Re: [PATCH 1/3] platform: x86: dell-rbtn: Dell Airplane Mode Switch driver

[Mika Westerberg]

On Sun, Nov 23, 2014 at 04:09:19PM +0100, Pali Rohár wrote:
> This is an ACPI driver for Dell laptops which receive HW switch events.
> It exports rfkill device dell-rbtn which provide correct hard rfkill state.
> 
> It does not provide support for setting soft rfkill state yet.
> 
> Signed-off-by: Pali Rohár <pali.rohar@xxxxxxxxx>
> ---
>  drivers/platform/x86/Kconfig     |   13 +++
>  drivers/platform/x86/Makefile    |    1 +
>  drivers/platform/x86/dell-rbtn.c |  179 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 193 insertions(+)
>  create mode 100644 drivers/platform/x86/dell-rbtn.c
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 4dcfb71..5a2ba64 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -137,6 +137,19 @@ config DELL_SMO8800
>  	  To compile this driver as a module, choose M here: the module will
>  	  be called dell-smo8800.
>  
> +config DELL_RBTN
> +	tristate "Dell Airplane Mode Switch driver"
> +	depends on ACPI
> +	depends on RFKILL
> +	---help---
> +	  Say Y here if you want to support Dell Airplane Mode Switch ACPI
> +	  device on Dell laptops. Sometimes it has names: DELLABCE or DELRBTN.
> +	  This driver register rfkill device and receives HW rfkill events
> +	  (when wifi/bluetooth was enabled) and set correct hard rfkill state.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called dell-rbtn.
> +
>  
>  config FUJITSU_LAPTOP
>  	tristate "Fujitsu Laptop Extras"
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index f82232b..b3e54ed 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_DELL_LAPTOP)	+= dell-laptop.o
>  obj-$(CONFIG_DELL_WMI)		+= dell-wmi.o
>  obj-$(CONFIG_DELL_WMI_AIO)	+= dell-wmi-aio.o
>  obj-$(CONFIG_DELL_SMO8800)	+= dell-smo8800.o
> +obj-$(CONFIG_DELL_RBTN)		+= dell-rbtn.o
>  obj-$(CONFIG_ACER_WMI)		+= acer-wmi.o
>  obj-$(CONFIG_ACERHDF)		+= acerhdf.o
>  obj-$(CONFIG_HP_ACCEL)		+= hp_accel.o
> diff --git a/drivers/platform/x86/dell-rbtn.c b/drivers/platform/x86/dell-rbtn.c
> new file mode 100644
> index 0000000..f1f039a
> --- /dev/null
> +++ b/drivers/platform/x86/dell-rbtn.c
> @@ -0,0 +1,179 @@
> +/*
> +    Dell Airplane Mode Switch driver
> +    Copyright (C) 2014  Pali Rohár <pali.rohar@xxxxxxxxx>
> +
> +    This program is free software; you can redistribute it and/or modify
> +    it under the terms of the GNU General Public License as published by
> +    the Free Software Foundation; either version 2 of the License, or
> +    (at your option) any later version.
> +
> +    This program is distributed in the hope that it will be useful,
> +    but WITHOUT ANY WARRANTY; without even the implied warranty of
> +    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +    GNU General Public License for more details.

Please check Documentation/CodingStyle, block comments look like this

 /*
  * This is block comment.
  */

> +*/
> +
> +#include <linux/module.h>
> +#include <linux/acpi.h>
> +#include <linux/rfkill.h>
> +
> +/*** helper functions ***/
> +
> +static int rbtn_check(struct acpi_device *device)
> +{
> +	acpi_status status;
> +	unsigned long long output;
> +
> +	status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);

Do you think it is worth documenting what CRBT is supposed to do? Why
return value <= 3 is OK and > 3 is not?

> +	if (ACPI_FAILURE(status))
> +		return -EINVAL;
> +
> +	if (output > 3)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +

Delete the second blank line.

> +/*** rfkill ops ***/
> +
> +static void rbtn_query(struct rfkill *rfkill, void *data)
> +{
> +	struct acpi_device *device = data;
> +	acpi_status status;
> +	unsigned long long output;
> +
> +	status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);

Same comment here about the documentation.

