[PATCH 0/3] Add new binding regulator-fixed-clock to regulator-fixed

[PATCH 0/3] Add new binding regulator-fixed-clock to regulator-fixed

[Philippe Schenker]

Our hardware has a FET that is switching power rail of the ethernet PHY
on and off. This switching enable signal is a clock from the SoC.

There is no possibility in regulator subsystem to have this hardware
reflected in software.

I already discussed with Mark Brown about possible solutions and he
suggested to create at least a new compatible. [1]
This discussion includes also a better explanation of our circuit as
well as schematics. So please refer to that link if you have questions
about that.

In this first attempt I created a new binding "regulator-fixed-clock"
that can take a clock from devicetree. This is a simple addition to
regulator-fixed. If the binding regulator-fixed-clock is given, the
clock is simply enabled on regulator enable and disabled on regulator
disable.
To be able to have multiple consumers a counter variable is also given
that tells how many consumers need power from this regulator.

Best regards,
Philippe

[1] https://lkml.org/lkml/2019/8/7/78



Philippe Schenker (3):
  regulator: fixed: add possibility to enable by clock
  ARM: dts: imx6ull-colibri: add phy-supply and respective regulator
  dt-bindings: regulator: add regulator-fixed-clock binding

 .../bindings/regulator/fixed-regulator.yaml   | 18 +++-
 arch/arm/boot/dts/imx6ull-colibri.dtsi        | 12 +++
 drivers/regulator/fixed.c                     | 86 ++++++++++++++++++-
 3 files changed, 112 insertions(+), 4 deletions(-)

-- 
2.23.0

[PATCH 1/3] regulator: fixed: add possibility to enable by clock

[Philippe Schenker]

This commit adds the possibility to choose the compatible
"regulator-fixed-clock" in devicetree.

This is a special regulator-fixed that has to have a clock, from which
the regulator gets switched on and off.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
---

 drivers/regulator/fixed.c | 86 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 83 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
index 999547dde99d..eadeca9a1a6c 100644
--- a/drivers/regulator/fixed.c
+++ b/drivers/regulator/fixed.c
@@ -23,14 +23,66 @@
 #include <linux/gpio/consumer.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/regulator/machine.h>
+#include <linux/clk.h>
+
 
 struct fixed_voltage_data {
 	struct regulator_desc desc;
 	struct regulator_dev *dev;
+
+	struct clk *enable_clock;
+	unsigned int clk_enable_counter;
+};
+
+struct fixed_dev_type {
+	bool has_enable_clock;
+};
+
+static const struct fixed_dev_type fixed_voltage_data = {
+	.has_enable_clock = false,
 };
 
+static const struct fixed_dev_type fixed_clkenable_data = {
+	.has_enable_clock = true,
+};
+
+static int reg_clock_enable(struct regulator_dev *rdev)
+{
+	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
+	int ret = 0;
+
+	ret = clk_prepare_enable(priv->enable_clock);
+	if (ret)
+		return ret;
+
+	priv->clk_enable_counter++;
+
+	return ret;
+}
+
+static int reg_clock_disable(struct regulator_dev *rdev)
+{
+	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
+
+	clk_disable_unprepare(priv->enable_clock);
+	priv->clk_enable_counter--;
+
+	return 0;
+}
+
+static int reg_clock_is_enabled(struct regulator_dev *rdev)
+{
+	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
+
+	if (priv->clk_enable_counter > 0)
+		return 1;
+
+	return 0;
+}
+
 
 /**
  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
@@ -84,10 +136,19 @@ of_get_fixed_voltage_config(struct device *dev,
 static struct regulator_ops fixed_voltage_ops = {
 };
 
