[PATCH v8 0/5] input: pwm-beeper: add feature to set volume level

[PATCH v8 0/5] input: pwm-beeper: add feature to set volume level

[Manuel Traut]

This implements volume control for the pwm-beeper via sysfs.

The first patch changes the devicetree documentation from txt to yaml.

The original author of this is Frieder Schrempf.
I picked them from this [0] LKML thread from 2017. Since it looks like
his email address changed in the meantime I changed it in the Author
and Signed-off-by, as well as in the copyright statements.
I did some minor changes on the patches that they apply and work with
the current kernel.

The last patch was added to fix loading/unloading of the driver.


checkpatch still reports warnings regarding the changes:
  * from txt to yaml of the devicetree documentation:
      WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
      WARNING: DT binding docs and includes should be a separate patch.
  * and the introduction of Documentation/ABI/testing/sysfs-devices-pwm-beeper:
      WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
  I am not sure how to fix these warnings. So any suggestion would be helpful.


Changes since v7 [1]:

 * yaml devicetree doc:
    * Use shorter subject
    * Fix indent
    * Use units
    * 'make dt_binding_check' succeeds
    * 'make dtbs_check' does not report new errors

 * Reworded commit messages avoiding 'this patch' phrase
 * Fix wrong indent in [PATCH 5/5 v7] input: pwm-beeper: handle module unloading properly
 * Use current date in Documentation/ABI/testing/sysfs-devices-pwm-beeper

 * Hopefully fixed my setup that
   * mails are CC'ed correctly
   * patches are sent as replies to the cover letter

Changes since v6 [2]:

 * Convert devicetree binding documentation from txt to yaml
 * Use DEVICE_ATTR_[RO|RW] properly
 * Change Frieders Mail address
 * Added Signed-off and Tested-by statements
 * Fix module unloading


Frieder Schrempf (2):
  input: pwm-beeper: add feature to set volume via sysfs
  input: pwm-beeper: set volume levels by devicetree

Manuel Traut (3):
  dt-bindings: input: pwm-beeper: Convert txt bindings to yaml
  dt-bindings: input: pwm-beeper: add volume
  input: pwm-beeper: handle module unloading properly

 .../ABI/testing/sysfs-devices-pwm-beeper      |  17 +++
 .../devicetree/bindings/input/pwm-beeper.txt  |  24 ----
 .../devicetree/bindings/input/pwm-beeper.yaml |  68 ++++++++++
 drivers/input/misc/pwm-beeper.c               | 122 +++++++++++++++++-
 4 files changed, 205 insertions(+), 26 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-pwm-beeper
 delete mode 100644 Documentation/devicetree/bindings/input/pwm-beeper.txt
 create mode 100644 Documentation/devicetree/bindings/input/pwm-beeper.yaml


Regards
Manuel

[0] https://lore.kernel.org/all/cover.1487323753.git.frieder.schrempf@exceet.de/
[1] https://lore.kernel.org/all/Y9AIq3cSNzI9T%2FdU@mt.com/
[2] https://lkml.org/lkml/2023/1/24/379

-- 
2.39.0

[PATCH v8 1/5] dt-bindings: input: pwm-beeper: Convert txt bindings to yaml

[Manuel Traut]

Converts txt binding to new YAML format.

Signed-off-by: Manuel Traut <manuel.traut@mt.com>
---
 .../devicetree/bindings/input/pwm-beeper.txt  | 24 ----------
 .../devicetree/bindings/input/pwm-beeper.yaml | 48 +++++++++++++++++++
 2 files changed, 48 insertions(+), 24 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/input/pwm-beeper.txt
 create mode 100644 Documentation/devicetree/bindings/input/pwm-beeper.yaml

diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt
deleted file mode 100644
index 8fc0e48c20db..000000000000
--- a/Documentation/devicetree/bindings/input/pwm-beeper.txt
+++ /dev/null
@@ -1,24 +0,0 @@
-* PWM beeper device tree bindings
-
-Registers a PWM device as beeper.
-
-Required properties:
-- compatible: should be "pwm-beeper"
-- pwms: phandle to the physical PWM device
-
-Optional properties:
-- amp-supply: phandle to a regulator that acts as an amplifier for the beeper
-- beeper-hz:  bell frequency in Hz
-
-Example:
-
-beeper_amp: amplifier {
-	compatible = "fixed-regulator";
-	gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
-};
-
-beeper {
-	compatible = "pwm-beeper";
-	pwms = <&pwm0>;
-	amp-supply = <&beeper_amp>;
-};
diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.yaml b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
new file mode 100644
index 000000000000..351df83d5cbe
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/input/pwm-beeper.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: PWM beeper
+
+maintainers:
+  - Dmitry Torokhov <dmitry.torokhov@gmail.com>
+
+description: Registers a PWM device as beeper.
+
+properties:
+  compatible:
+    const: pwm-beeper
+
+  pwms:
+    maxItems: 1
+
+  amp-supply:
+    description: >
+      phandle to a regulator that acts as an amplifier for
+      the beeper
+
+  beeper-hz:
+    description: bell frequency in Hz
+
+required:
+  - compatible
+  - pwms
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    beeper_amp: amplifier {
+      compatible = "fixed-regulator";
+      gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
+    };
+
+    beeper {
+      compatible = "pwm-beeper";
+      pwms = <&pwm0>;
+      amp-supply = <&beeper_amp>;
+    };
-- 
2.39.0

[PATCH v8 2/5] input: pwm-beeper: add feature to set volume via sysfs

[Manuel Traut]

From: Frieder Schrempf <frieder.schrempf@kontron.de>

Make the driver accept switching volume levels via sysfs.
This can be helpful if the beep/bell sound intensity needs
to be adapted to the environment of the device.

The volume adjustment is done by changing the duty cycle of
the pwm signal.

Add a sysfs interface with 5 default volume levels:
  0 - mute
  ..
  4 - max. volume

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Manuel Traut <manuel.traut@mt.com>
Tested-by: Manuel Traut <manuel.traut@mt.com>
---
 .../ABI/testing/sysfs-devices-pwm-beeper      | 17 ++++
 drivers/input/misc/pwm-beeper.c               | 83 ++++++++++++++++++-
 2 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/sysfs-devices-pwm-beeper

diff --git a/Documentation/ABI/testing/sysfs-devices-pwm-beeper b/Documentation/ABI/testing/sysfs-devices-pwm-beeper
new file mode 100644
index 000000000000..d2a22516f31d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-pwm-beeper
@@ -0,0 +1,17 @@
+What:		/sys/devices/.../pwm-beeper/volume
+Date:		January 2023
+KernelVersion:
+Contact:	Frieder Schrempf <frieder.schrempf@kontron.de>
+Description:
+		Control the volume of this pwm-beeper. Values
+		are between 0 and max_volume. This file will also
+		show the current volume level stored in the driver.
+
+What:		/sys/devices/.../pwm-beeper/max_volume
+Date:		February 2023
+KernelVersion:
+Contact:	Frieder Schrempf <frieder.schrempf@kontron.de>
+Description:
+		This file shows the maximum volume level that can be
+		assigned to volume.
+
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index d6b12477748a..865e1ec5c39d 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -1,9 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *
+ *  Copyright (C) 2016, Frieder Schrempf <frieder.schrempf@kontron.de>
+ *  (volume support)
+ *
  *  PWM beeper driver
  */
 
+#include <linux/device.h>
 #include <linux/input.h>
 #include <linux/regulator/consumer.h>
 #include <linux/module.h>
@@ -24,10 +29,61 @@ struct pwm_beeper {
 	unsigned int bell_frequency;
 	bool suspended;
 	bool amplifier_on;
+	unsigned int volume;
+	unsigned int *volume_levels;
+	unsigned int max_volume;
 };
 
