Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 772 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
new file mode 100644
index 000000000..b9b5fee16
--- /dev/null
+++ b/drivers/rtc/rtc-rv8803.c
@@ -0,0 +1,772 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC driver for the Micro Crystal RV8803
+ *
+ * Copyright (C) 2015 Micro Crystal SA
+ * Alexandre Belloni <alexandre.belloni@bootlin.com>
+ *
+ */
+
+#include <linux/bcd.h>
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/log2.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/rtc.h>
+#include <linux/pm_wakeirq.h>
+
+#define RV8803_I2C_TRY_COUNT		4
+
+#define RV8803_SEC			0x00
+#define RV8803_MIN			0x01
+#define RV8803_HOUR			0x02
+#define RV8803_WEEK			0x03
+#define RV8803_DAY			0x04
+#define RV8803_MONTH			0x05
+#define RV8803_YEAR			0x06
+#define RV8803_RAM			0x07
+#define RV8803_ALARM_MIN		0x08
+#define RV8803_ALARM_HOUR		0x09
+#define RV8803_ALARM_WEEK_OR_DAY	0x0A
+#define RV8803_EXT			0x0D
+#define RV8803_FLAG			0x0E
+#define RV8803_CTRL			0x0F
+#define RV8803_OSC_OFFSET		0x2C
+
+#define RV8803_EXT_WADA			BIT(6)
+
+#define RV8803_FLAG_V1F			BIT(0)
+#define RV8803_FLAG_V2F			BIT(1)
+#define RV8803_FLAG_AF			BIT(3)
+#define RV8803_FLAG_TF			BIT(4)
+#define RV8803_FLAG_UF			BIT(5)
+
+#define RV8803_CTRL_RESET		BIT(0)
+
+#define RV8803_CTRL_EIE			BIT(2)
+#define RV8803_CTRL_AIE			BIT(3)
+#define RV8803_CTRL_TIE			BIT(4)
+#define RV8803_CTRL_UIE			BIT(5)
+
+#define RX8803_CTRL_CSEL		GENMASK(7, 6)
+
+#define RX8900_BACKUP_CTRL		0x18
+#define RX8900_FLAG_SWOFF		BIT(2)
+#define RX8900_FLAG_VDETOFF		BIT(3)
+
+enum rv8803_type {
+	rv_8803,
+	rx_8803,
+	rx_8804,
+	rx_8900
+};
+
+struct rv8803_data {
+	struct i2c_client *client;
+	struct rtc_device *rtc;
+	struct mutex flags_lock;
+	u8 ctrl;
+	u8 backup;
+	u8 alarm_invalid:1;
+	enum rv8803_type type;
+};
+
+static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
+{
+	int try = RV8803_I2C_TRY_COUNT;
+	s32 ret;
+
+	/*
+	 * There is a 61µs window during which the RTC does not acknowledge I2C
+	 * transfers. In that case, ensure that there are multiple attempts.
+	 */
+	do
+		ret = i2c_smbus_read_byte_data(client, reg);
+	while ((ret == -ENXIO || ret == -EIO) && --try);
+	if (ret < 0)
+		dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
+
+	return ret;
+}
+
+static int rv8803_read_regs(const struct i2c_client *client,
+			    u8 reg, u8 count, u8 *values)
+{
+	int try = RV8803_I2C_TRY_COUNT;
+	s32 ret;
+
+	do
+		ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
+	while ((ret == -ENXIO || ret == -EIO) && --try);
+	if (ret != count) {
+		dev_err(&client->dev,
+			"Unable to read registers 0x%02x..0x%02x\n",
+			reg, reg + count - 1);
+		return ret < 0 ? ret : -EIO;
+	}
+
+	return 0;
+}
+
+static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
+{
+	int try = RV8803_I2C_TRY_COUNT;
+	s32 ret;
+
+	do
+		ret = i2c_smbus_write_byte_data(client, reg, value);
+	while ((ret == -ENXIO || ret == -EIO) && --try);
+	if (ret)
+		dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
+
+	return ret;
+}
+
+static int rv8803_write_regs(const struct i2c_client *client,
+			     u8 reg, u8 count, const u8 *values)
+{
+	int try = RV8803_I2C_TRY_COUNT;
+	s32 ret;
+
+	do
+		ret = i2c_smbus_write_i2c_block_data(client, reg, count,
+						     values);
+	while ((ret == -ENXIO || ret == -EIO) && --try);
+	if (ret)
+		dev_err(&client->dev,
+			"Unable to write registers 0x%02x..0x%02x\n",
+			reg, reg + count - 1);
+
+	return ret;
+}
+
+static int rv8803_regs_init(struct rv8803_data *rv8803)
+{
+	int ret;
+
+	ret = rv8803_write_reg(rv8803->client, RV8803_OSC_OFFSET, 0x00);
+	if (ret)
+		return ret;
+
+	ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
+			       FIELD_PREP(RX8803_CTRL_CSEL, 1)); /* 2s */
+	if (ret)
+		return ret;
+
+	ret = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3,
+				(u8[]){ 0, 0, 0 });
+	if (ret)
+		return ret;
+
+	return rv8803_write_reg(rv8803->client, RV8803_RAM, 0x00);
+}
+
+static int rv8803_regs_configure(struct rv8803_data *rv8803);
+
+static int rv8803_regs_reset(struct rv8803_data *rv8803, bool full)
+{
+	/*
+	 * The RV-8803 resets all registers to POR defaults after voltage-loss,
+	 * the Epson RTCs don't, so we manually reset the remainder here.
