[115/152] cs5535-gpio: dont apply errata #36 to edge detect GPIOs

Greg KH
2011-01-06T00:39:56Z

From: Andres Salomon <dilinger@queued.net>

commit 001851659354cce436b749a793f3512a53394d80 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/gpio/cs5535-gpio.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

--- 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 cs5
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 c
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)