 #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
 
+static ssize_t volume_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct pwm_beeper *beeper = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", beeper->volume);
+}
+
+static ssize_t max_volume_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct pwm_beeper *beeper = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", beeper->max_volume);
+}
+
+static ssize_t volume_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc;
+	struct pwm_beeper *beeper = dev_get_drvdata(dev);
+	unsigned int volume;
+
+	rc = kstrtouint(buf, 0, &volume);
+	if (rc)
+		return rc;
+
+	if (volume > beeper->max_volume)
+		return -EINVAL;
+	pr_debug("set volume to %u\n", volume);
+	beeper->volume = volume;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(volume);
+static DEVICE_ATTR_RO(max_volume);
+
+static struct attribute *pwm_beeper_attributes[] = {
+	&dev_attr_volume.attr,
+	&dev_attr_max_volume.attr,
+	NULL,
+};
+
+static struct attribute_group pwm_beeper_attribute_group = {
+	.attrs = pwm_beeper_attributes,
+};
+
 static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
 {
 	struct pwm_state state;
@@ -37,7 +93,7 @@ static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
 
 	state.enabled = true;
 	state.period = period;
-	pwm_set_relative_duty_cycle(&state, 50, 100);
+	pwm_set_relative_duty_cycle(&state, beeper->volume_levels[beeper->volume], 1000);
 
 	error = pwm_apply_state(beeper->pwm, &state);
 	if (error)
@@ -126,6 +182,7 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 	struct pwm_state state;
 	u32 bell_frequency;
 	int error;
+	size_t size;
 
 	beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
 	if (!beeper)
@@ -171,6 +228,24 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 
 	beeper->bell_frequency = bell_frequency;
 
+	beeper->max_volume = 4;
+
+	size = sizeof(*beeper->volume_levels) *
+		(beeper->max_volume + 1);
+
+	beeper->volume_levels = devm_kzalloc(&(pdev->dev), size,
+		GFP_KERNEL);
+	if (!beeper->volume_levels)
+		return -ENOMEM;
+
+	beeper->volume_levels[0] = 0;
+	beeper->volume_levels[1] = 8;
+	beeper->volume_levels[2] = 20;
+	beeper->volume_levels[3] = 40;
+	beeper->volume_levels[4] = 500;
+
+	beeper->volume = beeper->max_volume;
+
 	beeper->input = devm_input_allocate_device(dev);
 	if (!beeper->input) {
 		dev_err(dev, "Failed to allocate input device\n");
@@ -192,6 +267,12 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 
 	input_set_drvdata(beeper->input, beeper);
 
+	error = sysfs_create_group(&pdev->dev.kobj, &pwm_beeper_attribute_group);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to create sysfs group: %d\n", error);
+		return error;
+	}
+
 	error = input_register_device(beeper->input);
 	if (error) {
 		dev_err(dev, "Failed to register input device: %d\n", error);
-- 
2.39.0

[PATCH v8 3/5] input: pwm-beeper: set volume levels by devicetree

[Manuel Traut]

From: Frieder Schrempf <frieder.schrempf@kontron.de>

Add devicetree bindings to define supported volume levels and the
default volume level.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Manuel Traut <manuel.traut@mt.com>
Tested-by: Manuel Traut <manuel.traut@mt.com>
---
 drivers/input/misc/pwm-beeper.c | 58 +++++++++++++++++++++++----------
 1 file changed, 41 insertions(+), 17 deletions(-)

diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 865e1ec5c39d..82b05f7f4c70 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -181,8 +181,9 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 	struct pwm_beeper *beeper;
 	struct pwm_state state;
 	u32 bell_frequency;
-	int error;
+	int error, length;
 	size_t size;
+	u32 value;
 
 	beeper = devm_kzalloc(dev, sizeof(*beeper), GFP_KERNEL);
 	if (!beeper)
@@ -228,23 +229,46 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 
 	beeper->bell_frequency = bell_frequency;
 
