/* drivers/rtc/rtc-ds3234.c * * Driver for Dallas Semiconductor (DS3234) SPI RTC with Integrated Crystal * and SRAM. * * Copyright (C) 2008 MIMOMax Wireless 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. * * Changelog: * * 07-May-2008: Dennis Aberilla <denzzzhome@yahoo.com> * - Created based on the max6902 code. Only implements the * date/time keeping functions; no SRAM yet. */ #include <linux/device.h> #include <linux/platform_device.h> #include <linux/rtc.h> #include <linux/spi/spi.h> #include <linux/bcd.h> #define DS3234_REG_SECONDS 0x00 #define DS3234_REG_MINUTES 0x01 #define DS3234_REG_HOURS 0x02 #define DS3234_REG_DAY 0x03 #define DS3234_REG_DATE 0x04 #define DS3234_REG_MONTH 0x05 #define DS3234_REG_YEAR 0x06 #define DS3234_REG_CENTURY (1 << 7) /* Bit 7 of the Month register */ #define DS3234_REG_CONTROL 0x0E #define DS3234_REG_CONT_STAT 0x0F #undef DS3234_DEBUG struct ds3234 { struct rtc_device *rtc; u8 buf[8]; /* Burst read: addr + 7 regs */ u8 tx_buf[2]; u8 rx_buf[2]; }; static void ds3234_set_reg(struct device *dev, unsigned char address, unsigned char data) { struct spi_device *spi = to_spi_device(dev); unsigned char buf[2]; /* MSB must be '1' to indicate write */ buf[0] = address | 0x80; buf[1] = data; spi_write(spi, buf, 2); } static int ds3234_get_reg(struct device *dev, unsigned char address, unsigned char *data) { struct spi_device *spi = to_spi_device(dev); struct ds3234 *chip = dev_get_drvdata(dev); struct spi_message message; struct spi_transfer xfer; int status; if (!data) return -EINVAL; /* Build our spi message */ spi_message_init(&message); memset(&xfer, 0, sizeof(xfer)); /* Address + dummy tx byte */ xfer.len = 2; xfer.tx_buf = chip->tx_buf; xfer.rx_buf = chip->rx_buf; chip->tx_buf[0] = address; chip->tx_buf[1] = 0xff; spi_message_add_tail(&xfer, &message); /* do the i/o */ status = spi_sync(spi, &message); if (status == 0) status = message.status; else return status; *data = chip->rx_buf[1]; return status; } static int ds3234_get_datetime(struct device *dev, struct rtc_time *dt) { struct spi_device *spi = to_spi_device(dev); struct ds3234 *chip = dev_get_drvdata(dev); struct spi_message message; struct spi_transfer xfer; int status; /* build the message */ spi_message_init(&message); memset(&xfer, 0, sizeof(xfer)); xfer.len = 1 + 7; /* Addr + 7 registers */ xfer.tx_buf = chip->buf; xfer.rx_buf = chip->buf; chip->buf[0] = 0x00; /* Start address */ spi_message_add_tail(&xfer, &message); /* do the i/o */ status = spi_sync(spi, &message); if (status == 0) status = message.status; else return status; /* Seconds, Minutes, Hours, Day, Date, Month, Year */ dt->tm_sec = bcd2bin(chip->buf[1]); dt->tm_min = bcd2bin(chip->buf[2]); dt->tm_hour = bcd2bin(chip->buf[3] & 0x3f); dt->tm_wday = bcd2bin(chip->buf[4]) - 1; /* 0 = Sun */ dt->tm_mday = bcd2bin(chip->buf[5]); dt->tm_mon = bcd2bin(chip->buf[6] & 0x1f) - 1; /* 0 = Jan */ dt->tm_year = bcd2bin(chip->buf[7] & 0xff) + 100; /* Assume 20YY */ #ifdef DS3234_DEBUG dev_dbg(dev, "\n%s : Read RTC values\n", __func__); dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour); dev_dbg(dev, "tm_min : %i\n", dt->tm_min); dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec); dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday); dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday); dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon); dev_dbg(dev, "tm_year: %i\n", dt->tm_year); #endif return 0; } static int ds3234_set_datetime(struct device *dev, struct rtc_time *dt) { #ifdef DS3234_DEBUG dev_dbg(dev, "\n%s : Setting RTC values\n", __func__); dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec); dev_dbg(dev, "tm_min : %i\n", dt->tm_min); dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour); dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday); dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday); dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon); dev_dbg(dev, "tm_year: %i\n", dt->tm_year); #endif ds3234_set_reg(dev, DS3234_REG_SECONDS, bin2bcd(dt->tm_sec)); ds3234_set_reg(dev, DS3234_REG_MINUTES, bin2bcd(dt->tm_min)); ds3234_set_reg(dev, DS3234_REG_HOURS, bin2bcd(dt->tm_hour) & 0x3f); /* 0 = Sun */ ds3234_set_reg(dev, DS3234_REG_DAY, bin2bcd(dt->tm_wday + 1)); ds3234_set_reg(dev, DS3234_REG_DATE, bin2bcd(dt->tm_mday)); /* 0 = Jan */ ds3234_set_reg(dev, DS3234_REG_MONTH, bin2bcd(dt->tm_mon + 1)); /* Assume 20YY although we just want to make sure not to go negative. */ if (dt->tm_year > 100) dt->tm_year -= 100; ds3234_set_reg(dev, DS3234_REG_YEAR, bin2bcd(dt->tm_year)); return 0; } static int ds3234_read_time(struct device *dev, struct rtc_time *tm) { return ds3234_get_datetime(dev, tm); } static int ds3234_set_time(struct device *dev, struct rtc_time *tm) { return ds3234_set_datetime(dev, tm); } static const struct rtc_class_ops ds3234_rtc_ops = { .read_time = ds3234_read_time, .set_time = ds3234_set_time, }; static int ds3234_probe(struct spi_device *spi) { struct rtc_device *rtc; unsigned char tmp; struct ds3234 *chip; int res; rtc = rtc_device_register("ds3234", &spi->dev, &ds3234_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); spi->mode = SPI_MODE_3; spi->bits_per_word = 8; spi_setup(spi); chip = kzalloc(sizeof(struct ds3234), GFP_KERNEL); if (!chip) { rtc_device_unregister(rtc); return -ENOMEM; } chip->rtc = rtc; dev_set_drvdata(&spi->dev, chip); res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp); if (res) { rtc_device_unregister(rtc); return res; } /* Control settings * * CONTROL_REG * BIT 7 6 5 4 3 2 1 0 * EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE * * 0 0 0 1 1 1 0 0 * * CONTROL_STAT_REG * BIT 7 6 5 4 3 2 1 0 * OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F * * 1 0 0 0 1 0 0 0 */ ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp); ds3234_set_reg(&spi->dev, DS3234_REG_CONTROL, tmp & 0x1c); ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp); ds3234_set_reg(&spi->dev, DS3234_REG_CONT_STAT, tmp & 0x88); /* Print our settings */ ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp); dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp); ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp); dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp); return 0; } static int __exit ds3234_remove(struct spi_device *spi) { struct ds3234 *chip = platform_get_drvdata(spi); struct rtc_device *rtc = chip->rtc; if (rtc) rtc_device_unregister(rtc); kfree(chip); return 0; } static struct spi_driver ds3234_driver = { .driver = { .name = "ds3234", .bus = &spi_bus_type, .owner = THIS_MODULE, }, .probe = ds3234_probe, .remove = __devexit_p(ds3234_remove), }; static __init int ds3234_init(void) { printk(KERN_INFO "DS3234 SPI RTC Driver\n"); return spi_register_driver(&ds3234_driver); } module_init(ds3234_init); static __exit void ds3234_exit(void) { spi_unregister_driver(&ds3234_driver); } module_exit(ds3234_exit); MODULE_DESCRIPTION("DS3234 SPI RTC driver"); MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>"); MODULE_LICENSE("GPL");