rtc: add support for the S-35390A RTC chip
authorByron Bradley <byron.bbradley@gmail.com>
Tue, 4 Mar 2008 22:28:25 +0000 (14:28 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 5 Mar 2008 00:35:09 +0000 (16:35 -0800)
This adds basic get/set time support for the Seiko Instruments S-35390A.
This chip communicates using I2C and is used on the QNAP TS-109/TS-209 NAS
devices.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Byron Bradley <byron.bbradley@gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Acked-by: David Brownell <david-b@pacbell.net>
Tested-by: Tim Ellis <tim@ngndg.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
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-s35390a.c [new file with mode: 0644]

index 6402d699072b5a28a11069a5188dd2e34245a079..82f5ad9c3af479a86e711819b8cea6ddfc42f947 100644 (file)
@@ -250,6 +250,15 @@ config RTC_DRV_TWL92330
          platforms.  The support is integrated with the rest of
          the Menelaus driver; it's not separate module.
 
+config RTC_DRV_S35390A
+       tristate "Seiko Instruments S-35390A"
+       help
+         If you say yes here you will get support for the Seiko
+         Instruments S-35390A.
+
+         This driver can also be built as a module. If so the module
+         will be called rtc-s35390a.
+
 endif # I2C
 
 comment "SPI RTC drivers"
index ec703f34ab864da930d3eadbe594d0ca67fb5bfa..872f1218ff9f5d7e2480a8128b481a33e4a4d096 100644 (file)
@@ -45,6 +45,7 @@ obj-$(CONFIG_RTC_DRV_R9701)   += rtc-r9701.o
 obj-$(CONFIG_RTC_DRV_RS5C313)  += rtc-rs5c313.o
 obj-$(CONFIG_RTC_DRV_RS5C348)  += rtc-rs5c348.o
 obj-$(CONFIG_RTC_DRV_RS5C372)  += rtc-rs5c372.o
+obj-$(CONFIG_RTC_DRV_S35390A)  += rtc-s35390a.o
 obj-$(CONFIG_RTC_DRV_S3C)      += rtc-s3c.o
 obj-$(CONFIG_RTC_DRV_SA1100)   += rtc-sa1100.o
 obj-$(CONFIG_RTC_DRV_SH)       += rtc-sh.o
diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
new file mode 100644 (file)
index 0000000..e8abc90
--- /dev/null
@@ -0,0 +1,316 @@
+/*
+ * Seiko Instruments S-35390A RTC Driver
+ *
+ * Copyright (c) 2007 Byron Bradley
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/i2c.h>
+#include <linux/bitrev.h>
+#include <linux/bcd.h>
+#include <linux/slab.h>
+
+#define S35390A_CMD_STATUS1    0
+#define S35390A_CMD_STATUS2    1
+#define S35390A_CMD_TIME1      2
+
+#define S35390A_BYTE_YEAR      0
+#define S35390A_BYTE_MONTH     1
+#define S35390A_BYTE_DAY       2
+#define S35390A_BYTE_WDAY      3
+#define S35390A_BYTE_HOURS     4
+#define S35390A_BYTE_MINS      5
+#define S35390A_BYTE_SECS      6
+
+#define S35390A_FLAG_POC       0x01
+#define S35390A_FLAG_BLD       0x02
+#define S35390A_FLAG_24H       0x40
+#define S35390A_FLAG_RESET     0x80
+#define S35390A_FLAG_TEST      0x01
+
+struct s35390a {
+       struct i2c_client *client[8];
+       struct rtc_device *rtc;
+       int twentyfourhour;
+};
+
+static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
+{
+       struct i2c_client *client = s35390a->client[reg];
+       struct i2c_msg msg[] = {
+               { client->addr, 0, len, buf },
+       };
+
+       if ((i2c_transfer(client->adapter, msg, 1)) != 1)
+               return -EIO;
+
+       return 0;
+}
+
+static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
+{
+       struct i2c_client *client = s35390a->client[reg];
+       struct i2c_msg msg[] = {
+               { client->addr, I2C_M_RD, len, buf },
+       };
+
+       if ((i2c_transfer(client->adapter, msg, 1)) != 1)
+               return -EIO;
+
+       return 0;
+}
+
+static int s35390a_reset(struct s35390a *s35390a)
+{
+       char buf[1];
+
+       if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)
+               return -EIO;
+
+       if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))
+               return 0;
+
+       buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);
+       buf[0] &= 0xf0;
+       return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
+}
+
+static int s35390a_disable_test_mode(struct s35390a *s35390a)
+{
+       char buf[1];
+
+       if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
+               return -EIO;
+
+       if (!(buf[0] & S35390A_FLAG_TEST))
+               return 0;
+
+       buf[0] &= ~S35390A_FLAG_TEST;
+       return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
+}
+
+static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
+{
+       if (s35390a->twentyfourhour)
+               return BIN2BCD(hour);
+
+       if (hour < 12)
+               return BIN2BCD(hour);
+
+       return 0x40 | BIN2BCD(hour - 12);
+}
+
+static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
+{
+       unsigned hour;
+
+       if (s35390a->twentyfourhour)
+               return BCD2BIN(reg & 0x3f);
+
+       hour = BCD2BIN(reg & 0x3f);
+       if (reg & 0x40)
+               hour += 12;
+
+       return hour;
+}
+
+static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+       struct s35390a  *s35390a = i2c_get_clientdata(client);
+       int i, err;
+       char buf[7];
+
+       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);
+
+       buf[S35390A_BYTE_YEAR] = BIN2BCD(tm->tm_year - 100);
+       buf[S35390A_BYTE_MONTH] = BIN2BCD(tm->tm_mon + 1);
+       buf[S35390A_BYTE_DAY] = BIN2BCD(tm->tm_mday);