-	beeper->max_volume = 4;
-
-	size = sizeof(*beeper->volume_levels) *
-		(beeper->max_volume + 1);
-
-	beeper->volume_levels = devm_kzalloc(&(pdev->dev), size,
-		GFP_KERNEL);
-	if (!beeper->volume_levels)
-		return -ENOMEM;
-
-	beeper->volume_levels[0] = 0;
-	beeper->volume_levels[1] = 8;
-	beeper->volume_levels[2] = 20;
-	beeper->volume_levels[3] = 40;
-	beeper->volume_levels[4] = 500;
+	/* determine the number of volume levels */
+	length = device_property_read_u32_array(&pdev->dev, "volume-levels", NULL, 0);
+	if (length <= 0) {
+		dev_dbg(&pdev->dev, "no volume levels specified, using max volume\n");
+		beeper->max_volume = 1;
+	} else
+		beeper->max_volume = length;
+
+	/* read volume levels from DT property */
+	if (beeper->max_volume > 0) {
+		size = sizeof(*beeper->volume_levels) *	beeper->max_volume;
+
+		beeper->volume_levels = devm_kzalloc(&(pdev->dev), size,
+			GFP_KERNEL);
+		if (!beeper->volume_levels)
+			return -ENOMEM;
+
+		if (length > 0) {
+			error = device_property_read_u32_array(&pdev->dev, "volume-levels",
+						beeper->volume_levels,
+						beeper->max_volume);
+
+			if (error < 0)
+				return error;
+
+			error = device_property_read_u32(&pdev->dev, "default-volume-level",
+						   &value);
+
+			if (error < 0) {
+				dev_dbg(&pdev->dev, "no default volume specified, using max volume\n");
+				value = beeper->max_volume - 1;
+			}
+		} else {
+			beeper->volume_levels[0] = 500;
+			value = 0;
+		}
 
-	beeper->volume = beeper->max_volume;
+		beeper->volume = value;
+		beeper->max_volume--;
+	}
 
 	beeper->input = devm_input_allocate_device(dev);
 	if (!beeper->input) {
-- 
2.39.0

[PATCH v8 4/5] dt-bindings: input: pwm-beeper: add volume

[Manuel Traut]

Adds an array of supported volume levels and a default volume level.

Signed-off-by: Manuel Traut <manuel.traut@mt.com>
---
 .../devicetree/bindings/input/pwm-beeper.yaml | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.yaml b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
index 351df83d5cbe..f1f9283ca855 100644
--- a/Documentation/devicetree/bindings/input/pwm-beeper.yaml
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
@@ -26,6 +26,24 @@ properties:
   beeper-hz:
     description: bell frequency in Hz
 
+  volume-levels:
+    description: >
+      Array of PWM duty cycle values that correspond to
+      linear volume levels. These need to be in the range of
+      0 to 500, while 0 means 0% duty cycle (mute) and 500
+      means 50% duty cycle (max volume).
+      Please note that the actual volume of most beepers is
+      highly non-linear, which means that low volume levels
+      are probably somewhere in the range of 1 to 30 (0.1-3%
+      duty cycle).
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
+  default-volume-level:
+    description: >
+      The default volume level (index into the array defined
+      by the "volume-levels" property).
+    $ref: /schemas/types.yaml#/definitions/uint32
+
 required:
   - compatible
   - pwms
@@ -45,4 +63,6 @@ examples:
       compatible = "pwm-beeper";
       pwms = <&pwm0>;
       amp-supply = <&beeper_amp>;
+      volume-levels = <0 8 20 40 500>;
+      default-volume-level = <4>;
     };
-- 
2.39.0

[PATCH v8 5/5] input: pwm-beeper: handle module unloading properly

[Manuel Traut]

'input: pwm-beeper: add feature to set volume via sysfs' adds device
attributes without removing them on error or if the module is unloaded.

