tree a8d063a5a93760f7aeca9b32eb4e255b10be0dc7
parent dcfecd4d7a551906595351a26e1db91774b8563d
author Arnd Bergmann <arnd@arndb.de> 1562923449 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1564058122 +0200

mic: avoid statically declaring a 'struct device'.

Generally, declaring a platform device as a static variable is
a bad idea and can cause all kinds of problems, in particular
with the DMA configuration and lifetime rules.

A specific problem we hit here is from a bug in clang that warns
about certain (otherwise valid) macros when used in static variables:

drivers/misc/mic/card/mic_x100.c:285:27: warning: shift count >= width of type [-Wshift-count-overflow]
static u64 mic_dma_mask = DMA_BIT_MASK(64);
                          ^~~~~~~~~~~~~~~~
include/linux/dma-mapping.h:141:54: note: expanded from macro 'DMA_BIT_MASK'
 #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
                                                     ^ ~~~

A slightly better way here is to create the platform device dynamically
and set the dma mask in the probe function.
This avoids the warning and some other problems, but is still not ideal
because the device creation should really be separated from the driver,
and the fact that the device has no parent means we have to force
the dma mask rather than having it set up from the bus that the device
is actually on.

Fixes: dd8d8d44df64 ("misc: mic: MIC card driver specific changes to enable SCIF")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20190712092426.872625-1-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>