rtc: add NXP PCF2127 support (i2c)
authorRenaud Cerrato <r.cerrato@til-technologies.fr>
Wed, 3 Jul 2013 22:08:01 +0000 (15:08 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 3 Jul 2013 23:08:00 +0000 (16:08 -0700)
Added support for NXP PCF2127 RTC (i2c).

[akpm@linux-foundation.org: fix typo, fix warnings]
Signed-off-by: Renaud Cerrato <r.cerrato@til-technologies.fr>
Cc: Jingoo Han <jg1.han@samsung.com>
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-pcf2127.c [new file with mode: 0644]

index b9838130a7b0da42a3bc0f35724c9b53b553096f..8009e5d8776a4a00c1a2c3f3f35edd9d7a02581e 100644 (file)
@@ -313,6 +313,15 @@ config RTC_DRV_PALMAS
          This driver can also be built as a module. If so, the module
          will be called rtc-palma.
 
+config RTC_DRV_PCF2127
+       tristate "NXP PCF2127"
+       help
+         If you say yes here you get support for the NXP PCF2127/29 RTC
+         chips.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-pcf2127.
+
 config RTC_DRV_PCF8523
        tristate "NXP PCF8523"
        help
index c33f86f1a69b313f84f7c0e5ceb492474a59f892..994a2fac82774d3e38029996d8745141c7679dfd 100644 (file)
@@ -83,6 +83,7 @@ obj-$(CONFIG_RTC_DRV_NUC900)  += rtc-nuc900.o
 obj-$(CONFIG_RTC_DRV_OMAP)     += rtc-omap.o
 obj-$(CONFIG_RTC_DRV_PALMAS)   += rtc-palmas.o
 obj-$(CONFIG_RTC_DRV_PCAP)     += rtc-pcap.o
+obj-$(CONFIG_RTC_DRV_PCF2127)  += rtc-pcf2127.o
 obj-$(CONFIG_RTC_DRV_PCF8523)  += rtc-pcf8523.o
 obj-$(CONFIG_RTC_DRV_PCF8563)  += rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)  += rtc-pcf8583.o
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
new file mode 100644 (file)
index 0000000..205b9f7
--- /dev/null
@@ -0,0 +1,241 @@
+/*
+ * 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);
+
+       if (IS_ERR(pcf2127->rtc))
+               return PTR_ERR(pcf2127->rtc);
+
+       return 0;
+}
+
+static int pcf2127_remove(struct i2c_client *client)
+{
+       return 0;
+}
+
+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,
+       .remove         = pcf2127_remove,
+       .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);