[PATCH] collie: don't read GPSR
From: Lothar Waßmann <hidden>
Date: 2011-06-17 14:49:31
Hi, Dmitry Eremin-Solenikov writes:
On StrongARM GPSR is write-only according to docs, so don't read from it. Just set the required GPIO.
Anyway GPSR (and GPCR) is a bit oriented register that allows asserting individual bits without the need for read-modify-write cycles, making the access inherently multithread safe. Using read-modify-write on this register is contrary to the HW design. A quick grep of the kernel source shows another abuse like this in drivers/video/sa1100fb.c: GPSR |= SHANNON_GPIO_DISP_EN; drivers/video/sa1100fb.c: GPCR |= SHANNON_GPIO_DISP_EN; Lothar Wa?mann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstra?e 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Gesch?ftsf?hrer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info at karo-electronics.de ___________________________________________________________