linux/drivers/gpio/gpio-max730x.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2006 Juergen Beisert, Pengutronix
 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
 * Copyright (C) 2009 Wolfram Sang, Pengutronix
 *
 * The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
 * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
 * details
 * Note:
 * - DIN must be stable at the rising edge of clock.
 * - when writing:
 *   - always clock in 16 clocks at once
 *   - at DIN: D15 first, D0 last
 *   - D0..D7 = databyte, D8..D14 = commandbyte
 *   - D15 = low -> write command
 * - when reading
 *   - always clock in 16 clocks at once
 *   - at DIN: D15 first, D0 last
 *   - D0..D7 = dummy, D8..D14 = register address
 *   - D15 = high -> read command
 *   - raise CS and assert it again
 *   - always clock in 16 clocks at once
 *   - at DOUT: D15 first, D0 last
 *   - D0..D7 contains the data from the first cycle
 *
 * The driver exports a standard gpiochip interface
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/spi/max7301.h>
#include <linux/gpio/driver.h>
#include <linux/slab.h>

/*
 * Pin configurations, see MAX7301 datasheet page 6
 */
#define PIN_CONFIG_MASK …
#define PIN_CONFIG_IN_PULLUP …
#define PIN_CONFIG_IN_WO_PULLUP …
#define PIN_CONFIG_OUT …

#define PIN_NUMBER …

static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
{ … }

static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
{ … }

static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
				    int value)
{ … }

static int max7301_get(struct gpio_chip *chip, unsigned offset)
{ … }

static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
{ … }

int __max730x_probe(struct max7301 *ts)
{ … }
EXPORT_SYMBOL_GPL(…);

void __max730x_remove(struct device *dev)
{ … }
EXPORT_SYMBOL_GPL(…);

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