From a6c08b0d8418632529e5172624d638adbb51c230 Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Tue, 21 Dec 2010 13:04:52 -0800 Subject: [PATCH] cs5535-gpio: handle GPIO regs where higher (clear) bits are set The default for non-READ_BACK GPIO regs is to have the clear bits set; this means that our original errata fix was too simplistic. This changes it to the following behavior: - when setting GPIOs, ignore the higher order bits (they're for clearing, we don't need to care about them). - when clearing GPIOs, keep all the bits, but unset (via XOR) the lower order bit that negates the clear bit that we care about. That is, if we're clearing GPIO 26 (val = 0x04000000), we first XOR what's currently in the register with 0x0400 (GPIO 26's SET bit), and then OR that with the GPIO 26's CLEAR bit. Tested-by: Daniel Drake Signed-off-by: Andres Salomon Signed-off-by: Linus Torvalds --- drivers/gpio/cs5535-gpio.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/cs5535-gpio.c b/drivers/gpio/cs5535-gpio.c index 79eb9c5a2923d..d3e55a0ae92be 100644 --- a/drivers/gpio/cs5535-gpio.c +++ b/drivers/gpio/cs5535-gpio.c @@ -70,8 +70,12 @@ static void errata_outl(struct cs5535_gpio_chip *chip, u32 val, * Don't apply this errata to the edge status GPIOs, as writing * to their lower bits will clear them. */ - if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS) - val |= inl(addr); + if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS) { + if (val & 0xffff) + val |= (inl(addr) & 0xffff); /* ignore the high bits */ + else + val |= (inl(addr) ^ (val >> 16)); + } outl(val, addr); } -- 2.39.5