linux-imx

/*

 * GPIO driver for the Diamond Systems GPIO-MM

 * Copyright (C) 2016 William Breathitt Gray

 *

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

 * it under the terms of the GNU General Public License, version 2, as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * This driver supports the following Diamond Systems devices: GPIO-MM and

 * GPIO-MM-12.

 */

#include <linux/bitmap.h>

#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/errno.h>

#include <linux/gpio/driver.h>

#include <linux/io.h>

#include <linux/ioport.h>

#include <linux/isa.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/spinlock.h>

​

#define GPIOMM_EXTENT 8

#define MAX_NUM_GPIOMM max_num_isa_dev(GPIOMM_EXTENT)

​

static unsigned int base[MAX_NUM_GPIOMM];

static unsigned int num_gpiomm;

module_param_hw_array(base, uint, ioport, &num_gpiomm, 0);

MODULE_PARM_DESC(base, "Diamond Systems GPIO-MM base addresses");

​

/**

 * struct gpiomm_gpio - GPIO device private data structure

 * @chip:   instance of the gpio_chip

 * @io_state:   bit I/O state (whether bit is set to input or output)

 * @out_state:  output bits state

 * @control:    Control registers state

 * @lock:   synchronization lock to prevent I/O race conditions

 * @base:   base port address of the GPIO device

 */

struct gpiomm_gpio {

    struct gpio_chip chip;

    unsigned char io_state[6];

    unsigned char out_state[6];

    unsigned char control[2];

    spinlock_t lock;

    unsigned int base;

};

​

static int gpiomm_gpio_get_direction(struct gpio_chip *chip,

    unsigned int offset)

{

    struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);

    const unsigned int port = offset / 8;

    const unsigned int mask = BIT(offset % 8);

​

    return !!(gpiommgpio->io_state[port] & mask);

}

​

static int gpiomm_gpio_direction_input(struct gpio_chip *chip,

    unsigned int offset)

{

    struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);

    const unsigned int io_port = offset / 8;

    const unsigned int control_port = io_port / 3;

    const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;

    unsigned long flags;

    unsigned int control;

​

    spin_lock_irqsave(&gpiommgpio->lock, flags);

​

    /* Check if configuring Port C */

    if (io_port == 2 || io_port == 5) {

        /* Port C can be configured by nibble */

        if (offset % 8 > 3) {

            gpiommgpio->io_state[io_port] |= 0xF0;

            gpiommgpio->control[control_port] |= BIT(3);

        } else {

            gpiommgpio->io_state[io_port] |= 0x0F;

            gpiommgpio->control[control_port] |= BIT(0);

        }

    } else {

        gpiommgpio->io_state[io_port] |= 0xFF;

        if (io_port == 0 || io_port == 3)

            gpiommgpio->control[control_port] |= BIT(4);

        else