@@ -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>
@@ -129,6 +130,51 @@ static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
return !!(port_state & mask);
}
+static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
+ const unsigned int gpio_reg_size = 8;
+ size_t i;
+ const size_t num_ports = chip->ngpio / gpio_reg_size;
+ 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, 0);
+ unsigned long port_state;
+
+ /* 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 < num_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 = inb(ws16c48gpio->base + i);
+
+ /* store acquired bits at respective bits array offset */
+ bits[word_index] |= port_state << word_offset;
+ }
+
+ return 0;
+}
+
static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
@@ -383,6 +429,7 @@ static int ws16c48_probe(struct device *dev, unsigned int id)
ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
ws16c48gpio->chip.get = ws16c48_gpio_get;
+ ws16c48gpio->chip.get_multiple = ws16c48_gpio_get_multiple;
ws16c48gpio->chip.set = ws16c48_gpio_set;
ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
ws16c48gpio->base = base[id];
The WinSystems WS16C48 device provides 48 lines of digital I/O accessed via six 8-bit ports. Since eight input lines are acquired on a single port input read, the WS16C48 GPIO driver may improve multiple input reads by utilizing a get_multiple callback. This patch implements the ws16c48_gpio_get_multiple function which serves as the respective get_multiple callback. Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> --- drivers/gpio/gpio-ws16c48.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+)