+       buf[S35390A_BYTE_WDAY] = BIN2BCD(tm->tm_wday);
+       buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
+       buf[S35390A_BYTE_MINS] = BIN2BCD(tm->tm_min);
+       buf[S35390A_BYTE_SECS] = BIN2BCD(tm->tm_sec);
+
+       /* This chip expects the bits of each byte to be in reverse order */
+       for (i = 0; i < 7; ++i)
+               buf[i] = bitrev8(buf[i]);
+
+       err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
+
+       return err;
+}
+
+static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+       struct s35390a *s35390a = i2c_get_clientdata(client);
+       char buf[7];
+       int i, err;
+
+       err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
+       if (err < 0)
+               return err;
+
+       /* This chip returns the bits of each byte in reverse order */
+       for (i = 0; i < 7; ++i)
+               buf[i] = bitrev8(buf[i]);
+
+       tm->tm_sec = BCD2BIN(buf[S35390A_BYTE_SECS]);
+       tm->tm_min = BCD2BIN(buf[S35390A_BYTE_MINS]);
+       tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
+       tm->tm_wday = BCD2BIN(buf[S35390A_BYTE_WDAY]);
+       tm->tm_mday = BCD2BIN(buf[S35390A_BYTE_DAY]);
+       tm->tm_mon = BCD2BIN(buf[S35390A_BYTE_MONTH]) - 1;
+       tm->tm_year = BCD2BIN(buf[S35390A_BYTE_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);
+
+       return rtc_valid_tm(tm);
+}
+
+static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+       return s35390a_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+       return s35390a_set_datetime(to_i2c_client(dev), tm);
+}
+
+static const struct rtc_class_ops s35390a_rtc_ops = {
+       .read_time      = s35390a_rtc_read_time,
+       .set_time       = s35390a_rtc_set_time,
+};
+
+static struct i2c_driver s35390a_driver;
+
+static int s35390a_probe(struct i2c_client *client)
+{
+       int err;
+       unsigned int i;
+       struct s35390a *s35390a;
+       struct rtc_time tm;
+       char buf[1];
+
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+               err = -ENODEV;
+               goto exit;
+       }
+
+       s35390a = kzalloc(sizeof(struct s35390a), GFP_KERNEL);
+       if (!s35390a) {
+               err = -ENOMEM;
+               goto exit;
+       }
+
+       s35390a->client[0] = client;
+       i2c_set_clientdata(client, s35390a);
+
+       /* This chip uses multiple addresses, use dummy devices for them */
+       for (i = 1; i < 8; ++i) {
+               s35390a->client[i] = i2c_new_dummy(client->adapter,
+                                       client->addr + i, "rtc-s35390a");
+               if (!s35390a->client[i]) {
+                       dev_err(&client->dev, "Address %02x unavailable\n",
+                                               client->addr + i);
+                       err = -EBUSY;
+                       goto exit_dummy;
+               }
+       }
+
+       err = s35390a_reset(s35390a);
+       if (err < 0) {
+               dev_err(&client->dev, "error resetting chip\n");
+               goto exit_dummy;
+       }
+
+       err = s35390a_disable_test_mode(s35390a);
+       if (err < 0) {
+               dev_err(&client->dev, "error disabling test mode\n");
+               goto exit_dummy;
+       }
+
+       err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
+       if (err < 0) {
+               dev_err(&client->dev, "error checking 12/24 hour mode\n");
+               goto exit_dummy;
+       }
+       if (buf[0] & S35390A_FLAG_24H)
+               s35390a->twentyfourhour = 1;
+       else
+               s35390a->twentyfourhour = 0;
+
+       if (s35390a_get_datetime(client, &tm) < 0)
+               dev_warn(&client->dev, "clock needs to be set\n");
+
+       s35390a->rtc = rtc_device_register(s35390a_driver.driver.name,
+                               &client->dev, &s35390a_rtc_ops, THIS_MODULE);
+
+       if (IS_ERR(s35390a->rtc)) {
+               err = PTR_ERR(s35390a->rtc);
+               goto exit_dummy;
+       }
+       return 0;
+
+exit_dummy:
+       for (i = 1; i < 8; ++i)
+               if (s35390a->client[i])
+                       i2c_unregister_device(s35390a->client[i]);
+       kfree(s35390a);
+       i2c_set_clientdata(client, NULL);
+
+exit:
+       return err;
+}
+
+static int s35390a_remove(struct i2c_client *client)
+{
+       unsigned int i;
+
+       struct s35390a *s35390a = i2c_get_clientdata(client);
+       for (i = 1; i < 8; ++i)
+               if (s35390a->client[i])
+                       i2c_unregister_device(s35390a->client[i]);
+
+       rtc_device_unregister(s35390a->rtc);
+       kfree(s35390a);
+       i2c_set_clientdata(client, NULL);
+
+       return 0;
+}
+
+static struct i2c_driver s35390a_driver = {
+       .driver         = {
+               .name   = "rtc-s35390a",
+       },
+       .probe          = s35390a_probe,
+       .remove         = s35390a_remove,
+};
+
+static int __init s35390a_rtc_init(void)
+{
+       return i2c_add_driver(&s35390a_driver);
+}
+
+static void __exit s35390a_rtc_exit(void)
+{
+       i2c_del_driver(&s35390a_driver);
+}
+
+MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
+MODULE_DESCRIPTION("S35390A RTC driver");
+MODULE_LICENSE("GPL");
+
+module_init(s35390a_rtc_init);
+module_exit(s35390a_rtc_exit);