+	 */
+	if (full || rv8803->type == rx_8803 || rv8803->type == rx_8900) {
+		int ret = rv8803_regs_init(rv8803);
+		if (ret)
+			return ret;
+	}
+
+	return rv8803_regs_configure(rv8803);
+}
+
+static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
+{
+	struct i2c_client *client = dev_id;
+	struct rv8803_data *rv8803 = i2c_get_clientdata(client);
+	unsigned long events = 0;
+	int flags;
+
+	mutex_lock(&rv8803->flags_lock);
+
+	flags = rv8803_read_reg(client, RV8803_FLAG);
+	if (flags <= 0) {
+		mutex_unlock(&rv8803->flags_lock);
+		return IRQ_NONE;
+	}
+
+	if (flags & RV8803_FLAG_V1F)
+		dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+
+	if (flags & RV8803_FLAG_V2F)
+		dev_warn(&client->dev, "Voltage low, data loss detected.\n");
+
+	if (flags & RV8803_FLAG_TF) {
+		flags &= ~RV8803_FLAG_TF;
+		rv8803->ctrl &= ~RV8803_CTRL_TIE;
+		events |= RTC_PF;
+	}
+
+	if (flags & RV8803_FLAG_AF) {
+		flags &= ~RV8803_FLAG_AF;
+		rv8803->ctrl &= ~RV8803_CTRL_AIE;
+		events |= RTC_AF;
+	}
+
+	if (flags & RV8803_FLAG_UF) {
+		flags &= ~RV8803_FLAG_UF;
+		rv8803->ctrl &= ~RV8803_CTRL_UIE;
+		events |= RTC_UF;
+	}
+
+	if (events) {
+		rtc_update_irq(rv8803->rtc, 1, events);
+		rv8803_write_reg(client, RV8803_FLAG, flags);
+		rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
+	}
+
+	mutex_unlock(&rv8803->flags_lock);
+
+	return IRQ_HANDLED;
+}
+
+static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	u8 date1[7];
+	u8 date2[7];
+	u8 *date = date1;
+	int ret, flags;
+
+	if (rv8803->alarm_invalid) {
+		dev_warn(dev, "Corruption detected, data may be invalid.\n");
+		return -EINVAL;
+	}
+
+	flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
+	if (flags < 0)
+		return flags;
+
+	if (flags & RV8803_FLAG_V2F) {
+		dev_warn(dev, "Voltage low, data is invalid.\n");
+		return -EINVAL;
+	}
+
+	ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
+	if (ret)
+		return ret;
+
+	if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
+		ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
+		if (ret)
+			return ret;
+
+		if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
+			date = date2;
+	}
+
+	tm->tm_sec  = bcd2bin(date[RV8803_SEC] & 0x7f);
+	tm->tm_min  = bcd2bin(date[RV8803_MIN] & 0x7f);
+	tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
+	tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
+	tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
+	tm->tm_mon  = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
+	tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
+
+	return 0;
+}
+
+static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	u8 date[7];
+	int ctrl, flags, ret;
+
+	ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
+	if (ctrl < 0)
+		return ctrl;
+
+	/* Stop the clock */
+	ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
+			       ctrl | RV8803_CTRL_RESET);
+	if (ret)
+		return ret;
+
+	date[RV8803_SEC]   = bin2bcd(tm->tm_sec);
+	date[RV8803_MIN]   = bin2bcd(tm->tm_min);
+	date[RV8803_HOUR]  = bin2bcd(tm->tm_hour);
+	date[RV8803_WEEK]  = 1 << (tm->tm_wday);
+	date[RV8803_DAY]   = bin2bcd(tm->tm_mday);
+	date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
+	date[RV8803_YEAR]  = bin2bcd(tm->tm_year - 100);
+
+	ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
+	if (ret)
+		return ret;
+
+	/* Restart the clock */
+	ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
+			       ctrl & ~RV8803_CTRL_RESET);
+	if (ret)
+		return ret;
+
+	mutex_lock(&rv8803->flags_lock);
+
+	flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
+	if (flags < 0) {
+		mutex_unlock(&rv8803->flags_lock);
+		return flags;
+	}
+
+	if ((flags & RV8803_FLAG_V2F) || rv8803->alarm_invalid) {
+		/*
+		 * If we sense corruption in the alarm registers, but see no
+		 * voltage loss flag, we can't rely on other registers having
+		 * sensible values. Reset them fully.
