[PATCH 1/1] rfkill: add the GPS radio type

[PATCH 1/1] rfkill: add the GPS radio type

[Tomas Winkler]

Althoug GPS is a technology w/o transmitting radio
and thus not a primary candidate for rfkill switch,
rfkill gives unified interface point for devices with
wireless technology.

The input key is not supplied as it is too be deprecated.

Cc: johannes@sipsolutions.net
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
 include/linux/rfkill.h |    1 +
 net/rfkill/core.c      |    4 +++-
 2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/include/linux/rfkill.h b/include/linux/rfkill.h
index 1020290..21ca51b 100644
--- a/include/linux/rfkill.h
+++ b/include/linux/rfkill.h
@@ -47,6 +47,7 @@ enum rfkill_type {
 	RFKILL_TYPE_UWB,
 	RFKILL_TYPE_WIMAX,
 	RFKILL_TYPE_WWAN,
+	RFKILL_TYPE_GPS,
 	NUM_RFKILL_TYPES,
 };
 
diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 044de1c..dbeaf29 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -589,11 +589,13 @@ static const char *rfkill_get_type_str(enum rfkill_type type)
 		return "wimax";
 	case RFKILL_TYPE_WWAN:
 		return "wwan";
+	case RFKILL_TYPE_GPS:
+		return "gps";
 	default:
 		BUG();
 	}
 
-	BUILD_BUG_ON(NUM_RFKILL_TYPES != RFKILL_TYPE_WWAN + 1);
+	BUILD_BUG_ON(NUM_RFKILL_TYPES != RFKILL_TYPE_GPS + 1);
 }
 
 static ssize_t rfkill_type_show(struct device *dev,
-- 
1.6.0.6

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Re: [PATCH 1/1] rfkill: add the GPS radio type

[Marcel Holtmann]

Hi Tomas,

> Althoug GPS is a technology w/o transmitting radio
> and thus not a primary candidate for rfkill switch,
> rfkill gives unified interface point for devices with
> wireless technology.
> 
> The input key is not supplied as it is too be deprecated.
> 
> Cc: johannes@sipsolutions.net
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>

we don't have a GPS subsystem, but even without it, I think this is a
good thing to have.

Acked-by: Marcel Holtmann <marcel@holtmann.org>

Please also send a patch updating the rfkill userspace utility.

Regards

Marcel

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Tomas Winkler]

On Sun, Aug 2, 2009 at 3:04 AM, Marcel Holtmann<marcel@holtmann.org> wrote:
> Hi Tomas,
>
>> Althoug GPS is a technology w/o transmitting radio
>> and thus not a primary candidate for rfkill switch,
>> rfkill gives unified interface point for devices with
>> wireless technology.
>>
>> The input key is not supplied as it is too be deprecated.
>>
>> Cc: johannes@sipsolutions.net
>> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
>
> we don't have a GPS subsystem, but even without it, I think this is a
> good thing to have.

GPS devices are usually serial devices.

> Acked-by: Marcel Holtmann <marcel@holtmann.org>
>
> Please also send a patch updating the rfkill userspace utility.

On the way....
Tomas

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Johannes Berg]

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On Sun, 2009-08-02 at 08:49 +0300, Tomas Winkler wrote:

> > we don't have a GPS subsystem, but even without it, I think this is a
> > good thing to have.
> 
> GPS devices are usually serial devices.

Yeah, this is interesting -- do we want something like /dev/urfkill
(cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
applies for 3G) can be controlled with rfkill?

johannes

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[-- Type: application/pgp-signature, Size: 801 bytes --]

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Tomas Winkler]

On Sun, Aug 2, 2009 at 10:45 AM, Johannes Berg<johannes@sipsolutions.net> wrote:
> On Sun, 2009-08-02 at 08:49 +0300, Tomas Winkler wrote:
>
>> > we don't have a GPS subsystem, but even without it, I think this is a
>> > good thing to have.
>>
>> GPS devices are usually serial devices.
>
> Yeah, this is interesting -- do we want something like /dev/urfkill
> (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
> applies for 3G) can be controlled with rfkill?

