From 001851659354cce436b749a793f3512a53394d80 Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Tue, 21 Dec 2010 13:04:42 -0800 Subject: 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 Signed-off-by: Andres Salomon Signed-off-by: Linus Torvalds --- drivers/gpio/cs5535-gpio.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'drivers') diff --git a/drivers/gpio/cs5535-gpio.c b/drivers/gpio/cs5535-gpio.c index 599f6c9e0fb..79eb9c5a292 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) -- cgit v1.2.3-18-g5258