The bcm283x mini-uart is only really usable as U-Boot serial output
when it is muxed to the UART pins of the RPi pin header.
So fail probing in case it is not muxed correctly, as in that case
firmware did not initialize it properly either.
Signed-off-by: Alexander Graf <agraf@suse.de>
The serial initialization doesn't always quite work for me, so let's
always skip it for now. We know that firmware on the RPi initializes
us properly already.
Signed-off-by: Alexander Graf <agraf@suse.de>
We are switching to a model where a serial device doesn't even get probed when
it's not muxed properly, so we don't need device specific disabling
functionality anymore.
Signed-off-by: Alexander Graf <agraf@suse.de>
These support the flat device tree. We want to use the dev_read_..()
prefix for functions that support both flat tree and live tree. So rename
the existing functions to avoid confusion.
In the end we will have:
1. dev_read_addr...() - works on devices, supports flat/live tree
2. devfdt_get_addr...() - current functions, flat tree only
3. of_get_address() etc. - new functions, live tree only
All drivers will be written to use 1. That function will in turn call
either 2 or 3 depending on whether the flat or live tree is in use.
Note this involves changing some dead code - the imx_lpi2c.c file.
Signed-off-by: Simon Glass <sjg@chromium.org>
At present devices use a simple integer offset to record the device tree
node associated with the device. In preparation for supporting a live
device tree, which uses a node pointer instead, refactor existing code to
access this field through an inline function.
Signed-off-by: Simon Glass <sjg@chromium.org>
For the Raspberry Pi 3 it needs to be possible to disable the serial
device after initialization happens, as only after the GPIO device is available
it is known whether the mini uart is usable.
Signed-off-by: Fabian Vogt <fvogt@suse.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This patch adds device tree support for the bcm283x mini-uart driver.
Signed-off-by: Fabian Vogt <fvogt@suse.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
On the raspberry pi, you can disable the serial port to gain dynamic frequency
scaling which can get handy at times.
However, in such a configuration the serial controller gets its rx queue filled
up with zero bytes which then happily get transmitted on to whoever calls
getc() today.
This patch adds detection logic for that case by checking whether the RX pin is
mapped to GPIO15 and disables the mini uart if it is not mapped properly.
That way we can leave the driver enabled in the tree and can determine during
runtime whether serial is usable or not, having a single binary that allows for
uart and non-uart operation.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
dm_serial_ops.pending should return the number of characters, not just a
valid C Boolean integer value. The existing code does already does this,
but only as an accident since BCM283X_MU_LSR_RX_READY happens to be
BIT(0). Enhance the code to be more explicit about the values it returns.
Suggested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
The RPi3 typically uses the regular UART for high-speed communication with
the Bluetooth device, leaving us the mini UART to use for the serial
console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>