[PATCH 0/3] mfd: syscon: Add optional clock support needed on stm32

[PATCH 0/3] mfd: syscon: Add optional clock support needed on stm32

[Fabrice Gasnier]

STM32 syscfg registers are accessed using syscon. It needs syscfg clock
to be enabled while accessing registers.
This adds support for optional clock on syscon, and the relevant clock
in stm32mp157 device tree.

Fabrice Gasnier (3):
  dt-bindings: mfd: syscon: Add optional clock support
  mfd: syscon: Add optional clock support
  ARM: dts: stm32: Add clock on stm32mp157c syscfg

 Documentation/devicetree/bindings/mfd/syscon.txt |  1 +
 arch/arm/boot/dts/stm32mp157c.dtsi               |  1 +
 drivers/mfd/syscon.c                             | 19 +++++++++++++++++++
 3 files changed, 21 insertions(+)

-- 
1.9.1

[PATCH 1/3] dt-bindings: mfd: syscon: Add optional clock support

[Fabrice Gasnier]

Some system control registers need to be clocked, so the registers can
be accessed. Add an optional clock.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 Documentation/devicetree/bindings/mfd/syscon.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
index 25d9e9c..a9aaa51 100644
--- a/Documentation/devicetree/bindings/mfd/syscon.txt
+++ b/Documentation/devicetree/bindings/mfd/syscon.txt
@@ -17,6 +17,7 @@ Optional property:
 - reg-io-width: the size (in bytes) of the IO accesses that should be
   performed on the device.
 - hwlocks: reference to a phandle of a hardware spinlock provider node.
+- clocks: phandle to the syscon clock
 
 Examples:
 gpr: iomuxc-gpr@20e0000 {
-- 
1.9.1

Re: [PATCH 1/3] dt-bindings: mfd: syscon: Add optional clock support

[Rob Herring]

On Tue, Nov 27, 2018 at 05:48:15PM +0100, Fabrice Gasnier wrote:
> Some system control registers need to be clocked, so the registers can
> be accessed. Add an optional clock.
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
> ---
>  Documentation/devicetree/bindings/mfd/syscon.txt | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
> index 25d9e9c..a9aaa51 100644
> --- a/Documentation/devicetree/bindings/mfd/syscon.txt
> +++ b/Documentation/devicetree/bindings/mfd/syscon.txt
> @@ -17,6 +17,7 @@ Optional property:
>  - reg-io-width: the size (in bytes) of the IO accesses that should be
>    performed on the device.
>  - hwlocks: reference to a phandle of a hardware spinlock provider node.
> +- clocks: phandle to the syscon clock

No. Add clocks to specific bindings using syscon. If you have a node 
with only 'syscon', then that should be fixed.

Rob

Re: [PATCH 1/3] dt-bindings: mfd: syscon: Add optional clock support

[Fabrice Gasnier]

On 12/11/18 11:16 PM, Rob Herring wrote:
> On Tue, Nov 27, 2018 at 05:48:15PM +0100, Fabrice Gasnier wrote:
>> Some system control registers need to be clocked, so the registers can
>> be accessed. Add an optional clock.
>>
>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
>> ---
>>  Documentation/devicetree/bindings/mfd/syscon.txt | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
>> index 25d9e9c..a9aaa51 100644
>> --- a/Documentation/devicetree/bindings/mfd/syscon.txt
>> +++ b/Documentation/devicetree/bindings/mfd/syscon.txt
>> @@ -17,6 +17,7 @@ Optional property:
>>  - reg-io-width: the size (in bytes) of the IO accesses that should be
>>    performed on the device.
>>  - hwlocks: reference to a phandle of a hardware spinlock provider node.
>> +- clocks: phandle to the syscon clock
> 
> No. Add clocks to specific bindings using syscon. If you have a node 
> with only 'syscon', then that should be fixed.

Hi Rob,

Thanks for reviewing, so I'll
- add it to Documentation/devicetree/bindings/arm/stm32/stm32-syscon.txt
- send a v2 with this change.

Best regards,
Fabrice
> 
> Rob
> 

[PATCH 2/3] mfd: syscon: Add optional clock support

[Fabrice Gasnier]

Some system control registers need to be clocked, so the registers can
be accessed. Add an optional clock and attach it to regmap.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 drivers/mfd/syscon.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index b6d05cd..a0ba4ff 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -12,6 +12,7 @@
  * (at your option) any later version.
  */
 
+#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/hwspinlock.h>
 #include <linux/io.h>
@@ -45,6 +46,7 @@ struct syscon {
 
 static struct syscon *of_syscon_register(struct device_node *np)
 {
+	struct clk *clk;
 	struct syscon *syscon;
 	struct regmap *regmap;
 	void __iomem *base;
@@ -119,6 +121,18 @@ static struct syscon *of_syscon_register(struct device_node *np)
 		goto err_regmap;
 	}
 
+	clk = of_clk_get(np, 0);
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		/* clock is optional */
+		if (ret != -ENOENT)
+			goto err_clk;
+	} else {
+		ret = regmap_mmio_attach_clk(regmap, clk);
+		if (ret)
+			goto err_attach;
+	}
+
 	syscon->regmap = regmap;
 	syscon->np = np;
 
@@ -128,6 +142,11 @@ static struct syscon *of_syscon_register(struct device_node *np)
 
 	return syscon;
 
+err_attach:
+	if (!IS_ERR(clk))
+		clk_put(clk);
+err_clk:
+	regmap_exit(regmap);
 err_regmap:
 	iounmap(base);
 err_map:
-- 
1.9.1

[PATCH 3/3] ARM: dts: stm32: Add clock on stm32mp157c syscfg

[Fabrice Gasnier]

STM32 syscfg needs a clock to access registers.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 arch/arm/boot/dts/stm32mp157c.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/stm32mp157c.dtsi b/arch/arm/boot/dts/stm32mp157c.dtsi
index 8bf1c17..61b2a70 100644
--- a/arch/arm/boot/dts/stm32mp157c.dtsi
+++ b/arch/arm/boot/dts/stm32mp157c.dtsi
@@ -820,6 +820,7 @@
 		syscfg: syscon@50020000 {
 			compatible = "st,stm32mp157-syscfg", "syscon";
 			reg = <0x50020000 0x400>;
+			clocks = <&rcc SYSCFG>;
 		};
 
 		lptimer2: timer@50021000 {
-- 
1.9.1