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, 692 insertions, 0 deletions

diff --git a/drivers/hwmon/tmp464.c b/drivers/hwmon/tmp464.c
new file mode 100644
index 000000000..c3e031044
--- /dev/null
+++ b/drivers/hwmon/tmp464.c
@@ -0,0 +1,692 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* Driver for the Texas Instruments TMP464 SMBus temperature sensor IC.
+ * Supported models: TMP464, TMP468
+
+ * Copyright (C) 2022 Agathe Porte <agathe.porte@nokia.com>
+ * Preliminary support by:
+ * Lionel Pouliquen <lionel.lp.pouliquen@nokia.com>
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END };
+
+#define TMP464_NUM_CHANNELS		5	/* chan 0 is internal, 1-4 are remote */
+#define TMP468_NUM_CHANNELS		9	/* chan 0 is internal, 1-8 are remote */
+
+#define MAX_CHANNELS			9
+
+#define TMP464_TEMP_REG(channel)	(channel)
+#define TMP464_TEMP_OFFSET_REG(channel)	(0x40 + ((channel) - 1) * 8)
+#define TMP464_N_FACTOR_REG(channel)	(0x41 + ((channel) - 1) * 8)
+
+static const u8 TMP464_THERM_LIMIT[MAX_CHANNELS] = {
+	0x39, 0x42, 0x4A, 0x52, 0x5A, 0x62, 0x6a, 0x72, 0x7a };
+static const u8 TMP464_THERM2_LIMIT[MAX_CHANNELS] = {
+	0x3A, 0x43, 0x4B, 0x53, 0x5B, 0x63, 0x6b, 0x73, 0x7b };
+
+#define TMP464_THERM_STATUS_REG			0x21
+#define TMP464_THERM2_STATUS_REG		0x22
+#define TMP464_REMOTE_OPEN_REG			0x23
+#define TMP464_CONFIG_REG			0x30
+#define TMP464_TEMP_HYST_REG			0x38
+#define TMP464_LOCK_REG				0xc4
+
+/* Identification */
+#define TMP464_MANUFACTURER_ID_REG		0xFE
+#define TMP464_DEVICE_ID_REG			0xFF
+
+/* Flags */
+#define TMP464_CONFIG_SHUTDOWN			BIT(5)
+#define TMP464_CONFIG_RANGE			0x04
+#define TMP464_CONFIG_REG_REN(x)		(BIT(7 + (x)))
+#define TMP464_CONFIG_REG_REN_MASK		GENMASK(15, 7)
+#define TMP464_CONFIG_CONVERSION_RATE_B0	2
+#define TMP464_CONFIG_CONVERSION_RATE_B2	4
+#define TMP464_CONFIG_CONVERSION_RATE_MASK      GENMASK(TMP464_CONFIG_CONVERSION_RATE_B2, \
+							TMP464_CONFIG_CONVERSION_RATE_B0)
+
+#define TMP464_UNLOCK_VAL			0xeb19
+#define TMP464_LOCK_VAL				0x5ca6
+#define TMP464_LOCKED				0x8000
+
+/* Manufacturer / Device ID's */
+#define TMP464_MANUFACTURER_ID			0x5449
+#define TMP464_DEVICE_ID			0x1468
+#define TMP468_DEVICE_ID			0x0468
+
+static const struct i2c_device_id tmp464_id[] = {
+	{ .name = "tmp464", .driver_data = TMP464_NUM_CHANNELS },
+	{ .name = "tmp468", .driver_data = TMP468_NUM_CHANNELS },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp464_id);
+
+static const struct of_device_id __maybe_unused tmp464_of_match[] = {
+	{
+		.compatible = "ti,tmp464",
+		.data = (void *)TMP464_NUM_CHANNELS
+	},
+	{
+		.compatible = "ti,tmp468",
+		.data = (void *)TMP468_NUM_CHANNELS
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, tmp464_of_match);
+
+struct tmp464_channel {
+	const char *label;
+	bool enabled;
+};
+
+struct tmp464_data {
+	struct regmap *regmap;
+	int channels;
+	s16 config_orig;
+	u16 open_reg;
+	unsigned long last_updated;
+	bool valid;
+	int update_interval;
+	struct tmp464_channel channel[MAX_CHANNELS];
+};
+
+static int temp_from_reg(s16 reg)
+{
+	return DIV_ROUND_CLOSEST((reg >> 3) * 625, 10);
+}
+
+static s16 temp_to_limit_reg(long temp)
+{
+	return DIV_ROUND_CLOSEST(temp, 500) << 6;
+}
+
+static s16 temp_to_offset_reg(long temp)
+{
+	return DIV_ROUND_CLOSEST(temp * 10, 625) << 3;
+}
+
+static int tmp464_enable_channels(struct tmp464_data *data)
+{
+	struct regmap *regmap = data->regmap;
+	u16 enable = 0;
+	int i;
+
+	for (i = 0; i < data->channels; i++)
+		if (data->channel[i].enabled)
+			enable |= TMP464_CONFIG_REG_REN(i);
+
+	return regmap_update_bits(regmap, TMP464_CONFIG_REG, TMP464_CONFIG_REG_REN_MASK, enable);
+}
+
+static int tmp464_chip_read(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct tmp464_data *data = dev_get_drvdata(dev);
