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