[PATCH V5 0/4] clk: new APIs to handle all available clocks

[PATCH V5 0/4] clk: new APIs to handle all available clocks

[Dong Aisheng]

This patch series is a continue of discussion from here,
https://patchwork.kernel.org/patch/9986293/
that some users may want to handle all available clocks from device
tree without need to know the detailed clock information likes clock
numbers and names. This is useful in writing some generic drivers to
handle clock part.

Note:
This patch series is tested on MX6Q SDB cpufreq driver with a minor change
to switch to use clk_bulk_get_all.
But patch 4 only test compiling. Hopefully someone could help test
the function.

v3->v4:
 * improve 'devres->clks = *clks' according to Stephen's suggestion
v2->v3:
 * address all comments from Stephen
 * fix build warnings on other architectures.
v1->v2:
 * add clk_bulk_{get|put}_all() which only supports DT platform currently
 * remove _all variants and the wrapper struct clk_bulk
 * make of_clk_bulk_get and of_clk_bulk_get_all private until someone
   proves they need it because they don't have a struct device pointer.

Dong Aisheng (4):
  clk: bulk: add of_clk_bulk_get()
  clk: add new APIs to operate on all available clocks
  clk: add managed version of clk_bulk_get_all
  video: simplefb: switch to use clk_bulk API to simplify clock
    operations

 drivers/clk/clk-bulk.c         | 80 ++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/clk-devres.c       | 24 +++++++++++++
 drivers/video/fbdev/simplefb.c | 68 ++++++++---------------------------
 include/linux/clk.h            | 65 +++++++++++++++++++++++++++++++++-
 4 files changed, 182 insertions(+), 55 deletions(-)

-- 
2.7.4

[PATCH V5 1/4] clk: bulk: add of_clk_bulk_get()

[Dong Aisheng]

'clock-names' property is optional in DT, so of_clk_bulk_get() is
introduced here to handle this for DT users without 'clock-names'
specified. Later clk_bulk_get_all() will be implemented on top of
it and this API will be kept private until someone proves they need
it because they don't have a struct device pointer.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reported-by: Shawn Guo <shawnguo@kernel.org>
Tested-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
v3->v4:
 * no changes
v2->v3:
 * remove #if define condition
 * remove EXPORT_SYMBOL
---
 drivers/clk/clk-bulk.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/clk/clk-bulk.c b/drivers/clk/clk-bulk.c
index 6904ed6..4460ac5 100644
--- a/drivers/clk/clk-bulk.c
+++ b/drivers/clk/clk-bulk.c
@@ -19,6 +19,35 @@
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/export.h>
+#include <linux/of.h>
+
+static int __must_check of_clk_bulk_get(struct device_node *np, int num_clks,
+					struct clk_bulk_data *clks)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < num_clks; i++)
+		clks[i].clk = NULL;
+
+	for (i = 0; i < num_clks; i++) {
+		clks[i].clk = of_clk_get(np, i);
+		if (IS_ERR(clks[i].clk)) {
+			ret = PTR_ERR(clks[i].clk);
+			pr_err("%pOF: Failed to get clk index: %d ret: %d\n",
+			       np, i, ret);
+			clks[i].clk = NULL;
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	clk_bulk_put(i, clks);
+
+	return ret;
+}
 
 void clk_bulk_put(int num_clks, struct clk_bulk_data *clks)
 {
-- 
2.7.4

[PATCH V5 2/4] clk: add new APIs to operate on all available clocks

[Dong Aisheng]

This patch introduces of_clk_bulk_get_all and clk_bulk_x_all APIs
to users who just want to handle all available clocks from device tree
without need to know the detailed clock information likes clock numbers
and names. This is useful in writing some generic drivers to handle clock
part.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
v3->v4:
 * no changes
v2->v3:
 * remove #if define condition
 * use kmalloc_array
v1->v2:
 * make of_clk_bulk_get_all private
 * add clk_bulk_get/put_all
---
 drivers/clk/clk-bulk.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/clk.h    | 42 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-bulk.c b/drivers/clk/clk-bulk.c
index 4460ac5..6a7118d 100644
--- a/drivers/clk/clk-bulk.c
+++ b/drivers/clk/clk-bulk.c
@@ -17,9 +17,11 @@
  */
 
