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Message-ID: <48FC442E.9070206@mimc.co.uk>
Date: Mon, 20 Oct 2008 09:41:18 +0100
From: Mark Jackson <mpfj@...c.co.uk>
To: dbrownell@...rs.sourceforge.net
CC: lkml <linux-kernel@...r.kernel.org>,
Alessandro Zummo <alessandro.zummo@...ertech.it>,
rtc-linux@...glegroups.com, spi-devel-general@...ts.sourceforge.net
Subject: [PATCH v2] Add Dallas DS1390 RTC chip
v2 of this patch with some code tidying as per previous comments.
This patch adds support for the Dallas DS1390 SPI RTC chip.
Signed-off-by: M.Jackson <mpfj@...c.co.uk>
---
drivers/rtc/Kconfig | 14 +++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-ds1390.c | 258 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 273 insertions(+), 0 deletions(-)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 9a9755c..7ec6abb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -292,6 +292,20 @@ 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"
+ help
+ If you say yes here you get support for the DS1390 and probably
+ other chips connected with SPI.
+
+ The first seven registers on these chips hold an RTC, and other
+ registers may add features such as NVRAM, a trickle charger for
+ the RTC/NVRAM backup power, and alarms. This driver may not
+ expose all those available chip features.
+
+ 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
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 18622ef..6306900 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -27,6 +27,7 @@ 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
index 0000000..2513d60
--- /dev/null
+++ b/drivers/rtc/rtc-ds1390.c
@@ -0,0 +1,258 @@
+/* drivers/rtc/rtc-ds1390.c
+ *
+ * Copyright (C) 2008 Mercury IMC 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.
+ *
+ * Driver for DS1390 spi RTC
+ *
+ * Changelog:
+ *
+ * 04-Apr-2008: Mark Jackson <mpfj@...c.co.uk>
+ * - Initial version based on rtc-max6902
+ * - No alarm support though !!
+ */
+
+#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 buf[9]; /* cmd + 8 registers */
+ u8 tx_buf[2];
+ u8 rx_buf[2];
+};
+
+static void ds1390_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 write */
+ buf[0] = address | 0x80;
+ buf[1] = data;
+
+ spi_write(spi, buf, 2);
+}
+
+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);
+ 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));
+ xfer.len = 2;
+ /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */
+ xfer.tx_buf = chip->tx_buf;
+ xfer.rx_buf = chip->rx_buf;
+
+ /* Clear MSB to indicate read */
+ chip->tx_buf[0] = address & 0x7f;
+
+ spi_message_add_tail(&xfer, &message);
+
+ /* do the i/o */
+ status = spi_sync(spi, &message);
+ if (status != 0)
+ return status;
+
+ *data = chip->rx_buf[1];
+
+ return message.status;
+}
+
+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);
+ 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; /* read command + 7 registers */
+ xfer.tx_buf = chip->buf;
+ xfer.rx_buf = chip->buf;
+ chip->buf[0] = DS1390_REG_SECONDS;
+ spi_message_add_tail(&xfer, &message);
+
+ /* do the i/o */
+ status = spi_sync(spi, &message);
+ 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->buf[1]);
+ dt->tm_min = BCD2BIN(chip->buf[2]);
+ dt->tm_hour = BCD2BIN(chip->buf[3]);
+ dt->tm_wday = BCD2BIN(chip->buf[4]);
+ dt->tm_mday = BCD2BIN(chip->buf[5]);
+ /* mask off century bit */
+ dt->tm_mon = BCD2BIN(chip->buf[6] & 0x7f) - 1;
+ /* adjust for century bit */
+ dt->tm_year = BCD2BIN(chip->buf[7]) + ((chip->buf[6] & 0x80) ? 100 : 0);
+
+ return 0;
+}
+
+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);
+ 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 + 8; /* write command + 8 registers */
+ xfer.tx_buf = chip->buf;
+ xfer.rx_buf = chip->buf;
+ chip->buf[0] = DS1390_REG_SECONDS | 0x80;
+ chip->buf[1] = BIN2BCD(dt->tm_sec);
+ chip->buf[2] = BIN2BCD(dt->tm_min);
+ chip->buf[3] = BIN2BCD(dt->tm_hour);
+ chip->buf[4] = BIN2BCD(dt->tm_wday);
+ chip->buf[5] = BIN2BCD(dt->tm_mday);
+ chip->buf[6] = BIN2BCD(dt->tm_mon + 1) |
+ ((dt->tm_year > 99) ? 0x80 : 0x00);
+ chip->buf[7] = BIN2BCD(dt->tm_year % 100);
+ spi_message_add_tail(&xfer, &message);
+
+ /* do the i/o */
+ status = spi_sync(spi, &message);
+ if (status == 0)
+ return message.status;
+
+ return 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",
+ .bus = &spi_bus_type,
+ .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 SPI RTC driver");
+MODULE_AUTHOR("Mark Jackson <mpfj@...c.co.uk>");
+MODULE_LICENSE("GPL");
--
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