If the module will be unloaded and loaded again it fails:
[ 1007.918180] sysfs: cannot create duplicate filename '/devices/platform/buzzer/volume'

Therefore remove device attributes on module unloading and in case
registration at the input subsystem fails.

Signed-off-by: Manuel Traut <manuel.traut@mt.com>
---
 drivers/input/misc/pwm-beeper.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 82b05f7f4c70..736b89bd1b42 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -299,6 +299,7 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 
 	error = input_register_device(beeper->input);
 	if (error) {
+		sysfs_remove_group(&pdev->dev.kobj, &pwm_beeper_attribute_group);
 		dev_err(dev, "Failed to register input device: %d\n", error);
 		return error;
 	}
@@ -308,6 +309,17 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int pwm_beeper_remove(struct platform_device *pdev)
+{
+	struct pwm_beeper *beeper;
+
+	beeper = platform_get_drvdata(pdev);
+	input_unregister_device(beeper->input);
+	sysfs_remove_group(&pdev->dev.kobj, &pwm_beeper_attribute_group);
+
+	return 0;
+}
+
 static int __maybe_unused pwm_beeper_suspend(struct device *dev)
 {
 	struct pwm_beeper *beeper = dev_get_drvdata(dev);
@@ -353,6 +365,7 @@ MODULE_DEVICE_TABLE(of, pwm_beeper_match);
 
 static struct platform_driver pwm_beeper_driver = {
 	.probe	= pwm_beeper_probe,
+	.remove	= pwm_beeper_remove,
 	.driver = {
 		.name	= "pwm-beeper",
 		.pm	= &pwm_beeper_pm_ops,
-- 
2.39.0

Re: [PATCH v8 1/5] dt-bindings: input: pwm-beeper: Convert txt bindings to yaml

[Krzysztof Kozlowski]

On 26/01/2023 10:18, Manuel Traut wrote:
> Converts txt binding to new YAML format.
> 
> Signed-off-by: Manuel Traut <manuel.traut@mt.com>

Thank you for your patch. There is something to discuss/improve.

> diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.yaml b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> new file mode 100644
> index 000000000000..351df83d5cbe
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> @@ -0,0 +1,48 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/input/pwm-beeper.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"

Drop quotes from both. Apologies for not noticing it earlier.

> +
> +title: PWM beeper
> +
> +maintainers:
> +  - Dmitry Torokhov <dmitry.torokhov@gmail.com>
> +
> +description: Registers a PWM device as beeper.
> +
> +properties:
> +  compatible:
> +    const: pwm-beeper
> +
> +  pwms:
> +    maxItems: 1
> +
> +  amp-supply:
> +    description: >
> +      phandle to a regulator that acts as an amplifier for
> +      the beeper

Drop "phandle to a"

> +
> +  beeper-hz:
> +    description: bell frequency in Hz
> +
> +required:
> +  - compatible
> +  - pwms
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    beeper_amp: amplifier {
> +      compatible = "fixed-regulator";
> +      gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
> +    };

Drop this device node, not related.

> +
> +    beeper {
> +      compatible = "pwm-beeper";
> +      pwms = <&pwm0>;
> +      amp-supply = <&beeper_amp>;
> +    };

Best regards,
Krzysztof

Re: [PATCH v8 4/5] dt-bindings: input: pwm-beeper: add volume

[Krzysztof Kozlowski]

On 26/01/2023 10:18, Manuel Traut wrote:
> Adds an array of supported volume levels and a default volume level.
> 
> Signed-off-by: Manuel Traut <manuel.traut@mt.com>

This is the second patch. Bindings must be introduced before you start
using them.

> ---
>  .../devicetree/bindings/input/pwm-beeper.yaml | 20 +++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.yaml b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> index 351df83d5cbe..f1f9283ca855 100644
> --- a/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> +++ b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> @@ -26,6 +26,24 @@ properties:
>    beeper-hz:
>      description: bell frequency in Hz
>  
> +  volume-levels:

use -bp suffix:
https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml#L44

which will mean the unit is 1/100 of %, not 1/10. Then you can also drop
the $ref.


