324 lines
9.0 KiB
C
324 lines
9.0 KiB
C
/*
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* An I2C driver for the Epson RX8581 RTC
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*
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* Author: Martyn Welch <martyn.welch@ge.com>
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* Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
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* Copyright 2005-06 Tower Technologies
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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#include <linux/log2.h>
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#define RX8581_REG_SC 0x00 /* Second in BCD */
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#define RX8581_REG_MN 0x01 /* Minute in BCD */
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#define RX8581_REG_HR 0x02 /* Hour in BCD */
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#define RX8581_REG_DW 0x03 /* Day of Week */
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#define RX8581_REG_DM 0x04 /* Day of Month in BCD */
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#define RX8581_REG_MO 0x05 /* Month in BCD */
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#define RX8581_REG_YR 0x06 /* Year in BCD */
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#define RX8581_REG_RAM 0x07 /* RAM */
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#define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/
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#define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */
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#define RX8581_REG_ADM 0x0A
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#define RX8581_REG_ADW 0x0A
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#define RX8581_REG_TMR0 0x0B
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#define RX8581_REG_TMR1 0x0C
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#define RX8581_REG_EXT 0x0D /* Extension Register */
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#define RX8581_REG_FLAG 0x0E /* Flag Register */
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#define RX8581_REG_CTRL 0x0F /* Control Register */
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/* Flag Register bit definitions */
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#define RX8581_FLAG_UF 0x20 /* Update */
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#define RX8581_FLAG_TF 0x10 /* Timer */
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#define RX8581_FLAG_AF 0x08 /* Alarm */
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#define RX8581_FLAG_VLF 0x02 /* Voltage Low */
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/* Control Register bit definitions */
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#define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */
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#define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */
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#define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */
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#define RX8581_CTRL_STOP 0x02 /* STOP bit */
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#define RX8581_CTRL_RESET 0x01 /* RESET bit */
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struct rx8581 {
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struct i2c_client *client;
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struct rtc_device *rtc;
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s32 (*read_block_data)(const struct i2c_client *client, u8 command,
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u8 length, u8 *values);
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s32 (*write_block_data)(const struct i2c_client *client, u8 command,
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u8 length, const u8 *values);
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};
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static struct i2c_driver rx8581_driver;
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static int rx8581_read_block_data(const struct i2c_client *client, u8 command,
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u8 length, u8 *values)
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{
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s32 i, data;
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for (i = 0; i < length; i++) {
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data = i2c_smbus_read_byte_data(client, command + i);
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if (data < 0)
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return data;
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values[i] = data;
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}
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return i;
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}
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static int rx8581_write_block_data(const struct i2c_client *client, u8 command,
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u8 length, const u8 *values)
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{
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s32 i, ret;
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for (i = 0; i < length; i++) {
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ret = i2c_smbus_write_byte_data(client, command + i,
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values[i]);
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if (ret < 0)
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return ret;
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}
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return length;
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}
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/*
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* In the routines that deal directly with the rx8581 hardware, we use
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* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
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*/
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static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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unsigned char date[7];
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int data, err;
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struct rx8581 *rx8581 = i2c_get_clientdata(client);
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/* First we ensure that the "update flag" is not set, we read the
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* time and date then re-read the "update flag". If the update flag
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* has been set, we know that the time has changed during the read so
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* we repeat the whole process again.