+static struct regulator_ops fixed_voltage_clkenabled_ops = {
+	.enable = reg_clock_enable,
+	.disable = reg_clock_disable,
+	.is_enabled = reg_clock_is_enabled,
+};
+
 static int reg_fixed_voltage_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct fixed_voltage_config *config;
 	struct fixed_voltage_data *drvdata;
+	const struct fixed_dev_type *drvtype =
+		of_match_device(dev->driver->of_match_table, dev)->data;
 	struct regulator_config cfg = { };
 	enum gpiod_flags gflags;
 	int ret;
@@ -118,7 +179,18 @@ static int reg_fixed_voltage_probe(struct platform_device *pdev)
 	}
 	drvdata->desc.type = REGULATOR_VOLTAGE;
 	drvdata->desc.owner = THIS_MODULE;
-	drvdata->desc.ops = &fixed_voltage_ops;
+
+	if (drvtype->has_enable_clock) {
+		drvdata->desc.ops = &fixed_voltage_clkenabled_ops;
+
+		drvdata->enable_clock = devm_clk_get(dev, NULL);
+		if (IS_ERR(drvdata->enable_clock)) {
+			dev_err(dev, "Cant get enable-clock from devicetree\n");
+			return -ENOENT;
+		}
+	} else {
+		drvdata->desc.ops = &fixed_voltage_ops;
+	}
 
 	drvdata->desc.enable_time = config->startup_delay;
 
@@ -191,8 +263,16 @@ static int reg_fixed_voltage_probe(struct platform_device *pdev)
 
 #if defined(CONFIG_OF)
 static const struct of_device_id fixed_of_match[] = {
-	{ .compatible = "regulator-fixed", },
-	{},
+	{
+		.compatible = "regulator-fixed",
+		.data = &fixed_voltage_data,
+	},
+	{
+		.compatible = "regulator-fixed-clock",
+		.data = &fixed_clkenable_data,
+	},
+	{
+	},
 };
 MODULE_DEVICE_TABLE(of, fixed_of_match);
 #endif
-- 
2.23.0

Re: [PATCH 1/3] regulator: fixed: add possibility to enable by clock

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 768 bytes --]

On Tue, Sep 03, 2019 at 08:03:46AM +0000, Philippe Schenker wrote:
> This commit adds the possibility to choose the compatible
> "regulator-fixed-clock" in devicetree.
> 
> This is a special regulator-fixed that has to have a clock, from which
> the regulator gets switched on and off.

This seems conceptually fine.  Minor issues though:

> +static int reg_clock_is_enabled(struct regulator_dev *rdev)
> +{
> +	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
> +
> +	if (priv->clk_enable_counter > 0)
> +		return 1;
> +
> +	return 0;
> +}

This could just be return priv->clk_enable_counter > 0 - ideally the
clock API would let us query if the clock is enabled but that might be a
bit confused anyway given that it's possibly shared.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH 1/3] regulator: fixed: add possibility to enable by clock

[Philippe Schenker]

On Thu, 2019-09-05 at 19:06 +0100, Mark Brown wrote:
> On Tue, Sep 03, 2019 at 08:03:46AM +0000, Philippe Schenker wrote:
> > This commit adds the possibility to choose the compatible
> > "regulator-fixed-clock" in devicetree.
> > 
> > This is a special regulator-fixed that has to have a clock, from
> > which
> > the regulator gets switched on and off.
> 
> This seems conceptually fine.  Minor issues though:

Thanks for your comments and I'm glad you like it! I will send a v2
shortly, also with Rob's fixes in. Can I expect it to be pulled for 5.4?

Best regards,
Philippe

> 
> > +static int reg_clock_is_enabled(struct regulator_dev *rdev)
> > +{
> > +	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
> > +
> > +	if (priv->clk_enable_counter > 0)
> > +		return 1;
> > +
> > +	return 0;
> > +}
> 
> This could just be return priv->clk_enable_counter > 0 - ideally the
> clock API would let us query if the clock is enabled but that might be
> a
> bit confused anyway given that it's possibly shared.

Re: [PATCH 1/3] regulator: fixed: add possibility to enable by clock

[Philippe Schenker]

On Tue, 2019-09-10 at 06:08 +0000, Philippe Schenker wrote:
> On Thu, 2019-09-05 at 19:06 +0100, Mark Brown wrote:
> > On Tue, Sep 03, 2019 at 08:03:46AM +0000, Philippe Schenker wrote:
> > > This commit adds the possibility to choose the compatible
> > > "regulator-fixed-clock" in devicetree.
> > > 
> > > This is a special regulator-fixed that has to have a clock, from
> > > which
> > > the regulator gets switched on and off.
> > 
> > This seems conceptually fine.  Minor issues though:
> 
> Thanks for your comments and I'm glad you like it! I will send a v2
> shortly, also with Rob's fixes in. Can I expect it to be pulled for
> 5.4?

