linux-imx

/* rtc-max6916.c

 *

 * Driver for MAXIM  max6916 Low Current, SPI Compatible

 * Real Time Clock

 *

 * Author : Venkat Prashanth B U <venkat.prashanth2498@gmail.com>

 *

 * 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.

 *

 */

​

#include <linux/init.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/spi/spi.h>

#include <linux/bcd.h>

​

/* Registers in max6916 rtc */

​

#define MAX6916_SECONDS_REG 0x01

#define MAX6916_MINUTES_REG 0x02

#define MAX6916_HOURS_REG   0x03

#define MAX6916_DATE_REG    0x04

#define MAX6916_MONTH_REG   0x05

#define MAX6916_DAY_REG 0x06

#define MAX6916_YEAR_REG    0x07

#define MAX6916_CONTROL_REG 0x08

#define MAX6916_STATUS_REG  0x0C

#define MAX6916_CLOCK_BURST 0x3F

​

static int max6916_read_reg(struct device *dev, unsigned char address,

                unsigned char *data)

{

    struct spi_device *spi = to_spi_device(dev);

​

    *data = address | 0x80;

​

    return spi_write_then_read(spi, data, 1, data, 1);

}

​

static int max6916_write_reg(struct device *dev, unsigned char address,

                 unsigned char data)

{

    struct spi_device *spi = to_spi_device(dev);

    unsigned char buf[2];

​

    buf[0] = address & 0x7F;

    buf[1] = data;

​

    return spi_write_then_read(spi, buf, 2, NULL, 0);

}

​

static int max6916_read_time(struct device *dev, struct rtc_time *dt)

{

    struct spi_device *spi = to_spi_device(dev);

    int err;

    unsigned char buf[8];

​

    buf[0] = MAX6916_CLOCK_BURST | 0x80;