[RESEND] CLK: ARC: Set initial pll output frequency specified in device tree

Message ID 20171114122020.9800-1-Eugeniy.Paltsev@synopsys.com
State New
Headers show
Series
  • [RESEND] CLK: ARC: Set initial pll output frequency specified in device tree
Related show

Commit Message

Eugeniy Paltsev Nov. 14, 2017, 12:20 p.m.
Add option to set initial output frequency of plls via
"clock-frequency" property in pll's device tree node.
This frequency will be set while pll driver probed.

The usage example is setting CPU clock frequency on boot
See discussion:
https://www.mail-archive.com/linux-snps-arc@lists.infradead.org/msg02689.html

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
---
 .../bindings/clock/snps,hsdk-pll-clock.txt         |  5 ++++
 .../devicetree/bindings/clock/snps,pll-clock.txt   |  5 ++++
 drivers/clk/axs10x/pll_clock.c                     | 34 ++++++++++++++++++++--
 drivers/clk/clk-hsdk-pll.c                         | 34 ++++++++++++++++++++--
 4 files changed, 74 insertions(+), 4 deletions(-)

Comments

Vladimir Zapolskiy Nov. 14, 2017, 5:01 p.m. | #1
On 11/14/2017 02:20 PM, Eugeniy Paltsev wrote:
> Add option to set initial output frequency of plls via
> "clock-frequency" property in pll's device tree node.
> This frequency will be set while pll driver probed.
> 
> The usage example is setting CPU clock frequency on boot
> See discussion:
> https://www.mail-archive.com/linux-snps-arc@lists.infradead.org/msg02689.html
> 
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> ---
>  .../bindings/clock/snps,hsdk-pll-clock.txt         |  5 ++++
>  .../devicetree/bindings/clock/snps,pll-clock.txt   |  5 ++++
>  drivers/clk/axs10x/pll_clock.c                     | 34 ++++++++++++++++++++--
>  drivers/clk/clk-hsdk-pll.c                         | 34 ++++++++++++++++++++--
>  4 files changed, 74 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
> index c56c755..5703059 100644
> --- a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
> +++ b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
> @@ -13,6 +13,10 @@ Required properties:
>  - clocks: shall be the input parent clock phandle for the PLL.
>  - #clock-cells: from common clock binding; Should always be set to 0.
>  
> +Optional properties:
> +- clock-frequency: output frequency generated by pll in Hz which will be set
> +while probing. Should be a single cell.
> +
>  Example:
>  	input_clk: input-clk {
>  		clock-frequency = <33333333>;
> @@ -25,4 +29,5 @@ Example:
>  		reg = <0x00 0x10>;
>  		#clock-cells = <0>;
>  		clocks = <&input_clk>;
> +		clock-frequency = <1000000000>;
>  	};
> diff --git a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
> index 11fe487..5908f99 100644
> --- a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
> +++ b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
> @@ -13,6 +13,10 @@ registers and second for corresponding LOCK CGU register.
>  - clocks: shall be the input parent clock phandle for the PLL.
>  - #clock-cells: from common clock binding; Should always be set to 0.
>  
> +Optional properties:
> +- clock-frequency: output frequency generated by pll in Hz which will be set
> +while probing. Should be a single cell.
> +
>  Example:
>  	input-clk: input-clk {
>  		clock-frequency = <33333333>;
> @@ -25,4 +29,5 @@ Example:
>  		reg = <0x80 0x10>, <0x100 0x10>;
>  		#clock-cells = <0>;
>  		clocks = <&input-clk>;
> +		clock-frequency = <100000000>;
>  	};

You may check Documentation/devicetree/bindings/clock/clock-bindings.txt
about how to assign initial clock rates, in general 'clock-frequency'
property is a property of clock consumers with two exceptions of simple
clock sources, namely it is used in fixed clock and PWM clock bindings.

--
With best wishes,
Vladimir
Alexey Brodkin Nov. 14, 2017, 9:19 p.m. | #2
Hi Vladimir,

On Tue, 2017-11-14 at 19:01 +0200, Vladimir Zapolskiy wrote:
> On 11/14/2017 02:20 PM, Eugeniy Paltsev wrote:

> > 

> > Add option to set initial output frequency of plls via

> > "clock-frequency" property in pll's device tree node.

> > This frequency will be set while pll driver probed.

