[PATCH] serial: 8250: Add CAP_MINI, set for bcm2835aux

Eric Anholt eric at anholt.net
Fri May 19 11:09:54 PDT 2017


Phil Elwell <phil at raspberrypi.org> writes:

> The AUX/mini-UART in the BCM2835 family of procesors is a cut-down
> 8250 clone. In particular it is lacking support for the following
> features: CSTOPB PARENB PARODD CMSPAR CS5 CS6
>
> Add a new capability (UART_CAP_MINI) that exposes the restrictions to
> the user of the termios API by turning off the unsupported features in
> the request.
>
> N.B. It is almost possible to automatically discover the missing
> features by reading back the LCR register, but the CSIZE bits don't
> cooperate (contrary to the documentation, both bits are significant,
> but CS5 and CS6 are mapped to CS7) and the code is much longer.
>
> See: https://github.com/raspberrypi/linux/issues/1561
>
> Signed-off-by: Phil Elwell <phil at raspberrypi.org>

Acked-by: Eric Anholt <eric at anholt.net>
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