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>
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>
The AMD Geode CS5536 Companion Device Silicon Revision B1 Specification
Update mentions the follow as issue #36:
"Atomic write transactions to the atomic GPIO High Bank Feature Bit
registers should only affect the bits selected [...]"
"after Suspend, an atomic write transaction [...] will clear all
non-selected bits of the accessed register."
In other words, writing to the high bank for a single GPIO bit will
clear every other GPIO bit (but only sometimes after a suspend).
The workaround described is obvious and simple; do a read-modify-write.
This patch does that, and documents why we're doing it.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
My Collabora address is no longer enabled - update the MODULE_AUTHOR
fields of drivers to my current email address.
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gpiolib doesn't need to modify the names and I assume most initializers
use string constants that shouldn't be modified anyhow.
[akpm@linux-foundation.org: fix drivers/gpio/cs5535-gpio.c]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Kevin Wells <kevin.wells@nxp.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The cs5535-gpio driver's get() function was returning the output value.
This means that the GPIO pins would never work as an input, even if
configured as an input.
The driver should return the READ_BACK value, which is the sensed line
value. To make that work when the direction is 'output', INPUT_ENABLE
needs to be set.
In addition, the driver was not disabling OUTPUT_ENABLE when the direction
is set to 'input'. That would cause the GPIO to continue to drive the pin
if the direction was ever set to output.
This issue was noticed when attempting to use the gpiolib driver to read
an external input. I had previously been using the char/cs5535-gpio
driver.
Signed-off-by: Ben Gardner <gardner.ben@gmail.com>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: <stable@kernel.org> [2.6.33.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changed number of gpio pins to 32 (according to datasheet)
Added mask to disable some pins
Added gpio_request for checking mask and disabling special pin functions
Added pin names
[dilinger@collabora.co.uk: make printk usage consistent]
Signed-off-by: Tobias Mueller <Tobias_Mueller@twam.info>
Signed-off-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andres Salomon <dilinger@collabora.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This creates a CS5535/CS5536 GPIO driver which uses a gpio_chip backend
(allowing GPIO users to use the generic GPIO API if desired) while also
allowing architecture-specific users directly (via the cs5535_gpio_*
functions).
Tested on an OLPC machine. Some Leemotes also use CS5536 (with a mips
cpu), which is why this is in drivers/gpio rather than arch/x86.
Currently, it conflicts with older geode GPIO support; once MFGPT support
is reworked to also be more generic, the older geode code will be removed.
Signed-off-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: David Brownell <david-b@pacbell.net>
Reviewed-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
