Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1001 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
new file mode 100644
index 000000000..9bdd5d121
--- /dev/null
+++ b/drivers/rtc/rtc-isl1208.c
@@ -0,0 +1,1001 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Intersil ISL1208 rtc class driver
+ *
+ * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
+ */
+
+#include <linux/bcd.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/rtc.h>
+
+/* Register map */
+/* rtc section */
+#define ISL1208_REG_SC  0x00
+#define ISL1208_REG_MN  0x01
+#define ISL1208_REG_HR  0x02
+#define ISL1208_REG_HR_MIL     (1<<7)	/* 24h/12h mode */
+#define ISL1208_REG_HR_PM      (1<<5)	/* PM/AM bit in 12h mode */
+#define ISL1208_REG_DT  0x03
+#define ISL1208_REG_MO  0x04
+#define ISL1208_REG_YR  0x05
+#define ISL1208_REG_DW  0x06
+#define ISL1208_RTC_SECTION_LEN 7
+
+/* control/status section */
+#define ISL1208_REG_SR  0x07
+#define ISL1208_REG_SR_ARST    (1<<7)	/* auto reset */
+#define ISL1208_REG_SR_XTOSCB  (1<<6)	/* crystal oscillator */
+#define ISL1208_REG_SR_WRTC    (1<<4)	/* write rtc */
+#define ISL1208_REG_SR_EVT     (1<<3)	/* event */
+#define ISL1208_REG_SR_ALM     (1<<2)	/* alarm */
+#define ISL1208_REG_SR_BAT     (1<<1)	/* battery */
+#define ISL1208_REG_SR_RTCF    (1<<0)	/* rtc fail */
+#define ISL1208_REG_INT 0x08
+#define ISL1208_REG_INT_ALME   (1<<6)   /* alarm enable */
+#define ISL1208_REG_INT_IM     (1<<7)   /* interrupt/alarm mode */
+#define ISL1219_REG_EV  0x09
+#define ISL1219_REG_EV_EVEN    (1<<4)   /* event detection enable */
+#define ISL1219_REG_EV_EVIENB  (1<<7)   /* event in pull-up disable */
+#define ISL1208_REG_ATR 0x0a
+#define ISL1208_REG_DTR 0x0b
+
+/* alarm section */
+#define ISL1208_REG_SCA 0x0c
+#define ISL1208_REG_MNA 0x0d
+#define ISL1208_REG_HRA 0x0e
+#define ISL1208_REG_DTA 0x0f
+#define ISL1208_REG_MOA 0x10
+#define ISL1208_REG_DWA 0x11
+#define ISL1208_ALARM_SECTION_LEN 6
+
+/* user section */
+#define ISL1208_REG_USR1 0x12
+#define ISL1208_REG_USR2 0x13
+#define ISL1208_USR_SECTION_LEN 2
+
+/* event section */
+#define ISL1219_REG_SCT 0x14
+#define ISL1219_REG_MNT 0x15
+#define ISL1219_REG_HRT 0x16
+#define ISL1219_REG_DTT 0x17
+#define ISL1219_REG_MOT 0x18
+#define ISL1219_REG_YRT 0x19
+#define ISL1219_EVT_SECTION_LEN 6
+
+static struct i2c_driver isl1208_driver;
+
+/* Chip capabilities table */
+struct isl1208_config {
+	unsigned int	nvmem_length;
+	unsigned	has_tamper:1;
+	unsigned	has_timestamp:1;
+	unsigned	has_inverted_osc_bit:1;
+};
+
+static const struct isl1208_config config_isl1208 = {
+	.nvmem_length = 2,
+	.has_tamper = false,
+	.has_timestamp = false
+};
+
+static const struct isl1208_config config_isl1209 = {
+	.nvmem_length = 2,
+	.has_tamper = true,
+	.has_timestamp = false
+};
+
+static const struct isl1208_config config_isl1218 = {
+	.nvmem_length = 8,
+	.has_tamper = false,
+	.has_timestamp = false
+};
+
+static const struct isl1208_config config_isl1219 = {
+	.nvmem_length = 2,
+	.has_tamper = true,
+	.has_timestamp = true
+};
+
+static const struct isl1208_config config_raa215300_a0 = {
+	.nvmem_length = 2,
+	.has_tamper = false,
+	.has_timestamp = false,
+	.has_inverted_osc_bit = true
+};
+
+static const struct i2c_device_id isl1208_id[] = {
+	{ .name = "isl1208", .driver_data = (kernel_ulong_t)&config_isl1208 },
+	{ .name = "isl1209", .driver_data = (kernel_ulong_t)&config_isl1209 },
+	{ .name = "isl1218", .driver_data = (kernel_ulong_t)&config_isl1218 },
+	{ .name = "isl1219", .driver_data = (kernel_ulong_t)&config_isl1219 },
