linux-imx

/*

 *  SYSCON GPIO driver

 *

 *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>

 *

 * 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; either version 2 of the License, or

 * (at your option) any later version.

 */

​

#include <linux/err.h>

#include <linux/gpio/driver.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/mfd/syscon.h>

​

#define GPIO_SYSCON_FEAT_IN BIT(0)

#define GPIO_SYSCON_FEAT_OUT    BIT(1)

#define GPIO_SYSCON_FEAT_DIR    BIT(2)

​

/* SYSCON driver is designed to use 32-bit wide registers */

#define SYSCON_REG_SIZE     (4)

#define SYSCON_REG_BITS     (SYSCON_REG_SIZE * 8)

​

/**

 * struct syscon_gpio_data - Configuration for the device.

 * compatible:      SYSCON driver compatible string.

 * flags:       Set of GPIO_SYSCON_FEAT_ flags:

 *          GPIO_SYSCON_FEAT_IN:    GPIOs supports input,

 *          GPIO_SYSCON_FEAT_OUT:   GPIOs supports output,

 *          GPIO_SYSCON_FEAT_DIR:   GPIOs supports switch direction.

 * bit_count:       Number of bits used as GPIOs.

 * dat_bit_offset:  Offset (in bits) to the first GPIO bit.

 * dir_bit_offset:  Optional offset (in bits) to the first bit to switch

 *          GPIO direction (Used with GPIO_SYSCON_FEAT_DIR flag).

 * set:     HW specific callback to assigns output value

 *          for signal "offset"

 */

​

struct syscon_gpio_data {

    const char  *compatible;

    unsigned int    flags;

    unsigned int    bit_count;

    unsigned int    dat_bit_offset;

    unsigned int    dir_bit_offset;

    void        (*set)(struct gpio_chip *chip,

                   unsigned offset, int value);

};

​

struct syscon_gpio_priv {

    struct gpio_chip        chip;

    struct regmap           *syscon;

    const struct syscon_gpio_data   *data;

    u32             dreg_offset;

    u32             dir_reg_offset;

};

​

static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)

{

    struct syscon_gpio_priv *priv = gpiochip_get_data(chip);

    unsigned int val, offs;

    int ret;

​

    offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;

​

    ret = regmap_read(priv->syscon,

              (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val);

    if (ret)

        return ret;

​

    return !!(val & BIT(offs % SYSCON_REG_BITS));

}

​

static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val)

{

    struct syscon_gpio_priv *priv = gpiochip_get_data(chip);

    unsigned int offs;

​

    offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;

​

    regmap_update_bits(priv->syscon,

               (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,

               BIT(offs % SYSCON_REG_BITS),

               val ? BIT(offs % SYSCON_REG_BITS) : 0);

}

​

static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)

{