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gpio: max730x: make pullups configurable via platformdata

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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>
This commit is contained in:
Marc Kleine-Budde 2010-08-10 18:02:23 -07:00 committed by Linus Torvalds
parent 22e3d63147
commit 4a22b8a4ad
2 changed files with 23 additions and 7 deletions
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22
drivers/gpio/max730x.c
View File

@ -54,7 +54,7 @@ static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
{
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 @@ static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
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 @@ int __devinit __max730x_probe(struct max7301 *ts)
/* 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 @@ int __devinit __max730x_probe(struct max7301 *ts)
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;

8
include/linux/spi/max7301.h
View File

@ -11,6 +11,7 @@ struct max7301 {
struct mutex lock;
u8 port_config[8]; /* field 0 is unused */
u32 out_level; /* cached output levels */
u32 input_pullup_active;
struct gpio_chip chip;
struct device *dev;
int (*write)(struct device *dev, unsigned int reg, unsigned int val);
@ -20,6 +21,13 @@ struct max7301 {
struct max7301_platform_data {
/* number assigned to the first GPIO */
unsigned base;
/*
* bitmask controlling the pullup configuration,
*
* _note_ the 4 lowest bits are unused, because the first 4
* ports of the controller are not used, too.
*/
u32 input_pullup_active;
};
extern int __max730x_remove(struct device *dev);