Make the synchronous serdev_device_write() helper behave analogous to
the asynchronous serdev_device_write_buf() by returning the number of
bytes written (or rather buffered) also on timeout.
This will allow drivers to distinguish the case where data was partially
written from the case where no data was written.
Also update the only two users that checked the return value.
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Passing a timeout of zero to the synchronous serdev_device_write()
helper does currently not imply to wait forever (unlike passing zero to
serdev_device_wait_until_sent()). Instead, if there's insufficient
room in the write buffer, we'd end up with an incomplete write.
Fixes: d2efbbd18b ("gnss: add driver for sirfstar-based receivers")
Cc: stable <stable@vger.kernel.org> # 4.19
Signed-off-by: Johan Hovold <johan@kernel.org>
Add a "type" device attribute and a "GNSS_TYPE" uevent variable which
can be used to determine the type of a GNSS receiver. The currently
identified types reflect the protocol(s) supported by a receiver:
"NMEA" NMEA 0183
"SiRF" SiRF Binary
"UBX" UBX
Note that both SiRF and UBX type receivers typically support a subset of
NMEA 0183 with vendor extensions (e.g. to allow switching to the vendor
protocol).
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add driver for serial-connected SiRFstar-based GNSS receivers.
These devices typically boot into hibernate mode from which they can be
woken using a pulse on the ON_OFF input pin. Once active, a pulse on the
same ON_OFF pin is used to put the device back into hibernate mode. The
current state can be determined by sampling the WAKEUP output.
Hardware configurations where WAKEUP has been connected to ON_OFF (and
where an initial WAKEUP pulse during boot is sufficient to have the
device boot into active mode) are also supported. In this case, device
power is managed using the main-supply regulator only.
Note that configurations where WAKEUP is left not connected, so that the
device power state can only indirectly be determined using the I/O
interface, is currently not supported. It should be fairly
straight-forward to extend the current implementation with such support
however (and this this is the main reason for not using the generic
serial implementation for this driver).
Note that timepulse-support is left unimplemented.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Johan Hovold