+ *
+ * Managed clk_register(). Clocks returned from this function are
+ * automatically clk_unregister()ed on driver detach. See clk_register() for
+ * more information.
+ */
+struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	ret = _clk_register(dev, hw, clk);
+	if (!ret) {
+		devres_add(dev, clk);
+	} else {
+		devres_free(clk);
+		clk = ERR_PTR(ret);
+	}
+
+	return clk;
+}
+EXPORT_SYMBOL_GPL(devm_clk_register);
+
+static int devm_clk_match(struct device *dev, void *res, void *data)
+{
+	struct clk *c = res;
+	if (WARN_ON(!c))
+		return 0;
+	return c == data;
+}
+
+/**
+ * devm_clk_unregister - resource managed clk_unregister()
+ * @clk: clock to unregister
+ *
+ * Deallocate a clock allocated with devm_clk_register(). Normally
+ * this function will not need to be called and the resource management
+ * code will ensure that the resource is freed.
+ */
+void devm_clk_unregister(struct device *dev, struct clk *clk)
+{
+	WARN_ON(devres_destroy(dev, devm_clk_release, devm_clk_match, clk));
+}
+EXPORT_SYMBOL(devm_clk_unregister);
+
 /***        clk rate change notifiers        ***/
 
 /**
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index c127315..710c6cb 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -327,8 +327,10 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
  * error code; drivers must test for an error code after calling clk_register.
  */
 struct clk *clk_register(struct device *dev, struct clk_hw *hw);
+struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw);
 
 void clk_unregister(struct clk *clk);
+void devm_clk_unregister(struct device *dev, struct clk *clk);
 
 /* helper functions */
 const char *__clk_get_name(struct clk *clk);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCH 2/3] clk: Add devm_clk_{register,unregister}()

[Stephen Boyd]

On 09/18/12 23:05, Stephen Boyd wrote:
> +void devm_clk_unregister(struct device *dev, struct clk *clk)
> +{
> +	WARN_ON(devres_destroy(dev, devm_clk_release, devm_clk_match, clk));

Hm... I guess this needs to be devres_release() instead of destroy. Can
you squash this in or should I resend for the few character change?

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 6852809..f02f4fe 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1509,7 +1509,7 @@ static int devm_clk_match(struct device *dev, void *res, void *data)
  */
 void devm_clk_unregister(struct device *dev, struct clk *clk)
 {
-       WARN_ON(devres_destroy(dev, devm_clk_release, devm_clk_match, clk));
+       WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
 }
 EXPORT_SYMBOL(devm_clk_unregister);
 

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

[PATCH 2/3] clk: Add devm_clk_{register,unregister}()

[Mike Turquette]

Quoting Stephen Boyd (2012-09-20 19:33:42)
> On 09/18/12 23:05, Stephen Boyd wrote:
> > +void devm_clk_unregister(struct device *dev, struct clk *clk)
> > +{
> > +     WARN_ON(devres_destroy(dev, devm_clk_release, devm_clk_match, clk));
> 
> Hm... I guess this needs to be devres_release() instead of destroy. Can
> you squash this in or should I resend for the few character change?
> 

I'm not taking any more changes for 3.7, so in the interest of me being
lazy can you resend with the fixup?

Thanks,
Mike

> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 6852809..f02f4fe 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1509,7 +1509,7 @@ static int devm_clk_match(struct device *dev, void *res, void *data)
>   */
>  void devm_clk_unregister(struct device *dev, struct clk *clk)
>  {
> -       WARN_ON(devres_destroy(dev, devm_clk_release, devm_clk_match, clk));
> +       WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
>  }
>  EXPORT_SYMBOL(devm_clk_unregister);
>  
> 
> -- 
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 2/3] clk: Add devm_clk_{register,unregister}()

[Stephen Boyd]

On 9/21/2012 6:07 PM, Mike Turquette wrote
> I'm not taking any more changes for 3.7, so in the interest of me being
> lazy can you resend with the fixup?

Sure. I'll pick up Mark's acks too and send the whole series again.

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

[PATCH 3/3] clk: wm831x: Use devm_clk_register() to simplify code

[Stephen Boyd]

Move this driver to use devm_clk_register() to simplify some
error paths and reduce lines of code.

Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/clk/clk-wm831x.c | 30 +++++++-----------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/drivers/clk/clk-wm831x.c b/drivers/clk/clk-wm831x.c
index eb1afaf..db4fbf2 100644
--- a/drivers/clk/clk-wm831x.c
+++ b/drivers/clk/clk-wm831x.c
@@ -370,43 +370,27 @@ static __devinit int wm831x_clk_probe(struct platform_device *pdev)
 	clkdata->xtal_ena = ret & WM831X_XTAL_ENA;
 
 	clkdata->xtal_hw.init = &wm831x_xtal_init;
-	clkdata->xtal = clk_register(&pdev->dev, &clkdata->xtal_hw);
+	clkdata->xtal = devm_clk_register(&pdev->dev, &clkdata->xtal_hw);
 	if (IS_ERR(clkdata->xtal))
 		return PTR_ERR(clkdata->xtal);
 
 	clkdata->fll_hw.init = &wm831x_fll_init;
-	clkdata->fll = clk_register(&pdev->dev, &clkdata->fll_hw);
-	if (IS_ERR(clkdata->fll)) {
-		ret = PTR_ERR(clkdata->fll);
-		goto err_xtal;
-	}
+	clkdata->fll = devm_clk_register(&pdev->dev, &clkdata->fll_hw);
+	if (IS_ERR(clkdata->fll))
+		return PTR_ERR(clkdata->fll);
 
 	clkdata->clkout_hw.init = &wm831x_clkout_init;
-	clkdata->clkout = clk_register(&pdev->dev, &clkdata->clkout_hw);
-	if (IS_ERR(clkdata->clkout)) {
-		ret = PTR_ERR(clkdata->clkout);
-		goto err_fll;
-	}
+	clkdata->clkout = devm_clk_register(&pdev->dev, &clkdata->clkout_hw);
+	if (IS_ERR(clkdata->clkout))
+		return PTR_ERR(clkdata->clkout);
 
 	dev_set_drvdata(&pdev->dev, clkdata);
 
 	return 0;
-
-err_fll:
-	clk_unregister(clkdata->fll);
-err_xtal:
-	clk_unregister(clkdata->xtal);
-	return ret;
 }
 
 static int __devexit wm831x_clk_remove(struct platform_device *pdev)
 {
-	struct wm831x_clk *clkdata = dev_get_drvdata(&pdev->dev);
-
-	clk_unregister(clkdata->clkout);
-	clk_unregister(clkdata->fll);
-	clk_unregister(clkdata->xtal);
-
 	return 0;
 }
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCH 3/3] clk: wm831x: Use devm_clk_register() to simplify code

[Mark Brown]

On Tue, Sep 18, 2012 at 11:05:30PM -0700, Stephen Boyd wrote:
> Move this driver to use devm_clk_register() to simplify some
> error paths and reduce lines of code.

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

[PATCH 0/3] Introduce devm_clk_register()

[Russell King - ARM Linux]

On Tue, Sep 18, 2012 at 11:05:27PM -0700, Stephen Boyd wrote:
> The first patch in this series fixes error checking in the wm831x clock
> driver and is here to prevent context conflicts in the third patch.
> I split it out in case it needed to merge sooner rather than later.
> 
> The goal of this series is to add devm_clk_register() so I can use it in
> some MSM clock code I'm sending out in the near future. The second 
> patch adds the API and the third patch moves over an existing user of
> clk_unregister() to the devm API.

Can we guarantee that the clocks are unused when the module is removed?
If we can't make that guarantee, then devm_* should not be used here,
and instead there should be refcounting done in the clocks (that's what
the __clk_get() and __clk_put() hooks are there for.)

[PATCH 0/3] Introduce devm_clk_register()

[Stephen Boyd]

On 09/22/12 03:06, Russell King - ARM Linux wrote:
> On Tue, Sep 18, 2012 at 11:05:27PM -0700, Stephen Boyd wrote:
>> The first patch in this series fixes error checking in the wm831x clock
>> driver and is here to prevent context conflicts in the third patch.
>> I split it out in case it needed to merge sooner rather than later.
>>
>> The goal of this series is to add devm_clk_register() so I can use it in
>> some MSM clock code I'm sending out in the near future. The second 
>> patch adds the API and the third patch moves over an existing user of
>> clk_unregister() to the devm API.
> Can we guarantee that the clocks are unused when the module is removed?
> If we can't make that guarantee, then devm_* should not be used here,
> and instead there should be refcounting done in the clocks (that's what
> the __clk_get() and __clk_put() hooks are there for.)