+		 */
+		ret = rv8803_regs_reset(rv8803, rv8803->alarm_invalid);
+		if (ret) {
+			mutex_unlock(&rv8803->flags_lock);
+			return ret;
+		}
+
+		rv8803->alarm_invalid = false;
+	}
+
+	ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
+			       flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
+
+	mutex_unlock(&rv8803->flags_lock);
+
+	return ret;
+}
+
+static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	struct i2c_client *client = rv8803->client;
+	u8 alarmvals[3];
+	int flags, ret;
+
+	ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
+	if (ret)
+		return ret;
+
+	flags = rv8803_read_reg(client, RV8803_FLAG);
+	if (flags < 0)
+		return flags;
+
+	alarmvals[0] &= 0x7f;
+	alarmvals[1] &= 0x3f;
+	alarmvals[2] &= 0x3f;
+
+	if (!bcd_is_valid(alarmvals[0]) ||
+	    !bcd_is_valid(alarmvals[1]) ||
+	    !bcd_is_valid(alarmvals[2]))
+		goto err_invalid;
+
+	alrm->time.tm_sec  = 0;
+	alrm->time.tm_min  = bcd2bin(alarmvals[0]);
+	alrm->time.tm_hour = bcd2bin(alarmvals[1]);
+	alrm->time.tm_mday = bcd2bin(alarmvals[2]);
+
+	alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
+	alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
+
+	if ((unsigned int)alrm->time.tm_mday > 31 ||
+	    (unsigned int)alrm->time.tm_hour >= 24 ||
+	    (unsigned int)alrm->time.tm_min >= 60)
+		goto err_invalid;
+
+	return 0;
+
+err_invalid:
+	rv8803->alarm_invalid = true;
+	return -EINVAL;
+}
+
+static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	u8 alarmvals[3];
+	u8 ctrl[2];
+	int ret, err;
+
+	/* The alarm has no seconds, round up to nearest minute */
+	if (alrm->time.tm_sec) {
+		time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
+
+		alarm_time += 60 - alrm->time.tm_sec;
+		rtc_time64_to_tm(alarm_time, &alrm->time);
+	}
+
+	mutex_lock(&rv8803->flags_lock);
+
+	ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
+	if (ret) {
+		mutex_unlock(&rv8803->flags_lock);
+		return ret;
+	}
+
+	alarmvals[0] = bin2bcd(alrm->time.tm_min);
+	alarmvals[1] = bin2bcd(alrm->time.tm_hour);
+	alarmvals[2] = bin2bcd(alrm->time.tm_mday);
+
+	if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
+		rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
+		err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
+				       rv8803->ctrl);
+		if (err) {
+			mutex_unlock(&rv8803->flags_lock);
+			return err;
+		}
+	}
+
+	ctrl[0] &= ~RV8803_FLAG_AF;
+	err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[0]);
+	mutex_unlock(&rv8803->flags_lock);
+	if (err)
+		return err;
+
+	err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
+	if (err)
+		return err;
+
+	if (alrm->enabled) {
+		if (rv8803->rtc->uie_rtctimer.enabled)
+			rv8803->ctrl |= RV8803_CTRL_UIE;
+		if (rv8803->rtc->aie_timer.enabled)
+			rv8803->ctrl |= RV8803_CTRL_AIE;
+
+		err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
+				       rv8803->ctrl);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	int ctrl, flags, err;
+
+	ctrl = rv8803->ctrl;
+
+	if (enabled) {
+		if (rv8803->rtc->uie_rtctimer.enabled)
+			ctrl |= RV8803_CTRL_UIE;
+		if (rv8803->rtc->aie_timer.enabled)
+			ctrl |= RV8803_CTRL_AIE;
+	} else {
+		if (!rv8803->rtc->uie_rtctimer.enabled)
+			ctrl &= ~RV8803_CTRL_UIE;
+		if (!rv8803->rtc->aie_timer.enabled)
+			ctrl &= ~RV8803_CTRL_AIE;
+	}
+
+	mutex_lock(&rv8803->flags_lock);
+	flags = rv8803_read_reg(client, RV8803_FLAG);
+	if (flags < 0) {
+		mutex_unlock(&rv8803->flags_lock);
+		return flags;
