Use IS_ERR() instead of comparing to NULL.

[akpm@linux-foundation.org: preserve the error code]
Signed-off-by: NJani Nikula <ext-jani.1.nikula@nokia.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This silences a false positive warning with kmemcheck.
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>

m68k allmodconfig:

| drivers/misc/c2port/core.c: In function 'c2port_reset':
| drivers/misc/c2port/core.c:73: error: dereferencing pointer to incomplete type
| drivers/misc/c2port/core.c: In function 'c2port_strobe_ck':
| drivers/misc/c2port/core.c:91: error: dereferencing pointer to incomplete type

Include <linux/sched.h> to fix it, as m68k's local_irq_enable() needs to know
about struct task_struct.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

C2port implements a two wire serial communication protocol (bit
banging) designed to enable in-system programming, debugging, and
boundary-scan testing on low pin-count Silicon Labs devices.

Currently this code supports only flash programming through sysfs
interface but extensions shoud be easy to add.
Signed-off-by: NRodolfo Giometti <giometti@linux.it>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>