linux-imx

/*

 * MOXA ART RTC driver.

 *

 * Copyright (C) 2013 Jonas Jensen

 *

 * Jonas Jensen <jonas.jensen@gmail.com>

 *

 * Based on code from

 * Moxa Technology Co., Ltd. <www.moxa.com>

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2.  This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 */

​

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/rtc.h>

#include <linux/platform_device.h>

#include <linux/module.h>

#include <linux/gpio.h>

#include <linux/of_gpio.h>

​

#define GPIO_RTC_RESERVED           0x0C

#define GPIO_RTC_DATA_SET           0x10

#define GPIO_RTC_DATA_CLEAR         0x14

#define GPIO_RTC_PIN_PULL_ENABLE        0x18

#define GPIO_RTC_PIN_PULL_TYPE          0x1C

#define GPIO_RTC_INT_ENABLE         0x20

#define GPIO_RTC_INT_RAW_STATE          0x24

#define GPIO_RTC_INT_MASKED_STATE       0x28

#define GPIO_RTC_INT_MASK           0x2C

#define GPIO_RTC_INT_CLEAR          0x30

#define GPIO_RTC_INT_TRIGGER            0x34

#define GPIO_RTC_INT_BOTH           0x38

#define GPIO_RTC_INT_RISE_NEG           0x3C

#define GPIO_RTC_BOUNCE_ENABLE          0x40

#define GPIO_RTC_BOUNCE_PRE_SCALE       0x44

#define GPIO_RTC_PROTECT_W          0x8E

#define GPIO_RTC_PROTECT_R          0x8F

#define GPIO_RTC_YEAR_W             0x8C

#define GPIO_RTC_YEAR_R             0x8D

#define GPIO_RTC_DAY_W              0x8A

#define GPIO_RTC_DAY_R              0x8B

#define GPIO_RTC_MONTH_W            0x88

#define GPIO_RTC_MONTH_R            0x89

#define GPIO_RTC_DATE_W             0x86

#define GPIO_RTC_DATE_R             0x87

#define GPIO_RTC_HOURS_W            0x84

#define GPIO_RTC_HOURS_R            0x85

#define GPIO_RTC_MINUTES_W          0x82

#define GPIO_RTC_MINUTES_R          0x83

#define GPIO_RTC_SECONDS_W          0x80

#define GPIO_RTC_SECONDS_R          0x81

#define GPIO_RTC_DELAY_TIME         8

​

struct moxart_rtc {

    struct rtc_device *rtc;

    spinlock_t rtc_lock;

    int gpio_data, gpio_sclk, gpio_reset;

};

​

static int day_of_year[12] =    { 0, 31, 59, 90, 120, 151, 181,

                  212, 243, 273, 304, 334 };

​

static void moxart_rtc_write_byte(struct device *dev, u8 data)

{

    struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);

    int i;

​

    for (i = 0; i < 8; i++, data >>= 1) {

        gpio_set_value(moxart_rtc->gpio_sclk, 0);

        gpio_set_value(moxart_rtc->gpio_data, ((data & 1) == 1));

        udelay(GPIO_RTC_DELAY_TIME);

        gpio_set_value(moxart_rtc->gpio_sclk, 1);

        udelay(GPIO_RTC_DELAY_TIME);

    }

}

​

static u8 moxart_rtc_read_byte(struct device *dev)

{

    struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);

    int i;

    u8 data = 0;

​

    for (i = 0; i < 8; i++) {

        gpio_set_value(moxart_rtc->gpio_sclk, 0);

        udelay(GPIO_RTC_DELAY_TIME);

        gpio_set_value(moxart_rtc->gpio_sclk, 1);

        udelay(GPIO_RTC_DELAY_TIME);

        if (gpio_get_value(moxart_rtc->gpio_data))