linux-imx

/*

 * An I2C driver for the Intersil ISL 12022

 *

 * Author: Roman Fietze <roman.fietze@telemotive.de>

 *

 * Based on the Philips PCF8563 RTC

 * by Alessandro Zummo <a.zummo@towertech.it>.

 *

 * 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/i2c.h>

#include <linux/bcd.h>

#include <linux/rtc.h>

#include <linux/slab.h>

#include <linux/module.h>

#include <linux/err.h>

#include <linux/of.h>

#include <linux/of_device.h>

​

/* ISL register offsets */

#define ISL12022_REG_SC     0x00

#define ISL12022_REG_MN     0x01

#define ISL12022_REG_HR     0x02

#define ISL12022_REG_DT     0x03

#define ISL12022_REG_MO     0x04

#define ISL12022_REG_YR     0x05

#define ISL12022_REG_DW     0x06

​

#define ISL12022_REG_SR     0x07

#define ISL12022_REG_INT    0x08

​

/* ISL register bits */

#define ISL12022_HR_MIL     (1 << 7)    /* military or 24 hour time */

​

#define ISL12022_SR_LBAT85  (1 << 2)

#define ISL12022_SR_LBAT75  (1 << 1)

​

#define ISL12022_INT_WRTC   (1 << 6)

​

​

static struct i2c_driver isl12022_driver;

​

struct isl12022 {

    struct rtc_device *rtc;

​

    bool write_enabled; /* true if write enable is set */

};

​

​

static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,

                  uint8_t *data, size_t n)

{

    struct i2c_msg msgs[] = {

        {

            .addr   = client->addr,

            .flags  = 0,

            .len    = 1,

            .buf    = data

        },      /* setup read ptr */

        {

            .addr   = client->addr,

            .flags  = I2C_M_RD,

            .len    = n,

            .buf    = data

        }

    };

​

    int ret;

​

    data[0] = reg;

    ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

    if (ret != ARRAY_SIZE(msgs)) {

        dev_err(&client->dev, "%s: read error, ret=%d\n",

            __func__, ret);

        return -EIO;

    }

​

    return 0;

}

​

​

static int isl12022_write_reg(struct i2c_client *client,

                  uint8_t reg, uint8_t val)

{

    uint8_t data[2] = { reg, val };

    int err;

​

    err = i2c_master_send(client, data, sizeof(data));

    if (err != sizeof(data)) {