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/of.h>
+#include <linux/slab.h>
 
 static int __must_check of_clk_bulk_get(struct device_node *np, int num_clks,
 					struct clk_bulk_data *clks)
@@ -49,6 +51,32 @@ static int __must_check of_clk_bulk_get(struct device_node *np, int num_clks,
 	return ret;
 }
 
+static int __must_check of_clk_bulk_get_all(struct device_node *np,
+					    struct clk_bulk_data **clks)
+{
+	struct clk_bulk_data *clk_bulk;
+	int num_clks;
+	int ret;
+
+	num_clks = of_clk_get_parent_count(np);
+	if (!num_clks)
+		return 0;
+
+	clk_bulk = kmalloc_array(num_clks, sizeof(*clk_bulk), GFP_KERNEL);
+	if (!clk_bulk)
+		return -ENOMEM;
+
+	ret = of_clk_bulk_get(np, num_clks, clk_bulk);
+	if (ret) {
+		kfree(clk_bulk);
+		return ret;
+	}
+
+	*clks = clk_bulk;
+
+	return num_clks;
+}
+
 void clk_bulk_put(int num_clks, struct clk_bulk_data *clks)
 {
 	while (--num_clks >= 0) {
@@ -88,6 +116,29 @@ int __must_check clk_bulk_get(struct device *dev, int num_clks,
 }
 EXPORT_SYMBOL(clk_bulk_get);
 
+void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks)
+{
+	if (IS_ERR_OR_NULL(clks))
+		return;
+
+	clk_bulk_put(num_clks, clks);
+
+	kfree(clks);
+}
+EXPORT_SYMBOL(clk_bulk_put_all);
+
+int __must_check clk_bulk_get_all(struct device *dev,
+				  struct clk_bulk_data **clks)
+{
+	struct device_node *np = dev_of_node(dev);
+
+	if (!np)
+		return 0;
+
+	return of_clk_bulk_get_all(np, clks);
+}
+EXPORT_SYMBOL(clk_bulk_get_all);
+
 #ifdef CONFIG_HAVE_CLK_PREPARE
 
 /**
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 4f750c4..e9433c7 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -312,7 +312,26 @@ struct clk *clk_get(struct device *dev, const char *id);
  */
 int __must_check clk_bulk_get(struct device *dev, int num_clks,
 			      struct clk_bulk_data *clks);
-
+/**
+ * clk_bulk_get_all - lookup and obtain all available references to clock
+ *		      producer.
+ * @dev: device for clock "consumer"
+ * @clks: pointer to the clk_bulk_data table of consumer
+ *
+ * This helper function allows drivers to get all clk consumers in one
+ * operation. If any of the clk cannot be acquired then any clks
+ * that were obtained will be freed before returning to the caller.
+ *
+ * Returns a positive value for the number of clocks obtained while the
+ * clock references are stored in the clk_bulk_data table in @clks field.
+ * Returns 0 if there're none and a negative value if something failed.
+ *
+ * Drivers must assume that the clock source is not enabled.
+ *
+ * clk_bulk_get should not be called from within interrupt context.
+ */
+int __must_check clk_bulk_get_all(struct device *dev,
+				  struct clk_bulk_data **clks);
 /**
  * devm_clk_bulk_get - managed get multiple clk consumers
  * @dev: device for clock "consumer"
@@ -488,6 +507,19 @@ void clk_put(struct clk *clk);
 void clk_bulk_put(int num_clks, struct clk_bulk_data *clks);
 
