linux-imx

can: ti_hecc: properly report state changes

The HECC_CANES register handles the flags specially, it only updates
the flags after a one is written to them. Since the interrupt for
frame errors is not enabled an old error can hence been seen when a
state interrupt arrives. For example if the device is not connected
to the CAN-bus the error warning interrupt will have HECC_CANES
indicating there is no ack. The error passive interrupt thereafter
will have HECC_CANES flagging that there is a warning level. And if
thereafter there is a message successfully send HECC_CANES points to
an error passive event, while in reality it became error warning
again. In summary, the state is not always reported correctly.

So handle the state changes and frame errors separately. The state
changes are now based on the interrupt flags and handled directly
when they occur. The reporting of the frame errors is still done as
before, as a side effect of another interrupt.

note: the hecc_clear_bit will do a read, modify, write. So it will
not only clear the bit, but also reset all other bits being set as
a side affect, hence it is replaced with only clearing the flags.

note: The HECC_CANMC_CCR is no longer cleared in the state change
interrupt, it is completely unrelated.

And use net_ratelimit to make checkpatch happy.

Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>