/* drivers/rtc/rtc-rx4581.c * * written by Torben Hohn * * Based on: * drivers/rtc/rtc-max6902.c * * Copyright (C) 2006 8D Technologies inc. * Copyright (C) 2004 Compulab Ltd. * * 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. * * Driver for MAX6902 spi RTC * * and based on: * drivers/rtc/rtc-rx8581.c * * An I2C driver for the Epson RX8581 RTC * * Author: Martyn Welch * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. * * 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. * * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) * Copyright 2005-06 Tower Technologies * */ #include #include #include #include #include #include #include #define RX4581_REG_SC 0x00 /* Second in BCD */ #define RX4581_REG_MN 0x01 /* Minute in BCD */ #define RX4581_REG_HR 0x02 /* Hour in BCD */ #define RX4581_REG_DW 0x03 /* Day of Week */ #define RX4581_REG_DM 0x04 /* Day of Month in BCD */ #define RX4581_REG_MO 0x05 /* Month in BCD */ #define RX4581_REG_YR 0x06 /* Year in BCD */ #define RX4581_REG_RAM 0x07 /* RAM */ #define RX4581_REG_AMN 0x08 /* Alarm Min in BCD*/ #define RX4581_REG_AHR 0x09 /* Alarm Hour in BCD */ #define RX4581_REG_ADM 0x0A #define RX4581_REG_ADW 0x0A #define RX4581_REG_TMR0 0x0B #define RX4581_REG_TMR1 0x0C #define RX4581_REG_EXT 0x0D /* Extension Register */ #define RX4581_REG_FLAG 0x0E /* Flag Register */ #define RX4581_REG_CTRL 0x0F /* Control Register */ /* Flag Register bit definitions */ #define RX4581_FLAG_UF 0x20 /* Update */ #define RX4581_FLAG_TF 0x10 /* Timer */ #define RX4581_FLAG_AF 0x08 /* Alarm */ #define RX4581_FLAG_VLF 0x02 /* Voltage Low */ /* Control Register bit definitions */ #define RX4581_CTRL_UIE 0x20 /* Update Interrupt Enable */ #define RX4581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ #define RX4581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ #define RX4581_CTRL_STOP 0x02 /* STOP bit */ #define RX4581_CTRL_RESET 0x01 /* RESET bit */ static int rx4581_set_reg(struct device *dev, unsigned char address, unsigned char data) { struct spi_device *spi = to_spi_device(dev); unsigned char buf[2]; /* high nibble must be '0' to write */ buf[0] = address & 0x0f; buf[1] = data; return spi_write_then_read(spi, buf, 2, NULL, 0); } static int rx4581_get_reg(struct device *dev, unsigned char address, unsigned char *data) { struct spi_device *spi = to_spi_device(dev); /* Set MSB to indicate read */ *data = address | 0x80; return spi_write_then_read(spi, data, 1, data, 1); } /* * In the routines that deal directly with the rx8581 hardware, we use * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. */ static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm) { struct spi_device *spi = to_spi_device(dev); unsigned char date[7]; unsigned char data; int err; /* First we ensure that the "update flag" is not set, we read the * time and date then re-read the "update flag". If the update flag * has been set, we know that the time has changed during the read so * we repeat the whole process again. */ err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); if (err != 0) { dev_err(dev, "Unable to read device flags\n"); return -EIO; } do { /* If update flag set, clear it */ if (data & RX4581_FLAG_UF) { err = rx4581_set_reg(dev, RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF)); if (err != 0) { dev_err(dev, "Unable to write device " "flags\n"); return -EIO; } } /* Now read time and date */ date[0] = 0x80; err = spi_write_then_read(spi, date, 1, date, 7); if (err < 0) { dev_err(dev, "Unable to read date\n"); return -EIO; } /* Check flag register */ err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); if (err != 0) { dev_err(dev, "Unable to read device flags\n"); return -EIO; } } while (data & RX4581_FLAG_UF); if (data & RX4581_FLAG_VLF) dev_info(dev, "low voltage detected, date/time is not reliable.\n"); dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, " "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", __func__, date[0], date[1], date[2], date[3], date[4], date[5], date[6]); tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F); tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F); tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */ tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F); tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F); tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ tm->tm_year = bcd2bin(date[RX4581_REG_YR]); if (tm->tm_year < 70) tm->tm_year += 100; /* assume we are in 1970...2069 */ dev_dbg(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); err = rtc_valid_tm(tm); if (err < 0) dev_err(dev, "retrieved date/time is not valid.\n"); return err; } static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm) { struct spi_device *spi = to_spi_device(dev); int err; unsigned char buf[8], data; dev_dbg(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); buf[0] = 0x00; /* hours, minutes and seconds */ buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec); buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min); buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour); buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday); /* month, 1 - 12 */ buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1); /* year and century */ buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100); buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday); /* Stop the clock */ err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); if (err != 0) { dev_err(dev, "Unable to read control register\n"); return -EIO; } err = rx4581_set_reg(dev, RX4581_REG_CTRL, (data | RX4581_CTRL_STOP)); if (err != 0) { dev_err(dev, "Unable to write control register\n"); return -EIO; } /* write register's data */ err = spi_write_then_read(spi, buf, 8, NULL, 0); if (err != 0) { dev_err(dev, "Unable to write to date registers\n"); return -EIO; } /* get VLF and clear it */ err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); if (err != 0) { dev_err(dev, "Unable to read flag register\n"); return -EIO; } err = rx4581_set_reg(dev, RX4581_REG_FLAG, (data & ~(RX4581_FLAG_VLF))); if (err != 0) { dev_err(dev, "Unable to write flag register\n"); return -EIO; } /* Restart the clock */ err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); if (err != 0) { dev_err(dev, "Unable to read control register\n"); return -EIO; } err = rx4581_set_reg(dev, RX4581_REG_CTRL, (data & ~(RX4581_CTRL_STOP))); if (err != 0) { dev_err(dev, "Unable to write control register\n"); return -EIO; } return 0; } static const struct rtc_class_ops rx4581_rtc_ops = { .read_time = rx4581_get_datetime, .set_time = rx4581_set_datetime, }; static int rx4581_probe(struct spi_device *spi) { struct rtc_device *rtc; unsigned char tmp; int res; res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp); if (res != 0) return res; rtc = devm_rtc_device_register(&spi->dev, "rx4581", &rx4581_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); spi_set_drvdata(spi, rtc); return 0; } static int rx4581_remove(struct spi_device *spi) { return 0; } static const struct spi_device_id rx4581_id[] = { { "rx4581", 0 }, { } }; MODULE_DEVICE_TABLE(spi, rx4581_id); static struct spi_driver rx4581_driver = { .driver = { .name = "rtc-rx4581", .owner = THIS_MODULE, }, .probe = rx4581_probe, .remove = rx4581_remove, .id_table = rx4581_id, }; module_spi_driver(rx4581_driver); MODULE_DESCRIPTION("rx4581 spi RTC driver"); MODULE_AUTHOR("Torben Hohn"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:rtc-rx4581");