// SPDX-License-Identifier: GPL-2.0-only /* * 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 */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #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 0x00 #define M41T80_REG_SEC 0x01 #define M41T80_REG_MIN 0x02 #define M41T80_REG_HOUR 0x03 #define M41T80_REG_WDAY 0x04 #define M41T80_REG_DAY 0x05 #define M41T80_REG_MON 0x06 #define M41T80_REG_YEAR 0x07 #define M41T80_REG_ALARM_MON 0x0a #define M41T80_REG_ALARM_DAY 0x0b #define M41T80_REG_ALARM_HOUR 0x0c #define M41T80_REG_ALARM_MIN 0x0d #define M41T80_REG_ALARM_SEC 0x0e #define M41T80_REG_FLAGS 0x0f #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_SQW_MAX_FREQ 32768 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */ #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */ #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */ #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */ #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */ #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */ #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */ #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */ #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */ #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */ #define M41T80_FEATURE_HT BIT(0) /* Halt feature */ #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */ #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */ #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */ #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */ 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 }, { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT }, { } }; MODULE_DEVICE_TABLE(i2c, m41t80_id); static const struct of_device_id m41t80_of_match[] = { { .compatible = "st,m41t62", .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT) }, { .compatible = "st,m41t65", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD) }, { .compatible = "st,m41t80", .data = (void *)(M41T80_FEATURE_SQ) }, { .compatible = "st,m41t81", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ) }, { .compatible = "st,m41t81s", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) }, { .compatible = "st,m41t82", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) }, { .compatible = "st,m41t83", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) }, { .compatible = "st,m41t84", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) }, { .compatible = "st,m41t85", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) }, { .compatible = "st,m41t87", .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ) }, { .compatible = "microcrystal,rv4162", .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) }, /* DT compatibility only, do not use compatibles below: */ { .compatible = "st,rv4162", .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) }, { .compatible = "rv4162", .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT) }, { } }; MODULE_DEVICE_TABLE(of, m41t80_of_match); struct m41t80_data { unsigned long features; struct i2c_client *client; struct rtc_device *rtc; #ifdef CONFIG_COMMON_CLK struct clk_hw sqw; unsigned long freq; unsigned int sqwe; #endif }; static irqreturn_t m41t80_handle_irq(int irq, void *dev_id) { struct i2c_client *client = dev_id; struct m41t80_data *m41t80 = i2c_get_clientdata(client); struct mutex *lock = &m41t80->rtc->ops_lock; unsigned long events = 0; int flags, flags_afe; mutex_lock(lock); flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); if (flags_afe < 0) { mutex_unlock(lock); return IRQ_NONE; } flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); if (flags <= 0) { mutex_unlock(lock); return IRQ_NONE; } if (flags & M41T80_FLAGS_AF) { flags &= ~M41T80_FLAGS_AF; flags_afe &= ~M41T80_ALMON_AFE; events |= RTC_AF; } if (events) { rtc_update_irq(m41t80->rtc, 1, events); i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags); i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags_afe); } mutex_unlock(lock); return IRQ_HANDLED; } static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); unsigned char buf[8]; int err, flags; flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); if (flags < 0) return flags; if (flags & M41T80_FLAGS_OF) { dev_err(&client->dev, "Oscillator failure, data is invalid.\n"); return -EINVAL; } err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC, sizeof(buf), buf); if (err < 0) { dev_err(&client->dev, "Unable to read date\n"); return err; } 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; } static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); struct m41t80_data *clientdata = i2c_get_clientdata(client); unsigned char buf[8]; int err, flags; if (tm->tm_year < 100 || tm->tm_year > 199) return -EINVAL; buf[M41T80_REG_SSEC] = 0; buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec); buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min); buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour); buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday); buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1); buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100); buf[M41T80_REG_WDAY] = tm->tm_wday; /* If