This is a new-style i2c driver for ST M41TXX RTC chip, derived from
works by Alexander Bigga <[email protected]> who wrote the original
rtc-m41txx.c based on drivers/i2c/chips/m41t00.c driver.
This driver supports M41T80, M41T81 and M41ST85. The old m41t00
driver supports M41T00, M41T81 and M41T85(M41ST85). While the M41T00
chip is now supported by rtc-ds1307 driver, this driver does not
include support for the chip.
Signed-off-by: Atsushi Nemoto <[email protected]>
Signed-off-by: Alexander Bigga <[email protected]>
---
drivers/rtc/Kconfig | 11 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-m41txx.c | 362 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/m41txx.h | 40 +++++
4 files changed, 414 insertions(+), 0 deletions(-)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 4e4c10a..c52f3ff 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -282,6 +282,17 @@ config RTC_DRV_DS1742
This driver can also be built as a module. If so, the module
will be called rtc-ds1742.
+config RTC_DRV_M41TXX
+ tristate "ST M41Txx series RTC"
+ depends on RTC_CLASS && I2C
+ help
+ If you say Y here you will get support for the
+ ST M41TXX RTC chips series. Currently following chips are
+ supported: M41T80, M41T81 and M41ST85
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-m41txx.
+
config RTC_DRV_M48T86
tristate "ST M48T86/Dallas DS12887"
depends on RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index a1afbc2..5ef1123 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_RTC_DRV_PCF8583) += rtc-pcf8583.o
obj-$(CONFIG_RTC_DRV_RS5C372) += rtc-rs5c372.o
obj-$(CONFIG_RTC_DRV_S3C) += rtc-s3c.o
obj-$(CONFIG_RTC_DRV_RS5C348) += rtc-rs5c348.o
+obj-$(CONFIG_RTC_DRV_M41TXX) += rtc-m41txx.o
obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
obj-$(CONFIG_RTC_DRV_DS1553) += rtc-ds1553.o
obj-$(CONFIG_RTC_DRV_RS5C313) += rtc-rs5c313.o
diff --git a/drivers/rtc/rtc-m41txx.c b/drivers/rtc/rtc-m41txx.c
new file mode 100644
index 0000000..7f05252
--- /dev/null
+++ b/drivers/rtc/rtc-m41txx.c
@@ -0,0 +1,362 @@
+/*
+ * I2C client/driver for the ST M41TXX family of i2c rtc chips.
+ *
+ * Author: Alexander Bigga <[email protected]>
+ *
+ * Based on m41t00.c by Mark A. Greer <[email protected]>
+ *
+ * 2006 (c) mycable GmbH
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/m41txx.h>
+
+#define M41TXX_REG_SSEC 0
+#define M41TXX_REG_SEC 1
+#define M41TXX_REG_MIN 2
+#define M41TXX_REG_HOUR 3
+#define M41TXX_REG_WDAY 4
+#define M41TXX_REG_DAY 5
+#define M41TXX_REG_MON 6
+#define M41TXX_REG_YEAR 7
+#define M41TXX_REG_ALARM_MON 0xa
+#define M41TXX_REG_ALARM_HOUR 0xc
+#define M41TXX_REG_FLAGS 0xf
+#define M41TXX_REG_SQW 0x13
+
+#define M41TXX_SEC_ST (1 << 7) /* ST: Stop Bit */
+#define M41TXX_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
+#define M41TXX_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
+
+#define M41TXX_FEATURE_HT (1 << 0)
+#define M41TXX_FEATURE_BL (1 << 1)
+
+#define DRV_VERSION "0.04"
+
+struct m41txx_chip_info {
