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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-09-20 08:15:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-09-20 08:15:23 -0700 |
| commit | bdab18633a302c82b5e5d5dbc4e38b0baf9c0837 (patch) | |
| tree | 0446500af9a76d4e8b2a72a0a41391ceede73a10 /drivers/leds/leds-expresswire.c | |
| download | linux-stable-bdab18633a302c82b5e5d5dbc4e38b0baf9c0837.tar.gz linux-stable-bdab18633a302c82b5e5d5dbc4e38b0baf9c0837.zip | |
Merge tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipgrafted
Pull futex fix from Ingo Molnar:
- Also allocate a default private futex hash on vfork() as well, to
avoid races with (private) futex waiters (Peter Zijlstra)
* tag 'locking-urgent-2026-09-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Also allocate private hash on vfork()
Diffstat (limited to 'drivers/leds/leds-expresswire.c')
| -rw-r--r-- | drivers/leds/leds-expresswire.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/drivers/leds/leds-expresswire.c b/drivers/leds/leds-expresswire.c new file mode 100644 index 000000000..25c6b159a --- /dev/null +++ b/drivers/leds/leds-expresswire.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Shared library for Kinetic's ExpressWire protocol. + * This protocol works by pulsing the ExpressWire IC's control GPIO. + * ktd2692 and ktd2801 are known to use this protocol. + */ + +#include <linux/bits.h> +#include <linux/delay.h> +#include <linux/export.h> +#include <linux/gpio/consumer.h> +#include <linux/irqflags.h> +#include <linux/types.h> + +#include <linux/leds-expresswire.h> + +void expresswire_power_off(struct expresswire_common_props *props) +{ + gpiod_set_value_cansleep(props->ctrl_gpio, 0); + fsleep(props->timing.poweroff_us); +} +EXPORT_SYMBOL_NS_GPL(expresswire_power_off, "EXPRESSWIRE"); + +void expresswire_enable(struct expresswire_common_props *props) +{ + unsigned long flags; + + local_irq_save(flags); + + gpiod_set_value(props->ctrl_gpio, 1); + udelay(props->timing.detect_delay_us); + gpiod_set_value(props->ctrl_gpio, 0); + udelay(props->timing.detect_us); + gpiod_set_value(props->ctrl_gpio, 1); + + local_irq_restore(flags); +} +EXPORT_SYMBOL_NS_GPL(expresswire_enable, "EXPRESSWIRE"); + +static void expresswire_start(struct expresswire_common_props *props) +{ + gpiod_set_value(props->ctrl_gpio, 1); + udelay(props->timing.data_start_us); +} + +static void expresswire_end(struct expresswire_common_props *props) +{ + gpiod_set_value(props->ctrl_gpio, 0); + udelay(props->timing.end_of_data_low_us); + gpiod_set_value(props->ctrl_gpio, 1); + udelay(props->timing.end_of_data_high_us); +} + +static void expresswire_set_bit(struct expresswire_common_props *props, bool bit) +{ + if (bit) { + gpiod_set_value(props->ctrl_gpio, 0); + udelay(props->timing.short_bitset_us); + gpiod_set_value(props->ctrl_gpio, 1); + udelay(props->timing.long_bitset_us); + } else { + gpiod_set_value(props->ctrl_gpio, 0); + udelay(props->timing.long_bitset_us); + gpiod_set_value(props->ctrl_gpio, 1); + udelay(props->timing.short_bitset_us); + } +} + +void expresswire_write_u8(struct expresswire_common_props *props, u8 val) +{ + unsigned long flags; + + local_irq_save(flags); + + expresswire_start(props); + for (int i = 7; i >= 0; i--) + expresswire_set_bit(props, val & BIT(i)); + expresswire_end(props); + + local_irq_restore(flags); +} +EXPORT_SYMBOL_NS_GPL(expresswire_write_u8, "EXPRESSWIRE"); |
