198 lines
5.1 KiB
C
198 lines
5.1 KiB
C
/*
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* An I2C driver for the PCF85063 RTC
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* Copyright 2014 Rose Technology
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*
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* Author: Søren Andersen <san@rosetechnology.dk>
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* Maintainers: http://www.nslu2-linux.org/
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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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* 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/module.h>
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#define DRV_VERSION "0.0.1"
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#define PCF85063_REG_CTRL1 0x00 /* status */
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#define PCF85063_REG_CTRL2 0x01
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#define PCF85063_REG_SC 0x04 /* datetime */
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#define PCF85063_REG_MN 0x05
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#define PCF85063_REG_HR 0x06
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#define PCF85063_REG_DM 0x07
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#define PCF85063_REG_DW 0x08
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#define PCF85063_REG_MO 0x09
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#define PCF85063_REG_YR 0x0A
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#define PCF85063_MO_C 0x80 /* century */
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static struct i2c_driver pcf85063_driver;
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struct pcf85063 {
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struct rtc_device *rtc;
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int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
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int voltage_low; /* indicates if a low_voltage was detected */
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};
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/*
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* In the routines that deal directly with the pcf85063 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 pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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struct pcf85063 *pcf85063 = i2c_get_clientdata(client);
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unsigned char buf[13] = { PCF85063_REG_CTRL1 };
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struct i2c_msg msgs[] = {
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{/* setup read ptr */
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.addr = client->addr,
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.len = 1,
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.buf = buf
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},
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{/* read status + date */
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = 13,
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.buf = buf
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},
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};
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/* read registers */
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if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
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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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tm->tm_sec = bcd2bin(buf[PCF85063_REG_SC] & 0x7F);
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tm->tm_min = bcd2bin(buf[PCF85063_REG_MN] & 0x7F);
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tm->tm_hour = bcd2bin(buf[PCF85063_REG_HR] & 0x3F); /* rtc hr 0-23 */
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tm->tm_mday = bcd2bin(buf[PCF85063_REG_DM] & 0x3F);
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tm->tm_wday = buf[PCF85063_REG_DW] & 0x07;
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tm->tm_mon = bcd2bin(buf[PCF85063_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
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tm->tm_year = bcd2bin(buf[PCF85063_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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/* detect the polarity heuristically. see note above. */
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pcf85063->c_polarity = (buf[PCF85063_REG_MO] & PCF85063_MO_C) ?
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(tm->tm_year >= 100) : (tm->tm_year < 100);
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return rtc_valid_tm(tm);
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}
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static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
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{
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int i = 0, err = 0;
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unsigned char buf[11];
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/* Control & status */
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buf[PCF85063_REG_CTRL1] = 0;
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buf[PCF85063_REG_CTRL2] = 5;
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/* hours, minutes and seconds */
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buf[PCF85063_REG_SC] = bin2bcd(tm->tm_sec) & 0x7F;
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buf[PCF85063_REG_MN] = bin2bcd(tm->tm_min);
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buf[PCF85063_REG_HR] = bin2bcd(tm->tm_hour);
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/* Day of month, 1 - 31 */
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buf[PCF85063_REG_DM] = bin2bcd(tm->tm_mday);
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/* Day, 0 - 6 */
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buf[PCF85063_REG_DW] = tm->tm_wday & 0x07;
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/* month, 1 - 12 */
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buf[PCF85063_REG_MO] = bin2bcd(tm->tm_mon + 1);
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/* year and century */
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buf[PCF85063_REG_YR] = bin2bcd(tm->tm_year % 100);
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/* write register's data */
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for (i = 0; i < sizeof(buf); i++) {
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unsigned char data[2] = { i, buf[i] };
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err = i2c_master_send(client, data, sizeof(data));
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if (err != sizeof(data)) {
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dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n",
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__func__, err, data[0], data[1]);
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return -EIO;
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}
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}
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return 0;
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}
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static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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return pcf85063_get_datetime(to_i2c_client(dev), tm);
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}
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static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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return pcf85063_set_datetime(to_i2c_client(dev), tm);
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}
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static const struct rtc_class_ops pcf85063_rtc_ops = {
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.read_time = pcf85063_rtc_read_time,
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.set_time = pcf85063_rtc_set_time
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};
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static int pcf85063_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct pcf85063 *pcf85063;
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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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pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063),
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GFP_KERNEL);
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if (!pcf85063)
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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, pcf85063);
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pcf85063->rtc = devm_rtc_device_register(&client->dev,
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pcf85063_driver.driver.name,
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&pcf85063_rtc_ops, THIS_MODULE);
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return PTR_ERR_OR_ZERO(pcf85063->rtc);
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}
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static const struct i2c_device_id pcf85063_id[] = {
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{ "pcf85063", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, pcf85063_id);
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#ifdef CONFIG_OF
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static const struct of_device_id pcf85063_of_match[] = {
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{ .compatible = "nxp,pcf85063" },
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{}
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};
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MODULE_DEVICE_TABLE(of, pcf85063_of_match);
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#endif
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static struct i2c_driver pcf85063_driver = {
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.driver = {
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.name = "rtc-pcf85063",
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.of_match_table = of_match_ptr(pcf85063_of_match),
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},
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.probe = pcf85063_probe,
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.id_table = pcf85063_id,
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};
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module_i2c_driver(pcf85063_driver);
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MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
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MODULE_DESCRIPTION("PCF85063 RTC driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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