rtc: add device driver for Dallas DS3234 SPI RTC chip
Add support for the Dallas DS3234 chip - extremely accurate SPI bus RTC with integrated crystal and SRAM. [akpm@linux-foundation.org: don't use BIN2BCD/BCD2BIN] Signed-off-by: Dennis Aberilla <denzzzhome@yahoo.com> Signed-off-by: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dennis Aberilla
Linus Torvalds
parent
986e36a5b8
commit
2f9b75e09e
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@ -319,6 +319,15 @@ config RTC_DRV_RS5C348
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This driver can also be built as a module. If so, the module
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will be called rtc-rs5c348.
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config RTC_DRV_DS3234
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tristate "Maxim/Dallas DS3234"
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help
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If you say yes here you get support for the
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Maxim/Dallas DS3234 SPI RTC chip.
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This driver can also be built as a module. If so, the module
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will be called rtc-ds3234.
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endif # SPI_MASTER
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comment "Platform RTC drivers"
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@ -32,6 +32,7 @@ obj-$(CONFIG_RTC_DRV_DS1511) += rtc-ds1511.o
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obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o
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obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o
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obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o
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obj-$(CONFIG_RTC_DRV_DS3234) += rtc-ds3234.o
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obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
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obj-$(CONFIG_RTC_DRV_FM3130) += rtc-fm3130.o
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obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
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@ -0,0 +1,290 @@
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/* drivers/rtc/rtc-ds3234.c
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*
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* Driver for Dallas Semiconductor (DS3234) SPI RTC with Integrated Crystal
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* and SRAM.
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*
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* Copyright (C) 2008 MIMOMax Wireless Ltd.
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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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* Changelog:
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*
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* 07-May-2008: Dennis Aberilla <denzzzhome@yahoo.com>
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* - Created based on the max6902 code. Only implements the
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* date/time keeping functions; no SRAM yet.
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*/
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#include <linux/spi/spi.h>
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#include <linux/bcd.h>
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#define DS3234_REG_SECONDS 0x00
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#define DS3234_REG_MINUTES 0x01
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#define DS3234_REG_HOURS 0x02
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#define DS3234_REG_DAY 0x03
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#define DS3234_REG_DATE 0x04
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#define DS3234_REG_MONTH 0x05
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#define DS3234_REG_YEAR 0x06
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#define DS3234_REG_CENTURY (1 << 7) /* Bit 7 of the Month register */
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#define DS3234_REG_CONTROL 0x0E
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#define DS3234_REG_CONT_STAT 0x0F
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#undef DS3234_DEBUG
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struct ds3234 {
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struct rtc_device *rtc;
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u8 buf[8]; /* Burst read: addr + 7 regs */
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u8 tx_buf[2];
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u8 rx_buf[2];
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};
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static void ds3234_set_reg(struct device *dev, unsigned char address,
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unsigned char data)
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{
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struct spi_device *spi = to_spi_device(dev);
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unsigned char buf[2];
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/* MSB must be '1' to indicate write */
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buf[0] = address | 0x80;
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buf[1] = data;
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spi_write(spi, buf, 2);
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}
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static int ds3234_get_reg(struct device *dev, unsigned char address,
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unsigned char *data)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct ds3234 *chip = dev_get_drvdata(dev);
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struct spi_message message;
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struct spi_transfer xfer;
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int status;
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if (!data)
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return -EINVAL;
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/* Build our spi message */
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spi_message_init(&message);
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memset(&xfer, 0, sizeof(xfer));
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/* Address + dummy tx byte */
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xfer.len = 2;
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xfer.tx_buf = chip->tx_buf;
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xfer.rx_buf = chip->rx_buf;
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chip->tx_buf[0] = address;
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chip->tx_buf[1] = 0xff;
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spi_message_add_tail(&xfer, &message);
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/* do the i/o */
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status = spi_sync(spi, &message);
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if (status == 0)
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status = message.status;
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else
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return status;
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*data = chip->rx_buf[1];
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return status;
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}
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static int ds3234_get_datetime(struct device *dev, struct rtc_time *dt)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct ds3234 *chip = dev_get_drvdata(dev);
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struct spi_message message;
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struct spi_transfer xfer;
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int status;
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/* build the message */
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spi_message_init(&message);
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memset(&xfer, 0, sizeof(xfer));
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xfer.len = 1 + 7; /* Addr + 7 registers */
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xfer.tx_buf = chip->buf;
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xfer.rx_buf = chip->buf;
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chip->buf[0] = 0x00; /* Start address */
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spi_message_add_tail(&xfer, &message);
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/* do the i/o */
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status = spi_sync(spi, &message);
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if (status == 0)
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status = message.status;
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else
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return status;
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/* Seconds, Minutes, Hours, Day, Date, Month, Year */
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dt->tm_sec = bcd2bin(chip->buf[1]);
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dt->tm_min = bcd2bin(chip->buf[2]);
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dt->tm_hour = bcd2bin(chip->buf[3] & 0x3f);
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dt->tm_wday = bcd2bin(chip->buf[4]) - 1; /* 0 = Sun */
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dt->tm_mday = bcd2bin(chip->buf[5]);
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dt->tm_mon = bcd2bin(chip->buf[6] & 0x1f) - 1; /* 0 = Jan */
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dt->tm_year = bcd2bin(chip->buf[7] & 0xff) + 100; /* Assume 20YY */
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#ifdef DS3234_DEBUG
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dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
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dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
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dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
