In ltc2952_poweroff_handler it is theoretically possible that the timer
fails to start on first pass (button press), but succeeds in starting on
the second (button release). This will cause the button press to be
misinterpreted, and will incorrectly shut down the system. Because a
picture says more than a thousand words:
Expected behavior:
tmr: ++++++++++
btn: -----__________-----
Faulty behavior:
tmr: +++++
btn: -----__________-----
Legend:
+ timer runs
_ button pressed
- button depressed
To prevent this from happening, check the value of the gpio before
starting the timer. If the button is active, we should start the timer,
else we should stop it.
The situation described can now still occur if the polarity of the input
pin is set incorrectly, but that at least is predictable behavior and
can be detected during the first tests.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Disable the timers when ltc2952_poweroff is removed. We don't want to
risk calling functions on data that no longer exist.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
The function pointers for the timers and pm_power_off are assigned with
C++ style
foo = &func;
Let's change it instead to the more C style
foo = func;
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
ltc2952_poweroff_handler uses gotos to return from the function. Since
we don't do cleanups exiting this function, just return IRQ_HANDLED on
the spot and be done with it.
While at it, remove the variable 'ret'. It was never used very much.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Documentation/SubmittingDrivers suggests these be implemented even when
they do nothing. On the other hand, the platform code calls these
functions 'legacy'. Suspend and resume operations should go into a
pm_ops structure, pointed at by the driver's pm field. This approach
would lead to a lot of boiler plate, while achieving nothing. Drop the
functions instead.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
As per Documentation/CodingStyle ch.4, we should keep global variables
to a mininum. Move the panic state into the driver data, regardless of
whether panic is a system state or not.
This removes the need for the custom _init and _exit functions, so
replace them with a call to the module_platform_driver() macro.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Documentation/CodingStyle ch.4 mentions in a side node that global
variables should only be used if you really need them. Reduce the use of
the global instance of ltc2952_poweroff so we may eventually remove it
entirely.
While at it, rename ltc2952_poweroff_data to ltc2952_poweroff, just to
save that little bit of typing.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
The three gpio's used by this driver are stored in an array of pointers.
This doesn't add much besides cleanups in a loop. In fact, it makes most
of the usage sites harder to read. Unroll the loop, and live with the
fact that cleanups become slightly larger.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Make use of the fact that we allocated resources can be automatically
deallocated. This reduces cleanup code and chance of errors. It also
removes the need for the virq member of the ltc2952_poweroff_data
struct.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Make use of the fact that the allocated resources can be automatically
deallocated. This reduces cleanup code and chance of leaks.
Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
This adds a driver for the LTC2952, an external power control chip,
which signals the OS to shut down. Additionally this driver lets the
kernel power down the board.
Signed-off-by: René Moll <rene.moll@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Frans Klaver