The ACCES I/O 104-DIO-48E series of devices contain two Programmable
Peripheral Interface (PPI) chips of type 82C55, which each feature three
8-bit ports of I/O. Since eight input lines are acquired on a single
port input read, the 104-DIO-48E GPIO driver may improve multiple input
reads by utilizing a get_multiple callback. This patch implements the
dio48e_gpio_get_multiple function which serves as the respective
get_multiple callback.
Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
---
drivers/gpio/gpio-104-dio-48e.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
index bab3b94c5cbc..35ae2357d2ba 100644
--- a/drivers/gpio/gpio-104-dio-48e.c
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -182,6 +182,46 @@ static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset)
return !!(port_state & mask);
}
+static int dio48e_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ unsigned int i;
+ const unsigned int gpio_reg_size = 8;
+ unsigned int bit_word_offset;
+ unsigned int bits_mask;
+ const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+ unsigned int port;
+ unsigned int in_port;
+ unsigned long port_state;
+
+ /* clear bits array to a clean slate */
+ for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+ bits[i / BITS_PER_LONG] = 0;
+
+ /* get bits are evaluated a gpio register size at a time */
+ for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+ bit_word_offset = i % BITS_PER_LONG;
+ bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+ if (!bits_mask) {
+ /* no get bits in this register so skip to next one */
+ continue;
+ }
+
+ /* compute input port offset */
+ port = i / gpio_reg_size;
+ in_port = (port > 2) ? port + 1 : port;
+
+ /* get input bits */
+ port_state = inb(dio48egpio->base + in_port);
+
+ /* store acquired bits */
+ bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+ }
+
+ return 0;
+}
+
static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
@@ -384,6 +424,7 @@ static int dio48e_probe(struct device *dev, unsigned int id)
dio48egpio->chip.direction_input = dio48e_gpio_direction_input;
dio48egpio->chip.direction_output = dio48e_gpio_direction_output;
dio48egpio->chip.get = dio48e_gpio_get;
+ dio48egpio->chip.get_multiple = dio48e_gpio_get_multiple;
dio48egpio->chip.set = dio48e_gpio_set;
dio48egpio->chip.set_multiple = dio48e_gpio_set_multiple;
dio48egpio->base = base[id];
--
2.16.2
--
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