Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6

1. Introduction

2. Implementation details

3. Kernel driver guidelines

4. Kernel API

5. Userspace support

3. Kernel API

4. Userspace support

1. Introduction

situations where transmitters need to be turned off, for example on

aircraft.

The rfkill subsystem has a concept of "hard" and "soft" block, which

differ little in their meaning (block == transmitters off) but rather in

whether they can be changed or not:

 - hard block: read-only radio block that cannot be overriden by software

 - soft block: writable radio block (need not be readable) that is set by

               the system software.

2. Implementation details

The rfkill subsystem is composed of various components: the rfkill class, the

rfkill-input module (an input layer handler), and some specific input layer

events.

The rfkill class is provided for kernel drivers to register their radio

transmitter with the kernel, provide methods for turning it on and off and,

optionally, letting the system know about hardware-disabled states that may

be implemented on the device. This code is enabled with the CONFIG_RFKILL

Kconfig option, which drivers can "select".

The rfkill class code also notifies userspace of state changes, this is

achieved via uevents. It also provides some sysfs files for userspace to

check the status of radio transmitters. See the "Userspace support" section

below.

The rfkill subsystem is composed of three main components:

 * the rfkill core,

 * the deprecated rfkill-input module (an input layer handler, being

   replaced by userspace policy code) and

 * the rfkill drivers.

The rfkill core provides API for kernel drivers to register their radio

transmitter with the kernel, methods for turning it on and off and, letting

the system know about hardware-disabled states that may be implemented on

the device.

The rfkill-input code implements a basic response to rfkill buttons -- it

implements turning on/off all devices of a certain class (or all).

The rfkill core code also notifies userspace of state changes, and provides

ways for userspace to query the current states. See the "Userspace support"

section below.

When the device is hard-blocked (either by a call to rfkill_set_hw_state()

or from query_hw_block) set_block() will be invoked but drivers can well

ignore the method call since they can use the return value of the function

rfkill_set_hw_state() to sync the software state instead of keeping track

of calls to set_block().

The entire functionality is spread over more than one subsystem:

 * The kernel input layer generates KEY_WWAN, KEY_WLAN etc. and

   SW_RFKILL_ALL -- when the user presses a button. Drivers for radio

   transmitters generally do not register to the input layer, unless the

   device really provides an input device (i.e. a button that has no

   effect other than generating a button press event)

 * The rfkill-input code hooks up to these events and switches the soft-block

   of the various radio transmitters, depending on the button type.

 * The rfkill drivers turn off/on their transmitters as requested.

 * The rfkill class will generate userspace notifications (uevents) to tell

   userspace what the current state is.

or from query_hw_block) set_block() will be invoked for additional software

block, but drivers can ignore the method call since they can use the return

value of the function rfkill_set_hw_state() to sync the software state

instead of keeping track of calls to set_block(). In fact, drivers should

use the return value of rfkill_set_hw_state() unless the hardware actually

keeps track of soft and hard block separately.

3. Kernel API

3. Kernel driver guidelines

Drivers for radio transmitters normally implement only the rfkill class.

These drivers may not unblock the transmitter based on own decisions, they

should act on information provided by the rfkill class only.

Drivers for radio transmitters normally implement an rfkill driver.

Platform drivers might implement input devices if the rfkill button is just

that, a button. If that button influences the hardware then you need to

implement an rfkill class instead. This also applies if the platform provides

implement an rfkill driver instead. This also applies if the platform provides

a way to turn on/off the transmitter(s).

During suspend/hibernation, transmitters should only be left enabled when

wake-on wlan or similar functionality requires it and the device wasn't

blocked before suspend/hibernate. Note that it may be necessary to update

the rfkill subsystem's idea of what the current state is at resume time if

the state may have changed over suspend.

For some platforms, it is possible that the hardware state changes during

suspend/hibernation, in which case it will be necessary to update the rfkill

core with the current state is at resume time.

To create an rfkill driver, driver's Kconfig needs to have

4. Kernel API

	depends on RFKILL || !RFKILL

To build a driver with rfkill subsystem support, the driver should depend on

(or select) the Kconfig symbol RFKILL.

The hardware the driver talks to may be write-only (where the current state

of the hardware is unknown), or read-write (where the hardware can be queried

about its current state).

to ensure the driver cannot be built-in when rfkill is modular. The !RFKILL

case allows the driver to be built when rfkill is not configured, which which

case all rfkill API can still be used but will be provided by static inlines

which compile to almost nothing.

Calling rfkill_set_hw_state() when a state change happens is required from

rfkill drivers that control devices that can be hard-blocked unless they also

5. Userspace support

The following sysfs entries exist for every rfkill device:

The recommended userspace interface to use is /dev/rfkill, which is a misc

character device that allows userspace to obtain and set the state of rfkill

devices and sets of devices. It also notifies userspace about device addition

and removal. The API is a simple read/write API that is defined in

linux/rfkill.h, with one ioctl that allows turning off the deprecated input

handler in the kernel for the transition period.

Except for the one ioctl, communication with the kernel is done via read()

and write() of instances of 'struct rfkill_event'. In this structure, the

soft and hard block are properly separated (unlike sysfs, see below) and

userspace is able to get a consistent snapshot of all rfkill devices in the

system. Also, it is possible to switch all rfkill drivers (or all drivers of

a specified type) into a state which also updates the default state for

hotplugged devices.

After an application opens /dev/rfkill, it can read the current state of

all devices, and afterwards can poll the descriptor for hotplug or state

change events.

Applications must ignore operations (the "op" field) they do not handle,

this allows the API to be extended in the future.