+
+	switch (attr) {
+	case hwmon_chip_update_interval:
+		*val = data->update_interval;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int tmp464_temp_read(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct tmp464_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	unsigned int regs[2];
+	unsigned int regval;
+	u16 regvals[2];
+	int err = 0;
+
+	switch (attr) {
+	case hwmon_temp_max_alarm:
+		err = regmap_read(regmap, TMP464_THERM_STATUS_REG, &regval);
+		if (err < 0)
+			break;
+		*val = !!(regval & BIT(channel + 7));
+		break;
+	case hwmon_temp_crit_alarm:
+		err = regmap_read(regmap, TMP464_THERM2_STATUS_REG, &regval);
+		if (err < 0)
+			break;
+		*val = !!(regval & BIT(channel + 7));
+		break;
+	case hwmon_temp_fault:
+		/*
+		 * The chip clears TMP464_REMOTE_OPEN_REG after it is read
+		 * and only updates it after the next measurement cycle is
+		 * complete. That means we have to cache the value internally
+		 * for one measurement cycle and report the cached value.
+		 */
+		if (!data->valid || time_after(jiffies, data->last_updated +
+					       msecs_to_jiffies(data->update_interval))) {
+			err = regmap_read(regmap, TMP464_REMOTE_OPEN_REG, &regval);
+			if (err < 0)
+				break;
+			data->open_reg = regval;
+			data->last_updated = jiffies;
+			data->valid = true;
+		}
+		*val = !!(data->open_reg & BIT(channel + 7));
+		break;
+	case hwmon_temp_max_hyst:
+		regs[0] = TMP464_THERM_LIMIT[channel];
+		regs[1] = TMP464_TEMP_HYST_REG;
+		err = regmap_multi_reg_read(regmap, regs, regvals, 2);
+		if (err < 0)
+			break;
+		*val = temp_from_reg(regvals[0] - regvals[1]);
+		break;
+	case hwmon_temp_max:
+		err = regmap_read(regmap, TMP464_THERM_LIMIT[channel], &regval);
+		if (err < 0)
+			break;
+		*val = temp_from_reg(regval);
+		break;
+	case hwmon_temp_crit_hyst:
+		regs[0] = TMP464_THERM2_LIMIT[channel];
+		regs[1] = TMP464_TEMP_HYST_REG;
+		err = regmap_multi_reg_read(regmap, regs, regvals, 2);
+		if (err < 0)
+			break;
+		*val = temp_from_reg(regvals[0] - regvals[1]);
+		break;
+	case hwmon_temp_crit:
+		err = regmap_read(regmap, TMP464_THERM2_LIMIT[channel], &regval);
+		if (err < 0)
+			break;
+		*val = temp_from_reg(regval);
+		break;
+	case hwmon_temp_offset:
+		err = regmap_read(regmap, TMP464_TEMP_OFFSET_REG(channel), &regval);
+		if (err < 0)
+			break;
+		*val = temp_from_reg(regval);
+		break;
+	case hwmon_temp_input:
+		if (!data->channel[channel].enabled) {
+			err = -ENODATA;
+			break;
+		}
+		err = regmap_read(regmap, TMP464_TEMP_REG(channel), &regval);
+		if (err < 0)
+			break;
+		*val = temp_from_reg(regval);
+		break;
+	case hwmon_temp_enable:
+		*val = data->channel[channel].enabled;
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+
+	return err;
+}
+
+static int tmp464_read(struct device *dev, enum hwmon_sensor_types type,
+		       u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_chip:
+		return tmp464_chip_read(dev, attr, channel, val);
+	case hwmon_temp:
+		return tmp464_temp_read(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int tmp464_read_string(struct device *dev, enum hwmon_sensor_types type,
+			      u32 attr, int channel, const char **str)
+{
+	struct tmp464_data *data = dev_get_drvdata(dev);
+
+	*str = data->channel[channel].label;
+
+	return 0;
+}
+
+static int tmp464_set_convrate(struct tmp464_data *data, long interval)
+{
+	int rate;
+
+	/*
+	 * For valid rates, interval in milli-seconds can be calculated as
+	 *      interval = 125 << (7 - rate);
+	 * or
+	 *      interval = (1 << (7 - rate)) * 125;
+	 * The rate is therefore
+	 *      rate = 7 - __fls(interval / 125);
+	 * and the rounded rate is
+	 *      rate = 7 - __fls(interval * 4 / (125 * 3));
+	 * Use clamp_val() to avoid overflows, and to ensure valid input
+	 * for __fls.
