[PATCH] clk: fixed-factor: add optional dt-binding clock-flags

[PATCH] clk: fixed-factor: add optional dt-binding clock-flags

[Jongsung Kim]

There is no way to set additional flags for a DT-initialized fixed-
factor-clock, and it can be problematic i.e., when the clock rate
needs to be changed. [1][2]

This patch introduces an optional dt-binding named "clock-flags" to
be used for passing any needed flags from dts.

[1] http://www.spinics.net/lists/linux-clk/msg09040.html
[2] https://lkml.org/lkml/2016/6/20/1025

Signed-off-by: Jongsung Kim <neidhard.kim@lge.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Mike Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
---
 .../bindings/clock/fixed-factor-clock.txt          |  4 ++++
 drivers/clk/clk-fixed-factor.c                     |  4 +++-
 include/dt-bindings/clk/clk.h                      | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 include/dt-bindings/clk/clk.h

diff --git a/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt b/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt
index 1bae8527..3e1b79e 100644
--- a/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt
+++ b/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt
@@ -13,12 +13,16 @@ Required properties:
 
 Optional properties:
 - clock-output-names : From common clock binding.
+- clock-flags : Additional flags to be used.
 
 Example:
+	#include <dt-bindings/clk/clk.h>
+
 	clock {
 		compatible = "fixed-factor-clock";
 		clocks = <&parentclk>;
 		#clock-cells = <0>;
 		clock-div = <2>;
 		clock-mult = <1>;
+		clock-flags = <CLK_SET_RATE_PARENT>;
 	};
diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
index 75cd6c7..da3cd9c 100644
--- a/drivers/clk/clk-fixed-factor.c
+++ b/drivers/clk/clk-fixed-factor.c
@@ -150,6 +150,7 @@ void __init of_fixed_factor_clk_setup(struct device_node *node)
 	struct clk *clk;
 	const char *clk_name = node->name;
 	const char *parent_name;
+	unsigned long flags = 0;
 	u32 div, mult;
 
 	if (of_property_read_u32(node, "clock-div", &div)) {
@@ -166,8 +167,9 @@ void __init of_fixed_factor_clk_setup(struct device_node *node)
 
 	of_property_read_string(node, "clock-output-names", &clk_name);
 	parent_name = of_clk_get_parent_name(node, 0);
+	of_property_read_u32(node, "clock-flags", &flags);
 
-	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
+	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, flags,
 					mult, div);
 	if (!IS_ERR(clk))
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
diff --git a/include/dt-bindings/clk/clk.h b/include/dt-bindings/clk/clk.h
new file mode 100644
index 0000000..1834933
--- /dev/null
+++ b/include/dt-bindings/clk/clk.h
@@ -0,0 +1,22 @@
+/*
+ * See include/linux/clk-provider.h for more information.
+ */
+
+#ifndef __DT_BINDINGS_CLK_CLK_H
+#define __DT_BINDINGS_CLK_CLK_H
+
+#define BIT(nr)	(1UL << (nr))
+
+#define CLK_SET_RATE_GATE		BIT(0)
+#define CLK_SET_PARENT_GATE		BIT(1)
+#define CLK_SET_RATE_PARENT		BIT(2)
+#define CLK_IGNORE_UNUSED		BIT(3)
+#define CLK_IS_BASIC			BIT(5)
+#define CLK_GET_RATE_NOCACHE		BIT(6)
+#define CLK_SET_RATE_NO_REPARENT	BIT(7)
+#define CLK_GET_ACCURACY_NOCACHE	BIT(8)
+#define CLK_RECALC_NEW_RATES		BIT(9)
+#define CLK_SET_RATE_UNGATE		BIT(10)
+#define CLK_IS_CRITICAL			BIT(11)
+
+#endif
-- 
2.7.4

[PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Jongsung Kim]

There is no way to set additional flags for a DT-initialized fixed-
factor-clock, and it can be problematic i.e., when the clock rate
needs to be changed. [1][2]

This patch introduces an optional dt-binding named "clock-flags" to
be used for passing any needed flags from dts.

[1] http://www.spinics.net/lists/linux-clk/msg09040.html
[2] https://lkml.org/lkml/2016/6/20/1025

Changes since v1:
 - fix possible build failure when using gcc-5 or gcc-6

Signed-off-by: Jongsung Kim <neidhard.kim@lge.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Mike Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
---
 .../bindings/clock/fixed-factor-clock.txt          |  4 ++++
 drivers/clk/clk-fixed-factor.c                     |  4 +++-
 include/dt-bindings/clk/clk.h                      | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 include/dt-bindings/clk/clk.h

diff --git a/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt b/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt
index 1bae8527..3e1b79e 100644
--- a/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt
+++ b/Documentation/devicetree/bindings/clock/fixed-factor-clock.txt
@@ -13,12 +13,16 @@ Required properties:
 
 Optional properties:
 - clock-output-names : From common clock binding.
+- clock-flags : Additional flags to be used.
 
