1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Shared library for Kinetic's ExpressWire protocol. |
4 | * This protocol works by pulsing the ExpressWire IC's control GPIO. |
5 | * ktd2692 and ktd2801 are known to use this protocol. |
6 | */ |
7 | |
8 | #include <linux/bits.h> |
9 | #include <linux/delay.h> |
10 | #include <linux/export.h> |
11 | #include <linux/gpio/consumer.h> |
12 | #include <linux/types.h> |
13 | |
14 | #include <linux/leds-expresswire.h> |
15 | |
16 | void expresswire_power_off(struct expresswire_common_props *props) |
17 | { |
18 | gpiod_set_value_cansleep(desc: props->ctrl_gpio, value: 0); |
19 | usleep_range(min: props->timing.poweroff_us, max: props->timing.poweroff_us * 2); |
20 | } |
21 | EXPORT_SYMBOL_NS_GPL(expresswire_power_off, EXPRESSWIRE); |
22 | |
23 | void expresswire_enable(struct expresswire_common_props *props) |
24 | { |
25 | gpiod_set_value(desc: props->ctrl_gpio, value: 1); |
26 | udelay(props->timing.detect_delay_us); |
27 | gpiod_set_value(desc: props->ctrl_gpio, value: 0); |
28 | udelay(props->timing.detect_us); |
29 | gpiod_set_value(desc: props->ctrl_gpio, value: 1); |
30 | } |
31 | EXPORT_SYMBOL_NS_GPL(expresswire_enable, EXPRESSWIRE); |
32 | |
33 | void expresswire_start(struct expresswire_common_props *props) |
34 | { |
35 | gpiod_set_value(desc: props->ctrl_gpio, value: 1); |
36 | udelay(props->timing.data_start_us); |
37 | } |
38 | EXPORT_SYMBOL_NS_GPL(expresswire_start, EXPRESSWIRE); |
39 | |
40 | void expresswire_end(struct expresswire_common_props *props) |
41 | { |
42 | gpiod_set_value(desc: props->ctrl_gpio, value: 0); |
43 | udelay(props->timing.end_of_data_low_us); |
44 | gpiod_set_value(desc: props->ctrl_gpio, value: 1); |
45 | udelay(props->timing.end_of_data_high_us); |
46 | } |
47 | EXPORT_SYMBOL_NS_GPL(expresswire_end, EXPRESSWIRE); |
48 | |
49 | void expresswire_set_bit(struct expresswire_common_props *props, bool bit) |
50 | { |
51 | if (bit) { |
52 | gpiod_set_value(desc: props->ctrl_gpio, value: 0); |
53 | udelay(props->timing.short_bitset_us); |
54 | gpiod_set_value(desc: props->ctrl_gpio, value: 1); |
55 | udelay(props->timing.long_bitset_us); |
56 | } else { |
57 | gpiod_set_value(desc: props->ctrl_gpio, value: 0); |
58 | udelay(props->timing.long_bitset_us); |
59 | gpiod_set_value(desc: props->ctrl_gpio, value: 1); |
60 | udelay(props->timing.short_bitset_us); |
61 | } |
62 | } |
63 | EXPORT_SYMBOL_NS_GPL(expresswire_set_bit, EXPRESSWIRE); |
64 | |
65 | void expresswire_write_u8(struct expresswire_common_props *props, u8 val) |
66 | { |
67 | expresswire_start(props); |
68 | for (int i = 7; i >= 0; i--) |
69 | expresswire_set_bit(props, val & BIT(i)); |
70 | expresswire_end(props); |
71 | } |
72 | EXPORT_SYMBOL_NS_GPL(expresswire_write_u8, EXPRESSWIRE); |
73 | |