> +	if (ACPI_FAILURE(status))
> +		return;
> +
> +	rfkill_set_states(rfkill, !output, !output);

You can also write it like:

	if (ACPI_SUCCESS(status))
		rfkill_set_states(rfkill, !output, !output);

which looks better to me at least.

> +}
> +
> +static int rbtn_set_block(void *data, bool blocked)
> +{
> +	/* FIXME: setting soft rfkill cause problems, so disable it for now */
> +	return -EINVAL;
> +}
> +
> +struct rfkill_ops rbtn_ops = {

static? const?

> +	.query = rbtn_query,
> +	.set_block = rbtn_set_block,
> +};
> +
> +

Delete the second blank line.

> +/*** acpi driver ***/
> +
> +static int rbtn_add(struct acpi_device *device);
> +static int rbtn_remove(struct acpi_device *device);
> +static void rbtn_notify(struct acpi_device *device, u32 event);
> +
> +static const struct acpi_device_id rbtn_ids[] = {
> +	{ "DELRBTN", 0 },
> +	{ "DELLABCE", 0 },
> +	{ "", 0 },
> +};
> +
> +static struct acpi_driver rbtn_driver = {
> +	.name = "dell-rbtn",
> +	.ids = rbtn_ids,
> +	.ops = {
> +		.add = rbtn_add,
> +		.remove = rbtn_remove,
> +		.notify = rbtn_notify,
> +	},
> +	.owner = THIS_MODULE,
> +};
> +
> +

Ditto.

> +/*** rfkill enable/disable ***/
> +
> +static int rbtn_enable(struct acpi_device *device)
> +{
> +	struct rfkill *rfkill = device->driver_data;
> +	int ret;
> +
> +	if (rfkill)
> +		return 0;
> +
> +	/* NOTE: rbtn controls all radio devices, not only WLAN
> +	         but rfkill interface does not support "ANY" type
> +	         so "WLAN" type is used
> +	 */

Block comment style.

> +	rfkill = rfkill_alloc("dell-rbtn", &device->dev, RFKILL_TYPE_WLAN,
> +			      &rbtn_ops, device);
> +	if (!rfkill)
> +		return -ENOMEM;
> +
> +	ret = rfkill_register(rfkill);
> +	if (ret) {
> +		rfkill_destroy(rfkill);
> +		return ret;
> +	}
> +
> +	device->driver_data = rfkill;
> +	return 0;
> +}
> +
> +static void rbtn_disable(struct acpi_device *device)
> +{
> +	struct rfkill *rfkill = device->driver_data;
> +
> +	if (!rfkill)
> +		return;
> +
> +	rfkill_unregister(rfkill);
> +	rfkill_destroy(rfkill);
> +	device->driver_data = NULL;
> +}
> +
> +

Extra blank line.

> +/*** acpi driver functions ***/
> +
> +static int rbtn_add(struct acpi_device *device)
> +{
> +	int ret;
> +
> +	ret = rbtn_check(device);
> +	if (ret < 0)
> +		return ret;
> +
> +	return rbtn_enable(device);
> +}
> +
> +static int rbtn_remove(struct acpi_device *device)
> +{
> +	rbtn_disable(device);
> +	return 0;
> +}
> +
> +static void rbtn_notify(struct acpi_device *device, u32 event)
> +{
> +	struct rfkill *rfkill = device->driver_data;
> +
> +	if (event == 0x80)
> +		rbtn_query(rfkill, device);
> +	else
> +		dev_info(&device->dev, "Received unknown event (0x%x)\n", event);
> +}
> +
> +

Extra blank line.

> +/*** module functions ***/
> +
> +static int __init rbtn_init(void)
> +{
> +	return acpi_bus_register_driver(&rbtn_driver);
> +}
> +
> +static void __exit rbtn_exit(void)
> +{
> +	acpi_bus_unregister_driver(&rbtn_driver);
> +}
> +
> +module_init(rbtn_init);
> +module_exit(rbtn_exit);

module_acpi_driver()?

> +
> +MODULE_DEVICE_TABLE(acpi, rbtn_ids);
> +MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
> +MODULE_AUTHOR("Pali Rohár <pali.rohar@xxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> -- 
> 1.7.9.5
> 
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