gpio: max730x: make pullups configurable via platformdata
The gpios on the max730x chips have support for internal pullups while in
input mode.
This patch adds support for configuring these pullups via platform data.
A new member ("input_pullup_active") to the platform data struct is
introduced. A set bit in this variable activates the pullups while the
respective port is in input mode. This is a compatible enhancement since
unset bits lead to disables pullups which was the default in the original
driver.
_Note_: the 4 lowest bits in "input_pullup_active" are unused because the
first 4 ports of the controller are not used, too.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
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>
diff --git a/drivers/gpio/max730x.c b/drivers/gpio/max730x.c
index 7696a56..94ce773 100644
--- a/drivers/gpio/max730x.c
+++ b/drivers/gpio/max730x.c
@@ -54,7 +54,7 @@
{
struct max7301 *ts = container_of(chip, struct max7301, chip);
u8 *config;
- u8 offset_bits;
+ u8 offset_bits, pin_config;
int ret;
/* First 4 pins are unused in the controller */
@@ -63,12 +63,15 @@
config = &ts->port_config[offset >> 2];
+ if (ts->input_pullup_active & BIT(offset))
+ pin_config = PIN_CONFIG_IN_PULLUP;
+ else
+ pin_config = PIN_CONFIG_IN_WO_PULLUP;
+
mutex_lock(&ts->lock);
- /* Standard GPIO API doesn't support pull-ups, has to be extended.
- * Hard-coding no pollup for now. */
*config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
- | (PIN_CONFIG_IN_WO_PULLUP << offset_bits);
+ | (pin_config << offset_bits);
ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
@@ -177,6 +180,7 @@
/* Power up the chip and disable IRQ output */
ts->write(dev, 0x04, 0x01);
+ ts->input_pullup_active = pdata->input_pullup_active;
ts->chip.label = dev->driver->name;
ts->chip.direction_input = max7301_direction_input;
@@ -191,13 +195,17 @@
ts->chip.owner = THIS_MODULE;
/*
- * tristate all pins in hardware and cache the
+ * initialize pullups according to platform data and cache the
* register values for later use.
*/
for (i = 1; i < 8; i++) {
int j;
- /* 0xAA means input with internal pullup disabled */
- ts->write(dev, 0x08 + i, 0xAA);
+ /*
+ * initialize port_config with "0xAA", which means
+ * input with internal pullup disabled. This is needed
+ * to avoid writing zeros (in the inner for loop),
+ * which is not allowed according to the datasheet.
+ */
ts->port_config[i] = 0xAA;
for (j = 0; j < 4; j++) {
int offset = (i - 1) * 4 + j;