Hello David,

Am 27.02.2017 um 19:11 schrieb David Lechner:

On 02/20/2017 02:37 AM, Heiko Schocher wrote:

quoted

From: Guan Ben <redacted>

extend the pwm-beeper driver to support customized frequency
for SND_BELL from device tree.

Signed-off-by: Guan Ben <redacted>
Signed-off-by: Mark Jonas <redacted>
[hs@denx.de: adapted to 4.10-rc7]
Signed-off-by: Heiko Schocher <redacted>
---

Changes in v2:
- add comment from Rob Herring:
  rename property name "bell-frequency" to "beeper-hz"

Is there a separate patch for the devicetree bindings documentation?

No, it is in this patch ... In the meantime I got an
Acked-by from Rob Herring ...

quoted

- add comment from Dmitry Torokhov:
  use device_property_read_u32() instead of of_property_read_u32()
- rebased against c470abd4fde40ea6a0846a2beab642a578c0b8cd
  Linux 4.10

 .../devicetree/bindings/input/pwm-beeper.txt       |  3 ++
 drivers/input/misc/pwm-beeper.c                    | 36 ++++++++++++++++------
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt

b/Documentation/devicetree/bindings/input/pwm-beeper.txt
index be332ae..4e4e128 100644

--- a/Documentation/devicetree/bindings/input/pwm-beeper.txt
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt

@@ -5,3 +5,6 @@ Registers a PWM device as beeper.
 Required properties:
 - compatible: should be "pwm-beeper"
 - pwms: phandle to the physical PWM device
+
+optional properties:
+- beeper-hz:  bell frequency in Hz

diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 5f9655d..5ea6fda 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c

@@ -27,6 +27,7 @@ struct pwm_beeper {
     struct pwm_device *pwm;
     struct work_struct work;
     unsigned long period;
+    unsigned int bell_frequency;
 };

 #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))

@@ -58,20 +59,17 @@ static int pwm_beeper_event(struct input_dev *input,
     if (type != EV_SND || value < 0)
         return -EINVAL;

-    switch (code) {
-    case SND_BELL:
-        value = value ? 1000 : 0;

This would be much simpler if you just changed the single line above:

         value = value ? beeper->bell_frequency : 0;

Ok, I readded the switch statement, and changed this line.

quoted

-        break;
-    case SND_TONE:
-        break;
-    default:
+    if (code != SND_BELL && code != SND_TONE)
         return -EINVAL;
-    }

     if (value == 0)
         beeper->period = 0;
-    else
+    else {
+        if (code == SND_BELL)
+            value = beeper->bell_frequency;
+
         beeper->period = HZ_TO_NANOSECONDS(value);
+    }

     schedule_work(&beeper->work);

@@ -93,6 +91,25 @@ static void pwm_beeper_close(struct input_dev *input)
     pwm_beeper_stop(beeper);
 }

+static void pwm_beeper_init_bell_frequency(struct device *dev,
+                       struct pwm_beeper *beeper)
+{
+    struct device_node *node;
+    unsigned int bell_frequency = 1000;
+    int err;
+
+    if (IS_ENABLED(CONFIG_OF)) {

I don't think the check for CONFIG_OF is needed when using device_property_read_u32().

Yes, removed.

quoted

+        node = dev->of_node;

node variable is never used

Removed.

quoted

+        err = device_property_read_u32(dev, "beeper-hz",
+                           &bell_frequency);

Does the device_property_read_u32() function guarantee that bell_frequency is not modified when err
< 0 ?

Yes. This function "ends" in of_property_read_variable_u32_array()
which first searches the property (If not found returns) and if all
checks are fine, fills the "*out_values" with the values from the
property...

quoted

+        if (err < 0)
+            dev_dbg(dev, "Failed to read beeper-hz, using default: %u Hz\n",

"Failed" sounds like an error, but this is a perfectly normal thing to happen. Maybe better to say
"'beeper-hz' not specified, using default: %u Hz\n".

Changed.

quoted

+                bell_frequency);
+    }
+
+    beeper->bell_frequency = bell_frequency;
+}
+
 static int pwm_beeper_probe(struct platform_device *pdev)
 {
     unsigned long pwm_id = (unsigned long)dev_get_platdata(&pdev->dev);

@@ -122,6 +139,7 @@ static int pwm_beeper_probe(struct platform_device *pdev)
     pwm_apply_args(beeper->pwm);

     INIT_WORK(&beeper->work, pwm_beeper_work);
+    pwm_beeper_init_bell_frequency(&pdev->dev, beeper);

This function is so simple, it could just be done inline here.

Indeed ... changed.

Thanks!

bye,
Heiko

quoted

     beeper->input = input_allocate_device();
     if (!beeper->input) {

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