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gpio: ws16c48: Add set_multiple callback function support 

The WinSystems WS16C48 provides registers where 8 lines of GPIO may be
set at a time. This patch add support for the set_multiple callback
function, thus allowing multiple GPIO output lines to be set more
efficiently in groups.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
William Breathitt Gray 2017-01-19 10:05:59 -05:00 committed by Linus Walleij
parent 65502a12ad
commit 99c8ac957e
1 changed files with 41 additions and 0 deletions
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41
drivers/gpio/gpio-ws16c48.c
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@ -155,6 +155,46 @@ static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
unsigned int i;
const unsigned int gpio_reg_size = 8;
unsigned int port;
unsigned int iomask;
unsigned int bitmask;
unsigned long flags;
/* set bits are evaluated a gpio register size at a time */
for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
/* no more set bits in this mask word; skip to the next word */
if (!mask[BIT_WORD(i)]) {
i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
continue;
}
port = i / gpio_reg_size;
/* mask out GPIO configured for input */
iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
bitmask = iomask & bits[BIT_WORD(i)];
spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* update output state data and set device gpio register */
ws16c48gpio->out_state[port] &= ~iomask;
ws16c48gpio->out_state[port] |= bitmask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
/* prepare for next gpio register set */
mask[BIT_WORD(i)] >>= gpio_reg_size;
bits[BIT_WORD(i)] >>= gpio_reg_size;
}
}
static void ws16c48_irq_ack(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
@ -329,6 +369,7 @@ static int ws16c48_probe(struct device *dev, unsigned int id)
ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
ws16c48gpio->chip.get = ws16c48_gpio_get;
ws16c48gpio->chip.set = ws16c48_gpio_set;
ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
ws16c48gpio->base = base[id];
ws16c48gpio->irq = irq[id];