 Example:
+	#include <dt-bindings/clk/clk.h>
+
 	clock {
 		compatible = "fixed-factor-clock";
 		clocks = <&parentclk>;
 		#clock-cells = <0>;
 		clock-div = <2>;
 		clock-mult = <1>;
+		clock-flags = <CLK_SET_RATE_PARENT>;
 	};
diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
index 75cd6c7..e626cad 100644
--- a/drivers/clk/clk-fixed-factor.c
+++ b/drivers/clk/clk-fixed-factor.c
@@ -150,6 +150,7 @@ void __init of_fixed_factor_clk_setup(struct device_node *node)
 	struct clk *clk;
 	const char *clk_name = node->name;
 	const char *parent_name;
+	u32 flags = 0;
 	u32 div, mult;
 
 	if (of_property_read_u32(node, "clock-div", &div)) {
@@ -166,8 +167,9 @@ void __init of_fixed_factor_clk_setup(struct device_node *node)
 
 	of_property_read_string(node, "clock-output-names", &clk_name);
 	parent_name = of_clk_get_parent_name(node, 0);
+	of_property_read_u32(node, "clock-flags", &flags);
 
-	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
+	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, flags,
 					mult, div);
 	if (!IS_ERR(clk))
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
diff --git a/include/dt-bindings/clk/clk.h b/include/dt-bindings/clk/clk.h
new file mode 100644
index 0000000..1834933
--- /dev/null
+++ b/include/dt-bindings/clk/clk.h
@@ -0,0 +1,22 @@
+/*
+ * See include/linux/clk-provider.h for more information.
+ */
+
+#ifndef __DT_BINDINGS_CLK_CLK_H
+#define __DT_BINDINGS_CLK_CLK_H
+
+#define BIT(nr)	(1UL << (nr))
+
+#define CLK_SET_RATE_GATE		BIT(0)
+#define CLK_SET_PARENT_GATE		BIT(1)
+#define CLK_SET_RATE_PARENT		BIT(2)
+#define CLK_IGNORE_UNUSED		BIT(3)
+#define CLK_IS_BASIC			BIT(5)
+#define CLK_GET_RATE_NOCACHE		BIT(6)
+#define CLK_SET_RATE_NO_REPARENT	BIT(7)
+#define CLK_GET_ACCURACY_NOCACHE	BIT(8)
+#define CLK_RECALC_NEW_RATES		BIT(9)
+#define CLK_SET_RATE_UNGATE		BIT(10)
+#define CLK_IS_CRITICAL			BIT(11)
+
+#endif
-- 
2.7.4

Re: [PATCH] clk: fixed-factor: add optional dt-binding clock-flags

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1977 bytes --]

Hi,

[auto build test ERROR on robh/for-next]
[also build test ERROR on v4.7-rc4 next-20160623]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Jongsung-Kim/clk-fixed-factor-add-optional-dt-binding-clock-flags/20160624-115201
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux for-next
config: x86_64-randconfig-s4-06241247 (attached as .config)
compiler: gcc-6 (Debian 6.1.1-1) 6.1.1 20160430
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   drivers/clk/clk-fixed-factor.c: In function 'of_fixed_factor_clk_setup':
>> drivers/clk/clk-fixed-factor.c:170:44: error: passing argument 3 of 'of_property_read_u32' from incompatible pointer type [-Werror=incompatible-pointer-types]
     of_property_read_u32(node, "clock-flags", &flags);
                                               ^
   In file included from include/linux/clk-provider.h:15:0,
                    from drivers/clk/clk-fixed-factor.c:11:
   include/linux/of.h:916:19: note: expected 'u32 * {aka unsigned int *}' but argument is of type 'long unsigned int *'
    static inline int of_property_read_u32(const struct device_node *np,
                      ^~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/of_property_read_u32 +170 drivers/clk/clk-fixed-factor.c

   164				__func__, node->name);
   165			return;
   166		}
   167	
   168		of_property_read_string(node, "clock-output-names", &clk_name);
   169		parent_name = of_clk_get_parent_name(node, 0);
 > 170		of_property_read_u32(node, "clock-flags", &flags);
   171	
   172		clk = clk_register_fixed_factor(NULL, clk_name, parent_name, flags,
   173						mult, div);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
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Re: [PATCH] clk: fixed-factor: add optional dt-binding clock-flags

