Hi Frieder,
On Thu, Jan 19, 2017 at 04:24:08PM +0100, Frieder Schrempf wrote:
> 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.
>
> This patch adds the sysfs interface with 5 default volume
> levels (0 - mute, 4 - max. volume).
>
> Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxx>
> ---
> Changes in v3:
> - update date
>
> .../ABI/testing/sysfs-class-input-pwm-beeper | 17 ++++++
> drivers/input/misc/pwm-beeper.c | 71 +++++++++++++++++++++-
> 2 files changed, 87 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/ABI/testing/sysfs-class-input-pwm-beeper
>
> diff --git a/Documentation/ABI/testing/sysfs-class-input-pwm-beeper b/Documentation/ABI/testing/sysfs-class-input-pwm-beeper
> new file mode 100644
> index 0000000..c878a1d
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-input-pwm-beeper
> @@ -0,0 +1,17 @@
> +What: /sys/class/input/input(x)/volume
Only generic (i.e. applicable to all input devices) attributes can be
present in /sys/class/input/input(x)/, and volume certainly isn't such
attribute. Please move them to the pwm-beeper platform device itself.
> +Date: January 2017
> +KernelVersion:
> +Contact: Frieder Schrempf <frieder.schrempf@xxxxxxxxx>
> +Description:
> + Control the volume of this pwm-beeper. Values
> + are between 0 and max_volume_level. This file will also
> + show the current volume level stored in the driver.
> +
> +What: /sys/class/input/input(x)/max_volume_level
> +Date: January 2017
> +KernelVersion:
> +Contact: Frieder Schrempf <frieder.schrempf@xxxxxxxxx>
> +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 5f9655d..3ed21da 100644
> --- a/drivers/input/misc/pwm-beeper.c
> +++ b/drivers/input/misc/pwm-beeper.c
> @@ -1,5 +1,9 @@
> /*
> * Copyright (C) 2010, Lars-Peter Clausen <lars@xxxxxxxxxx>
> + *
> + * Copyright (C) 2016, Frieder Schrempf <frieder.schrempf@xxxxxxxxx>
> + * (volume support)
> + *
> * PWM beeper driver
> *
> * This program is free software; you can redistribute it and/or modify it
> @@ -27,16 +31,77 @@ struct pwm_beeper {
> struct pwm_device *pwm;
> struct work_struct work;
> unsigned long period;
> + unsigned int volume;
> + unsigned int volume_levels[] = {0, 8, 20, 40, 500};
Does this actually work? Anyway, you are not allowing to set differentr
values in for different beepers, so take the array out of the structure.
> + unsigned int max_volume_level;
> };
>
> #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
>
> +static ssize_t beeper_show_volume(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 beeper_show_max_volume_level(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_level);
> +}
> +
> +static ssize_t beeper_store_volume(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;
> +
> + rc = -ENXIO;
Why? There are no failures below.
> + if (volume > beeper->max_volume_level)
> + volume = beeper->max_volume_level;
Return -EINVAL maybe?
> + pr_debug("set volume to %u\n", volume);
> + if (beeper->volume != volume)
> + beeper->volume = volume;
Why?
> + rc = count;
> +
> + return rc;
> +}
> +
> +static DEVICE_ATTR(volume, 0644, beeper_show_volume, beeper_store_volume);
> +static DEVICE_ATTR(max_volume_level, 0644, beeper_show_max_volume_level, NULL);
Drop "level", it is cleaner.
> +
> +static struct attribute *bp_device_attributes[] = {
pwm_beeper_atttributes
> + &dev_attr_volume.attr,
> + &dev_attr_max_volume_level.attr,
> + NULL,
> +};
> +
> +static struct attribute_group bp_device_attr_group = {
pwm_beeper_attribute_group
> + .attrs = bp_device_attributes,
> +};
> +
> +static const struct attribute_group *bp_device_attr_groups[] = {
> + &bp_device_attr_group,
> + NULL,
> +};
> +
> static void __pwm_beeper_set(struct pwm_beeper *beeper)
> {
> unsigned long period = beeper->period;
>
> if (period) {
> - pwm_config(beeper->pwm, period / 2, period);
> + pwm_config(beeper->pwm,
> + period / 1000 * beeper->volume_levels[beeper->volume],
> + period);
> pwm_enable(beeper->pwm);
> } else
> pwm_disable(beeper->pwm);
> @@ -123,6 +188,8 @@ static int pwm_beeper_probe(struct platform_device *pdev)
>
> INIT_WORK(&beeper->work, pwm_beeper_work);
>
> + beeper->max_volume_level = ARRAY_SIZE(beeper->volume_levels) - 1;
> +
> beeper->input = input_allocate_device();
> if (!beeper->input) {
> dev_err(&pdev->dev, "Failed to allocate input device\n");
> @@ -146,6 +213,8 @@ static int pwm_beeper_probe(struct platform_device *pdev)
>
> input_set_drvdata(beeper->input, beeper);
>
> + beeper->input->dev.groups = bp_device_attr_groups;
> +
> error = input_register_device(beeper->input);
> if (error) {
> dev_err(&pdev->dev, "Failed to register input device: %d\n", error);
> --
> 2.7.4
>
Thanks.
--
Dmitry
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