Sorry don't know much about /dev/uinput what is difference between
/dev/urfkill and /dev/rfkill, can you be, please more verbose
Thanks
Tomas

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Marcel Holtmann]

Hi Tomas,

> >> > we don't have a GPS subsystem, but even without it, I think this is a
> >> > good thing to have.
> >>
> >> GPS devices are usually serial devices.
> >
> > Yeah, this is interesting -- do we want something like /dev/urfkill
> > (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
> > applies for 3G) can be controlled with rfkill?
> 
> Sorry don't know much about /dev/uinput what is difference between
> /dev/urfkill and /dev/rfkill, can you be, please more verbose

the uinput allows you to write a input driver in userspace. So with
urfkill you could in theory write a RFKILL switch as a userspace
program.

Regards

Marcel

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Marcel Holtmann]

Hi Johannes,

> > > we don't have a GPS subsystem, but even without it, I think this is a
> > > good thing to have.
> > 
> > GPS devices are usually serial devices.
> 
> Yeah, this is interesting -- do we want something like /dev/urfkill
> (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
> applies for 3G) can be controlled with rfkill?

on one hand I think urfkill might be needed, on the other hand I think
we should not do it at all. Currently I would think it is better to
force the RFKILL integration in the kernel so that we have proper
subsystem integration, or platform RFKILL switches or in cases like GPS
and WWAN/3G it will be driver integration. For 3G we already have the
hso.ko driver which has a killswitch and we just need to fix the other
ones. I am actually looking into it, if this is possible without an AT
parser inside the kernel.

So the GPS world is evolving right now and that everybody implements
them as kernel-tty-passthrough pseudo driver and then a binary only
daemon and then gpsd/gypsy on top of it will only survive for certain
amount of time. The binary component will not get wide acceptance. And
even if the binary only userspace component stays, we might still need a
proper GPS subsystem since using TTY as pure transport is holding us
back. Could be that AF_GPS would have been a way better choice. This
will sort itself out over time.

Regards

Marcel

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Tomas Winkler]

On Sun, Aug 2, 2009 at 7:28 PM, Marcel Holtmann<marcel@holtmann.org> wrote:
> Hi Johannes,
>
>> > > we don't have a GPS subsystem, but even without it, I think this is a
>> > > good thing to have.
>> >
>> > GPS devices are usually serial devices.
>>
>> Yeah, this is interesting -- do we want something like /dev/urfkill
>> (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
>> applies for 3G) can be controlled with rfkill?
>
> on one hand I think urfkill might be needed, on the other hand I think
> we should not do it at all. Currently I would think it is better to
> force the RFKILL integration in the kernel so that we have proper
> subsystem integration, or platform RFKILL switches or in cases like GPS
> and WWAN/3G it will be driver integration. For 3G we already have the
> hso.ko driver which has a killswitch and we just need to fix the other
> ones. I am actually looking into it, if this is possible without an AT
> parser inside the kernel.

>
> So the GPS world is evolving right now and that everybody implements
> them as kernel-tty-passthrough pseudo driver and then a binary only
> daemon and then gpsd/gypsy on top of it will only survive for certain
> amount of time. The binary component will not get wide acceptance. And
> even if the binary only userspace component stays, we might still need a
> proper GPS subsystem since using TTY as pure transport is holding us
> back. Could be that AF_GPS would have been a way better choice. This
> will sort itself out over time.
>

BT also fails to the same category. BT driver also just servers as HCI
transport layer.
Current implementation of closing device driver is not sufficient to
really bring the device to rfkill mode. My point is from multi com
devices. What vendor implements are proprietary HCI commands that
brings device to rfkill mode, there is no standard. So in general you
would need HCI parser similar to AT parser or NMEA GPS parser  The
rfkill event is transferred inside the transport not visible to device
driver.
In other words RFKILL is happening between device and application w/o
kernel intervention. This is a problem since usually user application
and kernel has to be somehow notified.

Frankly I still don't understand what flow of how /dev/uevent is
helpful here. Who is notifying whom about rfkill event.