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2567 bytes --]

Hi,

[auto build test WARNING on robh/for-next]
[also build test WARNING on v4.7-rc4 next-20160623]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Jongsung-Kim/clk-fixed-factor-add-optional-dt-binding-clock-flags/20160624-115201
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux for-next
config: microblaze-mmu_defconfig (attached as .config)
compiler: microblaze-linux-gcc (GCC) 4.9.0
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=microblaze 

All warnings (new ones prefixed by >>):

   drivers/clk/clk-fixed-factor.c: In function 'of_fixed_factor_clk_setup':
>> drivers/clk/clk-fixed-factor.c:170:2: warning: passing argument 3 of 'of_property_read_u32' from incompatible pointer type
     of_property_read_u32(node, "clock-flags", &flags);
     ^
   In file included from include/linux/clk-provider.h:15:0,
                    from drivers/clk/clk-fixed-factor.c:11:
   include/linux/of.h:916:19: note: expected 'u32 *' but argument is of type 'long unsigned int *'
    static inline int of_property_read_u32(const struct device_node *np,
                      ^

vim +/of_property_read_u32 +170 drivers/clk/clk-fixed-factor.c

   154		u32 div, mult;
   155	
   156		if (of_property_read_u32(node, "clock-div", &div)) {
   157			pr_err("%s Fixed factor clock <%s> must have a clock-div property\n",
   158				__func__, node->name);
   159			return;
   160		}
   161	
   162		if (of_property_read_u32(node, "clock-mult", &mult)) {
   163			pr_err("%s Fixed factor clock <%s> must have a clock-mult property\n",
   164				__func__, node->name);
   165			return;
   166		}
   167	
   168		of_property_read_string(node, "clock-output-names", &clk_name);
   169		parent_name = of_clk_get_parent_name(node, 0);
 > 170		of_property_read_u32(node, "clock-flags", &flags);
   171	
   172		clk = clk_register_fixed_factor(NULL, clk_name, parent_name, flags,
   173						mult, div);
   174		if (!IS_ERR(clk))
   175			of_clk_add_provider(node, of_clk_src_simple_get, clk);
   176	}
   177	EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);
   178	CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 12638 bytes --]

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Rob Herring]

On Fri, Jun 24, 2016 at 01:12:52PM +0900, Jongsung Kim wrote:
> There is no way to set additional flags for a DT-initialized fixed-
> factor-clock, and it can be problematic i.e., when the clock rate
> needs to be changed. [1][2]
> 
> This patch introduces an optional dt-binding named "clock-flags" to
> be used for passing any needed flags from dts.

I don't think we want this in DT. If we did, the flags would need some 
documentation about what the flags mean.

Rob

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Michael Turquette]

Quoting Rob Herring (2016-06-28 13:55:18)
> On Fri, Jun 24, 2016 at 01:12:52PM +0900, Jongsung Kim wrote:
> > There is no way to set additional flags for a DT-initialized fixed-
> > factor-clock, and it can be problematic i.e., when the clock rate
> > needs to be changed. [1][2]
> > 
> > This patch introduces an optional dt-binding named "clock-flags" to
> > be used for passing any needed flags from dts.
> 
> I don't think we want this in DT. If we did, the flags would need some 
> documentation about what the flags mean.

Flags are specific to Linux implementation, so I agree with Rob. Better
to create a compatible string for your hardware that bakes in the flags.

Regards,
Mike

> 
> Rob

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Jongsung Kim]

On 2016년 06월 29일 05:55, Rob Herring wrote:
> On Fri, Jun 24, 2016 at 01:12:52PM +0900, Jongsung Kim wrote:
>> There is no way to set additional flags for a DT-initialized fixed-
>> factor-clock, and it can be problematic i.e., when the clock rate
>> needs to be changed. [1][2]
>>
>> This patch introduces an optional dt-binding named "clock-flags" to
>> be used for passing any needed flags from dts.
> I don't think we want this in DT. If we did, the flags would need some 
> documentation about what the flags mean.
Thanks for your comment. It looks not that big deal to provide a little documentation..? Some of the flags looks safe to be removed. Thinking of only fixed-factor-clock, most of them can be removed.