+	{ .name = "raa215300_a0", .driver_data = (kernel_ulong_t)&config_raa215300_a0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, isl1208_id);
+
+static const __maybe_unused struct of_device_id isl1208_of_match[] = {
+	{ .compatible = "isil,isl1208", .data = &config_isl1208 },
+	{ .compatible = "isil,isl1209", .data = &config_isl1209 },
+	{ .compatible = "isil,isl1218", .data = &config_isl1218 },
+	{ .compatible = "isil,isl1219", .data = &config_isl1219 },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, isl1208_of_match);
+
+/* Device state */
+struct isl1208_state {
+	struct nvmem_config nvmem_config;
+	struct rtc_device *rtc;
+	const struct isl1208_config *config;
+};
+
+/* block read */
+static int
+isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
+		      unsigned len)
+{
+	int ret;
+
+	WARN_ON(reg > ISL1219_REG_YRT);
+	WARN_ON(reg + len > ISL1219_REG_YRT + 1);
+
+	ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
+	return (ret < 0) ? ret : 0;
+}
+
+/* block write */
+static int
+isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
+		     unsigned len)
+{
+	int ret;
+
+	WARN_ON(reg > ISL1219_REG_YRT);
+	WARN_ON(reg + len > ISL1219_REG_YRT + 1);
+
+	ret = i2c_smbus_write_i2c_block_data(client, reg, len, buf);
+	return (ret < 0) ? ret : 0;
+}
+
+/* simple check to see whether we have a isl1208 */
+static int
+isl1208_i2c_validate_client(struct i2c_client *client)
+{
+	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
+	u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
+		0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
+	};
+	int i;
+	int ret;
+
+	ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
+		if (regs[i] & zero_mask[i])	/* check if bits are cleared */
+			return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int isl1208_set_xtoscb(struct i2c_client *client, int sr, int xtosb_val)
+{
+	/* Do nothing if bit is already set to desired value */
+	if (!!(sr & ISL1208_REG_SR_XTOSCB) == xtosb_val)
+		return 0;
+
+	if (xtosb_val)
+		sr |= ISL1208_REG_SR_XTOSCB;
+	else
+		sr &= ~ISL1208_REG_SR_XTOSCB;
+
+	return i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
+}
+
+static int
+isl1208_i2c_get_sr(struct i2c_client *client)
+{
+	return i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
+}
+
+static int
+isl1208_i2c_get_atr(struct i2c_client *client)
+{
+	int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
+	if (atr < 0)
+		return atr;
+
+	/* The 6bit value in the ATR register controls the load
+	 * capacitance C_load * in steps of 0.25pF
+	 *
+	 * bit (1<<5) of the ATR register is inverted
+	 *
+	 * C_load(ATR=0x20) =  4.50pF
+	 * C_load(ATR=0x00) = 12.50pF
+	 * C_load(ATR=0x1f) = 20.25pF
+	 *
+	 */
+
+	atr &= 0x3f;		/* mask out lsb */
+	atr ^= 1 << 5;		/* invert 6th bit */
+	atr += 2 * 9;		/* add offset of 4.5pF; unit[atr] = 0.25pF */
+
+	return atr;
+}
+
+/* returns adjustment value + 100 */
+static int
+isl1208_i2c_get_dtr(struct i2c_client *client)
+{
+	int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
+	if (dtr < 0)
+		return -EIO;
+
+	/* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
+	dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
+
+	return dtr + 100;
+}
+
+static int
+isl1208_i2c_get_usr(struct i2c_client *client)
+{
+	u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
+	int ret;
+
+	ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
+				    ISL1208_USR_SECTION_LEN);
+	if (ret < 0)
+		return ret;
+
+	return (buf[1] << 8) | buf[0];
+}
+
+static int
+isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
+{
+	u8 buf[ISL1208_USR_SECTION_LEN];
+
+	buf[0] = usr & 0xff;
+	buf[1] = (usr >> 8) & 0xff;
+