Thanks
Tomas

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Marcel Holtmann]

Hi Tomas,

> >> > > we don't have a GPS subsystem, but even without it, I think this is a
> >> > > good thing to have.
> >> >
> >> > GPS devices are usually serial devices.
> >>
> >> Yeah, this is interesting -- do we want something like /dev/urfkill
> >> (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
> >> applies for 3G) can be controlled with rfkill?
> >
> > on one hand I think urfkill might be needed, on the other hand I think
> > we should not do it at all. Currently I would think it is better to
> > force the RFKILL integration in the kernel so that we have proper
> > subsystem integration, or platform RFKILL switches or in cases like GPS
> > and WWAN/3G it will be driver integration. For 3G we already have the
> > hso.ko driver which has a killswitch and we just need to fix the other
> > ones. I am actually looking into it, if this is possible without an AT
> > parser inside the kernel.
> 
> >
> > So the GPS world is evolving right now and that everybody implements
> > them as kernel-tty-passthrough pseudo driver and then a binary only
> > daemon and then gpsd/gypsy on top of it will only survive for certain
> > amount of time. The binary component will not get wide acceptance. And
> > even if the binary only userspace component stays, we might still need a
> > proper GPS subsystem since using TTY as pure transport is holding us
> > back. Could be that AF_GPS would have been a way better choice. This
> > will sort itself out over time.
> >
> 
> BT also fails to the same category. BT driver also just servers as HCI
> transport layer.
> Current implementation of closing device driver is not sufficient to
> really bring the device to rfkill mode. My point is from multi com
> devices. What vendor implements are proprietary HCI commands that
> brings device to rfkill mode, there is no standard. So in general you
> would need HCI parser similar to AT parser or NMEA GPS parser  The
> rfkill event is transferred inside the transport not visible to device
> driver.
> In other words RFKILL is happening between device and application w/o
> kernel intervention. This is a problem since usually user application
> and kernel has to be somehow notified.

I have no idea what you are talking about here. The Bluetooth RFKILL
does exactly the right thing. The driver gets the down callback and is
responsible to bring the device down. It is expected that the radio will
be brought down at that point.

> Frankly I still don't understand what flow of how /dev/uevent is
> helpful here. Who is notifying whom about rfkill event.

Starting with 2.6.31 kernel we are using /dev/rfkill for notification
about RFKILL state changes. Previously it was done via uevents, but that
was more broken than helpful.

Regards

Marcel

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Tomas Winkler]

On Mon, Aug 3, 2009 at 7:24 PM, Marcel Holtmann<marcel@holtmann.org> wrote:
> Hi Tomas,
>
>> >> > > we don't have a GPS subsystem, but even without it, I think this is a
>> >> > > good thing to have.
>> >> >
>> >> > GPS devices are usually serial devices.
>> >>
>> >> Yeah, this is interesting -- do we want something like /dev/urfkill
>> >> (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
>> >> applies for 3G) can be controlled with rfkill?
>> >
>> > on one hand I think urfkill might be needed, on the other hand I think
>> > we should not do it at all. Currently I would think it is better to
>> > force the RFKILL integration in the kernel so that we have proper
>> > subsystem integration, or platform RFKILL switches or in cases like GPS
>> > and WWAN/3G it will be driver integration. For 3G we already have the
>> > hso.ko driver which has a killswitch and we just need to fix the other
>> > ones. I am actually looking into it, if this is possible without an AT
>> > parser inside the kernel.
>>
>> >
>> > So the GPS world is evolving right now and that everybody implements
>> > them as kernel-tty-passthrough pseudo driver and then a binary only
>> > daemon and then gpsd/gypsy on top of it will only survive for certain
>> > amount of time. The binary component will not get wide acceptance. And
>> > even if the binary only userspace component stays, we might still need a
>> > proper GPS subsystem since using TTY as pure transport is holding us
>> > back. Could be that AF_GPS would have been a way better choice. This
>> > will sort itself out over time.
>> >
>>
>> BT also fails to the same category. BT driver also just servers as HCI
>> transport layer.
>> Current implementation of closing device driver is not sufficient to
>> really bring the device to rfkill mode. My point is from multi com
>> devices. What vendor implements are proprietary HCI commands that
>> brings device to rfkill mode, there is no standard. So in general you
>> would need HCI parser similar to AT parser or NMEA GPS parser  The
>> rfkill event is transferred inside the transport not visible to device
>> driver.
>> In other words RFKILL is happening between device and application w/o
>> kernel intervention. This is a problem since usually user application
>> and kernel has to be somehow notified.
>
> I have no idea what you are talking about here. The Bluetooth RFKILL
> does exactly the right thing. The driver gets the down callback and is
> responsible to bring the device down. It is expected that the radio will
> be brought down at that point.

Let say you have USB device with 2 ports BT and Wifi  Closing prot
just releases urbs but it doesn't tell to particular port to shut the
radio it has no means for that., you have wifi running in parallel
playing with the radio its BT/WIFI coexistent games it has no
knowledge about rfkill event.   In SDIO things are little better since
you call sdio_disable_func() but you only guessing that device will
interpret it as rfkill  as well.

