linux-imx

/*

 *  MAX732x I2C Port Expander with 8/16 I/O

 *

 *  Copyright (C) 2007 Marvell International Ltd.

 *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>

 *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>

 *  Copyright (C) 2015 Linus Walleij <linus.walleij@linaro.org>

 *

 *  Derived from drivers/gpio/pca953x.c

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 */

​

#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/gpio/driver.h>

#include <linux/interrupt.h>

#include <linux/i2c.h>

#include <linux/platform_data/max732x.h>

#include <linux/of.h>

​

​

/*

 * Each port of MAX732x (including MAX7319) falls into one of the

 * following three types:

 *

 *   - Push Pull Output

 *   - Input

 *   - Open Drain I/O

 *

 * designated by 'O', 'I' and 'P' individually according to MAXIM's

 * datasheets. 'I' and 'P' ports are interrupt capables, some with

 * a dedicated interrupt mask.

 *

 * There are two groups of I/O ports, each group usually includes

 * up to 8 I/O ports, and is accessed by a specific I2C address:

 *

 *   - Group A : by I2C address 0b'110xxxx

 *   - Group B : by I2C address 0b'101xxxx

 *

 * where 'xxxx' is decided by the connections of pin AD2/AD0.  The

 * address used also affects the initial state of output signals.

 *

 * Within each group of ports, there are five known combinations of

 * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for

 * the detailed organization of these ports. Only Goup A is interrupt

 * capable.

 *

 * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',

 * and GPIOs from GROUP_A are numbered before those from GROUP_B

 * (if there are two groups).

 *

 * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so

 * they are not supported by this driver.

 */

​

#define PORT_NONE   0x0 /* '/' No Port */

#define PORT_OUTPUT 0x1 /* 'O' Push-Pull, Output Only */

#define PORT_INPUT  0x2 /* 'I' Input Only */