+	return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
+				    ISL1208_USR_SECTION_LEN);
+}
+
+static int
+isl1208_rtc_toggle_alarm(struct i2c_client *client, int enable)
+{
+	int icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
+
+	if (icr < 0) {
+		dev_err(&client->dev, "%s: reading INT failed\n", __func__);
+		return icr;
+	}
+
+	if (enable)
+		icr |= ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM;
+	else
+		icr &= ~(ISL1208_REG_INT_ALME | ISL1208_REG_INT_IM);
+
+	icr = i2c_smbus_write_byte_data(client, ISL1208_REG_INT, icr);
+	if (icr < 0) {
+		dev_err(&client->dev, "%s: writing INT failed\n", __func__);
+		return icr;
+	}
+
+	return 0;
+}
+
+static int
+isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	struct i2c_client *const client = to_i2c_client(dev);
+	int sr, dtr, atr, usr;
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
+		   (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
+		   (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
+		   (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
+		   (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
+		   (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
+		   (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
+
+	seq_printf(seq, "batt_status\t: %s\n",
+		   (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
+
+	dtr = isl1208_i2c_get_dtr(client);
+	if (dtr >= 0)
+		seq_printf(seq, "digital_trim\t: %d ppm\n", dtr - 100);
+
+	atr = isl1208_i2c_get_atr(client);
+	if (atr >= 0)
+		seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
+			   atr >> 2, (atr & 0x3) * 25);
+
+	usr = isl1208_i2c_get_usr(client);
+	if (usr >= 0)
+		seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
+
+	return 0;
+}
+
+static int
+isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
+{
+	int sr;
+	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return -EIO;
+	}
+
+	sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading RTC section failed\n",
+			__func__);
+		return sr;
+	}
+
+	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
+	tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
+
+	/* HR field has a more complex interpretation */
+	{
+		const u8 _hr = regs[ISL1208_REG_HR];
+		if (_hr & ISL1208_REG_HR_MIL)	/* 24h format */
+			tm->tm_hour = bcd2bin(_hr & 0x3f);
+		else {
+			/* 12h format */
+			tm->tm_hour = bcd2bin(_hr & 0x1f);
+			if (_hr & ISL1208_REG_HR_PM)	/* PM flag set */
+				tm->tm_hour += 12;
+		}
+	}
+
+	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
+	tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1;	/* rtc starts at 1 */
+	tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
+	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
+
+	return 0;
+}
+
+static int
+isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
+{
+	struct rtc_time *const tm = &alarm->time;
+	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
+	int icr, yr, sr = isl1208_i2c_get_sr(client);
+
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
+				   ISL1208_ALARM_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading alarm section failed\n",
+			__func__);
+		return sr;
+	}
+
+	/* MSB of each alarm register is an enable bit */
+	tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
+	tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
+	tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
+	tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
+	tm->tm_mon =
+		bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
+	tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
+
+	/* The alarm doesn't store the year so get it from the rtc section */