+	}
+	flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
+	err = rv8803_write_reg(client, RV8803_FLAG, flags);
+	mutex_unlock(&rv8803->flags_lock);
+	if (err)
+		return err;
+
+	if (ctrl != rv8803->ctrl) {
+		rv8803->ctrl = ctrl;
+		err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	unsigned int vl = 0;
+	int flags, ret = 0;
+
+	switch (cmd) {
+	case RTC_VL_READ:
+		flags = rv8803_read_reg(client, RV8803_FLAG);
+		if (flags < 0)
+			return flags;
+
+		if (flags & RV8803_FLAG_V1F) {
+			dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+			vl = RTC_VL_ACCURACY_LOW;
+		}
+
+		if (flags & RV8803_FLAG_V2F)
+			vl |= RTC_VL_DATA_INVALID;
+
+		return put_user(vl, (unsigned int __user *)arg);
+
+	case RTC_VL_CLR:
+		mutex_lock(&rv8803->flags_lock);
+		flags = rv8803_read_reg(client, RV8803_FLAG);
+		if (flags < 0) {
+			mutex_unlock(&rv8803->flags_lock);
+			return flags;
+		}
+
+		flags &= ~RV8803_FLAG_V1F;
+		ret = rv8803_write_reg(client, RV8803_FLAG, flags);
+		mutex_unlock(&rv8803->flags_lock);
+		if (ret)
+			return ret;
+
+		return 0;
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
+			      size_t bytes)
+{
+	return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
+}
+
+static int rv8803_nvram_read(void *priv, unsigned int offset,
+			     void *val, size_t bytes)
+{
+	int ret;
+
+	ret = rv8803_read_reg(priv, RV8803_RAM);
+	if (ret < 0)
+		return ret;
+
+	*(u8 *)val = ret;
+
+	return 0;
+}
+
+static const struct rtc_class_ops rv8803_rtc_ops = {
+	.read_time = rv8803_get_time,
+	.set_time = rv8803_set_time,
+	.ioctl = rv8803_ioctl,
+	.read_alarm = rv8803_get_alarm,
+	.set_alarm = rv8803_set_alarm,
+	.alarm_irq_enable = rv8803_alarm_irq_enable,
+};
+
+static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
+{
+	struct i2c_client *client = rv8803->client;
+	struct device_node *node = client->dev.of_node;
+	int err;
+	u8 flags;
+
+	if (!node)
+		return 0;
+
+	if (rv8803->type != rx_8900)
+		return 0;
+
+	err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
+	if (err < 0)
+		return err;
+
+	flags = (u8)err;
+	flags &= ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF);
+	flags |= rv8803->backup;
+
+	return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
+					 flags);
+}
+
+/* configure registers with values different than the Power-On reset defaults */
+static int rv8803_regs_configure(struct rv8803_data *rv8803)
+{
+	int err;
+
+	err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
+	if (err)
+		return err;
+
+	err = rx8900_trickle_charger_init(rv8803);
+	if (err) {
+		dev_err(&rv8803->client->dev, "failed to init charger\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static int rv8803_resume(struct device *dev)
+{
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+
+	if (rv8803->client->irq > 0 && device_may_wakeup(dev))
+		disable_irq_wake(rv8803->client->irq);
+
+	return 0;
+}
+
+static int rv8803_suspend(struct device *dev)
+{
+	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+
+	if (rv8803->client->irq > 0 && device_may_wakeup(dev))
+		enable_irq_wake(rv8803->client->irq);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(rv8803_pm_ops, rv8803_suspend, rv8803_resume);
+
+static const struct i2c_device_id rv8803_id[] = {
+	{ .name = "rv8803", .driver_data = rv_8803 },
+	{ .name = "rv8804", .driver_data = rx_8804 },
+	{ .name = "rx8803", .driver_data = rx_8803 },
