Hi Varka,
On Fri, Apr 10, 2015 at 09:31:30AM +0530, Varka Bhadram wrote:
>
> I think better interface would be get_tx_power() for returning the current power setting
No, we have already such functionality to get the current tx power and
the 802.15.4 standard describes this as part of the pib. [0] 802.15.4
describes this as integer and I hope s8 is enough as range. But this is
funny then, because transceivers allow also floating point dbm values :-)
That 802.15.4 describes this as integer we should use a int (s8) as well here,
that was a open question in my other mails.
This pib attribute should be also set if set_tx_power was successful
afterwards with the values which was set.
> and tx_power_supported() to get the all the available power levels.
>
Yes we talking about the capabilities here only:
The general question about this capability is:
1. Does this interface will report all power levels for all page/channel?
or
2. Does this interface will report all power levels for current
page/channel setting only?
The second one is much easier to implement. But this is a question
which should be answered before.
If you asking yourself "which tx_powers for each ch/page?" This is not
available for 2.4 Ghz transceivers, but transceivers like the
at86rf212 which operates in 700/800/900Mhz have different tx power
settings according the channel/page setting.
The subquestion is here more how we should implement it. Current
solutions are:
1. Create a big array with some mask and set the bit about some
tx_power range and do some mask |= BIT(SUPP_5DBM). But this will
restrict the available setting of dbm levels.
2. The second idea was do use a "context based iteration of available
tx power settings". Netlink can do this quite well with nested
attributes. Calltrace would look like:
nla_nest_start
rdev_get_tx_pwr(&pwr)
rdev->ops->get_tx_pwr(&pwr)
mac802154_get_tx_pwr(&pwr)
/* driver_will_set_tx_pwr #1 */
nla_put_s8(pwr)
rdev_get_tx_pwr(&pwr)
rdev->ops->get_tx_pwr(&pwr)
mac802154_get_tx_pwr(&pwr)
/* driver_will_set_tx_pwr #2 */
nla_put_s8(pwr)
rdev_get_tx_pwr(&pwr)
rdev->ops->get_tx_pwr(&pwr)
mac802154_get_tx_pwr(&pwr)
/* driver_will_set_tx_pwr #3 */
nla_put_s8(pwr)
....
....
....
rdev_get_tx_pwr(&pwr)
rdev->ops->get_tx_pwr(&pwr)
mac802154_get_tx_pwr(&pwr)
/* driver_will_set_tx_pwr last. Must return 1 */
nla_put_s8(pwr)
/* indicated because rdev_get_tx_pwr returned 1 */
nla_nest_end
If you tell me you want "tx_power_supported()", please give me more
details how this interface will be look like.
- Alex
[0] http://lxr.free-electrons.com/source/include/net/cfg802154.h#L78
[1] http://www.atmel.com/images/doc8168.pdf page 107
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