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dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
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dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
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dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
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dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
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dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
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#endif
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return 0;
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}
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static int ds3234_set_datetime(struct device *dev, struct rtc_time *dt)
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{
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#ifdef DS3234_DEBUG
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dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
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dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
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dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
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dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
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dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
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dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
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dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
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dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
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#endif
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ds3234_set_reg(dev, DS3234_REG_SECONDS, bin2bcd(dt->tm_sec));
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ds3234_set_reg(dev, DS3234_REG_MINUTES, bin2bcd(dt->tm_min));
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ds3234_set_reg(dev, DS3234_REG_HOURS, bin2bcd(dt->tm_hour) & 0x3f);
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/* 0 = Sun */
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ds3234_set_reg(dev, DS3234_REG_DAY, bin2bcd(dt->tm_wday + 1));
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ds3234_set_reg(dev, DS3234_REG_DATE, bin2bcd(dt->tm_mday));
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/* 0 = Jan */
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ds3234_set_reg(dev, DS3234_REG_MONTH, bin2bcd(dt->tm_mon + 1));
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/* Assume 20YY although we just want to make sure not to go negative. */
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if (dt->tm_year > 100)
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dt->tm_year -= 100;
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ds3234_set_reg(dev, DS3234_REG_YEAR, bin2bcd(dt->tm_year));
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return 0;
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}
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static int ds3234_read_time(struct device *dev, struct rtc_time *tm)
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{
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return ds3234_get_datetime(dev, tm);
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}
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static int ds3234_set_time(struct device *dev, struct rtc_time *tm)
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{
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return ds3234_set_datetime(dev, tm);
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}
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static const struct rtc_class_ops ds3234_rtc_ops = {
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.read_time = ds3234_read_time,
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.set_time = ds3234_set_time,
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};
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static int ds3234_probe(struct spi_device *spi)
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{
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struct rtc_device *rtc;
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unsigned char tmp;
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struct ds3234 *chip;
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int res;
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rtc = rtc_device_register("ds3234",
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&spi->dev, &ds3234_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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spi->mode = SPI_MODE_3;
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spi->bits_per_word = 8;
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spi_setup(spi);
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chip = kzalloc(sizeof(struct ds3234), GFP_KERNEL);
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if (!chip) {
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rtc_device_unregister(rtc);
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return -ENOMEM;
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}
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chip->rtc = rtc;
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dev_set_drvdata(&spi->dev, chip);
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res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp);
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if (res) {
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rtc_device_unregister(rtc);
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return res;
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}
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/* Control settings
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*
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* CONTROL_REG
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* BIT 7 6 5 4 3 2 1 0
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* EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE
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*
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* 0 0 0 1 1 1 0 0
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*
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* CONTROL_STAT_REG
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* BIT 7 6 5 4 3 2 1 0
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* OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F
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*
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* 1 0 0 0 1 0 0 0
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*/
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ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
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ds3234_set_reg(&spi->dev, DS3234_REG_CONTROL, tmp & 0x1c);
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ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
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ds3234_set_reg(&spi->dev, DS3234_REG_CONT_STAT, tmp & 0x88);
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/* Print our settings */
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ds3234_get_reg(&spi->dev, DS3234_REG_CONTROL, &tmp);
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dev_info(&spi->dev, "Control Reg: 0x%02x\n", tmp);
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ds3234_get_reg(&spi->dev, DS3234_REG_CONT_STAT, &tmp);
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dev_info(&spi->dev, "Ctrl/Stat Reg: 0x%02x\n", tmp);
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return 0;
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}
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static int __exit ds3234_remove(struct spi_device *spi)
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{
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struct ds3234 *chip = platform_get_drvdata(spi);
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struct rtc_device *rtc = chip->rtc;
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if (rtc)
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rtc_device_unregister(rtc);
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kfree(chip);
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return 0;
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}
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static struct spi_driver ds3234_driver = {
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.driver = {
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.name = "ds3234",
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.bus = &spi_bus_type,
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.owner = THIS_MODULE,
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},
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.probe = ds3234_probe,
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.remove = __devexit_p(ds3234_remove),
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};
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static __init int ds3234_init(void)
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{
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printk(KERN_INFO "DS3234 SPI RTC Driver\n");
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return spi_register_driver(&ds3234_driver);
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}
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module_init(ds3234_init);
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static __exit void ds3234_exit(void)
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{
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spi_unregister_driver(&ds3234_driver);
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}
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module_exit(ds3234_exit);
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MODULE_DESCRIPTION("DS3234 SPI RTC driver");
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MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
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MODULE_LICENSE("GPL");
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