 /**
+ * clk_bulk_put_all - "free" all the clock source
+ * @num_clks: the number of clk_bulk_data
+ * @clks: the clk_bulk_data table of consumer
+ *
+ * Note: drivers must ensure that all clk_bulk_enable calls made on this
+ * clock source are balanced by clk_bulk_disable calls prior to calling
+ * this function.
+ *
+ * clk_bulk_put_all should not be called from within interrupt context.
+ */
+void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks);
+
+/**
  * devm_clk_put	- "free" a managed clock source
  * @dev: device used to acquire the clock
  * @clk: clock source acquired with devm_clk_get()
@@ -642,6 +674,12 @@ static inline int __must_check clk_bulk_get(struct device *dev, int num_clks,
 	return 0;
 }
 
+static inline int __must_check clk_bulk_get_all(struct device *dev,
+					 struct clk_bulk_data **clks)
+{
+	return 0;
+}
+
 static inline struct clk *devm_clk_get(struct device *dev, const char *id)
 {
 	return NULL;
@@ -663,6 +701,8 @@ static inline void clk_put(struct clk *clk) {}
 
 static inline void clk_bulk_put(int num_clks, struct clk_bulk_data *clks) {}
 
+static inline void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks) {}
+
 static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
 
 
-- 
2.7.4

[PATCH V5 3/4] clk: add managed version of clk_bulk_get_all

[Dong Aisheng]

This patch introduces the managed version of clk_bulk_get_all.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
v3->v4:
 * improve 'devres->clks = *clks' according to Stephen's suggestion
v2->v3:
 * a minor fix of build warning on PowerPC platform.
v1->v2:
 * new patch
---
 drivers/clk/clk-devres.c | 24 ++++++++++++++++++++++++
 include/linux/clk.h      | 23 +++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index d854e26..12c8745 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -70,6 +70,30 @@ int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
 }
 EXPORT_SYMBOL_GPL(devm_clk_bulk_get);
 
+int __must_check devm_clk_bulk_get_all(struct device *dev,
+				       struct clk_bulk_data **clks)
+{
+	struct clk_bulk_devres *devres;
+	int ret;
+
+	devres = devres_alloc(devm_clk_bulk_release,
+			      sizeof(*devres), GFP_KERNEL);
+	if (!devres)
+		return -ENOMEM;
+
+	ret = clk_bulk_get_all(dev, &devres->clks);
+	if (ret > 0) {
+		*clks = devres->clks;
+		devres->num_clks = ret;
+		devres_add(dev, devres);
+	} else {
+		devres_free(devres);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all);
+
 static int devm_clk_match(struct device *dev, void *res, void *data)
 {
 	struct clk **c = res;
diff --git a/include/linux/clk.h b/include/linux/clk.h
index e9433c7..c705271 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -346,6 +346,22 @@ int __must_check clk_bulk_get_all(struct device *dev,
  */
 int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
 				   struct clk_bulk_data *clks);
+/**
+ * devm_clk_bulk_get_all - managed get multiple clk consumers
+ * @dev: device for clock "consumer"
+ * @clks: pointer to the clk_bulk_data table of consumer
+ *
+ * Returns a positive value for the number of clocks obtained while the
+ * clock references are stored in the clk_bulk_data table in @clks field.
+ * Returns 0 if there're none and a negative value if something failed.
+ *
+ * This helper function allows drivers to get several clk
+ * consumers in one operation with management, the clks will
+ * automatically be freed when the device is unbound.
+ */
+
+int __must_check devm_clk_bulk_get_all(struct device *dev,
+				       struct clk_bulk_data **clks);
 
 /**
  * devm_clk_get - lookup and obtain a managed reference to a clock producer.
@@ -691,6 +707,13 @@ static inline int __must_check devm_clk_bulk_get(struct device *dev, int num_clk
 	return 0;
 }
 
+static inline int __must_check devm_clk_bulk_get_all(struct device *dev,
+						     struct clk_bulk_data **clks)
+{
+
+	return 0;
+}
+
 static inline struct clk *devm_get_clk_from_child(struct device *dev,
 				struct device_node *np, const char *con_id)
 {
-- 
2.7.4

[PATCH V5 4/4] video: simplefb: switch to use clk_bulk API to simplify clock operations

[Dong Aisheng]

Switching to use clk_bulk API to simplify clock operations.

Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-fbdev at vger.kernel.org
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
v4->v5:
 * fix wrong setting of par->clks_enabled
v3->v4:
 * no changes
v2->v3:
 * fix a build warning on x86 platform due to a wrong
   of the prototype of simplefb_clocks_enable
v1->v2:
 * switch to clk_bulk_get_all from of_clk_bulk_get_all
---
 drivers/video/fbdev/simplefb.c | 68 +++++++++---------------------------------
 1 file changed, 14 insertions(+), 54 deletions(-)

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 9a9d748..8d1fbd6 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -182,7 +182,7 @@ struct simplefb_par {
 #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
 	bool clks_enabled;
 	unsigned int clk_count;
-	struct clk **clks;
+	struct clk_bulk_data *clks;
 #endif
 #if defined CONFIG_OF && defined CONFIG_REGULATOR
 	bool regulators_enabled;
@@ -214,37 +214,13 @@ static int simplefb_clocks_get(struct simplefb_par *par,
 			       struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
-	struct clk *clock;
-	int i;
 
 	if (dev_get_platdata(&pdev->dev) || !np)
 		return 0;
 
-	par->clk_count = of_clk_get_parent_count(np);
-	if (!par->clk_count)
-		return 0;
-
-	par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
-	if (!par->clks)
-		return -ENOMEM;
-
-	for (i = 0; i < par->clk_count; i++) {
-		clock = of_clk_get(np, i);
-		if (IS_ERR(clock)) {
-			if (PTR_ERR(clock) == -EPROBE_DEFER) {
-				while (--i >= 0) {
-					if (par->clks[i])
-						clk_put(par->clks[i]);
-				}
-				kfree(par->clks);
-				return -EPROBE_DEFER;
-			}
-			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
-				__func__, i, PTR_ERR(clock));
-			continue;
-		}
-		par->clks[i] = clock;
-	}
+	par->clk_count = clk_bulk_get_all(&pdev->dev, &par->clks);
+	if ((par->clk_count < 0) && (par->clk_count == -EPROBE_DEFER))
+		return -EPROBE_DEFER;
 
 	return 0;
 }
@@ -252,39 +228,23 @@ static int simplefb_clocks_get(struct simplefb_par *par,
 static void simplefb_clocks_enable(struct simplefb_par *par,
 				   struct platform_device *pdev)
 {
-	int i, ret;
+	int ret;
 
-	for (i = 0; i < par->clk_count; i++) {
-		if (par->clks[i]) {
-			ret = clk_prepare_enable(par->clks[i]);
-			if (ret) {
-				dev_err(&pdev->dev,
-					"%s: failed to enable clock %d: %d\n",
-					__func__, i, ret);
-				clk_put(par->clks[i]);
-				par->clks[i] = NULL;
-			}
-		}
+	ret = clk_bulk_prepare_enable(par->clk_count, par->clks);
+	if (ret) {
+		par->clks_enabled = false;
+		dev_warn(&pdev->dev, "failed to enable clocks\n");
+	} else {
+		par->clks_enabled = true;
 	}
-	par->clks_enabled = true;
 }
 
 static void simplefb_clocks_destroy(struct simplefb_par *par)
 {
-	int i;
-
-	if (!par->clks)
-		return;
-
-	for (i = 0; i < par->clk_count; i++) {
-		if (par->clks[i]) {
-			if (par->clks_enabled)
-				clk_disable_unprepare(par->clks[i]);
-			clk_put(par->clks[i]);
-		}
-	}
+	if (par->clks_enabled)
+		clk_bulk_disable_unprepare(par->clk_count, par->clks);
 
-	kfree(par->clks);
+	clk_bulk_put_all(par->clk_count, par->clks);
 }
 #else
 static int simplefb_clocks_get(struct simplefb_par *par,
-- 
2.7.4