the square wave output is controlled in the weekday register */ if (clientdata->features & M41T80_FEATURE_SQ_ALT) { int val; val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY); if (val < 0) return val; buf[M41T80_REG_WDAY] |= (val & 0xf0); } err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC, sizeof(buf), buf); if (err < 0) { dev_err(&client->dev, "Unable to write to date registers\n"); return err; } /* Clear the OF bit of Flags Register */ flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); if (flags < 0) return flags; err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags & ~M41T80_FLAGS_OF); if (err < 0) { dev_err(&client->dev, "Unable to write flags register\n"); return err; } return err; } 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); int reg; if (clientdata->features & M41T80_FEATURE_BL) { reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); if (reg < 0) return reg; seq_printf(seq, "battery\t\t: %s\n", (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok"); } return 0; } static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct i2c_client *client = to_i2c_client(dev); int flags, retval; flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); if (flags < 0) return flags; if (enabled) flags |= M41T80_ALMON_AFE; else flags &= ~M41T80_ALMON_AFE; retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags); if (retval < 0) { dev_err(dev, "Unable to enable alarm IRQ %d\n", retval); return retval; } return 0; } static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct i2c_client *client = to_i2c_client(dev); u8 alarmvals[5]; int ret, err; alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1); alarmvals[1] = bin2bcd(alrm->time.tm_mday); alarmvals[2] = bin2bcd(alrm->time.tm_hour); alarmvals[3] = bin2bcd(alrm->time.tm_min); alarmvals[4] = bin2bcd(alrm->time.tm_sec); /* Clear AF and AFE flags */ ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); if (ret < 0) return ret; err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret & ~(M41T80_ALMON_AFE)); if (err < 0) { dev_err(dev, "Unable to clear AFE bit\n"); return err; } /* Keep SQWE bit value */ alarmvals[0] |= (ret & M41T80_ALMON_SQWE); ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); if (ret < 0) return ret; err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, ret & ~(M41T80_FLAGS_AF)); if (err < 0) { dev_err(dev, "Unable to clear AF bit\n"); return err; } /* Write the alarm */ err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON, 5, alarmvals); if (err) return err; /* Enable the alarm interrupt */ if (alrm->enabled) { alarmvals[0] |= M41T80_ALMON_AFE; err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, alarmvals[0]); if (err) return err; } return 0; } static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct i2c_client *client = to_i2c_client(dev); u8 alarmvals[5]; int flags, ret; ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON, 5, alarmvals); if (ret != 5) return ret < 0 ? ret : -EIO; flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS); if (flags < 0) return flags; alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f); alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f); alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f); alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f); alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f) - 1; alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE); alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled; return 0; } static struct rtc_class_ops m41t80_rtc_ops = { .read_time = m41t80_rtc_read_time, .set_time = m41t80_rtc_set_time, .proc = m41t80_rtc_proc, }; #ifdef CONFIG_PM_SLEEP static int m41t80_suspend(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); if (client->irq >= 0 && device_may_wakeup(dev)) enable_irq_wake(client->irq); return 0; } static int m41t80_resume(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); if (client->irq >= 0 && device_may_wakeup(dev)) disable_irq_wake(client->irq); return 0; } #endif static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume); #ifdef CONFIG_COMMON_CLK #define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw) static unsigned long m41t80_decode_freq(int setting) { return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ : M41T80_SQW_MAX_FREQ >> setting; } static unsigned long m41t80_get_freq(struct m41t80_data *m41t80) { struct i2c_client *client = m41t80->client; int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ? M41T80_REG_WDAY : M41T80_REG_SQW; int ret = i2c_smbus_read_byte_data(client, reg_sqw); if (ret < 0) return 0; return m41t80_decode_freq(ret >> 4); } static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { return sqw_to_m41t80_data(hw)->freq; } static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *prate) { if (rate >= M41T80_SQW_MAX_FREQ) return M41T80_SQW_MAX_FREQ; if (rate >= M41T80_SQW_MAX_FREQ / 4) return M41T80_SQW_MAX_FREQ / 4; if (!rate) return 0; return 1 << ilog2(rate); } static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw); struct i2c_client *client = m41t80->client; int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ? M41T80_REG_WDAY : M41T80_REG_SQW; int reg, ret, val = 0; if (rate >= M41T80_SQW_MAX_FREQ) val = 1; else if (rate >= M41T80_SQW_MAX_FREQ / 4) val = 2; else if (rate) val = 15 - ilog2(rate); reg = i2c_smbus_read_byte_data(client, reg_sqw); if (reg < 0) return reg; reg = (reg & 0x0f) | (val << 4); ret = i2c_smbus_write_byte_data(client, reg_sqw, reg); if (!ret) m41t80->freq = m41t80_decode_freq(val); return ret; } static int m41t80_sqw_control(struct clk_hw *hw, bool enable) { struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw); struct i2c_client *client = m41t80->client; int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); if (ret < 0) return ret; if (enable) ret |= M41T80_ALMON_SQWE; else ret &= ~M41T80_ALMON_SQWE; ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret); if (!ret) m41t80->sqwe = enable; return ret; } static int m41t80_sqw_prepare(struct clk_hw *hw) { return m41t80_sqw_control(hw, 1); } static void m41t80_sqw_unprepare(struct clk_hw *hw) { m41t80_sqw_control(hw, 0); } static int m41t80_sqw_is_prepared(struct clk_hw *hw) { return sqw_to_m41t80_data(hw)->sqwe; } static const struct clk_ops m41t80_sqw_ops = { .prepare = m41t80_sqw_prepare, .unprepare = m41t80_sqw_unprepare, .is_prepared = m41t80_sqw_is_prepared, .recalc_rate = m41t80_sqw_recalc_rate, .round_rate = m41t80_sqw_round_rate, .set_rate = m41t80_sqw_set_rate, }; static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80) { struct i2c_client *client = m41t80->client; struct device_node *node = client->dev.of_node; struct clk *clk; struct clk_init_data init; int ret; /* First disable the clock */ ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON); if (ret < 0) return ERR_PTR(ret); ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret & ~(M41T80_ALMON_SQWE)); if (ret < 0) return ERR_PTR(ret); init.name = "m41t80-sqw"; init.ops = &m41t80_sqw_ops; init.flags = 0; init.parent_names = NULL; init.num_parents = 0; m41t80->sqw.init = &init; m41t80->freq = m41t80_get_freq(m41t80); /* optional override of the clockname */ of_property_read_string(node, "clock-output-names", &init.name); /* register the clock */ clk = clk_register(&client->dev, &m41t80->sqw); if (!IS_ERR(clk)) of_clk_add_provider(node, of_clk_src_simple_get, clk); return clk; } #endif #ifdef CONFIG_RTC_DRV_M41T80_WDT /* ***************************************************************************** * * Watchdog Driver * ***************************************************************************** */ static DEFINE_MUTEX(m41t80_rtc_mutex); 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 through */ 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("disable watchdog\n"); wdt_disable(); } if (rv & WDIOS_ENABLECARD) { pr_info("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 stream_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) { struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); int rc = 0; struct rtc_time tm; struct m41t80_data *m41t80_data = NULL; bool wakeup_source = false; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_BYTE_DATA)) { dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); return -ENODEV; } m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data), GFP_KERNEL); if (!m41t80_data) return -ENOMEM; m41t80_data->client = client; if (client->dev.of_node) m41t80_data->features = (unsigned long) of_device_get_match_data(&client->dev); else m41t80_data->features = id->driver_data; i2c_set_clientdata(client, m41t80_data); m41t80_data->rtc = devm_rtc_allocate_device(&client->dev); if (IS_ERR(m41t80_data->rtc)) return PTR_ERR(m41t80_data->rtc); #ifdef CONFIG_OF wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source"); #endif if (client->irq > 0) { rc = devm_request_threaded_irq(&client->dev, client->irq, NULL, m41t80_handle_irq, IRQF_TRIGGER_LOW | IRQF_ONESHOT, "m41t80", client); if (rc) { dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); client->irq = 0; wakeup_source = false; } } if (client->irq > 0 || wakeup_source) { m41t80_rtc_ops.read_alarm = m41t80_read_alarm; m41t80_rtc_ops.set_alarm = m41t80_set_alarm; m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable; /* Enable the wakealarm */ device_init_wakeup(&client->dev, true); } m41t80_data->rtc->ops = &m41t80_rtc_ops; if (client->irq <= 0) { /* We cannot support UIE mode if we do not have an IRQ line */ m41t80_data->rtc->uie_unsupported = 1; } /* 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 (m41t80_data->features & M41T80_FEATURE_HT) { m41t80_rtc_read_time(&client->dev, &tm); dev_info(&client->dev, "HT bit was set!\n"); dev_info(&client->dev, "Power Down at %ptR\n", &tm); } 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; } #ifdef CONFIG_RTC_DRV_M41T80_WDT if (m41t80_data->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 #ifdef CONFIG_COMMON_CLK if (m41t80_data->features & M41T80_FEATURE_SQ) m41t80_sqw_register_clk(m41t80_data); #endif rc = rtc_register_device(m41t80_data->rtc); if (rc) return rc; 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", .of_match_table = of_match_ptr(m41t80_of_match), .pm = &m41t80_pm, }, .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");