rtc: add Dallas DS1390/93/94 RTC chips
authorMark Jackson <mpfj@mimc.co.uk>
Wed, 12 Nov 2008 21:27:07 +0000 (13:27 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 13 Nov 2008 01:17:18 +0000 (17:17 -0800)
Add support for the Dallas DS1390/93/94 SPI RTC chip.

Signed-off-by: Mark Jackson <mpfj@mimc.co.uk>
Acked-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>
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-ds1390.c [new file with mode: 0644]

index 990020c1dae9696782d18a77cbe07512eed3296f..123092d8a98484aebde61d7c60cc77639e95c351 100644 (file)
@@ -310,6 +310,17 @@ config RTC_DRV_DS1305
          This driver can also be built as a module. If so, the module
          will be called rtc-ds1305.
 
+config RTC_DRV_DS1390
+       tristate "Dallas/Maxim DS1390/93/94"
+       help
+         If you say yes here you get support for the DS1390/93/94 chips.
+
+         This driver only supports the RTC feature, and not other chip
+         features such as alarms and trickle charging.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-ds1390.
+
 config RTC_DRV_MAX6902
        tristate "Maxim MAX6902"
        help
index 16368600643cb3a88b15f32371dde41276cdf9a4..6e79c912bf9ee1b44d30baafabe2ef424fb14f3b 100644 (file)
@@ -28,6 +28,7 @@ obj-$(CONFIG_RTC_DRV_DS1302)  += rtc-ds1302.o
 obj-$(CONFIG_RTC_DRV_DS1305)   += rtc-ds1305.o
 obj-$(CONFIG_RTC_DRV_DS1307)   += rtc-ds1307.o
 obj-$(CONFIG_RTC_DRV_DS1374)   += rtc-ds1374.o
+obj-$(CONFIG_RTC_DRV_DS1390)   += rtc-ds1390.o
 obj-$(CONFIG_RTC_DRV_DS1511)   += rtc-ds1511.o
 obj-$(CONFIG_RTC_DRV_DS1553)   += rtc-ds1553.o
 obj-$(CONFIG_RTC_DRV_DS1672)   += rtc-ds1672.o
diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c
new file mode 100644 (file)
index 0000000..599e976
--- /dev/null
@@ -0,0 +1,220 @@
+/*
+ * rtc-ds1390.c -- driver for DS1390/93/94
+ *
+ * Copyright (C) 2008 Mercury IMC Ltd
+ * Written by Mark Jackson <mpfj@mimc.co.uk>
+ *
+ * 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.
+ *
+ * NOTE : Currently this driver only supports the bare minimum for read
+ * and write the RTC.  The extra features provided by the chip family
+ * (alarms, trickle charger, different control registers) are unavailable.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+
+#define DS1390_REG_100THS              0x00
+#define DS1390_REG_SECONDS             0x01
+#define DS1390_REG_MINUTES             0x02
+#define DS1390_REG_HOURS               0x03
+#define DS1390_REG_DAY                 0x04
+#define DS1390_REG_DATE                        0x05
+#define DS1390_REG_MONTH_CENT          0x06
+#define DS1390_REG_YEAR                        0x07
+
+#define DS1390_REG_ALARM_100THS                0x08
+#define DS1390_REG_ALARM_SECONDS       0x09
+#define DS1390_REG_ALARM_MINUTES       0x0A
+#define DS1390_REG_ALARM_HOURS         0x0B
+#define DS1390_REG_ALARM_DAY_DATE      0x0C
+
+#define DS1390_REG_CONTROL             0x0D
+#define DS1390_REG_STATUS              0x0E
+#define DS1390_REG_TRICKLE             0x0F
+
+struct ds1390 {
+       struct rtc_device *rtc;
+       u8 txrx_buf[9]; /* cmd + 8 registers */
+};
+
+static void ds1390_set_reg(struct device *dev, unsigned char address,
+                               unsigned char data)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct ds1390 *chip = dev_get_drvdata(dev);
+
+       /* Set MSB to indicate write */
+       chip->txrx_buf[0] = address | 0x80;
+       chip->txrx_buf[1] = data;
+
+       /* do the i/o */
+       spi_write_then_read(spi, chip->txrx_buf, 2, NULL, 0);
+}
+
+static int ds1390_get_reg(struct device *dev, unsigned char address,
+                               unsigned char *data)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct ds1390 *chip = dev_get_drvdata(dev);
+       int status;
+
+       if (!data)
+               return -EINVAL;
+
+       /* Clear MSB to indicate read */
+       chip->txrx_buf[0] = address & 0x7f;
+       /* do the i/o */
+       status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1);
+       if (status != 0)
+               return status;
+
+       *data = chip->txrx_buf[1];
+
+       return 0;
+}
+
