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authorAndres Salomon <dilinger@queued.net>2010-12-21 13:04:42 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-12-23 15:31:48 -0800
commit001851659354cce436b749a793f3512a53394d80 (patch)
treecbce3c7d8f68c384229c40b915514b4668051d4a /drivers
parente819eb8687767cefca7b6abf5ac6d5efcf581eeb (diff)
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpio/cs5535-gpio.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/gpio/cs5535-gpio.c b/drivers/gpio/cs5535-gpio.c
index 599f6c9e0fbf..79eb9c5a2923 100644
--- a/drivers/gpio/cs5535-gpio.c
+++ b/drivers/gpio/cs5535-gpio.c
@@ -56,15 +56,22 @@ static struct cs5535_gpio_chip {
* 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
* a write to the high bank GPIO register will clear all
* non-selected bits; the recommended workaround is a
* 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);
}
@@ -76,7 +83,7 @@ static void __cs5535_gpio_set(struct cs5535_gpio_chip *chip, unsigned offset,
outl(1 << offset, chip->base + reg);
else
/* 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)
@@ -98,7 +105,7 @@ static void __cs5535_gpio_clear(struct cs5535_gpio_chip *chip, unsigned offset,
outl(1 << (offset + 16), chip->base + reg);
else
/* 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)