Re: [PATCH] platform/x86: peaq-wmi: Add new peaq-wmi driver

[Darren Hart <dvhart@infradead.org>]

On Mon, May 08, 2017 at 09:56:31PM +0200, Hans de Goede wrote:
> PEAQ is a new European OEM, I've bought one of their 2-in-1 x86
> devices, which is actually quite a nice device. Under Windows it has
> Dolby software for "better" sound and you can select different equalizer
> presets using a special button.
> 
> This WMI interface for this button is not really nice, as it does not do
> notifies (it really does not I tripple checked), but since I had already
> figured out the entire WMI interface for this I decided to go the full
> mile anyways and also implent a WMI based input driver for this using
> input_polldev since, well, we need to poll.
> 
> This commit adds support for this button making it report KEY_SOUND input
> events. KEY_SOUND is already used in various places to switch sound into
> theatre mode and things like that so it seems appropriate here.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Thanks Hans,

A couple nits below, otherwise, looks good to me.

+Dmitry in case he cares to weigh in on input/input-polldev usage

> ---
>  drivers/platform/x86/Kconfig    |  7 +++
>  drivers/platform/x86/Makefile   |  1 +
>  drivers/platform/x86/peaq-wmi.c | 94 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 102 insertions(+)
>  create mode 100644 drivers/platform/x86/peaq-wmi.c
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index be2ffbd6eb6c..2bac2b2644f9 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -660,6 +660,13 @@ config MSI_WMI
>  	 To compile this driver as a module, choose M here: the module will
>  	 be called msi-wmi.
>  
> +config PEAQ_WMI
> +	tristate "PEAQ 2-in-1 WMI hotkey driver"
> +	depends on ACPI_WMI
> +	depends on INPUT
> +	help
> +	 Say Y here if you want to support WMI-based hotkeys on PEAQ 2-in-1s.
> +
>  config TOPSTAR_LAPTOP
>  	tristate "Topstar Laptop Extras"
>  	depends on ACPI
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index de4ffb594ba5..02487f95dd27 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -34,6 +34,7 @@ obj-$(CONFIG_PANASONIC_LAPTOP)	+= panasonic-laptop.o
>  obj-$(CONFIG_INTEL_MENLOW)	+= intel_menlow.o
>  obj-$(CONFIG_ACPI_WMI)		+= wmi.o
>  obj-$(CONFIG_MSI_WMI)		+= msi-wmi.o
> +obj-$(CONFIG_PEAQ_WMI)		+= peaq-wmi.o
>  obj-$(CONFIG_SURFACE3_WMI)	+= surface3-wmi.o
>  obj-$(CONFIG_TOPSTAR_LAPTOP)	+= topstar-laptop.o
>  
> diff --git a/drivers/platform/x86/peaq-wmi.c b/drivers/platform/x86/peaq-wmi.c
> new file mode 100644
> index 000000000000..8cd6b962ce5e
> --- /dev/null
> +++ b/drivers/platform/x86/peaq-wmi.c
> @@ -0,0 +1,94 @@
> +/*
> + * PEAQ 2-in-1 WMI hotkey driver
> + * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/input.h>

input-polldev includes input, no need for both.

> +#include <linux/input-polldev.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#define PEAQ_DOLBY_BUTTON_GUID		"ABBC0F6F-8EA1-11D1-00A0-C90629100000"
> +#define PEAQ_DOLBY_BUTTON_METHOD_ID	5
> +#define PEAQ_POLL_INTERVAL_MS		250
> +
> +MODULE_ALIAS("wmi:"PEAQ_DOLBY_BUTTON_GUID);
> +
> +struct input_polled_dev *peaq_poll_dev;
> +int peaq_ignore_events_counter;

Please make local globals static if they are needed.

Once we make WMI a bus with devices, we should be able to clean this up with
devm.

> +
> +/*
> + * The Dolby button (yes really a Dolby button) causes an ACPI variable to get
> + * set on both press and release. The WMI method checks and clears that flag.
> + * So for a press + release we will get back One from the WMI method either once
> + * (if polling after the release) or twice (polling between press and release).
> + * We ignore events for 0.5s after the first event to avoid reporting 2 presses.
> + */
> +static void peaq_wmi_poll(struct input_polled_dev *dev)
> +{
> +	union acpi_object obj;
> +	struct acpi_buffer buffer = { sizeof(obj), &obj };
> +	acpi_status status;
> +
> +	status = wmi_evaluate_method(PEAQ_DOLBY_BUTTON_GUID, 1,
> +				     PEAQ_DOLBY_BUTTON_METHOD_ID,
> +				     NULL, &buffer);
> +	if (ACPI_FAILURE(status))
> +		return;
> +
> +	if (obj.type != ACPI_TYPE_INTEGER) {
> +		dev_err(&peaq_poll_dev->input->dev,
> +			"Error WMBC did not return an integer\n");
> +		return;
> +	}
> +
> +	if (peaq_ignore_events_counter && --peaq_ignore_events_counter > 0)
> +		return;
> +
> +	if (obj.integer.value) {
> +		input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 1);
> +		input_event(peaq_poll_dev->input, EV_KEY, KEY_SOUND, 0);
> +		input_sync(peaq_poll_dev->input);
> +		peaq_ignore_events_counter = 500 / peaq_poll_dev->poll_interval;

Might as well define 500 above with the interval and keep these parameters
together, keep the units obvious, etc. e.g.

#define PEAQ_POLL_IGNORE_MS 500

Or similar

> +	}
> +}
> +
> +static int __init peaq_wmi_init(void)
> +{
> +	if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
> +		return -ENODEV;
> +
> +	peaq_poll_dev = input_allocate_polled_device();
> +	if (!peaq_poll_dev)
> +		return -ENOMEM;
> +
> +	peaq_poll_dev->poll = peaq_wmi_poll;
> +	peaq_poll_dev->poll_interval = PEAQ_POLL_INTERVAL_MS;
> +	peaq_poll_dev->poll_interval_max = 1000; /* 1 second */
> +	peaq_poll_dev->input->name = "PEAQ WMI hotkeys";

Are there additional keys/buttons?

> +	peaq_poll_dev->input->phys = "wmi/input0";
> +	peaq_poll_dev->input->id.bustype = BUS_HOST;
> +	input_set_capability(peaq_poll_dev->input, EV_KEY, KEY_SOUND);
> +
> +	return input_register_polled_device(peaq_poll_dev);
> +}
> +
> +static void __exit peaq_wmi_exit(void)
> +{
> +	if (!wmi_has_guid(PEAQ_DOLBY_BUTTON_GUID))
> +		return;
> +
> +	input_unregister_polled_device(peaq_poll_dev);
> +}
> +
> +module_init(peaq_wmi_init);
> +module_exit(peaq_wmi_exit);
> +
> +MODULE_DESCRIPTION("PEAQ 2-in-1 WMI hotkey driver");
> +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
> +MODULE_LICENSE("GPL");
> -- 
> 2.12.2
> 
> 

-- 
Darren Hart
VMware Open Source Technology Center