>> Frankly I still don't understand what flow of how /dev/uevent is
>> helpful here. Who is notifying whom about rfkill event.
>
> Starting with 2.6.31 kernel we are using /dev/rfkill for notification
> about RFKILL state changes. Previously it was done via uevents, but that
> was more broken than helpful.

So how /dev/rfkill differs from /dev/urfkill ?

Thanks
Tomas

Re: [PATCH 1/1] rfkill: add the GPS radio type

[Marcel Holtmann]

Hi Tomas,

> >> >> > > we don't have a GPS subsystem, but even without it, I think this is a
> >> >> > > good thing to have.
> >> >> >
> >> >> > GPS devices are usually serial devices.
> >> >>
> >> >> Yeah, this is interesting -- do we want something like /dev/urfkill
> >> >> (cf. /dev/uinput), so that gpsd or whatever is controlling the GPS (same
> >> >> applies for 3G) can be controlled with rfkill?
> >> >
> >> > on one hand I think urfkill might be needed, on the other hand I think
> >> > we should not do it at all. Currently I would think it is better to
> >> > force the RFKILL integration in the kernel so that we have proper
> >> > subsystem integration, or platform RFKILL switches or in cases like GPS
> >> > and WWAN/3G it will be driver integration. For 3G we already have the
> >> > hso.ko driver which has a killswitch and we just need to fix the other
> >> > ones. I am actually looking into it, if this is possible without an AT
> >> > parser inside the kernel.
> >>
> >> >
> >> > So the GPS world is evolving right now and that everybody implements
> >> > them as kernel-tty-passthrough pseudo driver and then a binary only
> >> > daemon and then gpsd/gypsy on top of it will only survive for certain
> >> > amount of time. The binary component will not get wide acceptance. And
> >> > even if the binary only userspace component stays, we might still need a
> >> > proper GPS subsystem since using TTY as pure transport is holding us
> >> > back. Could be that AF_GPS would have been a way better choice. This
> >> > will sort itself out over time.
> >> >
> >>
> >> BT also fails to the same category. BT driver also just servers as HCI
> >> transport layer.
> >> Current implementation of closing device driver is not sufficient to
> >> really bring the device to rfkill mode. My point is from multi com
> >> devices. What vendor implements are proprietary HCI commands that
> >> brings device to rfkill mode, there is no standard. So in general you
> >> would need HCI parser similar to AT parser or NMEA GPS parser  The
> >> rfkill event is transferred inside the transport not visible to device
> >> driver.
> >> In other words RFKILL is happening between device and application w/o
> >> kernel intervention. This is a problem since usually user application
> >> and kernel has to be somehow notified.
> >
> > I have no idea what you are talking about here. The Bluetooth RFKILL
> > does exactly the right thing. The driver gets the down callback and is
> > responsible to bring the device down. It is expected that the radio will
> > be brought down at that point.
> 
> Let say you have USB device with 2 ports BT and Wifi  Closing prot
> just releases urbs but it doesn't tell to particular port to shut the
> radio it has no means for that., you have wifi running in parallel
> playing with the radio its BT/WIFI coexistent games it has no
> knowledge about rfkill event.   In SDIO things are little better since
> you call sdio_disable_func() but you only guessing that device will
> interpret it as rfkill  as well.

this is a problem of the firmware inside the device. And if it is USB,
it could just have proper vendor specific control URBs that allow you to
control the radio RFKILL capabilities. If you happen to have a device
that has no notion of RFKILL at all, then that is just bad luck.

In embedded systems you can also have platform RFKILL switches that
toggle directly the power state via a GPIO. This is what we call a hard
killswitch. The subsystem integrated switches are softkill switches.

> >> Frankly I still don't understand what flow of how /dev/uevent is
> >> helpful here. Who is notifying whom about rfkill event.
> >
> > Starting with 2.6.31 kernel we are using /dev/rfkill for notification
> > about RFKILL state changes. Previously it was done via uevents, but that
> > was more broken than helpful.
> 
> So how /dev/rfkill differs from /dev/urfkill ?

I did explain that in the other email. We only have /dev/rfkill right
now and it might stay this way. The /dev/urfkill would be a way to
implement an RFKILL switch from within userspace.

Regards

Marcel