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1// SPDX-License-Identifier: GPL-2.0-only2/*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 16void expresswire_power_off(struct expresswire_common_props *props)17{18 gpiod_set_value_cansleep(props->ctrl_gpio, 0);19 usleep_range(props->timing.poweroff_us, props->timing.poweroff_us * 2);20}21EXPORT_SYMBOL_NS_GPL(expresswire_power_off, EXPRESSWIRE);22 23void expresswire_enable(struct expresswire_common_props *props)24{25 gpiod_set_value(props->ctrl_gpio, 1);26 udelay(props->timing.detect_delay_us);27 gpiod_set_value(props->ctrl_gpio, 0);28 udelay(props->timing.detect_us);29 gpiod_set_value(props->ctrl_gpio, 1);30}31EXPORT_SYMBOL_NS_GPL(expresswire_enable, EXPRESSWIRE);32 33void expresswire_start(struct expresswire_common_props *props)34{35 gpiod_set_value(props->ctrl_gpio, 1);36 udelay(props->timing.data_start_us);37}38EXPORT_SYMBOL_NS_GPL(expresswire_start, EXPRESSWIRE);39 40void expresswire_end(struct expresswire_common_props *props)41{42 gpiod_set_value(props->ctrl_gpio, 0);43 udelay(props->timing.end_of_data_low_us);44 gpiod_set_value(props->ctrl_gpio, 1);45 udelay(props->timing.end_of_data_high_us);46}47EXPORT_SYMBOL_NS_GPL(expresswire_end, EXPRESSWIRE);48 49void expresswire_set_bit(struct expresswire_common_props *props, bool bit)50{51 if (bit) {52 gpiod_set_value(props->ctrl_gpio, 0);53 udelay(props->timing.short_bitset_us);54 gpiod_set_value(props->ctrl_gpio, 1);55 udelay(props->timing.long_bitset_us);56 } else {57 gpiod_set_value(props->ctrl_gpio, 0);58 udelay(props->timing.long_bitset_us);59 gpiod_set_value(props->ctrl_gpio, 1);60 udelay(props->timing.short_bitset_us);61 }62}63EXPORT_SYMBOL_NS_GPL(expresswire_set_bit, EXPRESSWIRE);64 65void 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}72EXPORT_SYMBOL_NS_GPL(expresswire_write_u8, EXPRESSWIRE);73