+static int ds1390_get_datetime(struct device *dev, struct rtc_time *dt)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct ds1390 *chip = dev_get_drvdata(dev);
+       int status;
+
+       /* build the message */
+       chip->txrx_buf[0] = DS1390_REG_SECONDS;
+
+       /* do the i/o */
+       status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
+       if (status != 0)
+               return status;
+
+       /* The chip sends data in this order:
+        * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
+       dt->tm_sec      = bcd2bin(chip->txrx_buf[0]);
+       dt->tm_min      = bcd2bin(chip->txrx_buf[1]);
+       dt->tm_hour     = bcd2bin(chip->txrx_buf[2]);
+       dt->tm_wday     = bcd2bin(chip->txrx_buf[3]);
+       dt->tm_mday     = bcd2bin(chip->txrx_buf[4]);
+       /* mask off century bit */
+       dt->tm_mon      = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1;
+       /* adjust for century bit */
+       dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0);
+
+       return rtc_valid_tm(dt);
+}
+
+static int ds1390_set_datetime(struct device *dev, struct rtc_time *dt)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct ds1390 *chip = dev_get_drvdata(dev);
+
+       /* build the message */
+       chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80;
+       chip->txrx_buf[1] = bin2bcd(dt->tm_sec);
+       chip->txrx_buf[2] = bin2bcd(dt->tm_min);
+       chip->txrx_buf[3] = bin2bcd(dt->tm_hour);
+       chip->txrx_buf[4] = bin2bcd(dt->tm_wday);
+       chip->txrx_buf[5] = bin2bcd(dt->tm_mday);
+       chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) |
+                               ((dt->tm_year > 99) ? 0x80 : 0x00);
+       chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100);
+
+       /* do the i/o */
+       return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0);
+}
+
+static int ds1390_read_time(struct device *dev, struct rtc_time *tm)
+{
+       return ds1390_get_datetime(dev, tm);
+}
+
+static int ds1390_set_time(struct device *dev, struct rtc_time *tm)
+{
+       return ds1390_set_datetime(dev, tm);
+}
+
+static const struct rtc_class_ops ds1390_rtc_ops = {
+       .read_time      = ds1390_read_time,
+       .set_time       = ds1390_set_time,
+};
+
+static int __devinit ds1390_probe(struct spi_device *spi)
+{
+       struct rtc_device *rtc;
+       unsigned char tmp;
+       struct ds1390 *chip;
+       int res;
+
+       printk(KERN_DEBUG "DS1390 SPI RTC driver\n");
+
+       rtc = rtc_device_register("ds1390",
+                               &spi->dev, &ds1390_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rtc)) {
+               printk(KERN_ALERT "RTC : unable to register device\n");
+               return PTR_ERR(rtc);
+       }
+
+       spi->mode = SPI_MODE_3;
+       spi->bits_per_word = 8;
+       spi_setup(spi);
+
+       chip = kzalloc(sizeof *chip, GFP_KERNEL);
+       if (!chip) {
+               printk(KERN_ALERT "RTC : unable to allocate device memory\n");
+               rtc_device_unregister(rtc);
+               return -ENOMEM;
+       }
+       chip->rtc = rtc;
+       dev_set_drvdata(&spi->dev, chip);
+
+       res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
+       if (res) {
+               printk(KERN_ALERT "RTC : unable to read device\n");
+               rtc_device_unregister(rtc);
+               return res;
+       }
+
+       return 0;
+}
+
+static int __devexit ds1390_remove(struct spi_device *spi)
+{
+       struct ds1390 *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 ds1390_driver = {
+       .driver = {
+               .name   = "rtc-ds1390",
+               .owner  = THIS_MODULE,
+       },
+       .probe  = ds1390_probe,
+       .remove = __devexit_p(ds1390_remove),
+};
+
+static __init int ds1390_init(void)
+{
+       return spi_register_driver(&ds1390_driver);
+}
+module_init(ds1390_init);
+
+static __exit void ds1390_exit(void)
+{
+       spi_unregister_driver(&ds1390_driver);
+}
+module_exit(ds1390_exit);
+
+MODULE_DESCRIPTION("DS1390/93/94 SPI RTC driver");
+MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
+MODULE_LICENSE("GPL");