[PATCH v2 1/3] clk: meson-gxbb: expose clock CLKID_RNG0

[PATCH v2 1/3] clk: meson-gxbb: expose clock CLKID_RNG0

[Heiner Kallweit]

Expose clock CLKID_RNG0 which is needed for the HW random number generator.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- added clk and DT maintainers
- split exposing the clock and using it in DT into two patches
- comment out clock definition in drivers/clk/meson/gxbb.h
- silently move CLKID_SPI to the right place
---
 drivers/clk/meson/gxbb.h              | 2 +-
 include/dt-bindings/clock/gxbb-clkc.h | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/meson/gxbb.h b/drivers/clk/meson/gxbb.h
index 8ee2022c..cbd62e46 100644
--- a/drivers/clk/meson/gxbb.h
+++ b/drivers/clk/meson/gxbb.h
@@ -193,7 +193,7 @@
 /* CLKID_I2C */
 /* #define CLKID_SAR_ADC */
 #define CLKID_SMART_CARD	  24
-#define CLKID_RNG0		  25
+/* CLKID_RNG0 */
 #define CLKID_UART0		  26
 #define CLKID_SDHC		  27
 #define CLKID_STREAM		  28
diff --git a/include/dt-bindings/clock/gxbb-clkc.h b/include/dt-bindings/clock/gxbb-clkc.h
index 692846c7..63f4c2c4 100644
--- a/include/dt-bindings/clock/gxbb-clkc.h
+++ b/include/dt-bindings/clock/gxbb-clkc.h
@@ -12,9 +12,10 @@
 #define CLKID_FCLK_DIV4		6
 #define CLKID_CLK81		12
 #define CLKID_MPLL2		15
-#define CLKID_SPI		34
 #define CLKID_I2C		22
 #define CLKID_SAR_ADC		23
+#define CLKID_RNG0		25
+#define CLKID_SPI		34
 #define CLKID_ETH		36
 #define CLKID_USB0		50
 #define CLKID_USB1		51
-- 
2.11.1

[PATCH v2 2/3] ARM64: dts: meson-gx: add clock CLKID_RNG0 to hwrng node

[Heiner Kallweit]

Add clock CLKID_RNG0 to HW randon number generator node and
extend the DT binding documentation accordingly.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- splitted first version of patch into two
- add DT binding documentation
- mention that clock is optional
- replace spaces with tabs in DT binding example
---
 Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt | 8 ++++++--
 arch/arm64/boot/dts/amlogic/meson-gx.dtsi                   | 2 +-
 arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi                 | 5 +++++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt b/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt
index 202f2d09..4c012a04 100644
--- a/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt
+++ b/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt
@@ -5,10 +5,14 @@ Required properties:
 
 - compatible : should be "amlogic,meson-rng"
 - reg : Specifies base physical address and size of the registers.
+- clocks : Optional core clock
+- clock-names: Name of core clock, must be "core"
 
 Example:
 
 rng {
-        compatible = "amlogic,meson-rng";
-        reg = <0x0 0xc8834000 0x0 0x4>;
+	compatible = "amlogic,meson-rng";
+	reg = <0x0 0xc8834000 0x0 0x4>;
+	clocks = <&clkc CLKID_RNG0>;
+	clock-names = "core";
 };
diff --git a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
index 5d995f77..620495a4 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
@@ -380,7 +380,7 @@
 			#size-cells = <2>;
 			ranges = <0x0 0x0 0x0 0xc8834000 0x0 0x2000>;
 
-			rng {
+			hwrng: rng {
 				compatible = "amlogic,meson-rng";
 				reg = <0x0 0x0 0x0 0x4>;
 			};
diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
index 04b3324b..a375cb21 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
@@ -524,3 +524,8 @@
 &vpu {
 	compatible = "amlogic,meson-gxbb-vpu", "amlogic,meson-gx-vpu";
 };
+
+&hwrng {
+	clocks = <&clkc CLKID_RNG0>;
+	clock-names = "core";
+};
-- 
2.11.1

[PATCH v2 3/3] hwrng: meson: add clock handling to driver

[Heiner Kallweit]

Add handling of RNG0 clock to the driver.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- consider that clock is optional
- use managed call to clk_disable_unprepare to ensure that
  cleaning up is done in the right order if driver is removed
---
 drivers/char/hw_random/meson-rng.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
index 119d6984..2e23be80 100644
--- a/drivers/char/hw_random/meson-rng.c
+++ b/drivers/char/hw_random/meson-rng.c
@@ -62,6 +62,7 @@
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/of.h>
+#include <linux/clk.h>
 