I meant 5.5 of course.

> 
> Best regards,
> Philippe
> 
> > > +static int reg_clock_is_enabled(struct regulator_dev *rdev)
> > > +{
> > > +	struct fixed_voltage_data *priv = rdev_get_drvdata(rdev);
> > > +
> > > +	if (priv->clk_enable_counter > 0)
> > > +		return 1;
> > > +
> > > +	return 0;
> > > +}
> > 
> > This could just be return priv->clk_enable_counter > 0 - ideally the
> > clock API would let us query if the clock is enabled but that might
> > be
> > a
> > bit confused anyway given that it's possibly shared.

[PATCH 2/3] ARM: dts: imx6ull-colibri: add phy-supply and respective regulator

[Philippe Schenker]

This adds regulator-fixed-clock, a fixed-regulator that turns on and
off with a clock and add it to the phy.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
---

 arch/arm/boot/dts/imx6ull-colibri.dtsi | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/boot/dts/imx6ull-colibri.dtsi b/arch/arm/boot/dts/imx6ull-colibri.dtsi
index d56728f03c35..76021b842a97 100644
--- a/arch/arm/boot/dts/imx6ull-colibri.dtsi
+++ b/arch/arm/boot/dts/imx6ull-colibri.dtsi
@@ -47,6 +47,17 @@
 		states = <1800000 0x1 3300000 0x0>;
 		vin-supply = <&reg_module_3v3>;
 	};
+
+	reg_eth_phy: regulator-eth-phy {
+		compatible = "regulator-fixed-clock";
+		regulator-boot-on;
+		regulator-name = "eth_phy";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		clocks = <&clks IMX6UL_CLK_ENET2_REF_125M>;
+		startup-delay-us = <150000>;
+		vin-supply = <&reg_module_3v3>;
+	};
 };
 
 &adc1 {
@@ -66,6 +77,7 @@
 	pinctrl-0 = <&pinctrl_enet2>;
 	phy-mode = "rmii";
 	phy-handle = <&ethphy1>;
+	phy-supply = <&reg_eth_phy>;
 	status = "okay";
 
 	mdio {
-- 
2.23.0

[PATCH 3/3] dt-bindings: regulator: add regulator-fixed-clock binding

[Philippe Schenker]

This adds the documentation to the compatible regulator-fixed-clock

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>

---

 .../bindings/regulator/fixed-regulator.yaml    | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
index a650b457085d..5fd081e80b43 100644
--- a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
+++ b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
@@ -19,9 +19,19 @@ description:
 allOf:
   - $ref: "regulator.yaml#"
 
+select:
+  properties:
+    compatible:
+      contains:
+        const: regulator-fixed-clock
+  required:
+    - clocks
+
 properties:
   compatible:
-    const: regulator-fixed
+    items:
+      - const: regulator-fixed
+      - const: regulator-fixed-clock
 
   regulator-name: true
 
@@ -29,6 +39,12 @@ properties:
     description: gpio to use for enable control
     maxItems: 1
 
+  clocks:
+    description:
+      clock to use for enable control. This binding is only available if
+      the compatible is chosen to regulator-fixed-clock. The clock binding
+      is mandatory if compatible is chosen to regulator-fixed-clock.
+
   startup-delay-us:
     description: startup time in microseconds
     $ref: /schemas/types.yaml#/definitions/uint32
-- 
2.23.0

Re: [PATCH 3/3] dt-bindings: regulator: add regulator-fixed-clock binding

[Rob Herring]

On Tue, Sep 3, 2019 at 9:03 AM Philippe Schenker
<philippe.schenker@toradex.com> wrote:
>
> This adds the documentation to the compatible regulator-fixed-clock

Please explain what that is in this patch.

