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@raspberrypi.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes error condition check when requesting the irq,
that would not trigger because of uart_port.irq being
defined as unsigned int.
Reported by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The bcm2835 SOC contains an auxiliary uart, which is very close
to the ns16550 with some differences.
The big difference is that the uart HW is not using an internal divider
of 16 but 8, which results in an effictive baud-rate being twice
the requested baud-rate.
This driver handles this device correctly and handles the difference in
the HW divider by scaling up the clock by a factor of 2.
The approach to write a separate (wrapper) driver instead of using a
multiplying clock and "ns16550" as compatibility in the device-tree
has been recommended by Stephen Warren.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
