forked from luck/tmp_suning_uos_patched
653ebd75e9
The PCF2127 datasheet states that it's wrong to say that the date in unreliable if BLF (battery low flag) is set but instead, OSF (seconds register) should be used to check if oscillator, for any reason, stopped. Battery may be low (usually below 2V5 threshold) but the date may be anyway correct (typically date is unreliable when input voltage is below 1V2). Signed-off-by: Andrea Scian <andrea.scian@dave.eu> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
247 lines
6.6 KiB
C
247 lines
6.6 KiB
C
/*
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* An I2C driver for the NXP PCF2127 RTC
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* Copyright 2013 Til-Technologies
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*
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* Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
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*
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* based on the other drivers in this same directory.
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*
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* http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf
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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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#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/slab.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#define DRV_VERSION "0.0.1"
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#define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */
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#define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */
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#define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */
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#define PCF2127_REG_SC (0x03) /* datetime */
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#define PCF2127_REG_MN (0x04)
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#define PCF2127_REG_HR (0x05)
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#define PCF2127_REG_DM (0x06)
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#define PCF2127_REG_DW (0x07)
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#define PCF2127_REG_MO (0x08)
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#define PCF2127_REG_YR (0x09)
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#define PCF2127_OSF BIT(7) /* Oscillator Fail flag */
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static struct i2c_driver pcf2127_driver;
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struct pcf2127 {
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struct rtc_device *rtc;
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int voltage_low; /* indicates if a low_voltage was detected */
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int oscillator_failed; /* OSF was detected and date is unreliable */
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};
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/*
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* In the routines that deal directly with the pcf2127 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 pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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struct pcf2127 *pcf2127 = i2c_get_clientdata(client);
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unsigned char buf[10] = { PCF2127_REG_CTRL1 };
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/* read registers */
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if (i2c_master_send(client, buf, 1) != 1 ||
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i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) {
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dev_err(&client->dev, "%s: read error\n", __func__);
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return -EIO;
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}
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if (buf[PCF2127_REG_CTRL3] & 0x04) {
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pcf2127->voltage_low = 1;
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dev_info(&client->dev,
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"low voltage detected, check/replace RTC battery.\n");
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}
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if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
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/*
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* no need clear the flag here,
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* it will be cleared once the new date is saved
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*/
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pcf2127->oscillator_failed = 1;
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dev_warn(&client->dev,
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"oscillator stop detected, date/time is not reliable\n");
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return -EINVAL;
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}
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dev_dbg(&client->dev,
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"%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
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"sec=%02x, min=%02x, hr=%02x, "
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"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
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__func__,
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buf[0], buf[1], buf[2],
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buf[3], buf[4], buf[5],
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buf[6], buf[7], buf[8], buf[9]);
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tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
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tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
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tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
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tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
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tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
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tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
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tm->tm_year = bcd2bin(buf[PCF2127_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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return rtc_valid_tm(tm);
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}
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static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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struct pcf2127 *pcf2127 = i2c_get_clientdata(client);
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unsigned char buf[8];
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int i = 0, err;
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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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/* start register address */
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buf[i++] = PCF2127_REG_SC;
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/* hours, minutes and seconds */
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buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
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buf[i++] = bin2bcd(tm->tm_min);
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buf[i++] = bin2bcd(tm->tm_hour);
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buf[i++] = bin2bcd(tm->tm_mday);
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buf[i++] = tm->tm_wday & 0x07;
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/* month, 1 - 12 */
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buf[i++] = bin2bcd(tm->tm_mon + 1);
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/* year */
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buf[i++] = bin2bcd(tm->tm_year % 100);
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/* write register's data */
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err = i2c_master_send(client, buf, i);
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if (err != i) {
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dev_err(&client->dev,
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"%s: err=%d", __func__, err);
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return -EIO;
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}
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/* clear OSF flag in client data */
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pcf2127->oscillator_failed = 0;
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return 0;
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}
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#ifdef CONFIG_RTC_INTF_DEV
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static int pcf2127_rtc_ioctl(struct device *dev,
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unsigned int cmd, unsigned long arg)
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{
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struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev));
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switch (cmd) {
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case RTC_VL_READ:
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if (pcf2127->voltage_low)
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dev_info(dev, "low voltage detected, check/replace battery\n");
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if (pcf2127->oscillator_failed)
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dev_info(dev, "oscillator stop detected, date/time is not reliable\n");
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if (copy_to_user((void __user *)arg, &pcf2127->voltage_low,
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sizeof(int)))
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return -EFAULT;
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return 0;
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default:
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return -ENOIOCTLCMD;
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}
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}
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#else
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#define pcf2127_rtc_ioctl NULL
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#endif
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static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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return pcf2127_get_datetime(to_i2c_client(dev), tm);
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}
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static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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return pcf2127_set_datetime(to_i2c_client(dev), tm);
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}
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static const struct rtc_class_ops pcf2127_rtc_ops = {
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.ioctl = pcf2127_rtc_ioctl,
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.read_time = pcf2127_rtc_read_time,
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.set_time = pcf2127_rtc_set_time,
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};
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static int pcf2127_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct pcf2127 *pcf2127;
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dev_dbg(&client->dev, "%s\n", __func__);
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127),
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GFP_KERNEL);
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if (!pcf2127)
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return -ENOMEM;
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dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
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i2c_set_clientdata(client, pcf2127);
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pcf2127->rtc = devm_rtc_device_register(&client->dev,
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pcf2127_driver.driver.name,
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&pcf2127_rtc_ops, THIS_MODULE);
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return PTR_ERR_OR_ZERO(pcf2127->rtc);
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}
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static const struct i2c_device_id pcf2127_id[] = {
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{ "pcf2127", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, pcf2127_id);
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#ifdef CONFIG_OF
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static const struct of_device_id pcf2127_of_match[] = {
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{ .compatible = "nxp,pcf2127" },
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{}
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};
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MODULE_DEVICE_TABLE(of, pcf2127_of_match);
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#endif
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static struct i2c_driver pcf2127_driver = {
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.driver = {
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.name = "rtc-pcf2127",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(pcf2127_of_match),
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},
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.probe = pcf2127_probe,
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.id_table = pcf2127_id,
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};
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module_i2c_driver(pcf2127_driver);
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MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
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MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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