/* * I2C client/driver for the ST M41T80 family of i2c rtc chips. * * Author: Alexander Bigga * * Based on m41t00.c by Mark A. Greer * * 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 #include #include #include #include #include #include #include #include #ifdef CONFIG_RTC_DRV_M41T80_WDT #include #include #include #include #include #endif #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_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */ #define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */ #define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */ #define M41T80_FEATURE_HT (1 << 0) /* Halt feature */ #define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */ #define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */ #define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */ #define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */ static DEFINE_MUTEX(m41t80_rtc_mutex); static const struct i2c_device_id m41t80_id[] = { { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT }, { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD }, { "m41t80", M41T80_FEATURE_SQ }, { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ}, { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ }, { } }; MODULE_DEVICE_TABLE(i2c, m41t80_id); struct m41t80_data { u8 features; 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 rtc_valid_tm(tm); } /* 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->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); } /* * XXX - m41t80 alarm functionality is reported broken. * until it is fixed, don't register alarm functions. */ static struct rtc_class_ops m41t80_rtc_ops = { .read_time = m41t80_rtc_read_time, .set_time = m41t80_rtc_set_time, .proc = m41t80_rtc_proc, }; #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 val; 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); struct m41t80_data *clientdata = i2c_get_clientdata(client); int val, reg_sqw; if (!(clientdata->features & M41T80_FEATURE_SQ)) return -EINVAL; reg_sqw = M41T80_REG_SQW; if (clientdata->features & M41T80_FEATURE_SQ_ALT) reg_sqw = M41T80_REG_WDAY; val = i2c_smbus_read_byte_data(client, reg_sqw); if (val < 0) return val; 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); struct m41t80_data *clientdata = i2c_get_clientdata(client); int almon, sqw, reg_sqw, rc; int val = simple_strtoul(buf, NULL, 0); if (!(clientdata->features & M41T80_FEATURE_SQ)) return -EINVAL; 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 almon; reg_sqw = M41T80_REG_SQW; if (clientdata->features & M41T80_FEATURE_SQ_ALT) reg_sqw = M41T80_REG_WDAY; sqw = i2c_smbus_read_byte_data(client, reg_sqw); if (sqw < 0) return sqw; sqw = (sqw & 0x0f) | (val << 4); rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, almon & ~M41T80_ALMON_SQWE); if (rc < 0) return rc; if (val) { rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw); if (rc < 0) return rc; rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, almon | M41T80_ALMON_SQWE); if (rc <0) return rc; } 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 #ifdef CONFIG_RTC_DRV_M41T80_WDT /* ***************************************************************************** * * Watchdog Driver * ***************************************************************************** */ static struct i2c_client *save_client; /* Default margin */ #define WD_TIMO 60 /* 1..31 seconds */ static int wdt_margin = WD_TIMO; module_param(wdt_margin, int, 0); MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)"); static unsigned long wdt_is_open; static int boot_flag; /** * wdt_ping: * * Reload counter one with the watchdog timeout. We don't bother reloading * the cascade counter. */ static void wdt_ping(void) { unsigned char i2c_data[2]; struct i2c_msg msgs1[1] = { { .addr = save_client->addr, .flags = 0, .len = 2, .buf = i2c_data, }, }; struct m41t80_data *clientdata = i2c_get_clientdata(save_client); i2c_data[0] = 0x09; /* watchdog register */ if (wdt_margin > 31) i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */ else /* * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02) */ i2c_data[1] = wdt_margin<<2 | 0x82; /* * M41T65 has three bits for watchdog resolution. Don't set bit 7, as * that would be an invalid resolution. */ if (clientdata->features & M41T80_FEATURE_WD) i2c_data[1] &= ~M41T80_WATCHDOG_RB2; i2c_transfer(save_client->adapter, msgs1, 1); } /** * wdt_disable: * * disables watchdog. */ static void wdt_disable(void) { unsigned char i2c_data[2], i2c_buf[0x10]; struct i2c_msg msgs0[2] = { { .addr = save_client->addr, .flags = 0, .len = 1, .buf = i2c_data, }, { .addr = save_client->addr, .flags = I2C_M_RD, .len = 1, .buf = i2c_buf, }, }; struct i2c_msg msgs1[1] = { { .addr = save_client->addr, .flags = 0, .len = 2, .buf = i2c_data, }, }; i2c_data[0] = 0x09; i2c_transfer(save_client->adapter, msgs0, 2); i2c_data[0] = 0x09; i2c_data[1] = 0x00; i2c_transfer(save_client->adapter, msgs1, 1); } /** * wdt_write: * @file: file handle to the watchdog * @buf: buffer to write (unused as data does not matter here * @count: count of bytes * @ppos: pointer to the position to write. No seeks allowed * * A write to a watchdog device is defined as a keepalive signal. Any * write of data will do, as we we don't define content meaning. */ static ssize_t wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) { wdt_ping(); return 1; } return 0; } static ssize_t wdt_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { return 0; } /** * wdt_ioctl: * @inode: inode of the device * @file: file handle to the device * @cmd: watchdog command * @arg: argument pointer * * The watchdog API defines a common set of functions for all watchdogs * according to their available features. We only actually usefully support * querying capabilities and current status. */ static int wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int new_margin, rv; static struct watchdog_info ident = { .