+	yr = i2c_smbus_read_byte_data(client, ISL1208_REG_YR);
+	if (yr < 0) {
+		dev_err(&client->dev, "%s: reading RTC YR failed\n", __func__);
+		return yr;
+	}
+	tm->tm_year = bcd2bin(yr) + 100;
+
+	icr = i2c_smbus_read_byte_data(client, ISL1208_REG_INT);
+	if (icr < 0) {
+		dev_err(&client->dev, "%s: reading INT failed\n", __func__);
+		return icr;
+	}
+	alarm->enabled = !!(icr & ISL1208_REG_INT_ALME);
+
+	return 0;
+}
+
+static int
+isl1208_i2c_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
+{
+	struct rtc_time *alarm_tm = &alarm->time;
+	u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
+	const int offs = ISL1208_REG_SCA;
+	struct rtc_time rtc_tm;
+	int err, enable;
+
+	err = isl1208_i2c_read_time(client, &rtc_tm);
+	if (err)
+		return err;
+
+	/* If the alarm time is before the current time disable the alarm */
+	if (!alarm->enabled || rtc_tm_sub(alarm_tm, &rtc_tm) <= 0)
+		enable = 0x00;
+	else
+		enable = 0x80;
+
+	/* Program the alarm and enable it for each setting */
+	regs[ISL1208_REG_SCA - offs] = bin2bcd(alarm_tm->tm_sec) | enable;
+	regs[ISL1208_REG_MNA - offs] = bin2bcd(alarm_tm->tm_min) | enable;
+	regs[ISL1208_REG_HRA - offs] = bin2bcd(alarm_tm->tm_hour) |
+		ISL1208_REG_HR_MIL | enable;
+
+	regs[ISL1208_REG_DTA - offs] = bin2bcd(alarm_tm->tm_mday) | enable;
+	regs[ISL1208_REG_MOA - offs] = bin2bcd(alarm_tm->tm_mon + 1) | enable;
+	regs[ISL1208_REG_DWA - offs] = bin2bcd(alarm_tm->tm_wday & 7) | enable;
+
+	/* write ALARM registers */
+	err = isl1208_i2c_set_regs(client, offs, regs,
+				  ISL1208_ALARM_SECTION_LEN);
+	if (err < 0) {
+		dev_err(&client->dev, "%s: writing ALARM section failed\n",
+			__func__);
+		return err;
+	}
+
+	err = isl1208_rtc_toggle_alarm(client, enable);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int
+isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	return isl1208_i2c_read_time(to_i2c_client(dev), tm);
+}
+
+static int
+isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
+{
+	int sr;
+	u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
+
+	/* The clock has an 8 bit wide bcd-coded register (they never learn)
+	 * for the year. tm_year is an offset from 1900 and we are interested
+	 * in the 2000-2099 range, so any value less than 100 is invalid.
+	 */
+	if (tm->tm_year < 100)
+		return -EINVAL;
+
+	regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
+	regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
+	regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
+
+	regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
+	regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
+	regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
+
+	regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	/* set WRTC */
+	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
+				       sr | ISL1208_REG_SR_WRTC);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
+		return sr;
+	}
+
+	/* write RTC registers */
+	sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: writing RTC section failed\n",
+			__func__);
+		return sr;
+	}
+
+	/* clear WRTC again */
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
+				       sr & ~ISL1208_REG_SR_WRTC);
+	if (sr < 0) {
+		dev_err(&client->dev, "%s: writing SR failed\n", __func__);
+		return sr;
+	}
+
+	return 0;
+}
+
+static int
+isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	return isl1208_i2c_set_time(to_i2c_client(dev), tm);
+}
+
+static int
+isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
+}
+
+static int
+isl1208_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	return isl1208_i2c_set_alarm(to_i2c_client(dev), alarm);