> > 

> > The usage example is setting CPU clock frequency on boot

> > See discussion:

> > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mail-2Darchive.com_linux-2Dsnps-2Darc-40lists.infradead.org_msg02689.html&d=DwICAg&c=DPL6

> > _X_6JkXFx7AXWqB0tg&r=lqdeeSSEes0GFDDl656eViXO7breS55ytWkhpk5R81I&m=vTFoSv1E8NyQC8nqe6pwvuTDxGvEefhAdGwAoABOrY4&s=sbmMnczdKP317bN973cZn2WcYF29kVMLW

> > chYfhSGT2M&e=

> > 

> > Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>

> > ---

> >  .../bindings/clock/snps,hsdk-pll-clock.txt         |  5 ++++

> >  .../devicetree/bindings/clock/snps,pll-clock.txt   |  5 ++++

> >  drivers/clk/axs10x/pll_clock.c                     | 34 ++++++++++++++++++++--

> >  drivers/clk/clk-hsdk-pll.c                         | 34 ++++++++++++++++++++--

> >  4 files changed, 74 insertions(+), 4 deletions(-)

> > 

> > diff --git a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt

> > index c56c755..5703059 100644

> > --- a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt

> > +++ b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt

> > @@ -13,6 +13,10 @@ Required properties:

> >  - clocks: shall be the input parent clock phandle for the PLL.

> >  - #clock-cells: from common clock binding; Should always be set to 0.

> >  

> > +Optional properties:

> > +- clock-frequency: output frequency generated by pll in Hz which will be set

> > +while probing. Should be a single cell.

> > +

> >  Example:

> >  	input_clk: input-clk {

> >  		clock-frequency = <33333333>;

> > @@ -25,4 +29,5 @@ Example:

> >  		reg = <0x00 0x10>;

> >  		#clock-cells = <0>;

> >  		clocks = <&input_clk>;

> > +		clock-frequency = <1000000000>;

> >  	};

> > diff --git a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt

> > index 11fe487..5908f99 100644

> > --- a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt

> > +++ b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt

> > @@ -13,6 +13,10 @@ registers and second for corresponding LOCK CGU register.

> >  - clocks: shall be the input parent clock phandle for the PLL.

> >  - #clock-cells: from common clock binding; Should always be set to 0.

> >  

> > +Optional properties:

> > +- clock-frequency: output frequency generated by pll in Hz which will be set

> > +while probing. Should be a single cell.

> > +

> >  Example:

> >  	input-clk: input-clk {

> >  		clock-frequency = <33333333>;

> > @@ -25,4 +29,5 @@ Example:

> >  		reg = <0x80 0x10>, <0x100 0x10>;

> >  		#clock-cells = <0>;

> >  		clocks = <&input-clk>;

> > +		clock-frequency = <100000000>;

> >  	};

> 

> You may check Documentation/devicetree/bindings/clock/clock-bindings.txt

> about how to assign initial clock rates, in general 'clock-frequency'

> property is a property of clock consumers with two exceptions of simple

> clock sources, namely it is used in fixed clock and PWM clock bindings.


I think that's what we agreed on with Rob Herring back in the day.
Have you checked this post of him on the topic?
http://lists.infradead.org/pipermail/linux-snps-arc/2017-September/002909.html

Just FYI it all started from my question here:
http://lists.infradead.org/pipermail/linux-snps-arc/2017-September/002900.html