We could guarantee that when clk_unregister() is actually implemented.
__clk_get() would need to forward a call to the module providing the
clock via try_module_get(). Similarly we would call module_put() in
__clk_put(). That would prevent unbinding the driver from the device via
module removal.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

[PATCH 0/3] Introduce devm_clk_register()

[Russell King - ARM Linux]

On Mon, Sep 24, 2012 at 01:20:42PM -0700, Stephen Boyd wrote:
> On 09/22/12 03:06, Russell King - ARM Linux wrote:
> > On Tue, Sep 18, 2012 at 11:05:27PM -0700, Stephen Boyd wrote:
> >> The first patch in this series fixes error checking in the wm831x clock
> >> driver and is here to prevent context conflicts in the third patch.
> >> I split it out in case it needed to merge sooner rather than later.
> >>
> >> The goal of this series is to add devm_clk_register() so I can use it in
> >> some MSM clock code I'm sending out in the near future. The second 
> >> patch adds the API and the third patch moves over an existing user of
> >> clk_unregister() to the devm API.
> > Can we guarantee that the clocks are unused when the module is removed?
> > If we can't make that guarantee, then devm_* should not be used here,
> > and instead there should be refcounting done in the clocks (that's what
> > the __clk_get() and __clk_put() hooks are there for.)
> 
> We could guarantee that when clk_unregister() is actually implemented.
> __clk_get() would need to forward a call to the module providing the
> clock via try_module_get(). Similarly we would call module_put() in
> __clk_put(). That would prevent unbinding the driver from the device via
> module removal.

Strangely enough... mach-integrator's clkdev.h... precisely because it
has a module which may provide a clock.

static inline int __clk_get(struct clk *clk)
{
        return try_module_get(clk->owner);
}

static inline void __clk_put(struct clk *clk)
{
        module_put(clk->owner);
}

[PATCHv2 1/3] clk: wm831x: Fix clk_register() error code checking

[Stephen Boyd]

clk_register() returns an ERR_PTR upon failure, not NULL. Fix
these error paths.

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---

v2: No changes

 drivers/clk/clk-wm831x.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/clk-wm831x.c b/drivers/clk/clk-wm831x.c
index e7b7765..eb1afaf 100644
--- a/drivers/clk/clk-wm831x.c
+++ b/drivers/clk/clk-wm831x.c
@@ -371,20 +371,20 @@ static __devinit int wm831x_clk_probe(struct platform_device *pdev)
 
 	clkdata->xtal_hw.init = &wm831x_xtal_init;
 	clkdata->xtal = clk_register(&pdev->dev, &clkdata->xtal_hw);
-	if (!clkdata->xtal)
-		return -EINVAL;
+	if (IS_ERR(clkdata->xtal))
+		return PTR_ERR(clkdata->xtal);
 
 	clkdata->fll_hw.init = &wm831x_fll_init;
 	clkdata->fll = clk_register(&pdev->dev, &clkdata->fll_hw);
-	if (!clkdata->fll) {
-		ret = -EINVAL;
+	if (IS_ERR(clkdata->fll)) {
+		ret = PTR_ERR(clkdata->fll);
 		goto err_xtal;
 	}
 
 	clkdata->clkout_hw.init = &wm831x_clkout_init;
 	clkdata->clkout = clk_register(&pdev->dev, &clkdata->clkout_hw);
-	if (!clkdata->clkout) {
-		ret = -EINVAL;
+	if (IS_ERR(clkdata->clkout)) {
+		ret = PTR_ERR(clkdata->clkout);
 		goto err_fll;
 	}
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCHv2 2/3] clk: Add devm_clk_{register,unregister}()

[Stephen Boyd]

Some clock drivers can be simplified if devres takes care of
unregistering any registered clocks along error paths. Introduce
devm_clk_register() so that clock drivers get unregistration for
free along with simplified error paths.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---

v2: Use devres_release()

 drivers/clk/clk.c            | 111 +++++++++++++++++++++++++++++++++++--------
 include/linux/clk-provider.h |   2 +
 2 files changed, 92 insertions(+), 21 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 56e4495e..6852809 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -17,6 +17,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/device.h>
 
 static DEFINE_SPINLOCK(enable_lock);
 static DEFINE_MUTEX(prepare_lock);
@@ -1361,28 +1362,9 @@ struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
 }
 EXPORT_SYMBOL_GPL(__clk_register);
 