> +    description: >
> +      Array of PWM duty cycle values that correspond to
> +      linear volume levels. These need to be in the range of
> +      0 to 500, while 0 means 0% duty cycle (mute) and 500
> +      means 50% duty cycle (max volume).
> +      Please note that the actual volume of most beepers is
> +      highly non-linear, which means that low volume levels
> +      are probably somewhere in the range of 1 to 30 (0.1-3%
> +      duty cycle).
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +
> +  default-volume-level:

I propose to use just the value, not the index, so the name should
finish with '-bp' and the $ref can be dropped.

> +    description: >
> +      The default volume level (index into the array defined
> +      by the "volume-levels" property).
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
>  required:
>    - compatible
>    - pwms
> @@ -45,4 +63,6 @@ examples:
>        compatible = "pwm-beeper";
>        pwms = <&pwm0>;
>        amp-supply = <&beeper_amp>;
> +      volume-levels = <0 8 20 40 500>;
> +      default-volume-level = <4>;
>      };

Best regards,
Krzysztof

Re: [PATCH v8 1/5] dt-bindings: input: pwm-beeper: Convert txt bindings to yaml

[Rob Herring]

On Thu, 26 Jan 2023 10:18:21 +0100, Manuel Traut wrote:
> Converts txt binding to new YAML format.
> 
> Signed-off-by: Manuel Traut <manuel.traut@mt.com>
> ---
>  .../devicetree/bindings/input/pwm-beeper.txt  | 24 ----------
>  .../devicetree/bindings/input/pwm-beeper.yaml | 48 +++++++++++++++++++
>  2 files changed, 48 insertions(+), 24 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/input/pwm-beeper.txt
>  create mode 100644 Documentation/devicetree/bindings/input/pwm-beeper.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/input/pwm-beeper.example.dtb: /example-0/amplifier: failed to match any schema with compatible: ['fixed-regulator']

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20230126091825.220646-2-manuel.traut@mt.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v8 4/5] dt-bindings: input: pwm-beeper: add volume

[Manuel Traut]

> This is the second patch. Bindings must be introduced before you start
> using them.

OK, will be done in v9.

> > ---
> >  .../devicetree/bindings/input/pwm-beeper.yaml | 20 +++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.yaml b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> > index 351df83d5cbe..f1f9283ca855 100644
> > --- a/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> > +++ b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
> > @@ -26,6 +26,24 @@ properties:
> >    beeper-hz:
> >      description: bell frequency in Hz
> >  
> > +  volume-levels:
> 
> use -bp suffix:
> https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml#L44
> 
> which will mean the unit is 1/100 of %, not 1/10. Then you can also drop
> the $ref.

OK, this is also fine for me. Chaned the description and implementation
for v9.
 
> > +    description: >
> > +      Array of PWM duty cycle values that correspond to
> > +      linear volume levels. These need to be in the range of
> > +      0 to 500, while 0 means 0% duty cycle (mute) and 500
> > +      means 50% duty cycle (max volume).
> > +      Please note that the actual volume of most beepers is
> > +      highly non-linear, which means that low volume levels
> > +      are probably somewhere in the range of 1 to 30 (0.1-3%
> > +      duty cycle).
> > +    $ref: /schemas/types.yaml#/definitions/uint32-array
> > +
> > +  default-volume-level:
> 
> I propose to use just the value, not the index, so the name should
> finish with '-bp' and the $ref can be dropped.

I am not so happy with this suggestion. What shall be displayed in
sysfs as volume if a user specifies a value that is not defined in
the array.. So I tend to keep this as is.