>
> Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
>
> ---
>
>  .../bindings/regulator/fixed-regulator.yaml    | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
> index a650b457085d..5fd081e80b43 100644
> --- a/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
> +++ b/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml
> @@ -19,9 +19,19 @@ description:
>  allOf:
>    - $ref: "regulator.yaml#"
>
> +select:
> +  properties:
> +    compatible:
> +      contains:
> +        const: regulator-fixed-clock
> +  required:
> +    - clocks

You don't need this.

If you add a new compatible, then this should probably be a new schema
doc. Is the 'gpio' property valid in this case as if a clock is the
enable, can you also have a gpio enable? That said, it seems like the
new compatible is only for validating the DT in the driver. You could
just use a clock if present and default to current behavior if not.
It's not the kernel's job to validate DTs.

>
>  properties:
>    compatible:
> -    const: regulator-fixed
> +    items:
> +      - const: regulator-fixed
> +      - const: regulator-fixed-clock

This says you must have 'compatible = "regulator-fixed",
"regulator-fixed-clock";'.

What you want is:

enum:
  - regulator-fixed
  - regulator-fixed-clock

>    regulator-name: true
>
> @@ -29,6 +39,12 @@ properties:
>      description: gpio to use for enable control
>      maxItems: 1
>
> +  clocks:
> +    description:
> +      clock to use for enable control. This binding is only available if
> +      the compatible is chosen to regulator-fixed-clock. The clock binding
> +      is mandatory if compatible is chosen to regulator-fixed-clock.

Need to define how many clocks (maxItems: 1).

> +
>    startup-delay-us:
>      description: startup time in microseconds
>      $ref: /schemas/types.yaml#/definitions/uint32
> --
> 2.23.0
>

Re: [PATCH 3/3] dt-bindings: regulator: add regulator-fixed-clock binding

[Philippe Schenker]

On Tue, 2019-09-03 at 09:45 +0100, Rob Herring wrote:
> On Tue, Sep 3, 2019 at 9:03 AM Philippe Schenker
> <philippe.schenker@toradex.com> wrote:
> > This adds the documentation to the compatible regulator-fixed-clock
> 
> Please explain what that is in this patch.

Hi Rob and thanks for your comments. I will change this commit message
for a possible v2 into this:

This adds the documentation to the compatible regulator-fixed-clock.
This binding is a special binding of regulator-fixed and adds the
ability to add a clock to regulator-fixed, so the regulator can be
enabled and disabled with that clock.
If the special compatible regulator-fixed-clock is used it is mandatory
to supply a clock.

> > 
> 
> > Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
> > 
> > ---
> > 
> >  .../bindings/regulator/fixed-regulator.yaml    | 18
> > +++++++++++++++++-
> >  1 file changed, 17 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/regulator/fixed-
> > regulator.yaml b/Documentation/devicetree/bindings/regulator/fixed-
> > regulator.yaml
> > index a650b457085d..5fd081e80b43 100644
> > --- a/Documentation/devicetree/bindings/regulator/fixed-
> > regulator.yaml
> > +++ b/Documentation/devicetree/bindings/regulator/fixed-
> > regulator.yaml
> > @@ -19,9 +19,19 @@ description:
> >  allOf:
> >    - $ref: "regulator.yaml#"
> > 
> > +select:
> > +  properties:
> > +    compatible:
> > +      contains:
> > +        const: regulator-fixed-clock
> > +  required:
> > +    - clocks
> 
> You don't need this.
> 
> If you add a new compatible, then this should probably be a new schema
> doc. Is the 'gpio' property valid in this case as if a clock is the
> enable, can you also have a gpio enable? That said, it seems like the
> new compatible is only for validating the DT in the driver. You could
> just use a clock if present and default to current behavior if not.
> It's not the kernel's job to validate DTs.

The gpio property is valid with this compatible. I added regulator-
fixed-clock to regulator-fixed hence I also don't want to create a new
schema file.

With the above select statement I wanted to state clocks as required
when the compatible regulator-fixed-clock is given.