-Alexey
Stephen Boyd Nov. 14, 2017, 11:46 p.m. | #3
On 11/14, Alexey Brodkin wrote:
> Hi Vladimir,
> 
> On Tue, 2017-11-14 at 19:01 +0200, Vladimir Zapolskiy wrote:
> > On 11/14/2017 02:20 PM, Eugeniy Paltsev wrote:
> > > 
> > > Add option to set initial output frequency of plls via
> > > "clock-frequency" property in pll's device tree node.
> > > This frequency will be set while pll driver probed.
> > > 
> > > The usage example is setting CPU clock frequency on boot
> > > See discussion:
> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mail-2Darchive.com_linux-2Dsnps-2Darc-40lists.infradead.org_msg02689.html&d=DwICAg&c=DPL6
> > > _X_6JkXFx7AXWqB0tg&r=lqdeeSSEes0GFDDl656eViXO7breS55ytWkhpk5R81I&m=vTFoSv1E8NyQC8nqe6pwvuTDxGvEefhAdGwAoABOrY4&s=sbmMnczdKP317bN973cZn2WcYF29kVMLW
> > > chYfhSGT2M&e=
> > > 
> > > Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> > > ---
> > >  .../bindings/clock/snps,hsdk-pll-clock.txt         |  5 ++++
> > >  .../devicetree/bindings/clock/snps,pll-clock.txt   |  5 ++++
> > >  drivers/clk/axs10x/pll_clock.c                     | 34 ++++++++++++++++++++--
> > >  drivers/clk/clk-hsdk-pll.c                         | 34 ++++++++++++++++++++--
> > >  4 files changed, 74 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
> > > index c56c755..5703059 100644
> > > --- a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
> > > +++ b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
> > > @@ -13,6 +13,10 @@ Required properties:
> > >  - clocks: shall be the input parent clock phandle for the PLL.
> > >  - #clock-cells: from common clock binding; Should always be set to 0.
> > >  
> > > +Optional properties:
> > > +- clock-frequency: output frequency generated by pll in Hz which will be set
> > > +while probing. Should be a single cell.
> > > +
> > >  Example:
> > >  	input_clk: input-clk {
> > >  		clock-frequency = <33333333>;
> > > @@ -25,4 +29,5 @@ Example:
> > >  		reg = <0x00 0x10>;
> > >  		#clock-cells = <0>;
> > >  		clocks = <&input_clk>;
> > > +		clock-frequency = <1000000000>;
> > >  	};
> > > diff --git a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
> > > index 11fe487..5908f99 100644
> > > --- a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
> > > +++ b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
> > > @@ -13,6 +13,10 @@ registers and second for corresponding LOCK CGU register.
> > >  - clocks: shall be the input parent clock phandle for the PLL.
> > >  - #clock-cells: from common clock binding; Should always be set to 0.
> > >  
> > > +Optional properties:
> > > +- clock-frequency: output frequency generated by pll in Hz which will be set
> > > +while probing. Should be a single cell.
> > > +
> > >  Example:
> > >  	input-clk: input-clk {
> > >  		clock-frequency = <33333333>;
> > > @@ -25,4 +29,5 @@ Example:
> > >  		reg = <0x80 0x10>, <0x100 0x10>;
> > >  		#clock-cells = <0>;
> > >  		clocks = <&input-clk>;
> > > +		clock-frequency = <100000000>;
> > >  	};
> > 
> > You may check Documentation/devicetree/bindings/clock/clock-bindings.txt
> > about how to assign initial clock rates, in general 'clock-frequency'
> > property is a property of clock consumers with two exceptions of simple
> > clock sources, namely it is used in fixed clock and PWM clock bindings.
> 
> I think that's what we agreed on with Rob Herring back in the day.
> Have you checked this post of him on the topic?
> http://lists.infradead.org/pipermail/linux-snps-arc/2017-September/002909.html
> 
> Just FYI it all started from my question here:
> http://lists.infradead.org/pipermail/linux-snps-arc/2017-September/002900.html

Why can't we use assigned-clock-rates? That would basically call
clk_set_rate() on the clk once it's added.

Patch

diff --git a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
index c56c755..5703059 100644
--- a/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
+++ b/Documentation/devicetree/bindings/clock/snps,hsdk-pll-clock.txt
@@ -13,6 +13,10 @@  Required properties:
 - clocks: shall be the input parent clock phandle for the PLL.
 - #clock-cells: from common clock binding; Should always be set to 0.
 
+Optional properties:
+- clock-frequency: output frequency generated by pll in Hz which will be set
+while probing. Should be a single cell.
+
 Example:
 	input_clk: input-clk {
 		clock-frequency = <33333333>;
@@ -25,4 +29,5 @@  Example:
 		reg = <0x00 0x10>;
 		#clock-cells = <0>;
 		clocks = <&input_clk>;
+		clock-frequency = <1000000000>;
 	};
diff --git a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
index 11fe487..5908f99 100644
--- a/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
+++ b/Documentation/devicetree/bindings/clock/snps,pll-clock.txt
@@ -13,6 +13,10 @@  registers and second for corresponding LOCK CGU register.
 - clocks: shall be the input parent clock phandle for the PLL.
 - #clock-cells: from common clock binding; Should always be set to 0.
 