 #define RNG_DATA 0x00
 
@@ -69,6 +70,7 @@ struct meson_rng_data {
 	void __iomem *base;
 	struct platform_device *pdev;
 	struct hwrng rng;
+	struct clk *core_clk;
 };
 
 static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -81,11 +83,17 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 	return sizeof(u32);
 }
 
+static void meson_rng_clk_disable(void *clk)
+{
+	clk_disable_unprepare(clk);
+}
+
 static int meson_rng_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct meson_rng_data *data;
 	struct resource *res;
+	int ret;
 
 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -98,6 +106,20 @@ static int meson_rng_probe(struct platform_device *pdev)
 	if (IS_ERR(data->base))
 		return PTR_ERR(data->base);
 
+	data->core_clk = devm_clk_get(dev, "core");
+	if (IS_ERR(data->core_clk))
+		data->core_clk = NULL;
+
+	if (data->core_clk) {
+		ret = clk_prepare_enable(data->core_clk);
+		if (ret)
+			return ret;
+		ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
+					       data->core_clk);
+		if (ret)
+			return ret;
+	}
+
 	data->rng.name = pdev->name;
 	data->rng.read = meson_rng_read;
 
-- 
2.11.1

Re: [PATCH v2 2/3] ARM64: dts: meson-gx: add clock CLKID_RNG0 to hwrng node

[Neil Armstrong]

On 02/21/2017 12:18 PM, Heiner Kallweit wrote:
> Add clock CLKID_RNG0 to HW randon number generator node and
> extend the DT binding documentation accordingly.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> v2:
> - splitted first version of patch into two
> - add DT binding documentation

Hi Heiner,

Can you move the dt-bindings to a separate patch ?

> - mention that clock is optional
> - replace spaces with tabs in DT binding example
> ---
>  Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt | 8 ++++++--
>  arch/arm64/boot/dts/amlogic/meson-gx.dtsi                   | 2 +-
>  arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi                 | 5 +++++
>  3 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt b/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt
> index 202f2d09..4c012a04 100644
> --- a/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt
> +++ b/Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt
> @@ -5,10 +5,14 @@ Required properties:
>  
>  - compatible : should be "amlogic,meson-rng"
>  - reg : Specifies base physical address and size of the registers.
> +- clocks : Optional core clock
> +- clock-names: Name of core clock, must be "core"

Please put these in a separate "Optional Properties" :

Optional Properties:
- clocks : phandle to the following named clocks
- clock-names: Name of core clock, must be "core"

>  
>  Example:
>  
>  rng {
> -        compatible = "amlogic,meson-rng";
> -        reg = <0x0 0xc8834000 0x0 0x4>;
> +	compatible = "amlogic,meson-rng";
> +	reg = <0x0 0xc8834000 0x0 0x4>;
> +	clocks = <&clkc CLKID_RNG0>;
> +	clock-names = "core";
>  };
> diff --git a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
> index 5d995f77..620495a4 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
> @@ -380,7 +380,7 @@
>  			#size-cells = <2>;
>  			ranges = <0x0 0x0 0x0 0xc8834000 0x0 0x2000>;
>  
> -			rng {
> +			hwrng: rng {
>  				compatible = "amlogic,meson-rng";
>  				reg = <0x0 0x0 0x0 0x4>;
>  			};
> diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
> index 04b3324b..a375cb21 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
> @@ -524,3 +524,8 @@
>  &vpu {
>  	compatible = "amlogic,meson-gxbb-vpu", "amlogic,meson-gx-vpu";
>  };
> +
> +&hwrng {
> +	clocks = <&clkc CLKID_RNG0>;
> +	clock-names = "core";
> +};
> 

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Re: [PATCH v2 3/3] hwrng: meson: add clock handling to driver

[Neil Armstrong]

On 02/21/2017 12:26 PM, Heiner Kallweit wrote:
> Add handling of RNG0 clock to the driver.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> v2:
> - consider that clock is optional
> - use managed call to clk_disable_unprepare to ensure that
>   cleaning up is done in the right order if driver is removed
> ---
>  drivers/char/hw_random/meson-rng.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
> index 119d6984..2e23be80 100644
> --- a/drivers/char/hw_random/meson-rng.c
> +++ b/drivers/char/hw_random/meson-rng.c
> @@ -62,6 +62,7 @@
>  #include <linux/slab.h>
>  #include <linux/types.h>
>  #include <linux/of.h>
> +#include <linux/clk.h>
>  
>  #define RNG_DATA 0x00
>  
> @@ -69,6 +70,7 @@ struct meson_rng_data {
>  	void __iomem *base;
>  	struct platform_device *pdev;
>  	struct hwrng rng;
> +	struct clk *core_clk;
>  };
>  
>  static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
> @@ -81,11 +83,17 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
>  	return sizeof(u32);
>  }
>  
> +static void meson_rng_clk_disable(void *clk)
> +{
> +	clk_disable_unprepare(clk);
> +}
> +
>  static int meson_rng_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct meson_rng_data *data;
>  	struct resource *res;
> +	int ret;
>  
>  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
> @@ -98,6 +106,20 @@ static int meson_rng_probe(struct platform_device *pdev)
>  	if (IS_ERR(data->base))
>  		return PTR_ERR(data->base);
>  
> +	data->core_clk = devm_clk_get(dev, "core");
> +	if (IS_ERR(data->core_clk))
> +		data->core_clk = NULL;
> +
> +	if (data->core_clk) {