Additionally, each rfkill device is registered in sysfs and there has the

following attributes:

	name: Name assigned by driver to this key (interface or driver name).

	type: Name of the key type ("wlan", "bluetooth", etc).

	type: Driver type string ("wlan", "bluetooth", etc).

	state: Current state of the transmitter

		0: RFKILL_STATE_SOFT_BLOCKED

			transmitter is turned off by software

		2: RFKILL_STATE_HARD_BLOCKED

			transmitter is forced off by something outside of

			the driver's control.

	claim: 0: Kernel handles events (currently always reads that value)

	       This file is deprecated because it can only properly show

	       three of the four possible states, soft-and-hard-blocked is

	       missing.

	claim: 0: Kernel handles events

	       This file is deprecated because there no longer is a way to

	       claim just control over a single rfkill instance.

rfkill devices also issue uevents (with an action of "change"), with the

following environment variables set:

The contents of these variables corresponds to the "name", "state" and

"type" sysfs files explained above.

An alternative userspace interface exists as a misc device /dev/rfkill,

which allows userspace to obtain and set the state of rfkill devices and

sets of devices. It also notifies userspace about device addition and

removal. The API is a simple read/write API that is defined in

linux/rfkill.h.

	/*

	 * Set the beacon register and enable all timers.

	 */

	/* When in AP mode zero timer0 to start TSF */

	if (ah->ah_op_mode == NL80211_IFTYPE_AP)

	/* When in AP or Mesh Point mode zero timer0 to start TSF */

	if (ah->ah_op_mode == NL80211_IFTYPE_AP ||

	    ah->ah_op_mode == NL80211_IFTYPE_MESH_POINT)

		ath5k_hw_reg_write(ah, 0, AR5K_TIMER0);

	ath5k_hw_reg_write(ah, next_beacon, AR5K_TIMER0);

config ATH9K

	tristate "Atheros 802.11n wireless cards support"

	depends on PCI && MAC80211 && WLAN_80211

	depends on RFKILL || RFKILL=n

	select ATH_COMMON

	select MAC80211_LEDS

	select LEDS_CLASS

#include <linux/device.h>

#include <net/mac80211.h>

#include <linux/leds.h>

#include <linux/rfkill.h>

#include "hw.h"

#include "rc.h"

	bool registered;

};

struct ath_rfkill {

	struct rfkill *rfkill;

	struct rfkill_ops ops;

	char rfkill_name[32];

};

/********************/

/* Main driver core */

/********************/

#define SC_OP_PROTECT_ENABLE    BIT(6)

#define SC_OP_RXFLUSH           BIT(7)

#define SC_OP_LED_ASSOCIATED    BIT(8)

#define SC_OP_RFKILL_REGISTERED BIT(9)

#define SC_OP_WAIT_FOR_BEACON   BIT(12)

#define SC_OP_LED_ON            BIT(13)

#define SC_OP_SCANNING          BIT(14)

	int beacon_interval;

	struct ath_rfkill rf_kill;

	struct ath_ani ani;

	struct ath9k_node_stats nodestats;

#ifdef CONFIG_ATH9K_DEBUG

	if (atomic_dec_and_test(&sc->ps_usecount))

		if ((sc->hw->conf.flags & IEEE80211_CONF_PS) &&

		    !(sc->sc_flags & (SC_OP_WAIT_FOR_BEACON |

				      SC_OP_WAIT_FOR_CAB |

				      SC_OP_WAIT_FOR_PSPOLL_DATA |

				      SC_OP_WAIT_FOR_TX_ACK)))

			ath9k_hw_setpower(sc->sc_ah,

	REG_WRITE(ah, AR_PHY_MASK2_P_61_45, tmp_mask);

}

static void ath9k_enable_rfkill(struct ath_hw *ah)

{

	REG_SET_BIT(ah, AR_GPIO_INPUT_EN_VAL,

		    AR_GPIO_INPUT_EN_VAL_RFSILENT_BB);

	REG_CLR_BIT(ah, AR_GPIO_INPUT_MUX2,

		    AR_GPIO_INPUT_MUX2_RFSILENT);

	ath9k_hw_cfg_gpio_input(ah, ah->rfkill_gpio);

	REG_SET_BIT(ah, AR_PHY_TEST, RFSILENT_BB);

}

int ath9k_hw_reset(struct ath_hw *ah, struct ath9k_channel *chan,

		    bool bChannelChange)

{

	ath9k_hw_init_interrupt_masks(ah, ah->opmode);

	ath9k_hw_init_qos(ah);

#if defined(CONFIG_RFKILL) || defined(CONFIG_RFKILL_MODULE)

	if (ah->caps.hw_caps & ATH9K_HW_CAP_RFSILENT)

		ath9k_enable_rfkill(ah);

#endif

	ath9k_hw_init_user_settings(ah);

	REG_WRITE(ah, AR_STA_ID1,

		AR_GPIO_BIT(gpio));

}

#if defined(CONFIG_RFKILL) || defined(CONFIG_RFKILL_MODULE)

void ath9k_enable_rfkill(struct ath_hw *ah)

{

	REG_SET_BIT(ah, AR_GPIO_INPUT_EN_VAL,

		    AR_GPIO_INPUT_EN_VAL_RFSILENT_BB);

	REG_CLR_BIT(ah, AR_GPIO_INPUT_MUX2,

		    AR_GPIO_INPUT_MUX2_RFSILENT);

	ath9k_hw_cfg_gpio_input(ah, ah->rfkill_gpio);

	REG_SET_BIT(ah, AR_PHY_TEST, RFSILENT_BB);

}

#endif

u32 ath9k_hw_getdefantenna(struct ath_hw *ah)

{

	return REG_READ(ah, AR_DEF_ANTENNA) & 0x7;