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Date: Tue, 28 Feb 2017 06:19:06 +0100
From: Heiko Schocher <hs@...x.de>
To: David Lechner <david@...hnology.com>
Cc: linux-input@...r.kernel.org, Guan Ben <ben.guan@...bosch.com>,
Mark Jonas <mark.jonas@...bosch.com>,
devicetree@...r.kernel.org,
Thierry Reding <thierry.reding@...il.com>,
linux-kernel@...r.kernel.org,
Boris Brezillon <boris.brezillon@...e-electrons.com>,
Rob Herring <robh+dt@...nel.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Manfred Schlaegl <manfred.schlaegl@....at>,
Mark Rutland <mark.rutland@....com>
Subject: Re: [v2] Input: pwm-beeper: support customized freq for SND_BELL
Hello David,
Am 27.02.2017 um 19:11 schrieb David Lechner:
> On 02/20/2017 02:37 AM, Heiko Schocher wrote:
>> From: Guan Ben <ben.guan@...bosch.com>
>>
>> extend the pwm-beeper driver to support customized frequency
>> for SND_BELL from device tree.
>>
>> Signed-off-by: Guan Ben <ben.guan@...bosch.com>
>> Signed-off-by: Mark Jonas <mark.jonas@...bosch.com>
>> [hs@...x.de: adapted to 4.10-rc7]
>> Signed-off-by: Heiko Schocher <hs@...x.de>
>> ---
>>
>> 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 ...
>> - 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.
>> - 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.
>
>> + node = dev->of_node;
>
> node variable is never used
Removed.
>
>> + 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...
>> + 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.
>
>> + 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
>
>>
>> beeper->input = input_allocate_device();
>> if (!beeper->input) {
>>
>
--
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