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cs5535-gpio: don't apply errata #36 to edge detect GPIOs 

The edge detect status GPIOs function differently from the other atomic
model CS5536 GPIO registers; writing 1 to the high bits clears the GPIO,
but writing 1 to the lower bits also clears the bit.

This means that read-modify-write doesn't actually work for it, so don't
apply the errata here.  If a negative edge status gets lost after
resume..  well, we tried our best!

Tested-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andres Salomon 2010-12-21 13:04:42 -08:00 committed by Linus Torvalds
parent e819eb8687
commit 0018516593
1 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/gpio/cs5535-gpio.c
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@ -56,15 +56,22 @@ static struct cs5535_gpio_chip {
* registers, see include/linux/cs5535.h. * registers, see include/linux/cs5535.h.
*/ */
static void errata_outl(u32 val, unsigned long addr) static void errata_outl(struct cs5535_gpio_chip *chip, u32 val,
unsigned int reg)
{ {
unsigned long addr = chip->base + 0x80 + reg;
/* /*
* According to the CS5536 errata (#36), after suspend * According to the CS5536 errata (#36), after suspend
* a write to the high bank GPIO register will clear all * a write to the high bank GPIO register will clear all
* non-selected bits; the recommended workaround is a * non-selected bits; the recommended workaround is a
* read-modify-write operation. * read-modify-write operation.
*
* Don't apply this errata to the edge status GPIOs, as writing
* to their lower bits will clear them.
*/ */
val |= inl(addr); if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS)
val |= inl(addr);
outl(val, addr); outl(val, addr);
} }
@ -76,7 +83,7 @@ static void __cs5535_gpio_set(struct cs5535_gpio_chip *chip, unsigned offset,
outl(1 << offset, chip->base + reg); outl(1 << offset, chip->base + reg);
else else
/* high bank register */ /* high bank register */
errata_outl(1 << (offset - 16), chip->base + 0x80 + reg); errata_outl(chip, 1 << (offset - 16), reg);
} }
void cs5535_gpio_set(unsigned offset, unsigned int reg) void cs5535_gpio_set(unsigned offset, unsigned int reg)
@ -98,7 +105,7 @@ static void __cs5535_gpio_clear(struct cs5535_gpio_chip *chip, unsigned offset,
outl(1 << (offset + 16), chip->base + reg); outl(1 << (offset + 16), chip->base + reg);
else else
/* high bank register */ /* high bank register */
errata_outl(1 << offset, chip->base + 0x80 + reg); errata_outl(chip, 1 << offset, reg);
} }
void cs5535_gpio_clear(unsigned offset, unsigned int reg) void cs5535_gpio_clear(unsigned offset, unsigned int reg)