+}
+
+static ssize_t timestamp0_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	int sr;
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	sr &= ~ISL1208_REG_SR_EVT;
+
+	sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
+	if (sr < 0)
+		dev_err(dev, "%s: writing SR failed\n",
+			__func__);
+
+	return count;
+};
+
+static ssize_t timestamp0_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	u8 regs[ISL1219_EVT_SECTION_LEN] = { 0, };
+	struct rtc_time tm;
+	int sr;
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(dev, "%s: reading SR failed\n", __func__);
+		return sr;
+	}
+
+	if (!(sr & ISL1208_REG_SR_EVT))
+		return 0;
+
+	sr = isl1208_i2c_read_regs(client, ISL1219_REG_SCT, regs,
+				   ISL1219_EVT_SECTION_LEN);
+	if (sr < 0) {
+		dev_err(dev, "%s: reading event section failed\n",
+			__func__);
+		return 0;
+	}
+
+	/* MSB of each alarm register is an enable bit */
+	tm.tm_sec = bcd2bin(regs[ISL1219_REG_SCT - ISL1219_REG_SCT] & 0x7f);
+	tm.tm_min = bcd2bin(regs[ISL1219_REG_MNT - ISL1219_REG_SCT] & 0x7f);
+	tm.tm_hour = bcd2bin(regs[ISL1219_REG_HRT - ISL1219_REG_SCT] & 0x3f);
+	tm.tm_mday = bcd2bin(regs[ISL1219_REG_DTT - ISL1219_REG_SCT] & 0x3f);
+	tm.tm_mon =
+		bcd2bin(regs[ISL1219_REG_MOT - ISL1219_REG_SCT] & 0x1f) - 1;
+	tm.tm_year = bcd2bin(regs[ISL1219_REG_YRT - ISL1219_REG_SCT]) + 100;
+
+	sr = rtc_valid_tm(&tm);
+	if (sr)
+		return sr;
+
+	return sprintf(buf, "%llu\n",
+				(unsigned long long)rtc_tm_to_time64(&tm));
+};
+
+static DEVICE_ATTR_RW(timestamp0);
+
+static irqreturn_t
+isl1208_rtc_interrupt(int irq, void *data)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+	struct i2c_client *client = data;
+	struct isl1208_state *isl1208 = i2c_get_clientdata(client);
+	int handled = 0, sr, err;
+
+	if (!isl1208->config->has_tamper) {
+		/*
+		 * The INT# output is pulled low 250ms after the alarm is
+		 * triggered. After the INT# output is pulled low, it is low for
+		 * at least 250ms, even if the correct action is taken to clear
+		 * it. It is impossible to clear ALM if it is still active. The
+		 * host must wait for the RTC to progress past the alarm time
+		 * plus the 250ms delay before clearing ALM.
+		 */
+		msleep(250);
+	}
+
+	/*
+	 * I2C reads get NAK'ed if we read straight away after an interrupt?
+	 * Using a mdelay/msleep didn't seem to help either, so we work around
+	 * this by continually trying to read the register for a short time.
+	 */
+	while (1) {
+		sr = isl1208_i2c_get_sr(client);
+		if (sr >= 0)
+			break;
+
+		if (time_after(jiffies, timeout)) {
+			dev_err(&client->dev, "%s: reading SR failed\n",
+				__func__);
+			return sr;
+		}
+	}
+
+	if (sr & ISL1208_REG_SR_ALM) {
+		dev_dbg(&client->dev, "alarm!\n");
+
+		rtc_update_irq(isl1208->rtc, 1, RTC_IRQF | RTC_AF);
+
+		/* Disable the alarm */
+		err = isl1208_rtc_toggle_alarm(client, 0);
+		if (err)
+			return err;
+
+		fsleep(275);
+
+		/* Clear the alarm */
+		sr &= ~ISL1208_REG_SR_ALM;
+		sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
+		if (sr < 0)
+			dev_err(&client->dev, "%s: writing SR failed\n",
+				__func__);
+		else
+			handled = 1;
+	}
+
+	if (isl1208->config->has_tamper && (sr & ISL1208_REG_SR_EVT)) {
+		dev_warn(&client->dev, "event detected");
+		handled = 1;
+		if (isl1208->config->has_timestamp)
+			sysfs_notify(&isl1208->rtc->dev.kobj, NULL,
+				     dev_attr_timestamp0.attr.name);
+	}
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static const struct rtc_class_ops isl1208_rtc_ops = {
+	.proc = isl1208_rtc_proc,
+	.read_time = isl1208_rtc_read_time,
+	.set_time = isl1208_rtc_set_time,
