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, 588 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-rx8025.c b/drivers/rtc/rtc-rx8025.c
new file mode 100644
index 000000000..5eeaa929f
--- /dev/null
+++ b/drivers/rtc/rtc-rx8025.c
@@ -0,0 +1,588 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Epson's RTC module RX-8025 SA/NB
+ *
+ * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
+ *
+ * Copyright (C) 2005 by Digi International Inc.
+ * All rights reserved.
+ *
+ * Modified by fengjh at rising.com.cn
+ * <lm-sensors@lm-sensors.org>
+ * 2006.11
+ *
+ * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
+ * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
+ * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
+ */
+#include <linux/bcd.h>
+#include <linux/bitops.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/kstrtox.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+
+/* Register definitions */
+#define RX8025_REG_SEC		0x00
+#define RX8025_REG_MIN		0x01
+#define RX8025_REG_HOUR		0x02
+#define RX8025_REG_WDAY		0x03
+#define RX8025_REG_MDAY		0x04
+#define RX8025_REG_MONTH	0x05
+#define RX8025_REG_YEAR		0x06
+#define RX8025_REG_DIGOFF	0x07
+#define RX8025_REG_ALWMIN	0x08
+#define RX8025_REG_ALWHOUR	0x09
+#define RX8025_REG_ALWWDAY	0x0a
+#define RX8025_REG_ALDMIN	0x0b
+#define RX8025_REG_ALDHOUR	0x0c
+/* 0x0d is reserved */
+#define RX8025_REG_CTRL1	0x0e
+#define RX8025_REG_CTRL2	0x0f
+
+#define RX8025_BIT_CTRL1_CT	(7 << 0)
+/* 1 Hz periodic level irq */
+#define RX8025_BIT_CTRL1_CT_1HZ	4
+#define RX8025_BIT_CTRL1_TEST	BIT(3)
+#define RX8025_BIT_CTRL1_1224	BIT(5)
+#define RX8025_BIT_CTRL1_DALE	BIT(6)
+#define RX8025_BIT_CTRL1_WALE	BIT(7)
+
+#define RX8025_BIT_CTRL2_DAFG	BIT(0)
+#define RX8025_BIT_CTRL2_WAFG	BIT(1)
+#define RX8025_BIT_CTRL2_CTFG	BIT(2)
+#define RX8025_BIT_CTRL2_PON	BIT(4)
+#define RX8025_BIT_CTRL2_XST	BIT(5)
+#define RX8025_BIT_CTRL2_VDET	BIT(6)
+
+#define RX8035_BIT_HOUR_1224	BIT(7)
+
+/* Clock precision adjustment */
+#define RX8025_ADJ_RESOLUTION	3050 /* in ppb */
+#define RX8025_ADJ_DATA_MAX	62
+#define RX8025_ADJ_DATA_MIN	-62
+
+enum rx_model {
+	model_rx_unknown,
+	model_rx_8025,
+	model_rx_8035,
+	model_last
+};
+
+static const struct i2c_device_id rx8025_id[] = {
+	{ .name = "rx8025", .driver_data = model_rx_8025 },
+	{ .name = "rx8035", .driver_data = model_rx_8035 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rx8025_id);
+
+struct rx8025_data {
+	struct rtc_device *rtc;
+	enum rx_model model;
+	u8 ctrl1;
+	int is_24;
+};
+
+static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
+{
+	return i2c_smbus_read_byte_data(client, number << 4);
+}
+
+static int rx8025_read_regs(const struct i2c_client *client,
+			    u8 number, u8 length, u8 *values)
+{
+	int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
+						values);
+	if (ret != length)
+		return ret < 0 ? ret : -EIO;
+
+	return 0;
+}
+
+static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
+			    u8 value)
+{
+	return i2c_smbus_write_byte_data(client, number << 4, value);
+}
+
+static s32 rx8025_write_regs(const struct i2c_client *client,
+			     u8 number, u8 length, const u8 *values)
+{
+	return i2c_smbus_write_i2c_block_data(client, number << 4,
+					      length, values);
+}
+
+static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
+{
+	int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
+	/* XSTP bit has different polarity on RX-8025 vs RX-8035.