+Optional properties:
+- clock-frequency: output frequency generated by pll in Hz which will be set
+while probing. Should be a single cell.
+
 Example:
 	input-clk: input-clk {
 		clock-frequency = <33333333>;
@@ -25,4 +29,5 @@  Example:
 		reg = <0x80 0x10>, <0x100 0x10>;
 		#clock-cells = <0>;
 		clocks = <&input-clk>;
+		clock-frequency = <100000000>;
 	};
diff --git a/drivers/clk/axs10x/pll_clock.c b/drivers/clk/axs10x/pll_clock.c
index 25d8c24..3f4345d 100644
--- a/drivers/clk/axs10x/pll_clock.c
+++ b/drivers/clk/axs10x/pll_clock.c
@@ -11,6 +11,7 @@ 
 #include <linux/platform_device.h>
 #include <linux/module.h>
 #include <linux/clk-provider.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/device.h>
@@ -215,6 +216,25 @@  static const struct clk_ops axs10x_pll_ops = {
 	.set_rate = axs10x_pll_set_rate,
 };
 
+static void set_pll_rate_from_of(struct clk *clk, struct device_node *node)
+{
+	u32 requested_rate;
+
+	/* If we specify initial pll output frequency try to set it */
+	if (of_property_read_u32(node, "clock-frequency", &requested_rate))
+		return;
+
+	if (clk_prepare_enable(clk)) {
+		pr_err("Cannot enable %s clock.\n", node->name);
+		return;
+	}
+
+	if (clk_set_rate(clk, requested_rate))
+		pr_err("Cannot set %s clock rate.\n", node->name);
+
+	pr_debug("Set %s clock to %u\n", node->name, requested_rate);
+}
+
 static int axs10x_pll_clk_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -258,8 +278,15 @@  static int axs10x_pll_clk_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	return of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
-			&pll_clk->hw);
+	ret =  of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
+				      &pll_clk->hw);
+	if (ret)
+		return ret;
+
+	/* If we specify initial pll output frequency in dts try to set it */
+	set_pll_rate_from_of(pll_clk->hw.clk, dev->of_node);
+
+	return 0;
 }
 
 static int axs10x_pll_clk_remove(struct platform_device *pdev)
@@ -311,6 +338,9 @@  static void __init of_axs10x_pll_clk_setup(struct device_node *node)
 		goto err_unregister_clk;
 	}
 
+	/* If we specify initial pll output frequency in dts try to set it */
+	set_pll_rate_from_of(pll_clk->hw.clk, node);
+
 	return;
 
 err_unregister_clk:
diff --git a/drivers/clk/clk-hsdk-pll.c b/drivers/clk/clk-hsdk-pll.c
index bbf23717..74fd006 100644
--- a/drivers/clk/clk-hsdk-pll.c
+++ b/drivers/clk/clk-hsdk-pll.c
@@ -9,6 +9,7 @@ 
  */
 
 #include <linux/clk-provider.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -295,6 +296,25 @@  static const struct clk_ops hsdk_pll_ops = {
 	.set_rate = hsdk_pll_set_rate,
 };
 
+static void set_pll_rate_from_of(struct clk *clk, struct device_node *node)
+{
+	u32 requested_rate;
+
+	/* If we specify initial pll output frequency try to set it */
+	if (of_property_read_u32(node, "clock-frequency", &requested_rate))
+		return;
+
+	if (clk_prepare_enable(clk)) {
+		pr_err("Cannot enable %s clock.\n", node->name);
+		return;
+	}
+
+	if (clk_set_rate(clk, requested_rate))
+		pr_err("Cannot set %s clock rate.\n", node->name);
+
+	pr_debug("Set %s clock to %u\n", node->name, requested_rate);
+}
+
 static int hsdk_pll_clk_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -340,8 +360,15 @@  static int hsdk_pll_clk_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	return of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
-			&pll_clk->hw);
+	ret =  of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
+				      &pll_clk->hw);
+	if (ret)
+		return ret;
+
+	/* If we specify initial pll output frequency in dts try to set it */
+	set_pll_rate_from_of(pll_clk->hw.clk, dev->of_node);
+
+	return 0;
 }
 
 static int hsdk_pll_clk_remove(struct platform_device *pdev)
@@ -400,6 +427,9 @@  static void __init of_hsdk_pll_clk_setup(struct device_node *node)
 		goto err_unmap_spec_regs;
 	}
 
+	/* If we specify initial pll output frequency in dts try to set it */
+	set_pll_rate_from_of(pll_clk->hw.clk, node);
+
 	return;
 
 err_unmap_spec_regs: