/* * An I2C driver for the NXP PCF2127 RTC * Copyright 2013 Til-Technologies * * Author: Renaud Cerrato * * based on the other drivers in this same directory. * * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf * * 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 #include #include #include #include #include #define DRV_VERSION "0.0.1" #define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */ #define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */ #define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */ #define PCF2127_REG_SC (0x03) /* datetime */ #define PCF2127_REG_MN (0x04) #define PCF2127_REG_HR (0x05) #define PCF2127_REG_DM (0x06) #define PCF2127_REG_DW (0x07) #define PCF2127_REG_MO (0x08) #define PCF2127_REG_YR (0x09) static struct i2c_driver pcf2127_driver; struct pcf2127 { struct rtc_device *rtc; int voltage_low; /* indicates if a low_voltage was detected */ }; /* * In the routines that deal directly with the pcf2127 hardware, we use * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. */ static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) { struct pcf2127 *pcf2127 = i2c_get_clientdata(client); unsigned char buf[10] = { PCF2127_REG_CTRL1 }; /* read registers */ if (i2c_master_send(client, buf, 1) != 1 || i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) { dev_err(&client->dev, "%s: read error\n", __func__); return -EIO; } if (buf[PCF2127_REG_CTRL3] & 0x04) { pcf2127->voltage_low = 1; dev_info(&client->dev, "low voltage detected, date/time is not reliable.\n"); } dev_dbg(&client->dev, "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " "sec=%02x, min=%02x, hr=%02x, " "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", __func__, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9]); tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */ tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F); tm->tm_wday = buf[PCF2127_REG_DW] & 0x07; tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]); if (tm->tm_year < 70) tm->tm_year += 100; /* assume we are in 1970...2069 */ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " "mday=%d, mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); /* the clock can give out invalid datetime, but we cannot return * -EINVAL otherwise hwclock will refuse to set the time on bootup. */ if (rtc_valid_tm(tm) < 0) dev_err(&client->dev, "retrieved date/time is not valid.\n"); return 0; } static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) { unsigned char buf[8]; int i = 0, err; dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " "mday=%d, mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); /* start register address */ buf[i++] = PCF2127_REG_SC; /* hours, minutes and seconds */ buf[i++] = bin2bcd(tm->tm_sec); buf[i++] = bin2bcd(tm->tm_min); buf[i++] = bin2bcd(tm->tm_hour); buf[i++] = bin2bcd(tm->tm_mday); buf[i++] = tm->tm_wday & 0x07; /* month, 1 - 12 */ buf[i++] = bin2bcd(tm->tm_mon + 1); /* year */ buf[i++] = bin2bcd(tm->tm_year % 100); /* write register's data */ err = i2c_master_send(client, buf, i); if (err != i) { dev_err(&client->dev, "%s: err=%d", __func__, err); return -EIO; } return 0; } #ifdef CONFIG_RTC_INTF_DEV static int pcf2127_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev)); switch (cmd) { case RTC_VL_READ: if (pcf2127->voltage_low) dev_info(dev, "low voltage detected, date/time is not reliable.\n"); if (copy_to_user((void __user *)arg, &pcf2127->voltage_low, sizeof(int))) return -EFAULT; return 0; default: return -ENOIOCTLCMD; } } #else #define pcf2127_rtc_ioctl NULL #endif static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) { return pcf2127_get_datetime(to_i2c_client(dev), tm); } static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm) { return pcf2127_set_datetime(to_i2c_client(dev), tm); } static const struct rtc_class_ops pcf2127_rtc_ops = { .ioctl = pcf2127_rtc_ioctl, .read_time = pcf2127_rtc_read_time, .set_time = pcf2127_rtc_set_time, }; static int pcf2127_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct pcf2127 *pcf2127; dev_dbg(&client->dev, "%s\n", __func__); if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127), GFP_KERNEL); if (!pcf2127) return -ENOMEM; dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); i2c_set_clientdata(client, pcf2127); pcf2127->rtc = devm_rtc_device_register(&client->dev, pcf2127_driver.driver.name, &pcf2127_rtc_ops, THIS_MODULE); return PTR_ERR_OR_ZERO(pcf2127->rtc); } static const struct i2c_device_id pcf2127_id[] = { { "pcf2127", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, pcf2127_id); #ifdef CONFIG_OF static const struct of_device_id pcf2127_of_match[] = { { .compatible = "nxp,pcf2127" }, {} }; MODULE_DEVICE_TABLE(of, pcf2127_of_match); #endif static struct i2c_driver pcf2127_driver = { .driver = { .name = "rtc-pcf2127", .owner = THIS_MODULE, .of_match_table = of_match_ptr(pcf2127_of_match), }, .probe = pcf2127_probe, .id_table = pcf2127_id, }; module_i2c_driver(pcf2127_driver); MODULE_AUTHOR("Renaud Cerrato "); MODULE_DESCRIPTION("NXP PCF2127 RTC driver"); MODULE_LICENSE("GPL"); MODULE_VERSION(DRV_VERSION);