--- /dev/null
+/* 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.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#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
+
+static int 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;
+
+ return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int ds3234_get_reg(struct device *dev, unsigned char address,
+ unsigned char *data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+
+ *data = address & 0x7f;
+
+ return spi_write_then_read(spi, data, 1, data, 1);
+}
+
+static int ds3234_read_time(struct device *dev, struct rtc_time *dt)
+{
+ int err;
+ unsigned char buf[8];
+ struct spi_device *spi = to_spi_device(dev);
+
+ buf[0] = 0x00; /* Start address */
+
+ err = spi_write_then_read(spi, buf, 1, buf, 8);
+ if (err != 0)
+ return err;
+
+ /* Seconds, Minutes, Hours, Day, Date, Month, Year */
+ dt->tm_sec = bcd2bin(buf[0]);
+ dt->tm_min = bcd2bin(buf[1]);
+ dt->tm_hour = bcd2bin(buf[2] & 0x3f);
+ dt->tm_wday = bcd2bin(buf[3]) - 1; /* 0 = Sun */
+ dt->tm_mday = bcd2bin(buf[4]);
+ dt->tm_mon = bcd2bin(buf[5] & 0x1f) - 1; /* 0 = Jan */
+ dt->tm_year = bcd2bin(buf[6] & 0xff) + 100; /* Assume 20YY */
+
+ return rtc_valid_tm(dt);
+}
+
+static int ds3234_set_time(struct device *dev, struct rtc_time *dt)
+{
+ 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 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;
+ int res;
+
+ spi->mode = SPI_MODE_3;
+ spi->bits_per_word = 8;
+ spi_setup(spi);
+
+ res = ds3234_get_reg(&spi->dev, DS3234_REG_SECONDS, &tmp);
+ if (res != 0)
+ 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);
+
+ rtc = devm_rtc_device_register(&spi->dev, "ds3234",
+ &ds3234_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ spi_set_drvdata(spi, rtc);
+
+ return 0;
+}
+
+static struct spi_driver ds3234_driver = {
+ .driver = {
+ .name = "ds3234",
+ .owner = THIS_MODULE,
+ },
+ .probe = ds3234_probe,
+};
+
+module_spi_driver(ds3234_driver);
+
+MODULE_DESCRIPTION("DS3234 SPI RTC driver");
+MODULE_AUTHOR("Dennis Aberilla <denzzzhome@yahoo.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:ds3234");
Code Review / kvmfornfv.git / blobdiff