Thanks for your feedback
Manuel

> > +    description: >
> > +      The default volume level (index into the array defined
> > +      by the "volume-levels" property).
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +
> >  required:
> >    - compatible
> >    - pwms
> > @@ -45,4 +63,6 @@ examples:
> >        compatible = "pwm-beeper";
> >        pwms = <&pwm0>;
> >        amp-supply = <&beeper_amp>;
> > +      volume-levels = <0 8 20 40 500>;
> > +      default-volume-level = <4>;
> >      };
> 
> Best regards,
> Krzysztof
> 

-- 
Manuel Traut

Re: [PATCH v8 4/5] dt-bindings: input: pwm-beeper: add volume

[Krzysztof Kozlowski]

On 26/01/2023 16:11, Manuel Traut wrote:
>> This is the second patch. Bindings must be introduced before you start
>> using them.
> 
> OK, will be done in v9.
> 
>>> ---
>>>  .../devicetree/bindings/input/pwm-beeper.yaml | 20 +++++++++++++++++++
>>>  1 file changed, 20 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.yaml b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
>>> index 351df83d5cbe..f1f9283ca855 100644
>>> --- a/Documentation/devicetree/bindings/input/pwm-beeper.yaml
>>> +++ b/Documentation/devicetree/bindings/input/pwm-beeper.yaml
>>> @@ -26,6 +26,24 @@ properties:
>>>    beeper-hz:
>>>      description: bell frequency in Hz
>>>  
>>> +  volume-levels:
>>
>> use -bp suffix:
>> https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml#L44
>>
>> which will mean the unit is 1/100 of %, not 1/10. Then you can also drop
>> the $ref.
> 
> OK, this is also fine for me. Chaned the description and implementation
> for v9.
>  
>>> +    description: >
>>> +      Array of PWM duty cycle values that correspond to
>>> +      linear volume levels. These need to be in the range of
>>> +      0 to 500, while 0 means 0% duty cycle (mute) and 500
>>> +      means 50% duty cycle (max volume).
>>> +      Please note that the actual volume of most beepers is
>>> +      highly non-linear, which means that low volume levels
>>> +      are probably somewhere in the range of 1 to 30 (0.1-3%
>>> +      duty cycle).
>>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
>>> +
>>> +  default-volume-level:
>>
>> I propose to use just the value, not the index, so the name should
>> finish with '-bp' and the $ref can be dropped.
> 
> I am not so happy with this suggestion. What shall be displayed in
> sysfs as volume if a user specifies a value that is not defined in
> the array.. So I tend to keep this as is.

sysfs is not related to bindings. To rephrase your question: what shall
be shown in anywhere if the index is not correct? The same problem, the
same solution.

Best regards,
Krzysztof

Re: [PATCH v8 4/5] dt-bindings: input: pwm-beeper: add volume

[Manuel Traut]

> >>> +  default-volume-level:
> >>
> >> I propose to use just the value, not the index, so the name should
> >> finish with '-bp' and the $ref can be dropped.
> > 
> > I am not so happy with this suggestion. What shall be displayed in
> > sysfs as volume if a user specifies a value that is not defined in
> > the array.. So I tend to keep this as is.
> 
> sysfs is not related to bindings. To rephrase your question: what shall
> be shown in anywhere if the index is not correct? The same problem, the
> same solution.

got it, thanks for the hint. I will implement it in v9.

Regards
Manuel

Re: [PATCH v8 5/5] input: pwm-beeper: handle module unloading properly

[Frieder Schrempf]

Hi Manuel,

On 26.01.23 10:18, Manuel Traut wrote:
> 'input: pwm-beeper: add feature to set volume via sysfs' adds device
> attributes without removing them on error or if the module is unloaded.
> 
> If the module will be unloaded and loaded again it fails:
> [ 1007.918180] sysfs: cannot create duplicate filename '/devices/platform/buzzer/volume'
> 
> Therefore remove device attributes on module unloading and in case
> registration at the input subsystem fails.
> 
> Signed-off-by: Manuel Traut <manuel.traut@mt.com>

Thanks for picking up these old patches!
I think you need to merge this fixup patch 5/5 into patch 2/5 of this
series.

Thanks
Frieder