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author | William Breathitt Gray <vilhelm.gray@gmail.com> | 2018-03-22 09:00:31 -0400 |
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committer | Linus Walleij <linus.walleij@linaro.org> | 2018-03-26 10:26:38 +0200 |
commit | f72b10713cf5a9f6a425bdbd8da093cb02990d4d (patch) | |
tree | aec5655ad4d1cfda5778443588433d34e0b04dc3 /drivers/gpio/gpio-104-idi-48.c | |
parent | d2d02bcdd52b889ec1bcabf8d0da6f3c2b87e9fc (diff) | |
download | op-kernel-dev-f72b10713cf5a9f6a425bdbd8da093cb02990d4d.zip op-kernel-dev-f72b10713cf5a9f6a425bdbd8da093cb02990d4d.tar.gz |
gpio: 104-idi-48: Implement get_multiple callback
The ACCES I/O 104-IDI-48 series of devices provides 48
optically-isolated inputs accessed via six 8-bit ports. Since eight
input lines are acquired on a single port input read, the 104-IDI-48
GPIO driver may improve multiple input reads by utilizing a get_multiple
callback. This patch implements the idi_48_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>
Diffstat (limited to 'drivers/gpio/gpio-104-idi-48.c')
-rw-r--r-- | drivers/gpio/gpio-104-idi-48.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c index add859d..f356326 100644 --- a/drivers/gpio/gpio-104-idi-48.c +++ b/drivers/gpio/gpio-104-idi-48.c @@ -14,6 +14,7 @@ * This driver supports the following ACCES devices: 104-IDI-48A, * 104-IDI-48AC, 104-IDI-48B, and 104-IDI-48BC. */ +#include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/device.h> #include <linux/errno.h> @@ -88,6 +89,51 @@ static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset) return 0; } +static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask, + unsigned long *bits) +{ + struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip); + size_t i; + const size_t ports[] = { 0, 1, 2, 4, 5, 6 }; + 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; + + /* 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 = inb(idi48gpio->base + ports[i]); + + /* store acquired bits at respective bits array offset */ + bits[word_index] |= port_state << word_offset; + } + + return 0; +} + static void idi_48_irq_ack(struct irq_data *data) { } @@ -256,6 +302,7 @@ static int idi_48_probe(struct device *dev, unsigned int id) idi48gpio->chip.get_direction = idi_48_gpio_get_direction; idi48gpio->chip.direction_input = idi_48_gpio_direction_input; idi48gpio->chip.get = idi_48_gpio_get; + idi48gpio->chip.get_multiple = idi_48_gpio_get_multiple; idi48gpio->base = base[id]; raw_spin_lock_init(&idi48gpio->lock); |