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>
So far we could only tell the gpio framework that a GPIO was mapped as input or
output, not as alternative function.
This patch adds support for determining whether a function is mapped as
alternative.
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Add a convenience function to access the private data that a uclass stores
for each of its devices. Convert over most existing uses for consistency
and to provide an example for others.
Signed-off-by: Simon Glass <sjg@chromium.org>
Now that the uclass supports gpio_request/free() there is no need for the
driver to implement it too. Drop this unnecessary code.
Signed-off-by: Simon Glass <sjg@chromium.org>
Convert the BCM2835 GPIO driver to use driver model, and switch over
Raspberry Pi to use this, since it is the only board.
Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
This SoC is used in the Raspberry Pi, for example.
For more details, see:
http://www.broadcom.com/products/BCM2835http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf.
Initial support is enough to boot to a serial console, execute a minimal
set of U-Boot commands, download data over a serial port, and boot a
Linux kernel. No storage or network drivers are implemented.
GPIO driver originally by Vikram Narayanan <vikram186@gmail.com>
with many fixes from myself.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
