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gpio: pci-idio-16: Implement get_multiple callback

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The ACCES I/O PCI-IDIO-16 series of devices provides 16
optically-isolated digital inputs accessed via two 8-bit ports. Since
eight input lines are acquired on a single port input read, the
PCI-IDIO-16 GPIO driver may improve multiple input reads by utilizing a
get_multiple callback. This patch implements the
idio_16_gpio_get_multiple function which serves as the respective
get_multiple callback.

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 2018-03-22 08:59:48 -04:00 committed by Linus Walleij
parent 15f59cfff9
commit 810ebfc5ef
1 changed files with 50 additions and 0 deletions
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50
drivers/gpio/gpio-pci-idio-16.c
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@ -11,6 +11,7 @@
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
@ -103,6 +104,54 @@ static int idio_16_gpio_get(struct gpio_chip *chip, unsigned int offset)
return !!(ioread8(&idio16gpio->reg->in8_15) & (mask >> 24));
}
static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
size_t i;
const unsigned int gpio_reg_size = 8;
unsigned int bits_offset;
size_t word_index;
unsigned int word_offset;
unsigned long word_mask;
const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
unsigned long port_state;
u8 __iomem ports[] = {
idio16gpio->reg->out0_7, idio16gpio->reg->out8_15,
idio16gpio->reg->in0_7, idio16gpio->reg->in8_15,
};
/* clear bits array to a clean slate */
bitmap_zero(bits, chip->ngpio);
/* get bits are evaluated a gpio port register at a time */
for (i = 0; i < ARRAY_SIZE(ports); i++) {
/* gpio offset in bits array */
bits_offset = i * gpio_reg_size;
/* word index for bits array */
word_index = BIT_WORD(bits_offset);
/* gpio offset within current word of bits array */
word_offset = bits_offset % BITS_PER_LONG;
/* mask of get bits for current gpio within current word */
word_mask = mask[word_index] & (port_mask << word_offset);
if (!word_mask) {
/* no get bits in this port so skip to next one */
continue;
}
/* read bits from current gpio port */
port_state = ioread8(ports + i);
/* store acquired bits at respective bits array offset */
bits[word_index] |= port_state << word_offset;
}
return 0;
}
static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
int value)
{
@ -299,6 +348,7 @@ static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
idio16gpio->chip.get = idio_16_gpio_get;
idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
idio16gpio->chip.set = idio_16_gpio_set;
idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;