diff options
| author | Andres Salomon <dilinger@queued.net> | 2010-12-21 13:04:52 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-12-23 15:31:48 -0800 |
| commit | 44658a11f312fb9217674cb90b1a11cbe17fd18d (patch) | |
| tree | 599549060943c051e8943f85da80e4905d941016 /drivers/gpio | |
| parent | 001851659354cce436b749a793f3512a53394d80 (diff) | |
| download | lwn-44658a11f312fb9217674cb90b1a11cbe17fd18d.tar.gz lwn-44658a11f312fb9217674cb90b1a11cbe17fd18d.zip | |
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 <dsd@laptop.org>
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/cs5535-gpio.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/gpio/cs5535-gpio.c b/drivers/gpio/cs5535-gpio.c index 79eb9c5a2923..d3e55a0ae92b 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); } |