-/**
- * clk_register - allocate a new clock, register it and return an opaque cookie
- * @dev: device that is registering this clock
- * @hw: link to hardware-specific clock data
- *
- * clk_register is the primary interface for populating the clock tree with new
- * clock nodes.  It returns a pointer to the newly allocated struct clk which
- * cannot be dereferenced by driver code but may be used in conjuction with the
- * rest of the clock API.  In the event of an error clk_register will return an
- * error code; drivers must test for an error code after calling clk_register.
- */
-struct clk *clk_register(struct device *dev, struct clk_hw *hw)
+static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
 {
 	int i, ret;
-	struct clk *clk;
-
-	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
-	if (!clk) {
-		pr_err("%s: could not allocate clk\n", __func__);
-		ret = -ENOMEM;
-		goto fail_out;
-	}
 
 	clk->name = kstrdup(hw->init->name, GFP_KERNEL);
 	if (!clk->name) {
@@ -1420,7 +1402,7 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
 
 	ret = __clk_init(dev, clk);
 	if (!ret)
-		return clk;
+		return 0;
 
 fail_parent_names_copy:
 	while (--i >= 0)
@@ -1429,6 +1411,36 @@ fail_parent_names_copy:
 fail_parent_names:
 	kfree(clk->name);
 fail_name:
+	return ret;
+}
+
+/**
+ * clk_register - allocate a new clock, register it and return an opaque cookie
+ * @dev: device that is registering this clock
+ * @hw: link to hardware-specific clock data
+ *
+ * clk_register is the primary interface for populating the clock tree with new
+ * clock nodes.  It returns a pointer to the newly allocated struct clk which
+ * cannot be dereferenced by driver code but may be used in conjuction with the
+ * rest of the clock API.  In the event of an error clk_register will return an
+ * error code; drivers must test for an error code after calling clk_register.
+ */
+struct clk *clk_register(struct device *dev, struct clk_hw *hw)
+{
+	int ret;
+	struct clk *clk;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk) {
+		pr_err("%s: could not allocate clk\n", __func__);
+		ret = -ENOMEM;
+		goto fail_out;
+	}
+
+	ret = _clk_register(dev, hw, clk);
+	if (!ret)
+		return clk;
+
 	kfree(clk);
 fail_out:
 	return ERR_PTR(ret);
@@ -1444,6 +1456,63 @@ EXPORT_SYMBOL_GPL(clk_register);
 void clk_unregister(struct clk *clk) {}
 EXPORT_SYMBOL_GPL(clk_unregister);
 
+static void devm_clk_release(struct device *dev, void *res)
+{
+	clk_unregister(res);
+}
+
+/**
+ * devm_clk_register - resource managed clk_register()
+ * @dev: device that is registering this clock
+ * @hw: link to hardware-specific clock data
+ *
+ * Managed clk_register(). Clocks returned from this function are
+ * automatically clk_unregister()ed on driver detach. See clk_register() for
+ * more information.
+ */
+struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	ret = _clk_register(dev, hw, clk);
+	if (!ret) {
+		devres_add(dev, clk);
+	} else {
+		devres_free(clk);
+		clk = ERR_PTR(ret);
+	}
+
+	return clk;
+}
+EXPORT_SYMBOL_GPL(devm_clk_register);
+
+static int devm_clk_match(struct device *dev, void *res, void *data)
+{
+	struct clk *c = res;
+	if (WARN_ON(!c))
+		return 0;
+	return c == data;
+}
+
+/**
+ * devm_clk_unregister - resource managed clk_unregister()
+ * @clk: clock to unregister
+ *
+ * Deallocate a clock allocated with devm_clk_register(). Normally
+ * this function will not need to be called and the resource management
+ * code will ensure that the resource is freed.
+ */
+void devm_clk_unregister(struct device *dev, struct clk *clk)
+{
+	WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
+}
+EXPORT_SYMBOL_GPL(devm_clk_unregister);
+
 /***        clk rate change notifiers        ***/
 
 /**
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index c127315..710c6cb 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -327,8 +327,10 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
  * error code; drivers must test for an error code after calling clk_register.
  */
 struct clk *clk_register(struct device *dev, struct clk_hw *hw);
+struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw);
 
 void clk_unregister(struct clk *clk);
+void devm_clk_unregister(struct device *dev, struct clk *clk);
 
 /* helper functions */
 const char *__clk_get_name(struct clk *clk);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCHv2 3/3] clk: wm831x: Use devm_clk_register() to simplify code

[Stephen Boyd]

Move this driver to use devm_clk_register() to simplify some
error paths and reduce lines of code.