+	 */
+	interval = clamp_val(interval, 125, 16000);
+	rate = 7 - __fls(interval * 4 / (125 * 3));
+	data->update_interval = 125 << (7 - rate);
+
+	return regmap_update_bits(data->regmap, TMP464_CONFIG_REG,
+				  TMP464_CONFIG_CONVERSION_RATE_MASK,
+				  rate << TMP464_CONFIG_CONVERSION_RATE_B0);
+}
+
+static int tmp464_chip_write(struct tmp464_data *data, u32 attr, int channel, long val)
+{
+	switch (attr) {
+	case hwmon_chip_update_interval:
+		return tmp464_set_convrate(data, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int tmp464_temp_write(struct tmp464_data *data, u32 attr, int channel, long val)
+{
+	struct regmap *regmap = data->regmap;
+	unsigned int regval;
+	int err = 0;
+
+	switch (attr) {
+	case hwmon_temp_max_hyst:
+		err = regmap_read(regmap, TMP464_THERM_LIMIT[0], &regval);
+		if (err < 0)
+			break;
+		val = clamp_val(val, -256000, 256000);	/* prevent overflow/underflow */
+		val = clamp_val(temp_from_reg(regval) - val, 0, 255000);
+		err = regmap_write(regmap, TMP464_TEMP_HYST_REG,
+				   DIV_ROUND_CLOSEST(val, 1000) << 7);
+		break;
+	case hwmon_temp_max:
+		val = temp_to_limit_reg(clamp_val(val, -255000, 255500));
+		err = regmap_write(regmap, TMP464_THERM_LIMIT[channel], val);
+		break;
+	case hwmon_temp_crit:
+		val = temp_to_limit_reg(clamp_val(val, -255000, 255500));
+		err = regmap_write(regmap, TMP464_THERM2_LIMIT[channel], val);
+		break;
+	case hwmon_temp_offset:
+		val = temp_to_offset_reg(clamp_val(val, -128000, 127937));
+		err = regmap_write(regmap, TMP464_TEMP_OFFSET_REG(channel), val);
+		break;
+	case hwmon_temp_enable:
+		data->channel[channel].enabled = !!val;
+		err = tmp464_enable_channels(data);
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+
+	return err;
+}
+
+static int tmp464_write(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long val)
+{
+	struct tmp464_data *data = dev_get_drvdata(dev);
+	int err;
+
+	switch (type) {
+	case hwmon_chip:
+		err = tmp464_chip_write(data, attr, channel, val);
+		break;
+	case hwmon_temp:
+		err = tmp464_temp_write(data, attr, channel, val);
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+
+	return err;
+}
+
+static umode_t tmp464_is_visible(const void *_data, enum hwmon_sensor_types type,
+				 u32 attr, int channel)
+{
+	const struct tmp464_data *data = _data;
+
+	if (channel >= data->channels)
+		return 0;
+
+	if (type == hwmon_chip) {
+		if (attr == hwmon_chip_update_interval)
+			return 0644;
+		return 0;
+	}
+
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_crit_alarm:
+	case hwmon_temp_crit_hyst:
+		return 0444;
+	case hwmon_temp_enable:
+	case hwmon_temp_max:
+	case hwmon_temp_crit:
+		return 0644;
+	case hwmon_temp_max_hyst:
+		if (!channel)
+			return 0644;
+		return 0444;
+	case hwmon_temp_label:
+		if (data->channel[channel].label)
+			return 0444;
+		return 0;
+	case hwmon_temp_fault:
+		if (channel)
+			return 0444;
+		return 0;
+	case hwmon_temp_offset:
+		if (channel)
+			return 0644;
+		return 0;
+	default:
+		return 0;
+	}
+}
+
+static void tmp464_restore_lock(void *regmap)
+{
+	regmap_write(regmap, TMP464_LOCK_REG, TMP464_LOCK_VAL);
+}
+
+static void tmp464_restore_config(void *_data)
+{
+	struct tmp464_data *data = _data;
+
