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f4b830a537
It is possible to put the KTD2801 chip in an unknown/undefined state by
changing the brightness very rapidly (for example, with a brightness
slider). When this happens, the brightness is stuck on max and cannot be
changed until the chip is power cycled.
Fix this by disabling interrupts while talking to the chip. While at it,
make expresswire_power_off() use fsleep() and also unexport some
functions meant to be internal.
Fixes: 1368d06dd2 ("leds: Introduce ExpressWire library")
Tested-by: Karel Balej <balejk@matfyz.cz>
Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
Link: https://patch.msgid.link/20251217-expresswire-fix-v2-1-4a02b10acd96@dujemihanovic.xyz
Signed-off-by: Lee Jones <lee@kernel.org>
36 lines
959 B
C
36 lines
959 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Shared library for Kinetic's ExpressWire protocol.
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* This protocol works by pulsing the ExpressWire IC's control GPIO.
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* ktd2692 and ktd2801 are known to use this protocol.
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*/
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#ifndef _LEDS_EXPRESSWIRE_H
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#define _LEDS_EXPRESSWIRE_H
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#include <linux/types.h>
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struct gpio_desc;
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struct expresswire_timing {
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unsigned long poweroff_us;
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unsigned long detect_delay_us;
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unsigned long detect_us;
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unsigned long data_start_us;
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unsigned long end_of_data_low_us;
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unsigned long end_of_data_high_us;
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unsigned long short_bitset_us;
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unsigned long long_bitset_us;
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};
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struct expresswire_common_props {
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struct gpio_desc *ctrl_gpio;
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struct expresswire_timing timing;
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};
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void expresswire_power_off(struct expresswire_common_props *props);
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void expresswire_enable(struct expresswire_common_props *props);
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void expresswire_write_u8(struct expresswire_common_props *props, u8 val);
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#endif /* _LEDS_EXPRESSWIRE_H */
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