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path: root/drivers/rtc/rtc-pcf2127.c
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Diffstat (limited to 'drivers/rtc/rtc-pcf2127.c')
-rw-r--r--drivers/rtc/rtc-pcf2127.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
new file mode 100644
index 00000000000..9bd842e9774
--- /dev/null
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -0,0 +1,232 @@
+/*
+ * An I2C driver for the NXP PCF2127 RTC
+ * Copyright 2013 Til-Technologies
+ *
+ * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
+ *
+ * based on the other drivers in this same directory.
+ *
+ * http://www.nxp.com/documents/data_sheet/PCF2127AT.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>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#define DRV_VERSION "0.0.1"
+
+#define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */
+#define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */
+#define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */
+#define PCF2127_REG_SC (0x03) /* datetime */
+#define PCF2127_REG_MN (0x04)
+#define PCF2127_REG_HR (0x05)
+#define PCF2127_REG_DM (0x06)
+#define PCF2127_REG_DW (0x07)
+#define PCF2127_REG_MO (0x08)
+#define PCF2127_REG_YR (0x09)
+
+static struct i2c_driver pcf2127_driver;
+
+struct pcf2127 {
+ struct rtc_device *rtc;
+ int voltage_low; /* indicates if a low_voltage was detected */
+};
+
+/*
+ * In the routines that deal directly with the pcf2127 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
+ */
+static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ struct pcf2127 *pcf2127 = i2c_get_clientdata(client);
+ unsigned char buf[10] = { PCF2127_REG_CTRL1 };
+
+ /* read registers */
+ if (i2c_master_send(client, buf, 1) != 1 ||
+ i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) {
+ dev_err(&client->dev, "%s: read error\n", __func__);
+ return -EIO;
+ }
+
+ if (buf[PCF2127_REG_CTRL3] & 0x04) {
+ pcf2127->voltage_low = 1;
+ dev_info(&client->dev,
+ "low voltage detected, date/time is not reliable.\n");
+ }
+
+ dev_dbg(&client->dev,
+ "%s: raw data is cr1=%02x, cr2=%02x, cr3=%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], buf[9]);
+
+
+ tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
+ tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
+ tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
+ tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
+ tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
+ tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
+ tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
+ if (tm->tm_year < 70)
+ tm->tm_year += 100; /* assume we are in 1970...2069 */
+
+ 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 pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ unsigned char buf[8];
+ int i = 0, err;
+
+ 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);
+
+ /* start register address */
+ buf[i++] = PCF2127_REG_SC;
+
+ /* hours, minutes and seconds */
+ buf[i++] = bin2bcd(tm->tm_sec);
+ buf[i++] = bin2bcd(tm->tm_min);
+ buf[i++] = bin2bcd(tm->tm_hour);
+ buf[i++] = bin2bcd(tm->tm_mday);
+ buf[i++] = tm->tm_wday & 0x07;
+
+ /* month, 1 - 12 */
+ buf[i++] = bin2bcd(tm->tm_mon + 1);
+
+ /* year */
+ buf[i++] = bin2bcd(tm->tm_year % 100);
+
+ /* write register's data */
+ err = i2c_master_send(client, buf, i);
+ if (err != i) {
+ dev_err(&client->dev,
+ "%s: err=%d", __func__, err);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_RTC_INTF_DEV
+static int pcf2127_rtc_ioctl(struct device *dev,
+ unsigned int cmd, unsigned long arg)
+{
+ struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev));
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ if (pcf2127->voltage_low)
+ dev_info(dev, "low voltage detected, date/time is not reliable.\n");
+
+ if (copy_to_user((void __user *)arg, &pcf2127->voltage_low,
+ sizeof(int)))
+ return -EFAULT;
+ return 0;
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+#else
+#define pcf2127_rtc_ioctl NULL
+#endif
+
+static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return pcf2127_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return pcf2127_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops pcf2127_rtc_ops = {
+ .ioctl = pcf2127_rtc_ioctl,
+ .read_time = pcf2127_rtc_read_time,
+ .set_time = pcf2127_rtc_set_time,
+};
+
+static int pcf2127_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct pcf2127 *pcf2127;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127),
+ GFP_KERNEL);
+ if (!pcf2127)
+ return -ENOMEM;
+
+ dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+ i2c_set_clientdata(client, pcf2127);
+
+ pcf2127->rtc = devm_rtc_device_register(&client->dev,
+ pcf2127_driver.driver.name,
+ &pcf2127_rtc_ops, THIS_MODULE);
+
+ return PTR_ERR_OR_ZERO(pcf2127->rtc);
+}
+
+static const struct i2c_device_id pcf2127_id[] = {
+ { "pcf2127", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, pcf2127_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id pcf2127_of_match[] = {
+ { .compatible = "nxp,pcf2127" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, pcf2127_of_match);
+#endif
+
+static struct i2c_driver pcf2127_driver = {
+ .driver = {
+ .name = "rtc-pcf2127",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(pcf2127_of_match),
+ },
+ .probe = pcf2127_probe,
+ .id_table = pcf2127_id,
+};
+
+module_i2c_driver(pcf2127_driver);
+
+MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
+MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 08:15:34 +0000