+	 * RX-8025: 0 == oscillator stopped
+	 * RX-8035: 1 == oscillator stopped
+	 */
+
+	if (model == model_rx_8025)
+		xstp = !xstp;
+
+	return xstp;
+}
+
+static int rx8025_check_validity(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *drvdata = dev_get_drvdata(dev);
+	int ctrl2;
+	int xstp;
+
+	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	if (ctrl2 & RX8025_BIT_CTRL2_VDET)
+		dev_warn(dev, "power voltage drop detected\n");
+
+	if (ctrl2 & RX8025_BIT_CTRL2_PON) {
+		dev_warn(dev, "power-on reset detected, date is invalid\n");
+		return -EINVAL;
+	}
+
+	xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
+	if (xstp) {
+		dev_warn(dev, "crystal stopped, date is invalid\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rx8025_reset_validity(struct i2c_client *client)
+{
+	struct rx8025_data *drvdata = i2c_get_clientdata(client);
+	int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
+
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
+
+	if (drvdata->model == model_rx_8025)
+		ctrl2 |= RX8025_BIT_CTRL2_XST;
+	else
+		ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
+
+	return rx8025_write_reg(client, RX8025_REG_CTRL2,
+				ctrl2);
+}
+
+static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
+{
+	struct i2c_client *client = dev_id;
+	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
+	int status, xstp;
+
+	rtc_lock(rx8025->rtc);
+	status = rx8025_read_reg(client, RX8025_REG_CTRL2);
+	if (status < 0)
+		goto out;
+
+	xstp = rx8025_is_osc_stopped(rx8025->model, status);
+	if (xstp)
+		dev_warn(&client->dev, "Oscillation stop was detected,"
+			 "you may have to readjust the clock\n");
+
+	if (status & RX8025_BIT_CTRL2_CTFG) {
+		/* periodic */
+		status &= ~RX8025_BIT_CTRL2_CTFG;
+		rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
+	}
+
+	if (status & RX8025_BIT_CTRL2_DAFG) {
+		/* alarm */
+		status &= RX8025_BIT_CTRL2_DAFG;
+		if (rx8025_write_reg(client, RX8025_REG_CTRL1,
+				     rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
+			goto out;
+		rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
+	}
+
+out:
+	rtc_unlock(rx8025->rtc);
+
+	return IRQ_HANDLED;
+}
+
+static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 date[7];
+	int err;
+
+	err = rx8025_check_validity(dev);
+	if (err)
+		return err;
+
+	err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
+	if (err)
+		return err;
+
+	dev_dbg(dev, "%s: read %7ph\n", __func__, date);
+
+	dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
+	dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
+	if (rx8025->is_24)
+		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
+	else
+		dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
+			+ (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
+
+	dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
+	dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
+	dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
+
+	dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
+
+	return 0;
+}
+
+static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 date[7];
+	int ret;
+
+	/*
+	 * Here the read-only bits are written as "0".  I'm not sure if that
+	 * is sound.
+	 */
+	date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
+	date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
+	if (rx8025->is_24)
+		date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
+	else
+		date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
+			| bin2bcd((dt->tm_hour + 11) % 12 + 1);
+
+	date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
+	date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
+	date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
+	date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
+
+	dev_dbg(dev, "%s: write %7ph\n", __func__, date);
+
+	ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
+	if (ret < 0)
+		return ret;
+
+	return rx8025_reset_validity(client);
+}
+
+static int rx8025_init_client(struct i2c_client *client)
+{
+	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
+	u8 ctrl[2], ctrl2;
+	int need_clear = 0;
+	int hour_reg;
+	int err;
+
+	err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
+	if (err)
+		goto out;
+
+	/* Keep test bit zero ! */
+	rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
+
+	if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
+		dev_warn(&client->dev, "Alarm was detected\n");
+		need_clear = 1;
+	}
+
+	if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
+		need_clear = 1;
+
+	if (need_clear) {
+		ctrl2 = ctrl[1];
+		ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
+			   RX8025_BIT_CTRL2_DAFG);
+
+		err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
+	}
+
+	if (rx8025->model == model_rx_8035) {
+		/* In RX-8035, 12/24 flag is in the hour register */
+		hour_reg = rx8025_read_reg(client, RX8025_REG_HOUR);
+		if (hour_reg < 0)
+			return hour_reg;
+		rx8025->is_24 = (hour_reg & RX8035_BIT_HOUR_1224);
+	} else {
+		rx8025->is_24 = (ctrl[0] & RX8025_BIT_CTRL1_1224);
+	}
+out:
+	return err;
+}
+
+/* Alarm support */
+static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 ald[2];
+	int ctrl2, err;
+
+	err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
+	if (err)
+		return err;
+
+	ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
+	if (ctrl2 < 0)
+		return ctrl2;
+
+	dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
+		__func__, ald[0], ald[1], ctrl2);
+
+	/* Hardware alarms precision is 1 minute! */
+	t->time.tm_sec = 0;
+	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
+	if (rx8025->is_24)
+		t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
+	else
+		t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
+			+ (ald[1] & 0x20 ? 12 : 0);
+