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Jongsung Kim]

On 2016년 06월 29일 06:18, Michael Turquette wrote:
> Quoting Rob Herring (2016-06-28 13:55:18)
>> On Fri, Jun 24, 2016 at 01:12:52PM +0900, Jongsung Kim wrote:
>>> There is no way to set additional flags for a DT-initialized fixed-
>>> factor-clock, and it can be problematic i.e., when the clock rate
>>> needs to be changed. [1][2]
>>>
>>> This patch introduces an optional dt-binding named "clock-flags" to
>>> be used for passing any needed flags from dts.
>> I don't think we want this in DT. If we did, the flags would need some 
>> documentation about what the flags mean.
> Flags are specific to Linux implementation, so I agree with Rob. Better
> to create a compatible string for your hardware that bakes in the flags.

Thank you for your comment, Mike. This conversation starts from lacking method to set CLK_SET_RATE_PARENT from DT. I understand compatible string can be a solution. But.. if someone starts talking about lacking method to set another flag, i.e., CLK_SET_PARENT_GATE, then we'll need another compatible string list.
How do you think about defining possible required subset of the flags and using some more neutral flag-names acceptable in DT?

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Stephen Boyd]

On 06/29, Jongsung Kim wrote:
> On 2016년 06월 29일 06:18, Michael Turquette wrote:
> > Quoting Rob Herring (2016-06-28 13:55:18)
> >> On Fri, Jun 24, 2016 at 01:12:52PM +0900, Jongsung Kim wrote:
> >>> There is no way to set additional flags for a DT-initialized fixed-
> >>> factor-clock, and it can be problematic i.e., when the clock rate
> >>> needs to be changed. [1][2]
> >>>
> >>> This patch introduces an optional dt-binding named "clock-flags" to
> >>> be used for passing any needed flags from dts.
> >> I don't think we want this in DT. If we did, the flags would need some 
> >> documentation about what the flags mean.
> > Flags are specific to Linux implementation, so I agree with Rob. Better
> > to create a compatible string for your hardware that bakes in the flags.
> 
> Thank you for your comment, Mike. This conversation starts from lacking method to set CLK_SET_RATE_PARENT from DT. I understand compatible string can be a solution. But.. if someone starts talking about lacking method to set another flag, i.e., CLK_SET_PARENT_GATE, then we'll need another compatible string list.
> How do you think about defining possible required subset of the flags and using some more neutral flag-names acceptable in DT?

Do you actually have an IC on the board that is doing some fixed
factor calculation? Or is this a clk driver design where we are
listing out each piece of an SoC's clk controller in DT?

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Jongsung Kim]

On 2016년 07월 02일 09:20, Stephen Boyd wrote:
> On 06/29, Jongsung Kim wrote:
>> On 2016년 06월 29일 06:18, Michael Turquette wrote:
>>> Quoting Rob Herring (2016-06-28 13:55:18)
>>>> On Fri, Jun 24, 2016 at 01:12:52PM +0900, Jongsung Kim wrote:
>>>>> There is no way to set additional flags for a DT-initialized fixed-
>>>>> factor-clock, and it can be problematic i.e., when the clock rate
>>>>> needs to be changed. [1][2]
>>>>>
>>>>> This patch introduces an optional dt-binding named "clock-flags" to
>>>>> be used for passing any needed flags from dts.
>>>> I don't think we want this in DT. If we did, the flags would need some 
>>>> documentation about what the flags mean.
>>> Flags are specific to Linux implementation, so I agree with Rob. Better
>>> to create a compatible string for your hardware that bakes in the flags.
>> Thank you for your comment, Mike. This conversation starts from lacking method to set CLK_SET_RATE_PARENT from DT. I understand compatible string can be a solution. But.. if someone starts talking about lacking method to set another flag, i.e., CLK_SET_PARENT_GATE, then we'll need another compatible string list.
>> How do you think about defining possible required subset of the flags and using some more neutral flag-names acceptable in DT?
> Do you actually have an IC on the board that is doing some fixed
> factor calculation? Or is this a clk driver design where we are
> listing out each piece of an SoC's clk controller in DT?
>
The SoC has several PLLs of identical design, and one of them is divided
to half and used for CPUs. The fixed-factor-clock represents the divider.

Re: [PATCH v2] clk: fixed-factor: add optional dt-binding clock-flags

[Stephen Boyd]

On 07/04, Jongsung Kim wrote:
> On 2016년 07월 02일 09:20, Stephen Boyd wrote:
> > Do you actually have an IC on the board that is doing some fixed
> > factor calculation? Or is this a clk driver design where we are
> > listing out each piece of an SoC's clk controller in DT?
> >
> The SoC has several PLLs of identical design, and one of them is divided
> to half and used for CPUs. The fixed-factor-clock represents the divider.
> 

Ok, so it sounds like we can have the driver that registers the
CPU PLL also register the fixed factor clk? I fail to see why we
need this from DT in that case.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project