[PATCH V5 4/4] video: simplefb: switch to use clk_bulk API to simplify clock operations

[Hans de Goede]

Hi,

On 29-08-18 16:41, Dong Aisheng wrote:
> Switching to use clk_bulk API to simplify clock operations.
> 
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: linux-fbdev at vger.kernel.org
> Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
> Cc: Stephen Boyd <sboyd@codeaurora.org>
> Tested-by: Thor Thayer <thor.thayer@linux.intel.com>
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> ---
> v4->v5:
>   * fix wrong setting of par->clks_enabled
> v3->v4:
>   * no changes
> v2->v3:
>   * fix a build warning on x86 platform due to a wrong
>     of the prototype of simplefb_clocks_enable
> v1->v2:
>   * switch to clk_bulk_get_all from of_clk_bulk_get_all
> ---
>   drivers/video/fbdev/simplefb.c | 68 +++++++++---------------------------------
>   1 file changed, 14 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
> index 9a9d748..8d1fbd6 100644
> --- a/drivers/video/fbdev/simplefb.c
> +++ b/drivers/video/fbdev/simplefb.c
> @@ -182,7 +182,7 @@ struct simplefb_par {
>   #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
>   	bool clks_enabled;
>   	unsigned int clk_count;
> -	struct clk **clks;
> +	struct clk_bulk_data *clks;
>   #endif
>   #if defined CONFIG_OF && defined CONFIG_REGULATOR
>   	bool regulators_enabled;
> @@ -214,37 +214,13 @@ static int simplefb_clocks_get(struct simplefb_par *par,
>   			       struct platform_device *pdev)
>   {
>   	struct device_node *np = pdev->dev.of_node;
> -	struct clk *clock;
> -	int i;
>   
>   	if (dev_get_platdata(&pdev->dev) || !np)
>   		return 0;
>   
> -	par->clk_count = of_clk_get_parent_count(np);
> -	if (!par->clk_count)
> -		return 0;
> -
> -	par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
> -	if (!par->clks)
> -		return -ENOMEM;
> -
> -	for (i = 0; i < par->clk_count; i++) {
> -		clock = of_clk_get(np, i);
> -		if (IS_ERR(clock)) {
> -			if (PTR_ERR(clock) == -EPROBE_DEFER) {
> -				while (--i >= 0) {
> -					if (par->clks[i])
> -						clk_put(par->clks[i]);
> -				}
> -				kfree(par->clks);
> -				return -EPROBE_DEFER;
> -			}
> -			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
> -				__func__, i, PTR_ERR(clock));
> -			continue;
> -		}
> -		par->clks[i] = clock;
> -	}
> +	par->clk_count = clk_bulk_get_all(&pdev->dev, &par->clks);
> +	if ((par->clk_count < 0) && (par->clk_count == -EPROBE_DEFER))
> +		return -EPROBE_DEFER;

I just noticed this now, but clk_count is unsigned so it will never
be < 0, please make it signed.

Also there is no need to check for < 0 just (par->clk_count == -EPROBE_DEFER)
is enough (if that is true < 0 also always is true).

>   
>   	return 0;
>   }
> @@ -252,39 +228,23 @@ static int simplefb_clocks_get(struct simplefb_par *par,
>   static void simplefb_clocks_enable(struct simplefb_par *par,
>   				   struct platform_device *pdev)
>   {
> -	int i, ret;
> +	int ret;
>   
> -	for (i = 0; i < par->clk_count; i++) {
> -		if (par->clks[i]) {
> -			ret = clk_prepare_enable(par->clks[i]);
> -			if (ret) {
> -				dev_err(&pdev->dev,
> -					"%s: failed to enable clock %d: %d\n",
> -					__func__, i, ret);
> -				clk_put(par->clks[i]);
> -				par->clks[i] = NULL;
> -			}
> -		}
> +	ret = clk_bulk_prepare_enable(par->clk_count, par->clks);

Hmm, what happens if par->clk_count < 0 (another <0 value then
-EPROBEDEFER) ?

