diff options
Diffstat (limited to 'drivers/rtc/rtc-ds3234.c')
| -rw-r--r-- | drivers/rtc/rtc-ds3234.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds3234.c b/drivers/rtc/rtc-ds3234.c new file mode 100644 index 00000000000..37d131d03f3 --- /dev/null +++ b/drivers/rtc/rtc-ds3234.c @@ -0,0 +1,290 @@ +/* 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"); |