This "if" is useless, if core_clk is NULL, this will work also.

> +		ret = clk_prepare_enable(data->core_clk);
> +		if (ret)
> +			return ret;
> +		ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
> +					       data->core_clk);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	data->rng.name = pdev->name;
>  	data->rng.read = meson_rng_read;
>  
> 

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Re: [PATCH v2 3/3] hwrng: meson: add clock handling to driver

[Heiner Kallweit]

Am 21.02.2017 um 22:21 schrieb Neil Armstrong:
> On 02/21/2017 12:26 PM, Heiner Kallweit wrote:
>> Add handling of RNG0 clock to the driver.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
>> v2:
>> - consider that clock is optional
>> - use managed call to clk_disable_unprepare to ensure that
>>   cleaning up is done in the right order if driver is removed
>> ---
>>  drivers/char/hw_random/meson-rng.c | 22 ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>>
>> diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
>> index 119d6984..2e23be80 100644
>> --- a/drivers/char/hw_random/meson-rng.c
>> +++ b/drivers/char/hw_random/meson-rng.c
>> @@ -62,6 +62,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/types.h>
>>  #include <linux/of.h>
>> +#include <linux/clk.h>
>>  
>>  #define RNG_DATA 0x00
>>  
>> @@ -69,6 +70,7 @@ struct meson_rng_data {
>>  	void __iomem *base;
>>  	struct platform_device *pdev;
>>  	struct hwrng rng;
>> +	struct clk *core_clk;
>>  };
>>  
>>  static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
>> @@ -81,11 +83,17 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
>>  	return sizeof(u32);
>>  }
>>  
>> +static void meson_rng_clk_disable(void *clk)
>> +{
>> +	clk_disable_unprepare(clk);
>> +}
>> +
>>  static int meson_rng_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>>  	struct meson_rng_data *data;
>>  	struct resource *res;
>> +	int ret;
>>  
>>  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>>  	if (!data)
>> @@ -98,6 +106,20 @@ static int meson_rng_probe(struct platform_device *pdev)
>>  	if (IS_ERR(data->base))
>>  		return PTR_ERR(data->base);
>>  
>> +	data->core_clk = devm_clk_get(dev, "core");
>> +	if (IS_ERR(data->core_clk))
>> +		data->core_clk = NULL;
>> +
>> +	if (data->core_clk) {
> 
> This "if" is useless, if core_clk is NULL, this will work also.
> 
Regarding clk_prepare_enable you're right. However we need this "if" for
the call to devm_add_action_or_reset because we can't provide a NULL
pointer as data argument.
And including clk_prepare_enable in the if clause creates no overhead
and is clearer IMHO.

>> +		ret = clk_prepare_enable(data->core_clk);
>> +		if (ret)
>> +			return ret;
>> +		ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
>> +					       data->core_clk);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>>  	data->rng.name = pdev->name;
>>  	data->rng.read = meson_rng_read;
>>  
>>
> 
> 

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Re: [PATCH v2 2/3] ARM64: dts: meson-gx: add clock CLKID_RNG0 to hwrng node

[Rob Herring]

On Tue, Feb 21, 2017 at 09:18:16PM +0100, Heiner Kallweit wrote:
> Add clock CLKID_RNG0 to HW randon number generator node and
> extend the DT binding documentation accordingly.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - splitted first version of patch into two
> - add DT binding documentation
> - mention that clock is optional
> - replace spaces with tabs in DT binding example
> ---
>  Documentation/devicetree/bindings/rng/amlogic,meson-rng.txt | 8 ++++++--
>  arch/arm64/boot/dts/amlogic/meson-gx.dtsi                   | 2 +-
>  arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi                 | 5 +++++
>  3 files changed, 12 insertions(+), 3 deletions(-)

Acked-by: Rob Herring <robh@kernel.org>