> +	if (ret) {
> +		par->clks_enabled = false;

No need to set false here.

> +		dev_warn(&pdev->dev, "failed to enable clocks\n");
> +	} else {
> +		par->clks_enabled = true;
>   	}
> -	par->clks_enabled = true;
>   }
>   
>   static void simplefb_clocks_destroy(struct simplefb_par *par)
>   {
> -	int i;
> -
> -	if (!par->clks)
> -		return;
> -
> -	for (i = 0; i < par->clk_count; i++) {
> -		if (par->clks[i]) {
> -			if (par->clks_enabled)
> -				clk_disable_unprepare(par->clks[i]);
> -			clk_put(par->clks[i]);
> -		}
> -	}
> +	if (par->clks_enabled)
> +		clk_bulk_disable_unprepare(par->clk_count, par->clks);
>   
> -	kfree(par->clks);
> +	clk_bulk_put_all(par->clk_count, par->clks);

Again what about par->clk_count < 0 ?

Regards,

Hans

[PATCH V5 4/4] video: simplefb: switch to use clk_bulk API to simplify clock operations

[A.s. Dong]

> -----Original Message-----
> From: Hans de Goede [mailto:hdegoede at redhat.com]
> Sent: Wednesday, August 29, 2018 11:22 PM

[...]

> On 29-08-18 16:41, Dong Aisheng wrote:
> > Switching to use clk_bulk API to simplify clock operations.
> >
> > Cc: Hans de Goede <hdegoede@redhat.com>
> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> > Cc: linux-fbdev at vger.kernel.org
> > Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
> > Cc: Stephen Boyd <sboyd@codeaurora.org>
> > Tested-by: Thor Thayer <thor.thayer@linux.intel.com>
> > Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> > ---
> > v4->v5:
> >   * fix wrong setting of par->clks_enabled
> > v3->v4:
> >   * no changes
> > v2->v3:
> >   * fix a build warning on x86 platform due to a wrong
> >     of the prototype of simplefb_clocks_enable
> > v1->v2:
> >   * switch to clk_bulk_get_all from of_clk_bulk_get_all
> > ---
> >   drivers/video/fbdev/simplefb.c | 68 +++++++++---------------------------------
> >   1 file changed, 14 insertions(+), 54 deletions(-)
> >
> > diff --git a/drivers/video/fbdev/simplefb.c
> > b/drivers/video/fbdev/simplefb.c index 9a9d748..8d1fbd6 100644
> > --- a/drivers/video/fbdev/simplefb.c
> > +++ b/drivers/video/fbdev/simplefb.c
> > @@ -182,7 +182,7 @@ struct simplefb_par {
> >   #if defined CONFIG_OF && defined CONFIG_COMMON_CLK
> >   	bool clks_enabled;
> >   	unsigned int clk_count;
> > -	struct clk **clks;
> > +	struct clk_bulk_data *clks;
> >   #endif
> >   #if defined CONFIG_OF && defined CONFIG_REGULATOR
> >   	bool regulators_enabled;
> > @@ -214,37 +214,13 @@ static int simplefb_clocks_get(struct simplefb_par
> *par,
> >   			       struct platform_device *pdev)
> >   {
> >   	struct device_node *np = pdev->dev.of_node;
> > -	struct clk *clock;
> > -	int i;
> >
> >   	if (dev_get_platdata(&pdev->dev) || !np)
> >   		return 0;
> >
> > -	par->clk_count = of_clk_get_parent_count(np);
> > -	if (!par->clk_count)
> > -		return 0;
> > -
> > -	par->clks = kcalloc(par->clk_count, sizeof(struct clk *), GFP_KERNEL);
> > -	if (!par->clks)
> > -		return -ENOMEM;
> > -
> > -	for (i = 0; i < par->clk_count; i++) {
> > -		clock = of_clk_get(np, i);
> > -		if (IS_ERR(clock)) {
> > -			if (PTR_ERR(clock) == -EPROBE_DEFER) {
> > -				while (--i >= 0) {
> > -					if (par->clks[i])
> > -						clk_put(par->clks[i]);
> > -				}
> > -				kfree(par->clks);
> > -				return -EPROBE_DEFER;
> > -			}
> > -			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
> > -				__func__, i, PTR_ERR(clock));
> > -			continue;
> > -		}
> > -		par->clks[i] = clock;
> > -	}
> > +	par->clk_count = clk_bulk_get_all(&pdev->dev, &par->clks);
> > +	if ((par->clk_count < 0) && (par->clk_count == -EPROBE_DEFER))
> > +		return -EPROBE_DEFER;
> 
> I just noticed this now, but clk_count is unsigned so it will never be < 0, please
> make it signed.
> 

Good findings.

> Also there is no need to check for < 0 just (par->clk_count == -EPROBE_DEFER)
> is enough (if that is true < 0 also always is true).
> 

Yes, you're right.

> >
> >   	return 0;
> >   }
> > @@ -252,39 +228,23 @@ static int simplefb_clocks_get(struct simplefb_par
> *par,
> >   static void simplefb_clocks_enable(struct simplefb_par *par,
> >   				   struct platform_device *pdev)
> >   {
> > -	int i, ret;
> > +	int ret;
> >
> > -	for (i = 0; i < par->clk_count; i++) {
> > -		if (par->clks[i]) {
> > -			ret = clk_prepare_enable(par->clks[i]);
> > -			if (ret) {
> > -				dev_err(&pdev->dev,
> > -					"%s: failed to enable clock %d: %d\n",
> > -					__func__, i, ret);
> > -				clk_put(par->clks[i]);
> > -				par->clks[i] = NULL;
> > -			}
> > -		}
> > +	ret = clk_bulk_prepare_enable(par->clk_count, par->clks);
> 
> Hmm, what happens if par->clk_count < 0 (another <0 value then
> -EPROBEDEFER) ?
> 

Good catch. I will add a checking of it.
diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 477e008..89fb1e7 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -230,6 +230,9 @@ static void simplefb_clocks_enable(struct simplefb_par *par,
 {
        int ret;
 
+       if (par->clk_count <= 0)
+               return;
+
        ret = clk_bulk_prepare_enable(par->clk_count, par->clks);
        if (ret)
                dev_warn(&pdev->dev, "failed to enable clocks\n");
@@ -239,6 +242,9 @@ static void simplefb_clocks_enable(struct simplefb_par *par,
 
 static void simplefb_clocks_destroy(struct simplefb_par *par)
 {
+       if (par->clk_count <= 0)
+               return;
+
        if (par->clks_enabled)
                clk_bulk_disable_unprepare(par->clk_count, par->clks);

> > +	if (ret) {
> > +		par->clks_enabled = false;
> 
> No need to set false here.
> 

Got it. Then let's reply on the kzalloc

> > +		dev_warn(&pdev->dev, "failed to enable clocks\n");
> > +	} else {
> > +		par->clks_enabled = true;
> >   	}
> > -	par->clks_enabled = true;
> >   }
> >
> >   static void simplefb_clocks_destroy(struct simplefb_par *par)
> >   {
> > -	int i;
> > -
> > -	if (!par->clks)
> > -		return;
> > -
> > -	for (i = 0; i < par->clk_count; i++) {
> > -		if (par->clks[i]) {
> > -			if (par->clks_enabled)
> > -				clk_disable_unprepare(par->clks[i]);
> > -			clk_put(par->clks[i]);
> > -		}
> > -	}
> > +	if (par->clks_enabled)
> > +		clk_bulk_disable_unprepare(par->clk_count, par->clks);
> >
> > -	kfree(par->clks);
> > +	clk_bulk_put_all(par->clk_count, par->clks);
> 
> Again what about par->clk_count < 0 ?
> 
> Regards,
> 
> Hans

Will resend a new patch series. Thanks for the carefully review.

Regards
Dong Aisheng