+	{ .name = "rx8900", .driver_data = rx_8900 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rv8803_id);
+
+static int rv8803_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct rv8803_data *rv8803;
+	int err, flags;
+	struct nvmem_config nvmem_cfg = {
+		.name = "rv8803_nvram",
+		.word_size = 1,
+		.stride = 1,
+		.size = 1,
+		.reg_read = rv8803_nvram_read,
+		.reg_write = rv8803_nvram_write,
+		.priv = client,
+	};
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_I2C_BLOCK)) {
+		dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
+		return -EIO;
+	}
+
+	rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
+			      GFP_KERNEL);
+	if (!rv8803)
+		return -ENOMEM;
+
+	mutex_init(&rv8803->flags_lock);
+	rv8803->client = client;
+	rv8803->type = (uintptr_t)i2c_get_match_data(client);
+	i2c_set_clientdata(client, rv8803);
+
+	flags = rv8803_read_reg(client, RV8803_FLAG);
+	if (flags < 0)
+		return flags;
+
+	if (flags & RV8803_FLAG_V1F)
+		dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+
+	if (flags & RV8803_FLAG_V2F)
+		dev_warn(&client->dev, "Voltage low, data loss detected.\n");
+
+	if (flags & RV8803_FLAG_AF)
+		dev_warn(&client->dev, "An alarm maybe have been missed.\n");
+
+	rv8803->rtc = devm_rtc_allocate_device(&client->dev);
+	if (IS_ERR(rv8803->rtc))
+		return PTR_ERR(rv8803->rtc);
+
+	if (client->irq > 0) {
+		unsigned long irqflags = IRQF_TRIGGER_LOW;
+
+		if (dev_fwnode(&client->dev))
+			irqflags = 0;
+
+		err = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, rv8803_handle_irq,
+						irqflags | IRQF_ONESHOT,
+						"rv8803", client);
+		if (err) {
+			dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
+			client->irq = 0;
+		} else {
+			device_init_wakeup(&client->dev, true);
+			err = dev_pm_set_wake_irq(&client->dev, client->irq);
+			if (err)
+				dev_err(&client->dev, "failed to set wake IRQ\n");
+		}
+	} else {
+		if (device_property_read_bool(&client->dev, "wakeup-source"))
+			device_init_wakeup(&client->dev, true);
+		else
+			clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
+	}
+
+	if (of_property_read_bool(client->dev.of_node, "epson,vdet-disable"))
+		rv8803->backup |= RX8900_FLAG_VDETOFF;
+
+	if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
+		rv8803->backup |= RX8900_FLAG_SWOFF;
+
+	err = rv8803_regs_configure(rv8803);
+	if (err)
+		return err;
+
+	rv8803->rtc->ops = &rv8803_rtc_ops;
+	rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+	rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
+	err = devm_rtc_register_device(rv8803->rtc);
+	if (err)
+		return err;
+
+	devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
+
+	return 0;
+}
+
+static const __maybe_unused struct of_device_id rv8803_of_match[] = {
+	{
+		.compatible = "microcrystal,rv8803",
+		.data = (void *)rv_8803
+	},
+	{
+		.compatible = "epson,rx8803",
+		.data = (void *)rx_8803
+	},
+	{
+		.compatible = "epson,rx8804",
+		.data = (void *)rx_8804
+	},
+	{
+		.compatible = "epson,rx8900",
+		.data = (void *)rx_8900
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rv8803_of_match);
+
+static struct i2c_driver rv8803_driver = {
+	.driver = {
+		.name = "rtc-rv8803",
+		.of_match_table = of_match_ptr(rv8803_of_match),
+		.pm = &rv8803_pm_ops,
+	},
+	.probe		= rv8803_probe,
+	.id_table	= rv8803_id,
+};
+module_i2c_driver(rv8803_driver);
+
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
+MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
+MODULE_LICENSE("GPL v2");