+	dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
+	t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
+	t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
+
+	return err;
+}
+
+static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 ald[2];
+	int err;
+
+	ald[0] = bin2bcd(t->time.tm_min);
+	if (rx8025->is_24)
+		ald[1] = bin2bcd(t->time.tm_hour);
+	else
+		ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
+			| bin2bcd((t->time.tm_hour + 11) % 12 + 1);
+
+	dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
+
+	if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
+		rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
+		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
+				       rx8025->ctrl1);
+		if (err)
+			return err;
+	}
+	err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
+	if (err)
+		return err;
+
+	if (t->enabled) {
+		rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
+		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
+				       rx8025->ctrl1);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct rx8025_data *rx8025 = dev_get_drvdata(dev);
+	u8 ctrl1;
+	int err;
+
+	ctrl1 = rx8025->ctrl1;
+	if (enabled)
+		ctrl1 |= RX8025_BIT_CTRL1_DALE;
+	else
+		ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
+
+	if (ctrl1 != rx8025->ctrl1) {
+		rx8025->ctrl1 = ctrl1;
+		err = rx8025_write_reg(client, RX8025_REG_CTRL1,
+				       rx8025->ctrl1);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/*
+ * According to the RX8025 SA/NB application manual the frequency and
+ * temperature characteristics can be approximated using the following
+ * equation:
+ *
+ *   df = a * (ut - t)**2
+ *
+ *   df: Frequency deviation in any temperature
+ *   a : Coefficient = (-35 +-5) * 10**-9
+ *   ut: Ultimate temperature in degree = +25 +-5 degree
+ *   t : Any temperature in degree
+ */
+static int rx8025_read_offset(struct device *dev, long *offset)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int digoff;
+
+	digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
+	if (digoff < 0)
+		return digoff;
+
+	*offset = digoff >= 64 ? digoff - 128 : digoff;
+	if (*offset > 0)
+		(*offset)--;
+	*offset *= RX8025_ADJ_RESOLUTION;
+
+	return 0;
+}
+
+static int rx8025_set_offset(struct device *dev, long offset)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	u8 digoff;
+
+	offset /= RX8025_ADJ_RESOLUTION;
+	if (offset > RX8025_ADJ_DATA_MAX)
+		offset = RX8025_ADJ_DATA_MAX;
+	else if (offset < RX8025_ADJ_DATA_MIN)
+		offset = RX8025_ADJ_DATA_MIN;
+	else if (offset > 0)
+		offset++;
+	else if (offset < 0)
+		offset += 128;
+	digoff = offset;
+
+	return rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
+}
+
+static const struct rtc_class_ops rx8025_rtc_ops = {
+	.read_time = rx8025_get_time,
+	.set_time = rx8025_set_time,
+	.read_alarm = rx8025_read_alarm,
+	.set_alarm = rx8025_set_alarm,
+	.alarm_irq_enable = rx8025_alarm_irq_enable,
+	.read_offset = rx8025_read_offset,
+	.set_offset = rx8025_set_offset,
+};
+
+static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
+					      struct device_attribute *attr,
+					      char *buf)
+{
+	long adj;
+	int err;
+
+	dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
+	err = rx8025_read_offset(dev, &adj);
+	if (err)
+		return err;
+
+	return sprintf(buf, "%ld\n", -adj);
+}
+
+static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
+					       struct device_attribute *attr,
+					       const char *buf, size_t count)
+{
+	long adj;
+	int err;
+
+	dev_warn_once(dev, "clock_adjust_ppb is deprecated, use offset\n");
+	if (kstrtol(buf, 10, &adj) != 0)
+		return -EINVAL;
+
+	err = rx8025_set_offset(dev, -adj);
+
+	return err ? err : count;
+}
+
+static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
+		   rx8025_sysfs_show_clock_adjust,
+		   rx8025_sysfs_store_clock_adjust);
+
+static struct attribute *rx8025_attrs[] = {
+	&dev_attr_clock_adjust_ppb.attr,
+	NULL
+};
+
+static const struct attribute_group rx8025_attr_group = {
+	.attrs	= rx8025_attrs,
+};
+
+static int rx8025_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct rx8025_data *rx8025;
+	int err = 0;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
+				     | I2C_FUNC_SMBUS_I2C_BLOCK)) {
+		dev_err(&adapter->dev,
+			"doesn't support required functionality\n");
+		return -EIO;
+	}
+
+	rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
+	if (!rx8025)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, rx8025);
+
+	rx8025->model = (uintptr_t)i2c_get_match_data(client);
+
+	err = rx8025_init_client(client);
+	if (err)
+		return err;
+
+	rx8025->rtc = devm_rtc_allocate_device(&client->dev);
+	if (IS_ERR(rx8025->rtc))
+		return PTR_ERR(rx8025->rtc);
+
+	rx8025->rtc->ops = &rx8025_rtc_ops;
+	rx8025->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
+	rx8025->rtc->range_max = RTC_TIMESTAMP_END_2099;
+
+	if (client->irq > 0) {
+		dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
+		err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+						rx8025_handle_irq,
+						IRQF_ONESHOT,
+						"rx8025", client);
+		if (err)
+			clear_bit(RTC_FEATURE_ALARM, rx8025->rtc->features);
+	}
+
+	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rx8025->rtc->features);
+	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rx8025->rtc->features);
+
+	err = rtc_add_group(rx8025->rtc, &rx8025_attr_group);
+	if (err)
+		return err;
+
+	return devm_rtc_register_device(rx8025->rtc);
+}
+
+static struct i2c_driver rx8025_driver = {
+	.driver = {
+		.name = "rtc-rx8025",
+	},
+	.probe		= rx8025_probe,
+	.id_table	= rx8025_id,
+};
+
+module_i2c_driver(rx8025_driver);
+
+MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
+MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
+MODULE_LICENSE("GPL");