> 
> >  properties:
> >    compatible:
> > -    const: regulator-fixed
> > +    items:
> > +      - const: regulator-fixed
> > +      - const: regulator-fixed-clock
> 
> This says you must have 'compatible = "regulator-fixed",
> "regulator-fixed-clock";'.
> 
> What you want is:
> 
> enum:
>   - regulator-fixed
>   - regulator-fixed-clock

Thanks, this was exactly what I wanted to do.

> 
> >    regulator-name: true
> > 
> > @@ -29,6 +39,12 @@ properties:
> >      description: gpio to use for enable control
> >      maxItems: 1
> > 
> > +  clocks:
> > +    description:
> > +      clock to use for enable control. This binding is only
> > available if
> > +      the compatible is chosen to regulator-fixed-clock. The clock
> > binding
> > +      is mandatory if compatible is chosen to regulator-fixed-
> > clock.
> 
> Need to define how many clocks (maxItems: 1).

Will do for a possible v2. I want to wait what Mark Brown says about the
addition in general, maybe I have to change all over how this speciality
is added into regulator subsystem and therefore also the binding will
change.

Philippe
> 
> > +
> >    startup-delay-us:
> >      description: startup time in microseconds
> >      $ref: /schemas/types.yaml#/definitions/uint32
> > --
> > 2.23.0
> > 

Re: [PATCH 3/3] dt-bindings: regulator: add regulator-fixed-clock binding

[Rob Herring]

On Wed, Sep 4, 2019 at 9:07 AM Philippe Schenker
<philippe.schenker@toradex.com> wrote:
>
> On Tue, 2019-09-03 at 09:45 +0100, Rob Herring wrote:
> > On Tue, Sep 3, 2019 at 9:03 AM Philippe Schenker
> > <philippe.schenker@toradex.com> wrote:
> > > This adds the documentation to the compatible regulator-fixed-clock
> >
> > Please explain what that is in this patch.
>
> Hi Rob and thanks for your comments. I will change this commit message
> for a possible v2 into this:
>
> This adds the documentation to the compatible regulator-fixed-clock.
> This binding is a special binding of regulator-fixed and adds the
> ability to add a clock to regulator-fixed, so the regulator can be
> enabled and disabled with that clock.
> If the special compatible regulator-fixed-clock is used it is mandatory
> to supply a clock.
>
> > >
> >
> > > Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
> > >
> > > ---
> > >
> > >  .../bindings/regulator/fixed-regulator.yaml    | 18
> > > +++++++++++++++++-
> > >  1 file changed, 17 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/regulator/fixed-
> > > regulator.yaml b/Documentation/devicetree/bindings/regulator/fixed-
> > > regulator.yaml
> > > index a650b457085d..5fd081e80b43 100644
> > > --- a/Documentation/devicetree/bindings/regulator/fixed-
> > > regulator.yaml
> > > +++ b/Documentation/devicetree/bindings/regulator/fixed-
> > > regulator.yaml
> > > @@ -19,9 +19,19 @@ description:
> > >  allOf:
> > >    - $ref: "regulator.yaml#"
> > >
> > > +select:
> > > +  properties:
> > > +    compatible:
> > > +      contains:
> > > +        const: regulator-fixed-clock
> > > +  required:
> > > +    - clocks
> >
> > You don't need this.
> >
> > If you add a new compatible, then this should probably be a new schema
> > doc. Is the 'gpio' property valid in this case as if a clock is the
> > enable, can you also have a gpio enable? That said, it seems like the
> > new compatible is only for validating the DT in the driver. You could
> > just use a clock if present and default to current behavior if not.
> > It's not the kernel's job to validate DTs.
>
> The gpio property is valid with this compatible. I added regulator-
> fixed-clock to regulator-fixed hence I also don't want to create a new
> schema file.

Okay, if all the other properties are valid then adding to this file is fine.

> With the above select statement I wanted to state clocks as required
> when the compatible regulator-fixed-clock is given.

select is not the right way to do that. select is for whether to apply
the schema to a node or not. What you have will silently not apply the
schema if 'clocks' is missing or compatible is 'regulator-fixed'.
Essentially what you need to do here is:

if:
  properties:
    compatible:
      contains:
        const: regulator-fixed-clock
then:
  required:
    - clocks

Rob