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Subject[PATCH 3/5] gpio: gpio-mm: Add set_multiple callback function support
Date
The Diamond Systems GPIO-MM series 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>
---
drivers/gpio/gpio-gpio-mm.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/drivers/gpio/gpio-gpio-mm.c b/drivers/gpio/gpio-gpio-mm.c
index 1e7def9449ce..093489556c54 100644
--- a/drivers/gpio/gpio-gpio-mm.c
+++ b/drivers/gpio/gpio-gpio-mm.c
@@ -192,6 +192,44 @@ static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset,
spin_unlock_irqrestore(&gpiommgpio->lock, flags);
}

+static void gpiomm_gpio_set_multiple(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+ unsigned int i;
+ const unsigned int gpio_reg_size = 8;
+ unsigned int port;
+ unsigned int out_port;
+ 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;
+ out_port = (port > 2) ? port + 1 : port;
+ bitmask = mask[BIT_WORD(i)] & bits[BIT_WORD(i)];
+
+ spin_lock_irqsave(&gpiommgpio->lock, flags);
+
+ /* update output state data and set device gpio register */
+ gpiommgpio->out_state[port] &= ~mask[BIT_WORD(i)];
+ gpiommgpio->out_state[port] |= bitmask;
+ outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);
+
+ spin_unlock_irqrestore(&gpiommgpio->lock, flags);
+
+ /* prepare for next gpio register set */
+ mask[BIT_WORD(i)] >>= gpio_reg_size;
+ bits[BIT_WORD(i)] >>= gpio_reg_size;
+ }
+}
+
static int gpiomm_probe(struct device *dev, unsigned int id)
{
struct gpiomm_gpio *gpiommgpio;
@@ -218,6 +256,7 @@ static int gpiomm_probe(struct device *dev, unsigned int id)
gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output;
gpiommgpio->chip.get = gpiomm_gpio_get;
gpiommgpio->chip.set = gpiomm_gpio_set;
+ gpiommgpio->chip.set_multiple = gpiomm_gpio_set_multiple;
gpiommgpio->base = base[id];

spin_lock_init(&gpiommgpio->lock);
--
2.11.0
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