+	.read_alarm = isl1208_rtc_read_alarm,
+	.set_alarm = isl1208_rtc_set_alarm,
+};
+
+/* sysfs interface */
+
+static ssize_t
+isl1208_sysfs_show_atrim(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	int atr = isl1208_i2c_get_atr(to_i2c_client(dev->parent));
+	if (atr < 0)
+		return atr;
+
+	return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
+}
+
+static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
+
+static ssize_t
+isl1208_sysfs_show_dtrim(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev->parent));
+	if (dtr < 0)
+		return dtr;
+
+	return sprintf(buf, "%d ppm\n", dtr - 100);
+}
+
+static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
+
+static ssize_t
+isl1208_sysfs_show_usr(struct device *dev,
+		       struct device_attribute *attr, char *buf)
+{
+	int usr = isl1208_i2c_get_usr(to_i2c_client(dev->parent));
+	if (usr < 0)
+		return usr;
+
+	return sprintf(buf, "0x%.4x\n", usr);
+}
+
+static ssize_t
+isl1208_sysfs_store_usr(struct device *dev,
+			struct device_attribute *attr,
+			const char *buf, size_t count)
+{
+	int usr = -1;
+
+	if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
+		if (sscanf(buf, "%x", &usr) != 1)
+			return -EINVAL;
+	} else {
+		if (sscanf(buf, "%d", &usr) != 1)
+			return -EINVAL;
+	}
+
+	if (usr < 0 || usr > 0xffff)
+		return -EINVAL;
+
+	if (isl1208_i2c_set_usr(to_i2c_client(dev->parent), usr))
+		return -EIO;
+
+	return count;
+}
+
+static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
+		   isl1208_sysfs_store_usr);
+
+static struct attribute *isl1208_rtc_attrs[] = {
+	&dev_attr_atrim.attr,
+	&dev_attr_dtrim.attr,
+	&dev_attr_usr.attr,
+	NULL
+};
+
+static const struct attribute_group isl1208_rtc_sysfs_files = {
+	.attrs	= isl1208_rtc_attrs,
+};
+
+static struct attribute *isl1219_rtc_attrs[] = {
+	&dev_attr_timestamp0.attr,
+	NULL
+};
+
+static const struct attribute_group isl1219_rtc_sysfs_files = {
+	.attrs	= isl1219_rtc_attrs,
+};
+
+static int isl1208_nvmem_read(void *priv, unsigned int off, void *buf,
+			      size_t count)
+{
+	struct isl1208_state *isl1208 = priv;
+	struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
+
+	/* nvmem sanitizes offset/count for us, but count==0 is possible */
+	if (!count)
+		return count;
+
+	return isl1208_i2c_read_regs(client, ISL1208_REG_USR1 + off, buf,
+				    count);
+}
+
+static int isl1208_nvmem_write(void *priv, unsigned int off, void *buf,
+			       size_t count)
+{
+	struct isl1208_state *isl1208 = priv;
+	struct i2c_client *client = to_i2c_client(isl1208->rtc->dev.parent);
+
+	/* nvmem sanitizes off/count for us, but count==0 is possible */
+	if (!count)
+		return count;
+
+	return isl1208_i2c_set_regs(client, ISL1208_REG_USR1 + off, buf,
+				   count);
+}
+
+static const struct nvmem_config isl1208_nvmem_config = {
+	.name = "isl1208_nvram",
+	.word_size = 1,
+	.stride = 1,
+	/* .size from chip specific config */
+	.reg_read = isl1208_nvmem_read,
+	.reg_write = isl1208_nvmem_write,
+};
+
+static void isl1208_disable_irq_wake_action(void *data)
+{
+	disable_irq_wake((unsigned long)data);
+}
+
+static int isl1208_setup_irq(struct i2c_client *client, int irq)
+{
+	int rc = devm_request_threaded_irq(&client->dev, irq, NULL,
+					isl1208_rtc_interrupt,
+					IRQF_SHARED | IRQF_ONESHOT,
+					isl1208_driver.driver.name,
+					client);
+	if (!rc) {
+		device_init_wakeup(&client->dev, true);
+		rc = enable_irq_wake(irq);
+		if (rc)
+			return rc;
+
+		rc = devm_add_action_or_reset(&client->dev,
+					      isl1208_disable_irq_wake_action,
+					      (void *)(unsigned long)irq);
+		if (rc)
+			return rc;
+	} else {
+		dev_err(&client->dev,