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*/
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data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
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if (data < 0) {
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dev_err(&client->dev, "Unable to read device flags\n");
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return -EIO;
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}
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do {
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/* If update flag set, clear it */
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if (data & RX8581_FLAG_UF) {
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err = i2c_smbus_write_byte_data(client,
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RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
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if (err != 0) {
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dev_err(&client->dev, "Unable to write device flags\n");
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return -EIO;
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}
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}
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/* Now read time and date */
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err = rx8581->read_block_data(client, RX8581_REG_SC,
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7, date);
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if (err < 0) {
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dev_err(&client->dev, "Unable to read date\n");
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return -EIO;
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}
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/* Check flag register */
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data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
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if (data < 0) {
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dev_err(&client->dev, "Unable to read device flags\n");
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return -EIO;
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}
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} while (data & RX8581_FLAG_UF);
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if (data & RX8581_FLAG_VLF)
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dev_info(&client->dev,
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"low voltage detected, date/time is not reliable.\n");
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dev_dbg(&client->dev,
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"%s: raw data is sec=%02x, min=%02x, hr=%02x, "
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"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
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__func__,
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date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
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tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
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tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
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tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
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tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
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tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
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tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
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tm->tm_year = bcd2bin(date[RX8581_REG_YR]);
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if (tm->tm_year < 70)
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tm->tm_year += 100; /* assume we are in 1970...2069 */
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dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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err = rtc_valid_tm(tm);
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if (err < 0)
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dev_err(&client->dev, "retrieved date/time is not valid.\n");
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return err;
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}
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static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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int data, err;
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unsigned char buf[7];
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struct rx8581 *rx8581 = i2c_get_clientdata(client);
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dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
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"mday=%d, mon=%d, year=%d, wday=%d\n",
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__func__,
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tm->tm_sec, tm->tm_min, tm->tm_hour,
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tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
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/* hours, minutes and seconds */
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buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
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buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
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buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
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buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
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/* month, 1 - 12 */
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buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
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/* year and century */
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buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100);
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buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
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/* Stop the clock */
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data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
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if (data < 0) {
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dev_err(&client->dev, "Unable to read control register\n");
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return -EIO;
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}
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err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
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(data | RX8581_CTRL_STOP));
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if (err < 0) {
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dev_err(&client->dev, "Unable to write control register\n");
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return -EIO;
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}
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/* write register's data */
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err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf);
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if (err < 0) {
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dev_err(&client->dev, "Unable to write to date registers\n");
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return -EIO;
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}
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/* get VLF and clear it */
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data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
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if (data < 0) {
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dev_err(&client->dev, "Unable to read flag register\n");
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return -EIO;
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}
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err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
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(data & ~(RX8581_FLAG_VLF)));
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if (err != 0) {
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dev_err(&client->dev, "Unable to write flag register\n");
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return -EIO;
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}
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/* Restart the clock */
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data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
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if (data < 0) {
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dev_err(&client->dev, "Unable to read control register\n");
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return -EIO;
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}
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err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
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(data & ~(RX8581_CTRL_STOP)));
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if (err != 0) {
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dev_err(&client->dev, "Unable to write control register\n");
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return -EIO;
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}
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return 0;
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}
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static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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return rx8581_get_datetime(to_i2c_client(dev), tm);
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}
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static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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return rx8581_set_datetime(to_i2c_client(dev), tm);
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}
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static const struct rtc_class_ops rx8581_rtc_ops = {
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.read_time = rx8581_rtc_read_time,
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.set_time = rx8581_rtc_set_time,
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};
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static int rx8581_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct rx8581 *rx8581;
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dev_dbg(&client->dev, "%s\n", __func__);
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)
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&& !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
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return -EIO;
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rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
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if (!rx8581)
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return -ENOMEM;
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i2c_set_clientdata(client, rx8581);
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rx8581->client = client;
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if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
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rx8581->read_block_data = i2c_smbus_read_i2c_block_data;
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rx8581->write_block_data = i2c_smbus_write_i2c_block_data;
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} else {
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rx8581->read_block_data = rx8581_read_block_data;
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rx8581->write_block_data = rx8581_write_block_data;
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}
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rx8581->rtc = devm_rtc_device_register(&client->dev,
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rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE);
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if (IS_ERR(rx8581->rtc)) {
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dev_err(&client->dev,
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"unable to register the class device\n");
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return PTR_ERR(rx8581->rtc);
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}
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return 0;
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}
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static const struct i2c_device_id rx8581_id[] = {
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{ "rx8581", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, rx8581_id);
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static struct i2c_driver rx8581_driver = {
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.driver = {
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.name = "rtc-rx8581",
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},
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.probe = rx8581_probe,
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.id_table = rx8581_id,
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};
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module_i2c_driver(rx8581_driver);
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MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
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MODULE_DESCRIPTION("Epson RX-8581 RTC driver");
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MODULE_LICENSE("GPL");
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