--- /dev/null
+/*
+ * I2C client/driver for the ST M41T80 family of i2c rtc chips.
+ *
+ * Author: Alexander Bigga <ab@mycable.de>
+ *
+ * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
+ *
+ * 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>
+
+#define M41T80_REG_SSEC 0
+#define M41T80_REG_SEC 1
+#define M41T80_REG_MIN 2
+#define M41T80_REG_HOUR 3
+#define M41T80_REG_WDAY 4
+#define M41T80_REG_DAY 5
+#define M41T80_REG_MON 6
+#define M41T80_REG_YEAR 7
+#define M41T80_REG_ALARM_MON 0xa
+#define M41T80_REG_ALARM_DAY 0xb
+#define M41T80_REG_ALARM_HOUR 0xc
+#define M41T80_REG_ALARM_MIN 0xd
+#define M41T80_REG_ALARM_SEC 0xe
+#define M41T80_REG_FLAGS 0xf
+#define M41T80_REG_SQW 0x13
+
+#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
+#define M41T80_ALARM_REG_SIZE \
+ (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
+
+#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
+#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
+#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
+#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
+#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
+#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
+
+#define M41T80_FEATURE_HT (1 << 0)
+#define M41T80_FEATURE_BL (1 << 1)
+
+#define DRV_VERSION "0.05"
+
+struct m41t80_chip_info {
+ const char *name;
+ u8 features;
+};
+
+static const struct m41t80_chip_info m41t80_chip_info_tbl[] = {
+ {
+ .name = "m41t80",
+ .features = 0,
+ },
+ {
+ .name = "m41t81",
+ .features = M41T80_FEATURE_HT,
+ },
+ {
+ .name = "m41t81s",
+ .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
+ },
+ {
+ .name = "m41t82",
+ .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
+ },
+ {
+ .name = "m41t83",
+ .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
+ },
+ {
+ .name = "m41st84",
+ .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
+ },
+ {
+ .name = "m41st85",
+ .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
+ },
+ {
+ .name = "m41st87",
+ .features = M41T80_FEATURE_HT | M41T80_FEATURE_BL,
+ },
+};
+
+struct m41t80_data {
+ const struct m41t80_chip_info *chip;
+ struct rtc_device *rtc;
+};
+
+static int m41t80_get_datetime(struct i2c_client *client,
+ struct rtc_time *tm)
+{
+ u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
+ .buf = buf + M41T80_REG_SEC,
+ },
+ };
+
+ if (i2c_transfer(client->adapter, msgs, 2) < 0) {
+ dev_err(&client->dev, "read error\n");
+ return -EIO;
+ }
+
+ tm->tm_sec = BCD2BIN(buf[M41T80_REG_SEC] & 0x7f);
+ tm->tm_min = BCD2BIN(buf[M41T80_REG_MIN] & 0x7f);
+ tm->tm_hour = BCD2BIN(buf[M41T80_REG_HOUR] & 0x3f);
+ tm->tm_mday = BCD2BIN(buf[M41T80_REG_DAY] & 0x3f);
+ tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
+ tm->tm_mon = BCD2BIN(buf[M41T80_REG_MON] & 0x1f) - 1;
+
+ /* assume 20YY not 19YY, and ignore the Century Bit */
+ tm->tm_year = BCD2BIN(buf[M41T80_REG_YEAR]) + 100;
+ return 0;
+}
+
+/* Sets the given date and time to the real time clock. */
+static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+ u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
+ u8 *buf = &wbuf[1];
+ u8 dt_addr[1] = { M41T80_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 = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
+ .buf = buf + M41T80_REG_SEC,
+ },
+ };
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1 + M41T80_DATETIME_REG_SIZE,
+ .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[M41T80_REG_SSEC] = 0;
+ buf[M41T80_REG_SEC] =
+ BIN2BCD(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
+ buf[M41T80_REG_MIN] =
+ BIN2BCD(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
+ buf[M41T80_REG_HOUR] =
+ BIN2BCD(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
+ buf[M41T80_REG_WDAY] =
+ (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
+ buf[M41T80_REG_DAY] =
+ BIN2BCD(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
+ buf[M41T80_REG_MON] =
+ BIN2BCD(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
+ /* assume 20YY not 19YY */
+ buf[M41T80_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 m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct m41t80_data *clientdata = i2c_get_clientdata(client);
+ u8 reg;
+
+ if (clientdata->chip->features & M41T80_FEATURE_BL) {
+ reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
+ seq_printf(seq, "battery\t\t: %s\n",
+ (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
+ }
+ return 0;
+}
+#else
+#define m41t80_rtc_proc NULL
+#endif
+
+static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ return m41t80_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return m41t80_set_datetime(to_i2c_client(dev), tm);
+}
+
+#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
+static int
+m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int rc;
+
+ switch (cmd) {
+ case RTC_AIE_OFF:
+ case RTC_AIE_ON:
+ break;
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
+ if (rc < 0)
+ goto err;
+ switch (cmd) {
+ case RTC_AIE_OFF:
+ rc &= ~M41T80_ALMON_AFE;
+ break;
+ case RTC_AIE_ON:
+ rc |= M41T80_ALMON_AFE;
+ break;
+ }
+ if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
+ goto err;
+ return 0;
+err:
+ return -EIO;
+}
+#else
+#define m41t80_rtc_ioctl NULL
+#endif
+
+static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
+ u8 *buf = &wbuf[1];
+ u8 *reg = buf - M41T80_REG_ALARM_MON;
+ u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
+ struct i2c_msg msgs_in[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = M41T80_ALARM_REG_SIZE,
+ .buf = buf,
+ },
+ };
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1 + M41T80_ALARM_REG_SIZE,
+ .buf = wbuf,
+ },
+ };
+
+ if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
+ dev_err(&client->dev, "read error\n");
+ return -EIO;
+ }
+ reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
+ reg[M41T80_REG_ALARM_DAY] = 0;
+ reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
+ reg[M41T80_REG_ALARM_MIN] = 0;
+ reg[M41T80_REG_ALARM_SEC] = 0;
+
+ wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
+ reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
+ BIN2BCD(t->time.tm_sec) : 0x80;
+ reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
+ BIN2BCD(t->time.tm_min) : 0x80;
+ reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
+ BIN2BCD(t->time.tm_hour) : 0x80;
+ reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
+ BIN2BCD(t->time.tm_mday) : 0x80;
+ if (t->time.tm_mon >= 0)
+ reg[M41T80_REG_ALARM_MON] |= BIN2BCD(t->time.tm_mon + 1);
+ else
+ reg[M41T80_REG_ALARM_DAY] |= 0x40;
+
+ if (i2c_transfer(client->adapter, msgs, 1) != 1) {
+ dev_err(&client->dev, "write error\n");
+ return -EIO;
+ }
+
+ if (t->enabled) {
+ reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
+ if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
+ reg[M41T80_REG_ALARM_MON]) < 0) {
+ dev_err(&client->dev, "write error\n");
+ return -EIO;
+ }
+ }
+ return 0;
+}
+
+static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
+ u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
+ u8 *reg = buf - M41T80_REG_ALARM_MON;
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = dt_addr,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = M41T80_ALARM_REG_SIZE + 1,
+ .buf = buf,
+ },
+ };
+
+ if (i2c_transfer(client->adapter, msgs, 2) < 0) {
+ dev_err(&client->dev, "read error\n");
+ return -EIO;
+ }
+ t->time.tm_sec = -1;
+ t->time.tm_min = -1;
+ t->time.tm_hour = -1;
+ t->time.tm_mday = -1;
+ t->time.tm_mon = -1;
+ if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
+ t->time.tm_sec = BCD2BIN(reg[M41T80_REG_ALARM_SEC] & 0x7f);
+ if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
+ t->time.tm_min = BCD2BIN(reg[M41T80_REG_ALARM_MIN] & 0x7f);
+ if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
+ t->time.tm_hour = BCD2BIN(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
+ if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
+ t->time.tm_mday = BCD2BIN(reg[M41T80_REG_ALARM_DAY] & 0x3f);
+ if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
+ t->time.tm_mon = BCD2BIN(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
+ t->time.tm_year = -1;
+ t->time.tm_wday = -1;
+ t->time.tm_yday = -1;
+ t->time.tm_isdst = -1;
+ t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
+ t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
+ return 0;
+}
+
+static struct rtc_class_ops m41t80_rtc_ops = {
+ .read_time = m41t80_rtc_read_time,
+ .set_time = m41t80_rtc_set_time,
+ .read_alarm = m41t80_rtc_read_alarm,