+			"Unable to request irq %d, no alarm support\n",
+			irq);
+	}
+	return rc;
+}
+
+static int
+isl1208_clk_present(struct i2c_client *client, const char *name)
+{
+	struct clk *clk;
+
+	clk = devm_clk_get_optional(&client->dev, name);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	return !!clk;
+}
+
+static int
+isl1208_probe(struct i2c_client *client)
+{
+	struct isl1208_state *isl1208;
+	int evdet_irq = -1;
+	int xtosb_val = 0;
+	int rc = 0;
+	int sr;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENODEV;
+
+	if (isl1208_i2c_validate_client(client) < 0)
+		return -ENODEV;
+
+	/* Allocate driver state, point i2c client data to it */
+	isl1208 = devm_kzalloc(&client->dev, sizeof(*isl1208), GFP_KERNEL);
+	if (!isl1208)
+		return -ENOMEM;
+	i2c_set_clientdata(client, isl1208);
+
+	/* Determine which chip we have */
+	isl1208->config = i2c_get_match_data(client);
+	if (!isl1208->config)
+		return -ENODEV;
+
+	rc = isl1208_clk_present(client, "xin");
+	if (rc < 0)
+		return rc;
+
+	if (!rc) {
+		rc = isl1208_clk_present(client, "clkin");
+		if (rc < 0)
+			return rc;
+
+		if (rc)
+			xtosb_val = 1;
+	}
+
+	isl1208->rtc = devm_rtc_allocate_device(&client->dev);
+	if (IS_ERR(isl1208->rtc))
+		return PTR_ERR(isl1208->rtc);
+
+	isl1208->rtc->ops = &isl1208_rtc_ops;
+
+	/* Setup nvmem configuration in driver state struct */
+	isl1208->nvmem_config = isl1208_nvmem_config;
+	isl1208->nvmem_config.size = isl1208->config->nvmem_length;
+	isl1208->nvmem_config.priv = isl1208;
+
+	sr = isl1208_i2c_get_sr(client);
+	if (sr < 0) {
+		dev_err(&client->dev, "reading status failed\n");
+		return sr;
+	}
+
+	if (isl1208->config->has_inverted_osc_bit)
+		xtosb_val = !xtosb_val;
+
+	rc = isl1208_set_xtoscb(client, sr, xtosb_val);
+	if (rc)
+		return rc;
+
+	if (sr & ISL1208_REG_SR_RTCF)
+		dev_warn(&client->dev, "rtc power failure detected, "
+			 "please set clock.\n");
+
+	if (isl1208->config->has_tamper) {
+		struct device_node *np = client->dev.of_node;
+		u32 evienb;
+
+		rc = i2c_smbus_read_byte_data(client, ISL1219_REG_EV);
+		if (rc < 0) {
+			dev_err(&client->dev, "failed to read EV reg\n");
+			return rc;
+		}
+		rc |= ISL1219_REG_EV_EVEN;
+		if (!of_property_read_u32(np, "isil,ev-evienb", &evienb)) {
+			if (evienb)
+				rc |= ISL1219_REG_EV_EVIENB;
+			else
+				rc &= ~ISL1219_REG_EV_EVIENB;
+		}
+		rc = i2c_smbus_write_byte_data(client, ISL1219_REG_EV, rc);
+		if (rc < 0) {
+			dev_err(&client->dev, "could not enable tamper detection\n");
+			return rc;
+		}
+		evdet_irq = of_irq_get_byname(np, "evdet");
+	}
+	if (isl1208->config->has_timestamp) {
+		rc = rtc_add_group(isl1208->rtc, &isl1219_rtc_sysfs_files);
+		if (rc)
+			return rc;
+	}
+
+	rc = rtc_add_group(isl1208->rtc, &isl1208_rtc_sysfs_files);
+	if (rc)
+		return rc;
+
+	if (client->irq > 0) {
+		rc = isl1208_setup_irq(client, client->irq);
+		if (rc)
+			return rc;
+	} else {
+		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, isl1208->rtc->features);
+	}
+
+	if (evdet_irq > 0 && evdet_irq != client->irq)
+		rc = isl1208_setup_irq(client, evdet_irq);
+	if (rc)
+		return rc;
+
+	rc = devm_rtc_nvmem_register(isl1208->rtc, &isl1208->nvmem_config);
+	if (rc)
+		return rc;
+
+	return devm_rtc_register_device(isl1208->rtc);
+}
+
+static struct i2c_driver isl1208_driver = {
+	.driver = {
+		.name = "rtc-isl1208",
+		.of_match_table = of_match_ptr(isl1208_of_match),
+	},
+	.probe = isl1208_probe,
+	.id_table = isl1208_id,
+};
+
+module_i2c_driver(isl1208_driver);
+
+MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
+MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
+MODULE_LICENSE("GPL");