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path: root/drivers/rtc/rtc-pcf8563.c
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Diffstat (limited to 'drivers/rtc/rtc-pcf8563.c')
-rw-r--r--drivers/rtc/rtc-pcf8563.c277
1 files changed, 277 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
new file mode 100644
index 0000000..b725913
--- /dev/null
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -0,0 +1,277 @@
+/*
+ * An I2C driver for the Philips PCF8563 RTC
+ * Copyright 2005-06 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ * Maintainers: http://www.nslu2-linux.org/
+ *
+ * based on the other drivers in this same directory.
+ *
+ * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
+ *
+ * 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/i2c.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+
+#define DRV_VERSION "0.4.3"
+
+#define PCF8563_REG_ST1 0x00 /* status */
+#define PCF8563_REG_ST2 0x01
+
+#define PCF8563_REG_SC 0x02 /* datetime */
+#define PCF8563_REG_MN 0x03
+#define PCF8563_REG_HR 0x04
+#define PCF8563_REG_DM 0x05
+#define PCF8563_REG_DW 0x06
+#define PCF8563_REG_MO 0x07
+#define PCF8563_REG_YR 0x08
+
+#define PCF8563_REG_AMN 0x09 /* alarm */
+#define PCF8563_REG_AHR 0x0A
+#define PCF8563_REG_ADM 0x0B
+#define PCF8563_REG_ADW 0x0C
+
+#define PCF8563_REG_CLKO 0x0D /* clock out */
+#define PCF8563_REG_TMRC 0x0E /* timer control */
+#define PCF8563_REG_TMR 0x0F /* timer */
+
+#define PCF8563_SC_LV 0x80 /* low voltage */
+#define PCF8563_MO_C 0x80 /* century */
+
+static struct i2c_driver pcf8563_driver;
+
+struct pcf8563 {
+ struct rtc_device *rtc;
+ /*
+ * The meaning of MO_C bit varies by the chip type.
+ * From PCF8563 datasheet: this bit is toggled when the years
+ * register overflows from 99 to 00
+ * 0 indicates the century is 20xx
+ * 1 indicates the century is 19xx
+ * From RTC8564 datasheet: this bit indicates change of
+ * century. When the year digit data overflows from 99 to 00,
+ * this bit is set. By presetting it to 0 while still in the
+ * 20th century, it will be set in year 2000, ...
+ * There seems no reliable way to know how the system use this
+ * bit. So let's do it heuristically, assuming we are live in
+ * 1970...2069.
+ */
+ int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
+};
+
+/*
+ * In the routines that deal directly with the pcf8563 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
+ */
+static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
+ unsigned char buf[13] = { PCF8563_REG_ST1 };
+
+ struct i2c_msg msgs[] = {
+ { client->addr, 0, 1, buf }, /* setup read ptr */
+ { client->addr, I2C_M_RD, 13, buf }, /* read status + date */
+ };
+
+ /* read registers */
+ if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)
+ dev_info(&client->dev,
+ "low voltage detected, date/time is not reliable.\n");
+
+ dev_dbg(&client->dev,
+ "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
+ "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
+ __func__,
+ buf[0], buf[1], buf[2], buf[3],
+ buf[4], buf[5], buf[6], buf[7],
+ buf[8]);
+
+
+ tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
+ tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
+ tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
+ tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
+ tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
+ tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
+ tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
+ if (tm->tm_year < 70)
+ tm->tm_year += 100; /* assume we are in 1970...2069 */
+ /* detect the polarity heuristically. see note above. */
+ pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
+ (tm->tm_year >= 100) : (tm->tm_year < 100);
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n",
+ __func__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ /* the clock can give out invalid datetime, but we cannot return
+ * -EINVAL otherwise hwclock will refuse to set the time on bootup.
+ */
+ if (rtc_valid_tm(tm) < 0)
+ dev_err(&client->dev, "retrieved date/time is not valid.\n");
+
+ return 0;
+}
+
+static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
+ int i, err;
+ unsigned char buf[9];
+
+ dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n",
+ __func__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ /* hours, minutes and seconds */
+ buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
+ buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
+ buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
+
+ buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
+
+ /* month, 1 - 12 */
+ buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
+
+ /* year and century */
+ buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
+ if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
+ buf[PCF8563_REG_MO] |= PCF8563_MO_C;
+
+ buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
+
+ /* write register's data */
+ for (i = 0; i < 7; i++) {
+ unsigned char data[2] = { PCF8563_REG_SC + i,
+ buf[PCF8563_REG_SC + i] };
+
+ err = i2c_master_send(client, data, sizeof(data));
+ if (err != sizeof(data)) {
+ dev_err(&client->dev,
+ "%s: err=%d addr=%02x, data=%02x\n",
+ __func__, err, data[0], data[1]);
+ return -EIO;
+ }
+ };
+
+ return 0;
+}
+
+struct pcf8563_limit
+{
+ unsigned char reg;
+ unsigned char mask;
+ unsigned char min;
+ unsigned char max;
+};
+
+static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return pcf8563_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return pcf8563_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops pcf8563_rtc_ops = {
+ .read_time = pcf8563_rtc_read_time,
+ .set_time = pcf8563_rtc_set_time,
+};
+
+static int pcf8563_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct pcf8563 *pcf8563;
+
+ int err = 0;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL);
+ if (!pcf8563)
+ return -ENOMEM;
+
+ dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+ pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name,
+ &client->dev, &pcf8563_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(pcf8563->rtc)) {
+ err = PTR_ERR(pcf8563->rtc);
+ goto exit_kfree;
+ }
+
+ i2c_set_clientdata(client, pcf8563);
+
+ return 0;
+
+exit_kfree:
+ kfree(pcf8563);
+
+ return err;
+}
+
+static int pcf8563_remove(struct i2c_client *client)
+{
+ struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
+
+ if (pcf8563->rtc)
+ rtc_device_unregister(pcf8563->rtc);
+
+ kfree(pcf8563);
+
+ return 0;
+}
+
+static const struct i2c_device_id pcf8563_id[] = {
+ { "pcf8563", 0 },
+ { "rtc8564", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, pcf8563_id);
+
+static struct i2c_driver pcf8563_driver = {
+ .driver = {
+ .name = "rtc-pcf8563",
+ },
+ .probe = pcf8563_probe,
+ .remove = pcf8563_remove,
+ .id_table = pcf8563_id,
+};
+
+static int __init pcf8563_init(void)
+{
+ return i2c_add_driver(&pcf8563_driver);
+}
+
+static void __exit pcf8563_exit(void)
+{
+ i2c_del_driver(&pcf8563_driver);
+}
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(pcf8563_init);
+module_exit(pcf8563_exit);
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