+ .set_alarm = m41t80_rtc_set_alarm,
+ .proc = m41t80_rtc_proc,
+ .ioctl = m41t80_rtc_ioctl,
+};
+
+#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
+static ssize_t m41t80_sysfs_show_flags(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int val;
+
+ val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
+ if (val < 0)
+ return -EIO;
+ return sprintf(buf, "%#x\n", val);
+}
+static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
+
+static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int val;
+
+ val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
+ if (val < 0)
+ return -EIO;
+ val = (val >> 4) & 0xf;
+ switch (val) {
+ case 0:
+ break;
+ case 1:
+ val = 32768;
+ break;
+ default:
+ val = 32768 >> val;
+ }
+ return sprintf(buf, "%d\n", val);
+}
+static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int almon, sqw;
+ int val = simple_strtoul(buf, NULL, 0);
+
+ if (val) {
+ if (!is_power_of_2(val))
+ return -EINVAL;
+ val = ilog2(val);
+ if (val == 15)
+ val = 1;
+ else if (val < 14)
+ val = 15 - val;
+ else
+ return -EINVAL;
+ }
+ /* disable SQW, set SQW frequency & re-enable */
+ almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
+ if (almon < 0)
+ return -EIO;
+ sqw = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
+ if (sqw < 0)
+ return -EIO;
+ sqw = (sqw & 0x0f) | (val << 4);
+ if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
+ almon & ~M41T80_ALMON_SQWE) < 0 ||
+ i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0)
+ return -EIO;
+ if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
+ almon | M41T80_ALMON_SQWE) < 0)
+ return -EIO;
+ return count;
+}
+static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
+ m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
+
+static struct attribute *attrs[] = {
+ &dev_attr_flags.attr,
+ &dev_attr_sqwfreq.attr,
+ NULL,
+};
+static struct attribute_group attr_group = {
+ .attrs = attrs,
+};
+
+static int m41t80_sysfs_register(struct device *dev)
+{
+ return sysfs_create_group(&dev->kobj, &attr_group);
+}
+#else
+static int m41t80_sysfs_register(struct device *dev)
+{
+ return 0;
+}
+#endif
+
+/*
+ *****************************************************************************
+ *
+ * Driver Interface
+ *
+ *****************************************************************************
+ */
+static int m41t80_probe(struct i2c_client *client)
+{
+ int i, rc = 0;
+ struct rtc_device *rtc = NULL;
+ struct rtc_time tm;
+ const struct m41t80_chip_info *chip;
+ struct m41t80_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(m41t80_chip_info_tbl); i++) {
+ if (!strcmp(m41t80_chip_info_tbl[i].name, client->name)) {
+ chip = &m41t80_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,
+ &m41t80_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);
+
+ /* Make sure HT (Halt Update) bit is cleared */
+ rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
+ if (rc < 0)
+ goto ht_err;
+
+ if (rc & M41T80_ALHOUR_HT) {
+ if (chip->features & M41T80_FEATURE_HT) {
+ m41t80_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,
+ M41T80_REG_ALARM_HOUR,
+ rc & ~M41T80_ALHOUR_HT) < 0)
+ goto ht_err;
+ }
+
+ /* Make sure ST (stop) bit is cleared */
+ rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
+ if (rc < 0)
+ goto st_err;
+
+ if (rc & M41T80_SEC_ST) {
+ if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
+ rc & ~M41T80_SEC_ST) < 0)
+ goto st_err;
+ }
+
+ rc = m41t80_sysfs_register(&client->dev);
+ if (rc)
+ goto exit;
+
+ 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;
+
+exit:
+ if (rtc)
+ rtc_device_unregister(rtc);
+ kfree(clientdata);
+ return rc;
+}
+
+static int m41t80_remove(struct i2c_client *client)
+{
+ struct m41t80_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 m41t80_driver = {
+ .driver = {
+ .name = "m41t80",
+ },
+ .probe = m41t80_probe,
+ .remove = m41t80_remove,
+};
+
+static int __init m41t80_rtc_init(void)
+{
+ return i2c_add_driver(&m41t80_driver);
+}
+
+static void __exit m41t80_rtc_exit(void)
+{
+ i2c_del_driver(&m41t80_driver);
+}
+
+MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
+MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(m41t80_rtc_init);
+module_exit(m41t80_rtc_exit);
projects / linux-2.6 / commitdiff