From 4a22b8a4ad5561436b16f5278d2f9e406ffb8705 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Tue, 10 Aug 2010 18:02:23 -0700 Subject: [PATCH] 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 Reviewed-by: Wolfram Sang Cc: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/gpio/max730x.c | 22 +++++++++++++++------- include/linux/spi/max7301.h | 8 ++++++++ 2 files changed, 23 insertions(+), 7 deletions(-) diff --git a/drivers/gpio/max730x.c b/drivers/gpio/max730x.c index 7696a5625d58..94ce773f95f8 100644 --- a/drivers/gpio/max730x.c +++ b/drivers/gpio/max730x.c @@ -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; diff --git a/include/linux/spi/max7301.h b/include/linux/spi/max7301.h index 34af0a3477bf..bcaa2f762cc1 100644 --- a/include/linux/spi/max7301.h +++ b/include/linux/spi/max7301.h @@ -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);