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, .firmware_version = 1, .identity = "M41T80 WTD" }; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user((struct watchdog_info __user *)arg, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(boot_flag, (int __user *)arg); case WDIOC_KEEPALIVE: wdt_ping(); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_margin, (int __user *)arg)) return -EFAULT; /* Arbitrary, can't find the card's limits */ if (new_margin < 1 || new_margin > 124) return -EINVAL; wdt_margin = new_margin; wdt_ping(); /* Fall */ case WDIOC_GETTIMEOUT: return put_user(wdt_margin, (int __user *)arg); case WDIOC_SETOPTIONS: if (copy_from_user(&rv, (int __user *)arg, sizeof(int))) return -EFAULT; if (rv & WDIOS_DISABLECARD) { pr_info("rtc-m41t80: disable watchdog\n"); wdt_disable(); } if (rv & WDIOS_ENABLECARD) { pr_info("rtc-m41t80: enable watchdog\n"); wdt_ping(); } return -EINVAL; } return -ENOTTY; } static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int ret; mutex_lock(&m41t80_rtc_mutex); ret = wdt_ioctl(file, cmd, arg); mutex_unlock(&m41t80_rtc_mutex); return ret; } /** * wdt_open: * @inode: inode of device * @file: file handle to device * */ static int wdt_open(struct inode *inode, struct file *file) { if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { mutex_lock(&m41t80_rtc_mutex); if (test_and_set_bit(0, &wdt_is_open)) { mutex_unlock(&m41t80_rtc_mutex); return -EBUSY; } /* * Activate */ wdt_is_open = 1; mutex_unlock(&m41t80_rtc_mutex); return nonseekable_open(inode, file); } return -ENODEV; } /** * wdt_close: * @inode: inode to board * @file: file handle to board * */ static int wdt_release(struct inode *inode, struct file *file) { if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) clear_bit(0, &wdt_is_open); return 0; } /** * notify_sys: * @this: our notifier block * @code: the event being reported * @unused: unused * * Our notifier is called on system shutdowns. We want to turn the card * off at reboot otherwise the machine will reboot again during memory * test or worse yet during the following fsck. This would suck, in fact * trust me - if it happens it does suck. */ static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) /* Disable Watchdog */ wdt_disable(); return NOTIFY_DONE; } static const struct file_operations wdt_fops = { .owner = THIS_MODULE, .read = wdt_read, .unlocked_ioctl = wdt_unlocked_ioctl, .write = wdt_write, .open = wdt_open, .release = wdt_release, .llseek = no_llseek, }; static struct miscdevice wdt_dev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wdt_fops, }; /* * The WDT card needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block wdt_notifier = { .notifier_call = wdt_notify_sys, }; #endif /* CONFIG_RTC_DRV_M41T80_WDT */ /* ***************************************************************************** * * Driver Interface * ***************************************************************************** */ static int m41t80_probe(struct i2c_client *client, const struct i2c_device_id *id) { int rc = 0; struct rtc_device *rtc = NULL; struct rtc_time tm; struct m41t80_data *clientdata = NULL; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE_DATA)) return -ENODEV; clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata), GFP_KERNEL); if (!clientdata) return -ENOMEM; clientdata->features = id->driver_data; i2c_set_clientdata(client, clientdata); rtc = devm_rtc_device_register(&client->dev, client->name, &m41t80_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); clientdata->rtc = rtc; /* Make sure HT (Halt Update) bit is cleared */ rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR); if (rc >= 0 && rc & M41T80_ALHOUR_HT) { if (clientdata->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); } rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR, rc & ~M41T80_ALHOUR_HT); } if (rc < 0) { dev_err(&client->dev, "Can't clear HT bit\n"); return rc; } /* Make sure ST (stop) bit is cleared */ rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC); if (rc >= 0 && rc & M41T80_SEC_ST) rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC, rc & ~M41T80_SEC_ST); if (rc < 0) { dev_err(&client->dev, "Can't clear ST bit\n"); return rc; } rc = m41t80_sysfs_register(&client->dev); if (rc) return rc; #ifdef CONFIG_RTC_DRV_M41T80_WDT if (clientdata->features & M41T80_FEATURE_HT) { save_client = client; rc = misc_register(&wdt_dev); if (rc) return rc; rc = register_reboot_notifier(&wdt_notifier); if (rc) { misc_deregister(&wdt_dev); return rc; } } #endif return 0; } static int m41t80_remove(struct i2c_client *client) { #ifdef CONFIG_RTC_DRV_M41T80_WDT struct m41t80_data *clientdata = i2c_get_clientdata(client); if (clientdata->features & M41T80_FEATURE_HT) { misc_deregister(&wdt_dev); unregister_reboot_notifier(&wdt_notifier); } #endif return 0; } static struct i2c_driver m41t80_driver = { .driver = { .name = "rtc-m41t80", }, .probe = m41t80_probe, .remove = m41t80_remove, .id_table = m41t80_id, }; module_i2c_driver(m41t80_driver); MODULE_AUTHOR("Alexander Bigga "); MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver"); MODULE_LICENSE("GPL");