v4.19.13 snapshot.
diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
new file mode 100644
index 0000000..ad03e2f
--- /dev/null
+++ b/drivers/rtc/rtc-m41t80.c
@@ -0,0 +1,1022 @@
+/*
+ * 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.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bcd.h>
+#include <linux/clk-provider.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#ifdef CONFIG_RTC_DRV_M41T80_WDT
+#include <linux/fs.h>
+#include <linux/ioctl.h>
+#include <linux/miscdevice.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+#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 -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;
+}
+
+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;
+
+ if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
+ flags & ~M41T80_FLAGS_OF)) {
+ dev_err(&client->dev, "Unable to write flags register\n");
+ return -EIO;
+ }
+
+ 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);
+ 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;
+}
+
+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);
+
+ 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 */
+ 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 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)
+{
+ 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 %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;
+ }
+
+#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 <ab@mycable.de>");
+MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
+MODULE_LICENSE("GPL");