diff options
| -rw-r--r-- | Documentation/driver-api/gpio/board.rst | 19 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.c | 35 |
2 files changed, 39 insertions, 15 deletions
diff --git a/Documentation/driver-api/gpio/board.rst b/Documentation/driver-api/gpio/board.rst index c66821e033c2..a0f294e2e250 100644 --- a/Documentation/driver-api/gpio/board.rst +++ b/Documentation/driver-api/gpio/board.rst @@ -202,9 +202,18 @@ mapped to the device determines if the array qualifies for fast bitmap processing. If yes, a bitmap is passed over get/set array functions directly between a caller and a respective .get/set_multiple() callback of a GPIO chip. -In order to qualify for fast bitmap processing, the pin mapping must meet the +In order to qualify for fast bitmap processing, the array must meet the following requirements: -- it must belong to the same chip as other 'fast' pins of the function, -- its index within the function must match its hardware number within the chip. - -Open drain and open source pins are excluded from fast bitmap output processing. +- pin hardware number of array member 0 must also be 0, +- pin hardware numbers of consecutive array members which belong to the same + chip as member 0 does must also match their array indexes. + +Otherwise fast bitmap processing path is not used in order to avoid consecutive +pins which belong to the same chip but are not in hardware order being processed +separately. + +If the array applies for fast bitmap processing path, pins which belong to +different chips than member 0 does, as well as those with indexes different from +their hardware pin numbers, are excluded from the fast path, both input and +output. Moreover, open drain and open source pins are excluded from fast bitmap +output processing. diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index aa0b4b46fccc..03d15d84bdd8 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -4376,11 +4376,10 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev, chip = gpiod_to_chip(desc); /* - * Select a chip of first array member - * whose index matches its pin hardware number - * as a candidate for fast bitmap processing. + * If pin hardware number of array member 0 is also 0, select + * its chip as a candidate for fast bitmap processing path. */ - if (!array_info && gpio_chip_hwgpio(desc) == descs->ndescs) { + if (descs->ndescs == 0 && gpio_chip_hwgpio(desc) == 0) { struct gpio_descs *array; bitmap_size = BITS_TO_LONGS(chip->ngpio > count ? @@ -4414,14 +4413,30 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev, count - descs->ndescs); descs->info = array_info; } - /* - * Unmark members which don't qualify for fast bitmap - * processing (different chip, not in hardware order) - */ - if (array_info && (chip != array_info->chip || - gpio_chip_hwgpio(desc) != descs->ndescs)) { + /* Unmark array members which don't belong to the 'fast' chip */ + if (array_info && array_info->chip != chip) { __clear_bit(descs->ndescs, array_info->get_mask); __clear_bit(descs->ndescs, array_info->set_mask); + } + /* + * Detect array members which belong to the 'fast' chip + * but their pins are not in hardware order. + */ + else if (array_info && + gpio_chip_hwgpio(desc) != descs->ndescs) { + /* + * Don't use fast path if all array members processed so + * far belong to the same chip as this one but its pin + * hardware number is different from its array index. + */ + if (bitmap_full(array_info->get_mask, descs->ndescs)) { + array_info = NULL; + } else { + __clear_bit(descs->ndescs, + array_info->get_mask); + __clear_bit(descs->ndescs, + array_info->set_mask); + } } else if (array_info) { /* Exclude open drain or open source from fast output */ if (gpiochip_line_is_open_drain(chip, descs->ndescs) || |