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path: root/drivers/rtc/rtc-ds3234.c
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-rw-r--r--drivers/rtc/rtc-ds3234.c290
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 0000000..37d131d
--- /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");
generated by cgit v1.1 at 2024-12-27 14:35:44 +0000