Messages in this thread | | | Subject | Re: [PATCH 08/15] rfkill: add read-write rfkill switch support | Date | Tue, 20 May 2008 12:08:47 +0200 | From | Ivo van Doorn <> |
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On Sunday 18 May 2008, Henrique de Moraes Holschuh wrote: > Currently, rfkill support for read/write rfkill switches is hacked through > a round-trip over the input layer and rfkill-input to let a driver sync > rfkill->state to hardware changes. > > This is buggy and sub-optimal. It causes real problems. It is best to > think of the rfkill class as supporting only write-only switches at the > moment. > > In order to implement the read/write functionality properly: > > Add a get_state() hook that is called by the class every time it needs to > fetch the current state of the switch. Add a call to this hook every time > the *current* state of the radio plays a role in a decision. > > Also add a force_state() method that can be used to forcefully syncronize > the class' idea of the current state of the switch. This allows for a > faster implementation of the read/write functionality, as a driver which > get events on switch changes can avoid the need for a get_state() hook. > > If the get_state() hook is left as NULL, current behaviour is maintained, > so this change is fully backwards compatible with the current rfkill > drivers. > > For hardware that issues events when the rfkill state changes, leave > get_state() NULL in the rfkill struct, set the initial state properly > before registering with the rfkill class, and use the force_state() method > in the driver to keep the rfkill interface up-to-date. > > get_state() can be called by the class from atomic context. It must not > sleep. > > Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
> Cc: Ivo van Doorn <IvDoorn@gmail.com> > Cc: Dmitry Torokhov <dtor@mail.ru> > --- > include/linux/rfkill.h | 5 ++++ > net/rfkill/rfkill.c | 49 +++++++++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 51 insertions(+), 3 deletions(-) > > diff --git a/include/linux/rfkill.h b/include/linux/rfkill.h > index ca89ae1..844e961 100644 > --- a/include/linux/rfkill.h > +++ b/include/linux/rfkill.h > @@ -61,6 +61,8 @@ enum rfkill_state { > * @data: Pointer to the RF button drivers private data which will be > * passed along when toggling radio state. > * @toggle_radio(): Mandatory handler to control state of the radio. > + * @get_state(): handler to read current radio state from hardware, > + * may be called from atomic context, should return 0 on success. > * @led_trigger: A LED trigger for this button's LED. > * @dev: Device structure integrating the switch into device tree. > * @node: Used to place switch into list of all switches known to the > @@ -80,6 +82,7 @@ struct rfkill { > > void *data; > int (*toggle_radio)(void *data, enum rfkill_state state); > + int (*get_state)(void *data, enum rfkill_state *state); > > #ifdef CONFIG_RFKILL_LEDS > struct led_trigger led_trigger; > @@ -95,6 +98,8 @@ void rfkill_free(struct rfkill *rfkill); > int rfkill_register(struct rfkill *rfkill); > void rfkill_unregister(struct rfkill *rfkill); > > +int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state); > + > /** > * rfkill_get_led_name - Get the LED trigger name for the button's LED. > * This function might return a NULL pointer if registering of the > diff --git a/net/rfkill/rfkill.c b/net/rfkill/rfkill.c > index 3edc585..2e19b68 100644 > --- a/net/rfkill/rfkill.c > +++ b/net/rfkill/rfkill.c > @@ -62,19 +62,39 @@ static void rfkill_led_trigger(struct rfkill *rfkill, > #endif /* CONFIG_RFKILL_LEDS */ > } > > +static void update_rfkill_state(struct rfkill *rfkill) > +{ > + enum rfkill_state newstate; > + > + if (rfkill->get_state) { > + mutex_lock(&rfkill->mutex); > + if (!rfkill->get_state(rfkill->data, &newstate)) > + rfkill->state = newstate; > + mutex_unlock(&rfkill->mutex); > + } > +} > + > static int rfkill_toggle_radio(struct rfkill *rfkill, > enum rfkill_state state) > { > int retval = 0; > + enum rfkill_state oldstate, newstate; > + > + oldstate = rfkill->state; > + > + if (rfkill->get_state && > + !rfkill->get_state(rfkill->data, &newstate)) > + rfkill->state = newstate; > > if (state != rfkill->state) { > retval = rfkill->toggle_radio(rfkill->data, state); > - if (!retval) { > + if (!retval) > rfkill->state = state; > - rfkill_led_trigger(rfkill, state); > - } > } > > + if (rfkill->state != oldstate) > + rfkill_led_trigger(rfkill, rfkill->state); > + > return retval; > } > > @@ -105,6 +125,28 @@ void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state) > } > EXPORT_SYMBOL(rfkill_switch_all); > > +/** > + * rfkill_force_state - Force the internal rfkill radio state > + * @rfkill: pointer to the rfkill class to modify. > + * @state: the current radio state the class should be forced to. > + * > + * This function updates the internal state of the radio cached > + * by the rfkill class. It should be used when the driver gets > + * a notification by the firmware/hardware of the current *real* > + * state of the radio rfkill switch. > + * > + * It may not be called from an atomic context. > + */ > +int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state) > +{ > + mutex_lock(&rfkill->mutex); > + rfkill->state = state; > + mutex_unlock(&rfkill->mutex); > + > + return 0; > +} > +EXPORT_SYMBOL(rfkill_force_state); > + > static ssize_t rfkill_name_show(struct device *dev, > struct device_attribute *attr, > char *buf) > @@ -147,6 +189,7 @@ static ssize_t rfkill_state_show(struct device *dev, > { > struct rfkill *rfkill = to_rfkill(dev); > > + update_rfkill_state(rfkill); > return sprintf(buf, "%d\n", rfkill->state); > } >
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