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---

v2: No changes

 drivers/clk/clk-wm831x.c | 30 +++++++-----------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/drivers/clk/clk-wm831x.c b/drivers/clk/clk-wm831x.c
index eb1afaf..db4fbf2 100644
--- a/drivers/clk/clk-wm831x.c
+++ b/drivers/clk/clk-wm831x.c
@@ -370,43 +370,27 @@ static __devinit int wm831x_clk_probe(struct platform_device *pdev)
 	clkdata->xtal_ena = ret & WM831X_XTAL_ENA;
 
 	clkdata->xtal_hw.init = &wm831x_xtal_init;
-	clkdata->xtal = clk_register(&pdev->dev, &clkdata->xtal_hw);
+	clkdata->xtal = devm_clk_register(&pdev->dev, &clkdata->xtal_hw);
 	if (IS_ERR(clkdata->xtal))
 		return PTR_ERR(clkdata->xtal);
 
 	clkdata->fll_hw.init = &wm831x_fll_init;
-	clkdata->fll = clk_register(&pdev->dev, &clkdata->fll_hw);
-	if (IS_ERR(clkdata->fll)) {
-		ret = PTR_ERR(clkdata->fll);
-		goto err_xtal;
-	}
+	clkdata->fll = devm_clk_register(&pdev->dev, &clkdata->fll_hw);
+	if (IS_ERR(clkdata->fll))
+		return PTR_ERR(clkdata->fll);
 
 	clkdata->clkout_hw.init = &wm831x_clkout_init;
-	clkdata->clkout = clk_register(&pdev->dev, &clkdata->clkout_hw);
-	if (IS_ERR(clkdata->clkout)) {
-		ret = PTR_ERR(clkdata->clkout);
-		goto err_fll;
-	}
+	clkdata->clkout = devm_clk_register(&pdev->dev, &clkdata->clkout_hw);
+	if (IS_ERR(clkdata->clkout))
+		return PTR_ERR(clkdata->clkout);
 
 	dev_set_drvdata(&pdev->dev, clkdata);
 
 	return 0;
-
-err_fll:
-	clk_unregister(clkdata->fll);
-err_xtal:
-	clk_unregister(clkdata->xtal);
-	return ret;
 }
 
 static int __devexit wm831x_clk_remove(struct platform_device *pdev)
 {
-	struct wm831x_clk *clkdata = dev_get_drvdata(&pdev->dev);
-
-	clk_unregister(clkdata->clkout);
-	clk_unregister(clkdata->fll);
-	clk_unregister(clkdata->xtal);
-
 	return 0;
 }
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

[PATCHv2 1/3] clk: wm831x: Fix clk_register() error code checking

[Mike Turquette]

Quoting Stephen Boyd (2012-09-24 13:38:03)
> clk_register() returns an ERR_PTR upon failure, not NULL. Fix
> these error paths.
> 
> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Thanks for sending V2.  Taken into clk-next.

Regards,
Mike

> ---
> 
> v2: No changes
> 
>  drivers/clk/clk-wm831x.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/clk/clk-wm831x.c b/drivers/clk/clk-wm831x.c
> index e7b7765..eb1afaf 100644
> --- a/drivers/clk/clk-wm831x.c
> +++ b/drivers/clk/clk-wm831x.c
> @@ -371,20 +371,20 @@ static __devinit int wm831x_clk_probe(struct platform_device *pdev)
>  
>         clkdata->xtal_hw.init = &wm831x_xtal_init;
>         clkdata->xtal = clk_register(&pdev->dev, &clkdata->xtal_hw);
> -       if (!clkdata->xtal)
> -               return -EINVAL;
> +       if (IS_ERR(clkdata->xtal))
> +               return PTR_ERR(clkdata->xtal);
>  
>         clkdata->fll_hw.init = &wm831x_fll_init;
>         clkdata->fll = clk_register(&pdev->dev, &clkdata->fll_hw);
> -       if (!clkdata->fll) {
> -               ret = -EINVAL;
> +       if (IS_ERR(clkdata->fll)) {
> +               ret = PTR_ERR(clkdata->fll);
>                 goto err_xtal;
>         }
>  
>         clkdata->clkout_hw.init = &wm831x_clkout_init;
>         clkdata->clkout = clk_register(&pdev->dev, &clkdata->clkout_hw);
> -       if (!clkdata->clkout) {
> -               ret = -EINVAL;
> +       if (IS_ERR(clkdata->clkout)) {
> +               ret = PTR_ERR(clkdata->clkout);
>                 goto err_fll;
>         }
>  
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation