[PATCH 0/2] clk: add devm variant of clk_notifier_register

[PATCH 0/2] clk: add devm variant of clk_notifier_register

[Jerome Brunet]

This patchset adds memory managed variant of clk_notifier_register and
a first usage of it the amlogic clock controller of the g12 SoC family.

Jerome Brunet (2):
  clk: add devm variant of clk_notifier_register
  clk: meson: g12: use devm variant to register notifiers

 drivers/clk/clk.c        | 36 ++++++++++++++++++++++++++++++++++++
 drivers/clk/meson/g12a.c | 34 ++++++++++++++++++++--------------
 include/linux/clk.h      | 18 ++++++++++++++++++
 3 files changed, 74 insertions(+), 14 deletions(-)

-- 
2.25.4

[PATCH 1/2] clk: add devm variant of clk_notifier_register

[Jerome Brunet]

Add a memory managed variant of clk_notifier_register() to make life easier
on clock consumers using notifiers

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/clk/clk.c   | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/clk.h | 10 ++++++++++
 2 files changed, 46 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index d27153f26fa9..e9fdd1d9b3f5 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4395,6 +4395,42 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(clk_notifier_unregister);
 
+struct clk_notifier_devres {
+	struct clk *clk;
+	struct notifier_block *nb;
+};
+
+static void devm_clk_notifier_release(struct device *dev, void *res)
+{
+	struct clk_notifier_devres *devres = res;
+
+	clk_notifier_unregister(devres->clk, devres->nb);
+}
+
+int devm_clk_notifier_register(struct device *dev, struct clk *clk,
+			       struct notifier_block *nb)
+{
+	struct clk_notifier_devres *devres;
+	int ret;
+
+	devres = devres_alloc(devm_clk_notifier_release,
+			      sizeof(*devres), GFP_KERNEL);
+
+	if (!devres)
+		return -ENOMEM;
+
+	ret = clk_notifier_register(clk, nb);
+	if (!ret) {
+		devres->clk = clk;
+		devres->nb = nb;
+	} else {
+		devres_free(devres);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_clk_notifier_register);
+
 #ifdef CONFIG_OF
 static void clk_core_reparent_orphans(void)
 {
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 7fd6a1febcf4..79fb52f93053 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -109,6 +109,16 @@ int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
  */
 int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
 
+/**
+ * devm_clk_notifier_register: register a managed rate-change notifier callback
+ * @dev: device for clock "consumer"
+ * @clk: clock whose rate we are interested in
+ * @nb: notifier block with callback function pointer
+ *
+ * Returns 0 on success, -EERROR otherwise
+ */
+int devm_clk_notifier_register(struct device *dev, struct clk *clk, struct notifier_block *nb);
+
 /**
  * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion)
  *		      for a clock source.
-- 
2.25.4

[PATCH 2/2] clk: meson: g12: use devm variant to register notifiers

[Jerome Brunet]

Until now, nothing was done to unregister the dvfs clock notifiers of the
Amlogic g12 SoC family. This is not great but this driver was not really
expected to be unloaded. With the ongoing effort to build everything as
module for this platform, this needs to be cleanly handled.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---

 This clean application of this patch depends on
 https://lore.kernel.org/r/20201021162147.563655-4-jbrunet@baylibre.com

 drivers/clk/meson/g12a.c | 34 ++++++++++++++++++++--------------
 include/linux/clk.h      | 10 +++++++++-
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
index bbb75541dad9..bb4fa19442be 100644
--- a/drivers/clk/meson/g12a.c
+++ b/drivers/clk/meson/g12a.c
@@ -5171,8 +5171,8 @@ static int meson_g12a_dvfs_setup_common(struct device *dev,
 	g12a_cpu_clk_postmux0_nb_data.xtal = xtal;
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12a_cpu_clk_postmux0.hw,
 					   DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk,
-				    &g12a_cpu_clk_postmux0_nb_data.nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12a_cpu_clk_postmux0_nb_data.nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpu_clk_postmux0 notifier\n");
 		return ret;
@@ -5181,7 +5181,8 @@ static int meson_g12a_dvfs_setup_common(struct device *dev,
 	/* Setup clock notifier for cpu_clk_dyn mux */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12a_cpu_clk_dyn.hw,
 					   DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk, &g12a_cpu_clk_mux_nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12a_cpu_clk_mux_nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpu_clk_dyn notifier\n");
 		return ret;
@@ -5207,7 +5208,8 @@ static int meson_g12b_dvfs_setup(struct platform_device *pdev)
 	/* Setup clock notifier for cpu_clk mux */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12b_cpu_clk.hw,
 					   DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk, &g12a_cpu_clk_mux_nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12a_cpu_clk_mux_nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpu_clk notifier\n");
 		return ret;
@@ -5216,8 +5218,8 @@ static int meson_g12b_dvfs_setup(struct platform_device *pdev)
 	/* Setup clock notifier for sys1_pll */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12b_sys1_pll.hw,
 					   DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk,
-				    &g12b_cpu_clk_sys1_pll_nb_data.nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12b_cpu_clk_sys1_pll_nb_data.nb);
 	if (ret) {
 		dev_err(dev, "failed to register the sys1_pll notifier\n");
 		return ret;
@@ -5229,8 +5231,8 @@ static int meson_g12b_dvfs_setup(struct platform_device *pdev)
 	g12b_cpub_clk_postmux0_nb_data.xtal = xtal;
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12b_cpub_clk_postmux0.hw,
 					   DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk,
-				    &g12b_cpub_clk_postmux0_nb_data.nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12b_cpub_clk_postmux0_nb_data.nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpub_clk_postmux0 notifier\n");
 		return ret;
@@ -5238,7 +5240,8 @@ static int meson_g12b_dvfs_setup(struct platform_device *pdev)
 
 	/* Setup clock notifier for cpub_clk_dyn mux */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12b_cpub_clk_dyn.hw, "dvfs");
-	ret = clk_notifier_register(notifier_clk, &g12a_cpu_clk_mux_nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12a_cpu_clk_mux_nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpub_clk_dyn notifier\n");
 		return ret;
@@ -5246,7 +5249,8 @@ static int meson_g12b_dvfs_setup(struct platform_device *pdev)
 
 	/* Setup clock notifier for cpub_clk mux */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12b_cpub_clk.hw, DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk, &g12a_cpu_clk_mux_nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12a_cpu_clk_mux_nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpub_clk notifier\n");
 		return ret;
@@ -5254,8 +5258,8 @@ static int meson_g12b_dvfs_setup(struct platform_device *pdev)
 
 	/* Setup clock notifier for sys_pll */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12a_sys_pll.hw, DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk,
-				    &g12b_cpub_clk_sys_pll_nb_data.nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12b_cpub_clk_sys_pll_nb_data.nb);
 	if (ret) {
 		dev_err(dev, "failed to register the sys_pll notifier\n");
 		return ret;
@@ -5277,7 +5281,8 @@ static int meson_g12a_dvfs_setup(struct platform_device *pdev)
 
 	/* Setup clock notifier for cpu_clk mux */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12a_cpu_clk.hw, DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk, &g12a_cpu_clk_mux_nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+				    &g12a_cpu_clk_mux_nb);
 	if (ret) {
 		dev_err(dev, "failed to register the cpu_clk notifier\n");
 		return ret;
@@ -5285,7 +5290,8 @@ static int meson_g12a_dvfs_setup(struct platform_device *pdev)
 
 	/* Setup clock notifier for sys_pll */
 	notifier_clk = devm_clk_hw_get_clk(dev, &g12a_sys_pll.hw, DVFS_CON_ID);
-	ret = clk_notifier_register(notifier_clk, &g12a_sys_pll_nb_data.nb);
+	ret = devm_clk_notifier_register(dev, notifier_clk,
+					 &g12a_sys_pll_nb_data.nb);
 	if (ret) {
 		dev_err(dev, "failed to register the sys_pll notifier\n");
 		return ret;
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 79fb52f93053..db113495d315 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -117,7 +117,8 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
  *
  * Returns 0 on success, -EERROR otherwise
  */
-int devm_clk_notifier_register(struct device *dev, struct clk *clk, struct notifier_block *nb);
+int devm_clk_notifier_register(struct device *dev, struct clk *clk,
+			       struct notifier_block *nb);
 
 /**
  * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion)
@@ -196,6 +197,13 @@ static inline int clk_notifier_unregister(struct clk *clk,
 	return -ENOTSUPP;
 }
 
+static inline int devm_clk_notifier_register(struct device *dev,
+					     struct clk *clk,
+					     struct notifier_block *nb)
+{
+	return -ENOTSUPP;
+}
+
 static inline long clk_get_accuracy(struct clk *clk)
 {
 	return -ENOTSUPP;
-- 
2.25.4

Re: [PATCH 1/2] clk: add devm variant of clk_notifier_register

[Stephen Boyd]

Quoting Jerome Brunet (2020-10-21 09:38:46)
> Add a memory managed variant of clk_notifier_register() to make life easier
> on clock consumers using notifiers
> 
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---

Applied to clk-next

Re: [PATCH 2/2] clk: meson: g12: use devm variant to register notifiers

[Stephen Boyd]

Quoting Jerome Brunet (2020-10-21 09:38:47)
> Until now, nothing was done to unregister the dvfs clock notifiers of the
> Amlogic g12 SoC family. This is not great but this driver was not really
> expected to be unloaded. With the ongoing effort to build everything as
> module for this platform, this needs to be cleanly handled.
> 
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---

Applied to clk-next

Re: [PATCH 0/2] clk: add devm variant of clk_notifier_register

[Stephen Boyd]

Quoting Jerome Brunet (2020-10-21 09:38:45)
> This patchset adds memory managed variant of clk_notifier_register and
> a first usage of it the amlogic clock controller of the g12 SoC family.
> 
> Jerome Brunet (2):
>   clk: add devm variant of clk_notifier_register

I'm not sure if we want to document these in the devres document?

Documentation/driver-api/driver-model/devres.rst

It would be nice if that thing could auto-generate the list of devres
APIs somehow.