+ const char *name;
+ u8 features;
+};
+
+static const struct m41txx_chip_info m41txx_chip_info_tbl[] = {
+ { /* M41T80 */
+ .name = "m41t80",
+ .features = 0,
+ },
+ { /* M41T81 */
+ .name = "m41t81",
+ .features = M41TXX_FEATURE_HT,
+ },
+ { /* M41ST84/85/87/94 */
+ .name = "m41t85",
+ .features = M41TXX_FEATURE_HT | M41TXX_FEATURE_BL,
+ },
+};
+
+struct m41txx_data {
+ const struct m41txx_chip_info *chip;
+ struct rtc_device *rtc;
+};
+
+static int m41txx_get_datetime(struct i2c_client *client,
+ struct rtc_time *tm)
+{
+ u8 buf[M41TXX_REG_YEAR + 1], dt_addr[1] = { M41TXX_REG_SEC };
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = M41TXX_REG_YEAR + 1 - M41TXX_REG_SEC,
+ .buf = buf + M41TXX_REG_SEC,
+ },
+ };
+
+ if (i2c_transfer(client->adapter, msgs, 2) < 0) {
+ dev_err(&client->dev, "read error\n");
+ return -EIO;
+ }
+
+ tm->tm_sec = BCD2BIN(buf[M41TXX_REG_SEC] & 0x7f);
+ tm->tm_min = BCD2BIN(buf[M41TXX_REG_MIN] & 0x7f);
+ tm->tm_hour = BCD2BIN(buf[M41TXX_REG_HOUR] & 0x3f);
+ tm->tm_mday = BCD2BIN(buf[M41TXX_REG_DAY] & 0x3f);
+ tm->tm_wday = buf[M41TXX_REG_WDAY] & 0x07;
+ tm->tm_mon = BCD2BIN(buf[M41TXX_REG_MON] & 0x1f) - 1;
+
+ /* assume 20YY not 19YY, and ignore the Century Bit */
+ tm->tm_year = BCD2BIN(buf[M41TXX_REG_YEAR]) + 100;
+ return 0;
+}
+
+/* Sets the given date and time to the real time clock. */
+static int m41txx_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ unsigned char wbuf[1 + M41TXX_REG_YEAR + 1];
+ unsigned char *buf = &wbuf[1];
+ unsigned char dt_addr[1] = { M41TXX_REG_SEC };
+ struct i2c_msg msgs_in[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = M41TXX_REG_YEAR + 1 - M41TXX_REG_SEC,
+ .buf = buf + M41TXX_REG_SEC,
+ },
+ };
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1 + M41TXX_REG_YEAR + 1,
+ .buf = wbuf,
+ },
+ };
+
+ /* Read current reg values into buf[1..7] */
+ if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
+ dev_err(&client->dev, "read error\n");
+ return -EIO;
+ }
+
+ wbuf[0] = 0; /* offset into rtc's regs */
+ /* Merge time-data and register flags into buf[0..7] */
+ buf[M41TXX_REG_SSEC] = 0;
+ buf[M41TXX_REG_SEC] =
+ BIN2BCD(tm->tm_sec) | (buf[M41TXX_REG_SEC] & ~0x7f);
+ buf[M41TXX_REG_MIN] =
+ BIN2BCD(tm->tm_min) | (buf[M41TXX_REG_MIN] & ~0x7f);
+ buf[M41TXX_REG_HOUR] =
+ BIN2BCD(tm->tm_hour) | (buf[M41TXX_REG_HOUR] & ~0x3f) ;
+ buf[M41TXX_REG_WDAY] =
+ (tm->tm_wday & 0x07) | (buf[M41TXX_REG_WDAY] & ~0x07);
+ buf[M41TXX_REG_DAY] =
+ BIN2BCD(tm->tm_mday) | (buf[M41TXX_REG_DAY] & ~0x3f);
+ buf[M41TXX_REG_MON] =
+ BIN2BCD(tm->tm_mon + 1) | (buf[M41TXX_REG_MON] & ~0x1f);
+ /* assume 20YY not 19YY */
+ buf[M41TXX_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
+
+ if (i2c_transfer(client->adapter, msgs, 1) != 1) {
+ dev_err(&client->dev, "write error\n");
+ return -EIO;
+ }
+ return 0;
+}
+
+#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
+static int m41txx_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct m41txx_data *clientdata = i2c_get_clientdata(client);
