linux/drivers/i2c/muxes/i2c-arb-gpio-challenge.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * GPIO-based I2C Arbitration Using a Challenge & Response Mechanism
 *
 * Copyright (C) 2012 Google, Inc
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>


/**
 * struct i2c_arbitrator_data - Driver data for I2C arbitrator
 *
 * @our_gpio: GPIO descriptor we'll use to claim.
 * @their_gpio: GPIO descriptor that the other side will use to claim.
 * @slew_delay_us: microseconds to wait for a GPIO to go high.
 * @wait_retry_us: we'll attempt another claim after this many microseconds.
 * @wait_free_us: we'll give up after this many microseconds.
 */

struct i2c_arbitrator_data { … };


/*
 * i2c_arbitrator_select - claim the I2C bus
 *
 * Use the GPIO-based signalling protocol; return -EBUSY if we fail.
 */
static int i2c_arbitrator_select(struct i2c_mux_core *muxc, u32 chan)
{ … }

/*
 * i2c_arbitrator_deselect - release the I2C bus
 *
 * Release the I2C bus using the GPIO-based signalling protocol.
 */
static int i2c_arbitrator_deselect(struct i2c_mux_core *muxc, u32 chan)
{ … }

static int i2c_arbitrator_probe(struct platform_device *pdev)
{ … }

static void i2c_arbitrator_remove(struct platform_device *pdev)
{ … }

static const struct of_device_id i2c_arbitrator_of_match[] = …;
MODULE_DEVICE_TABLE(of, i2c_arbitrator_of_match);

static struct platform_driver i2c_arbitrator_driver = …;

module_platform_driver(…) …;

MODULE_DESCRIPTION(…) …;
MODULE_AUTHOR(…) …;
MODULE_LICENSE(…) …;
MODULE_ALIAS(…) …;