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    Subject[PATCH v3 4/8] gpio: pcie-idio-24: Implement get_multiple/set_multiple callbacks
    Date
    The ACCES I/O PCIe-IDIO-24 series of devices provides 24
    optically-isolated digital I/O accessed via six 8-bit ports. Since eight
    input lines are acquired on a single port input read -- and similarly
    eight output lines are set on a single port output write -- the
    PCIe-IDIO-24 GPIO driver may improve multiple I/O reads/writes by
    utilizing a get_multiple/set_multiple callbacks. This patch implements
    the idio_24_gpio_get_multiple function which serves as the respective
    get_multiple callback, and implements the idio_24_gpio_set_multiple
    function which serves as the respective set_multiple callback.

    Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
    ---
    drivers/gpio/gpio-pcie-idio-24.c | 117 +++++++++++++++++++++++++++++++++++++++
    1 file changed, 117 insertions(+)

    diff --git a/drivers/gpio/gpio-pcie-idio-24.c b/drivers/gpio/gpio-pcie-idio-24.c
    index f666e2e69074..412aca253c76 100644
    --- a/drivers/gpio/gpio-pcie-idio-24.c
    +++ b/drivers/gpio/gpio-pcie-idio-24.c
    @@ -15,6 +15,7 @@
    * This driver supports the following ACCES devices: PCIe-IDIO-24,
    * PCIe-IDI-24, PCIe-IDO-24, and PCIe-IDIO-12.
    */
    +#include <linux/bitmap.h>
    #include <linux/bitops.h>
    #include <linux/device.h>
    #include <linux/errno.h>
    @@ -193,6 +194,61 @@ static int idio_24_gpio_get(struct gpio_chip *chip, unsigned int offset)
    return !!(ioread8(&idio24gpio->reg->ttl_in0_7) & offset_mask);
    }

    +static int idio_24_gpio_get_multiple(struct gpio_chip *chip,
    + unsigned long *mask, unsigned long *bits)
    +{
    + struct idio_24_gpio *const idio24gpio = 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, 0);
    + unsigned long port_state;
    + u8 __iomem ports[] = {
    + idio24gpio->reg->out0_7, idio24gpio->reg->out8_15,
    + idio24gpio->reg->out16_23, idio24gpio->reg->in0_7,
    + idio24gpio->reg->in8_15, idio24gpio->reg->in16_23
    + };
    + const unsigned long out_mode_mask = BIT(1);
    +
    + /* 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 6 is TTL GPIO) */
    + if (i < 6)
    + port_state = ioread8(ports + i);
    + else if (ioread8(&idio24gpio->reg->ctl) & out_mode_mask)
    + port_state = ioread8(&idio24gpio->reg->ttl_out0_7);
    + else
    + port_state = ioread8(&idio24gpio->reg->ttl_in0_7);
    +
    + /* store acquired bits at respective bits array offset */
    + bits[word_index] |= port_state << word_offset;
    + }
    +
    + return 0;
    +}
    +
    static void idio_24_gpio_set(struct gpio_chip *chip, unsigned int offset,
    int value)
    {
    @@ -234,6 +290,65 @@ static void idio_24_gpio_set(struct gpio_chip *chip, unsigned int offset,
    raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
    }

    +static void idio_24_gpio_set_multiple(struct gpio_chip *chip,
    + unsigned long *mask, unsigned long *bits)
    +{
    + struct idio_24_gpio *const idio24gpio = gpiochip_get_data(chip);
    + size_t i;
    + unsigned long bits_offset;
    + unsigned long gpio_mask;
    + const unsigned int gpio_reg_size = 8;
    + const unsigned long port_mask = GENMASK(gpio_reg_size, 0);
    + unsigned long flags;
    + unsigned int out_state;
    + u8 __iomem ports[] = {
    + idio24gpio->reg->out0_7, idio24gpio->reg->out8_15,
    + idio24gpio->reg->out16_23
    + };
    + const unsigned long out_mode_mask = BIT(1);
    + const unsigned int ttl_offset = 48;
    + const size_t ttl_i = BIT_WORD(ttl_offset);
    + const unsigned int word_offset = ttl_offset % BITS_PER_LONG;
    + const unsigned long ttl_mask = (mask[ttl_i] >> word_offset) & port_mask;
    + const unsigned long ttl_bits = (bits[ttl_i] >> word_offset) & ttl_mask;
    +
    + /* set bits are processed 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;
    +
    + /* check if any set bits for current port */
    + gpio_mask = (*mask >> bits_offset) & port_mask;
    + if (!gpio_mask) {
    + /* no set bits for this port so move on to next port */
    + continue;
    + }
    +
    + raw_spin_lock_irqsave(&idio24gpio->lock, flags);
    +
    + /* process output lines */
    + out_state = ioread8(ports + i) & ~gpio_mask;
    + out_state |= (*bits >> bits_offset) & gpio_mask;
    + iowrite8(out_state, ports + i);
    +
    + raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
    + }
    +
    + /* check if setting TTL lines and if they are in output mode */
    + if (!ttl_mask || !(ioread8(&idio24gpio->reg->ctl) & out_mode_mask))
    + return;
    +
    + /* handle TTL output */
    + raw_spin_lock_irqsave(&idio24gpio->lock, flags);
    +
    + /* process output lines */
    + out_state = ioread8(&idio24gpio->reg->ttl_out0_7) & ~ttl_mask;
    + out_state |= ttl_bits;
    + iowrite8(out_state, &idio24gpio->reg->ttl_out0_7);
    +
    + raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
    +}
    +
    static void idio_24_irq_ack(struct irq_data *data)
    {
    }
    @@ -397,7 +512,9 @@ static int idio_24_probe(struct pci_dev *pdev, const struct pci_device_id *id)
    idio24gpio->chip.direction_input = idio_24_gpio_direction_input;
    idio24gpio->chip.direction_output = idio_24_gpio_direction_output;
    idio24gpio->chip.get = idio_24_gpio_get;
    + idio24gpio->chip.get_multiple = idio_24_gpio_get_multiple;
    idio24gpio->chip.set = idio_24_gpio_set;
    + idio24gpio->chip.set_multiple = idio_24_gpio_set_multiple;

    raw_spin_lock_init(&idio24gpio->lock);

    --
    2.16.2
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