+ unsigned char reg;
+
+ if (clientdata->chip->features & M41TXX_FEATURE_BL) {
+ reg = i2c_smbus_read_byte_data(client, M41TXX_REG_FLAGS);
+ seq_printf(seq, "battery\t\t: %s\n",
+ (reg & M41TXX_FLAGS_BATT_LOW) ? "exhausted" : "ok");
+ }
+ return 0;
+}
+#else
+#define m41txx_rtc_proc NULL
+#endif
+
+static int m41txx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return m41txx_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int m41txx_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return m41txx_set_datetime(to_i2c_client(dev), tm);
+}
+
+static struct rtc_class_ops m41txx_rtc_ops = {
+ .read_time = m41txx_rtc_read_time,
+ .set_time = m41txx_rtc_set_time,
+ .proc = m41txx_rtc_proc,
+};
+
+/*
+ *****************************************************************************
+ *
+ * Driver Interface
+ *
+ *****************************************************************************
+ */
+static int m41txx_probe(struct i2c_client *client)
+{
+ int i, rc = 0;
+ struct rtc_device *rtc = NULL;
+ struct rtc_time tm;
+ struct m41txx_platform_data *pdata = client->dev.platform_data;
+ const static struct m41txx_chip_info *chip;
+ struct m41txx_data *clientdata = NULL;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
+ | I2C_FUNC_SMBUS_BYTE_DATA)) {
+ rc = -ENODEV;
+ goto exit;
+ }
+
+ dev_info(&client->dev,
+ "chip found, driver version " DRV_VERSION "\n");
+
+ chip = NULL;
+ for (i = 0; i < ARRAY_SIZE(m41txx_chip_info_tbl); i++) {
+ if (!strcmp(m41txx_chip_info_tbl[i].name, client->name)) {
+ chip = &m41txx_chip_info_tbl[i];
+ break;
+ }
+ }
+ if (!chip) {
+ dev_err(&client->dev, "%s is not supported\n", client->name);
+ rc = -ENODEV;
+ goto exit;
+ }
+
+ clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
+ if (!clientdata) {
+ rc = -ENOMEM;
+ goto exit;
+ }
+
+ rtc = rtc_device_register(client->name, &client->dev,
+ &m41txx_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc)) {
+ rc = PTR_ERR(rtc);
+ rtc = NULL;
+ goto exit;
+ }
+
+ clientdata->rtc = rtc;
+ clientdata->chip = chip;
+ i2c_set_clientdata(client, clientdata);
+
+ /* If asked, disable SQW, set SQW frequency & re-enable */
+ if (pdata && pdata->sqw_freq) {
+ rc = i2c_smbus_read_byte_data(client, M41TXX_REG_ALARM_MON);
+ if (rc < 0)
+ goto sqw_err;
+ if (i2c_smbus_write_byte_data(client, M41TXX_REG_ALARM_MON,
+ rc & ~0x40) < 0 ||
+ i2c_smbus_write_byte_data(client, M41TXX_REG_SQW,
+ pdata->sqw_freq) < 0 ||
+ i2c_smbus_write_byte_data(client, M41TXX_REG_ALARM_MON,
+ rc | 0x40) < 0)
+ goto sqw_err;
+ }
+
+ /* Make sure HT (Halt Update) bit is cleared */
+ rc = i2c_smbus_read_byte_data(client, M41TXX_REG_ALARM_HOUR);
+ if (rc < 0)
+ goto ht_err;
+
+ if (rc & M41TXX_ALHOUR_HT) {
+ if (chip->features & M41TXX_FEATURE_HT) {
+ m41txx_get_datetime(client, &tm);
+ dev_info(&client->dev, "HT bit was set!\n");
+ dev_info(&client->dev,
+ "Power Down at "
+ "%04i-%02i-%02i %02i:%02i:%02i\n",
+ tm.tm_year + 1900,
+ tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
+ tm.tm_min, tm.tm_sec);
+ }
+ if (i2c_smbus_write_byte_data(client,
+ M41TXX_REG_ALARM_HOUR,
+ rc & ~M41TXX_ALHOUR_HT) < 0)
+ goto ht_err;
+ }
+
+ /* Make sure ST (stop) bit is cleared */
+ rc = i2c_smbus_read_byte_data(client, M41TXX_REG_SEC);
+ if (rc < 0)
+ goto st_err;
+
+ if (rc & M41TXX_SEC_ST) {
+ if (i2c_smbus_write_byte_data(client, M41TXX_REG_SEC,
+ rc & ~M41TXX_SEC_ST) < 0)
+ goto st_err;
+ }
+
+ return 0;
+
+st_err:
+ rc = -EIO;
+ dev_err(&client->dev, "Can't clear ST bit\n");
+ goto exit;
+ht_err:
+ rc = -EIO;
+ dev_err(&client->dev, "Can't clear HT bit\n");
+ goto exit;
+sqw_err:
+ rc = -EIO;
+ dev_err(&client->dev, "Can't set SQW Frequency\n");
+
+exit:
+ if (rtc)
+ rtc_device_unregister(rtc);
+ kfree(clientdata);
+ return rc;
+}
+
+static int m41txx_remove(struct i2c_client *client)
+{
+ struct m41txx_data *clientdata = i2c_get_clientdata(client);
+ struct rtc_device *rtc = clientdata->rtc;
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+ kfree(clientdata);
+
+ return 0;
+}
+
+static struct i2c_driver m41txx_driver = {
+ .driver = {
+ .name = M41TXX_DRV_NAME,
+ },
+ .probe = m41txx_probe,
+ .remove = m41txx_remove,
+};
+
+static int __init m41txx_rtc_init(void)
+{
+ return i2c_add_driver(&m41txx_driver);
+}
+
+static void __exit m41txx_rtc_exit(void)
+{
+ i2c_del_driver(&m41txx_driver);
+}
+
+MODULE_AUTHOR("Alexander Bigga <[email protected]>");
+MODULE_DESCRIPTION("ST Microelectronics M41TXX RTC I2C Client Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(m41txx_rtc_init);
+module_exit(m41txx_rtc_exit);
diff --git a/include/linux/m41txx.h b/include/linux/m41txx.h
new file mode 100644
index 0000000..c67c97d
--- /dev/null
+++ b/include/linux/m41txx.h
@@ -0,0 +1,40 @@
+/*
+ * Definitions for the ST M41TXX family of i2c rtc chips.
+ *
+ * Based on m41t00.h by Mark A. Greer <[email protected]>
+ *
+ * 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.
+ */
+
+#ifndef _M41TXX_H
+#define _M41TXX_H
+
+#define M41TXX_DRV_NAME "m41txx"
+#define M41TXX_I2C_ADDR 0x68
+
+struct m41txx_platform_data {
+ u8 sqw_freq;
+};
+
+/* SQW output disabled, this is default value by power on */
+#define M41TXX_SQW_DISABLE (0)
+
+#define M41TXX_SQW_32KHZ (1<<4) /* 32.768 KHz */
+#define M41TXX_SQW_8KHZ (2<<4) /* 8.192 KHz */
+#define M41TXX_SQW_4KHZ (3<<4) /* 4.096 KHz */
+#define M41TXX_SQW_2KHZ (4<<4) /* 2.048 KHz */
+#define M41TXX_SQW_1KHZ (5<<4) /* 1.024 KHz */
+#define M41TXX_SQW_512HZ (6<<4) /* 512 Hz */
+#define M41TXX_SQW_256HZ (7<<4) /* 256 Hz */
+#define M41TXX_SQW_128HZ (8<<4) /* 128 Hz */
+#define M41TXX_SQW_64HZ (9<<4) /* 64 Hz */
+#define M41TXX_SQW_32HZ (10<<4) /* 32 Hz */
+#define M41TXX_SQW_16HZ (11<<4) /* 16 Hz */
+#define M41TXX_SQW_8HZ (12<<4) /* 8 Hz */
+#define M41TXX_SQW_4HZ (13<<4) /* 4 Hz */
+#define M41TXX_SQW_2HZ (14<<4) /* 2 Hz */
+#define M41TXX_SQW_1HZ (15<<4) /* 1 Hz */
+
+#endif /* _M41TXX_H */
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