+	regmap_write(data->regmap, TMP464_CONFIG_REG, data->config_orig);
+}
+
+static int tmp464_init_client(struct device *dev, struct tmp464_data *data)
+{
+	struct regmap *regmap = data->regmap;
+	unsigned int regval;
+	int err;
+
+	err = regmap_read(regmap, TMP464_LOCK_REG, &regval);
+	if (err)
+		return err;
+	if (regval == TMP464_LOCKED) {
+		/* Explicitly unlock chip if it is locked */
+		err = regmap_write(regmap, TMP464_LOCK_REG, TMP464_UNLOCK_VAL);
+		if (err)
+			return err;
+		/* and lock it again when unloading the driver */
+		err = devm_add_action_or_reset(dev, tmp464_restore_lock, regmap);
+		if (err)
+			return err;
+	}
+
+	err = regmap_read(regmap, TMP464_CONFIG_REG, &regval);
+	if (err)
+		return err;
+	data->config_orig = regval;
+	err = devm_add_action_or_reset(dev, tmp464_restore_config, data);
+	if (err)
+		return err;
+
+	/* Default to 500 ms update interval */
+	err = regmap_update_bits(regmap, TMP464_CONFIG_REG,
+				 TMP464_CONFIG_CONVERSION_RATE_MASK | TMP464_CONFIG_SHUTDOWN,
+				 BIT(TMP464_CONFIG_CONVERSION_RATE_B0) |
+				 BIT(TMP464_CONFIG_CONVERSION_RATE_B2));
+	if (err)
+		return err;
+
+	data->update_interval = 500;
+
+	return tmp464_enable_channels(data);
+}
+
+static int tmp464_detect(struct i2c_client *client,
+			 struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	char *name, *chip;
+	int reg;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	reg = i2c_smbus_read_word_swapped(client, TMP464_MANUFACTURER_ID_REG);
+	if (reg < 0)
+		return reg;
+	if (reg != TMP464_MANUFACTURER_ID)
+		return -ENODEV;
+
+	/* Check for "always return zero" bits */
+	reg = i2c_smbus_read_word_swapped(client, TMP464_THERM_STATUS_REG);
+	if (reg < 0)
+		return reg;
+	if (reg & 0x1f)
+		return -ENODEV;
+	reg = i2c_smbus_read_word_swapped(client, TMP464_THERM2_STATUS_REG);
+	if (reg < 0)
+		return reg;
+	if (reg & 0x1f)
+		return -ENODEV;
+
+	reg = i2c_smbus_read_word_swapped(client, TMP464_DEVICE_ID_REG);
+	if (reg < 0)
+		return reg;
+	switch (reg) {
+	case TMP464_DEVICE_ID:
+		name = "tmp464";
+		chip = "TMP464";
+		break;
+	case TMP468_DEVICE_ID:
+		name = "tmp468";
+		chip = "TMP468";
+		break;
+	default:
+		return -ENODEV;
+	}
+
+	strscpy(info->type, name, I2C_NAME_SIZE);
+	dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n", chip, client->addr);
+
+	return 0;
+}
+
+static int tmp464_probe_child_from_dt(struct device *dev,
+				      struct device_node *child,
+				      struct tmp464_data *data)
+
+{
+	struct regmap *regmap = data->regmap;
+	u32 channel;
+	s32 nfactor;
+	int err;
+
+	err = of_property_read_u32(child, "reg", &channel);
+	if (err) {
+		dev_err(dev, "missing reg property of %pOFn\n", child);
+		return err;
+	}
+
+	if (channel >= data->channels) {
+		dev_err(dev, "invalid reg %d of %pOFn\n", channel, child);
+		return -EINVAL;
+	}
+
+	of_property_read_string(child, "label", &data->channel[channel].label);
+
+	data->channel[channel].enabled = of_device_is_available(child);
+
+	err = of_property_read_s32(child, "ti,n-factor", &nfactor);
+	if (err && err != -EINVAL)
+		return err;
+	if (!err) {
+		if (channel == 0) {
+			dev_err(dev, "n-factor can't be set for internal channel\n");
+			return -EINVAL;
+		}
+		if (nfactor > 127 || nfactor < -128) {
+			dev_err(dev, "n-factor for channel %d invalid (%d)\n",
+				channel, nfactor);
+			return -EINVAL;
+		}
+		err = regmap_write(regmap, TMP464_N_FACTOR_REG(channel),
+				   (nfactor << 8) & 0xff00);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int tmp464_probe_from_dt(struct device *dev, struct tmp464_data *data)
+{
+	const struct device_node *np = dev->of_node;
+	int err;
+
+	for_each_child_of_node_scoped(np, child) {
+		if (strcmp(child->name, "channel"))
+			continue;
+
+		err = tmp464_probe_child_from_dt(dev, child, data);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops tmp464_ops = {
+	.is_visible = tmp464_is_visible,
+	.read = tmp464_read,
+	.read_string = tmp464_read_string,
+	.write = tmp464_write,
+};
+
+static const struct hwmon_channel_info * const tmp464_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_UPDATE_INTERVAL),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST | HWMON_T_CRIT |
+			   HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE,
+			   HWMON_T_INPUT | HWMON_T_OFFSET | HWMON_T_MAX | HWMON_T_MAX_HYST |
+			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT_ALARM | HWMON_T_FAULT | HWMON_T_LABEL | HWMON_T_ENABLE),
+	NULL
+};
+
+static const struct hwmon_chip_info tmp464_chip_info = {
+	.ops = &tmp464_ops,
+	.info = tmp464_info,
+};
+
+/* regmap */
+
+static bool tmp464_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	return (reg < TMP464_TEMP_REG(TMP468_NUM_CHANNELS) ||
+		reg == TMP464_THERM_STATUS_REG ||
+		reg == TMP464_THERM2_STATUS_REG ||
+		reg == TMP464_REMOTE_OPEN_REG);
+}
+
+static const struct regmap_config tmp464_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = TMP464_DEVICE_ID_REG,
+	.volatile_reg = tmp464_is_volatile_reg,
+	.val_format_endian = REGMAP_ENDIAN_BIG,
+	.cache_type = REGCACHE_MAPLE,
+	.use_single_read = true,
+	.use_single_write = true,
+};
+
+static int tmp464_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct tmp464_data *data;
+	int i, err;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
+		dev_err(&client->dev, "i2c functionality check failed\n");
+		return -ENODEV;
+	}
+	data = devm_kzalloc(dev, sizeof(struct tmp464_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->channels = (int)(unsigned long)i2c_get_match_data(client);
+
+	data->regmap = devm_regmap_init_i2c(client, &tmp464_regmap_config);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
+	for (i = 0; i < data->channels; i++)
+		data->channel[i].enabled = true;
+
+	err = tmp464_init_client(dev, data);
+	if (err)
+		return err;
+
+	if (dev->of_node) {
+		err = tmp464_probe_from_dt(dev, data);
+		if (err)
+			return err;
+	}
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data, &tmp464_chip_info, NULL);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct i2c_driver tmp464_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "tmp464",
+		.of_match_table = of_match_ptr(tmp464_of_match),
+	},
+	.probe = tmp464_probe,
+	.id_table = tmp464_id,
+	.detect = tmp464_detect,
+	.address_list = normal_i2c,
+};
+
+module_i2c_driver(tmp464_driver);
+
+MODULE_AUTHOR("Agathe Porte <agathe.porte@nokia.com>");
+MODULE_DESCRIPTION("Texas Instruments TMP464 temperature sensor driver");
+MODULE_LICENSE("GPL");