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, 793 insertions, 0 deletions

diff --git a/drivers/hwmon/chipcap2.c b/drivers/hwmon/chipcap2.c
new file mode 100644
index 000000000..9bef767b5
--- /dev/null
+++ b/drivers/hwmon/chipcap2.c
@@ -0,0 +1,793 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * cc2.c - Support for the Amphenol ChipCap 2 relative humidity, temperature sensor
+ *
+ * Part numbers supported:
+ * CC2D23, CC2D23S, CC2D25, CC2D25S, CC2D33, CC2D33S, CC2D35, CC2D35S
+ *
+ * Author: Javier Carrasco <javier.carrasco.cruz@gmail.com>
+ *
+ * Datasheet and application notes:
+ * https://www.amphenol-sensors.com/en/telaire/humidity/527-humidity-sensors/3095-chipcap-2
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/cleanup.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+
+#define CC2_START_CM			0xA0
+#define CC2_START_NOM			0x80
+#define CC2_R_ALARM_H_ON		0x18
+#define CC2_R_ALARM_H_OFF		0x19
+#define CC2_R_ALARM_L_ON		0x1A
+#define CC2_R_ALARM_L_OFF		0x1B
+#define CC2_RW_OFFSET			0x40
+#define CC2_W_ALARM_H_ON		(CC2_R_ALARM_H_ON + CC2_RW_OFFSET)
+#define CC2_W_ALARM_H_OFF		(CC2_R_ALARM_H_OFF + CC2_RW_OFFSET)
+#define CC2_W_ALARM_L_ON		(CC2_R_ALARM_L_ON + CC2_RW_OFFSET)
+#define CC2_W_ALARM_L_OFF		(CC2_R_ALARM_L_OFF + CC2_RW_OFFSET)
+
+#define CC2_STATUS_FIELD		GENMASK(7, 6)
+#define CC2_STATUS_VALID_DATA		0x00
+#define CC2_STATUS_STALE_DATA		0x01
+#define CC2_STATUS_CMD_MODE		0x02
+
+#define CC2_RESPONSE_FIELD		GENMASK(1, 0)
+#define CC2_RESPONSE_BUSY		0x00
+#define CC2_RESPONSE_ACK		0x01
+#define CC2_RESPONSE_NACK		0x02
+
+#define CC2_ERR_CORR_EEPROM		BIT(2)
+#define CC2_ERR_UNCORR_EEPROM		BIT(3)
+#define CC2_ERR_RAM_PARITY		BIT(4)
+#define CC2_ERR_CONFIG_LOAD		BIT(5)
+
+#define CC2_EEPROM_SIZE			10
+#define CC2_EEPROM_DATA_LEN		3
+#define CC2_MEASUREMENT_DATA_LEN	4
+
+#define CC2_RH_DATA_FIELD		GENMASK(13, 0)
+
+/* ensure clean off -> on transitions */
+#define CC2_POWER_CYCLE_MS		80
+
+#define CC2_STARTUP_TO_DATA_MS		55
+#define CC2_RESP_START_CM_US		100
+#define CC2_RESP_EEPROM_R_US		100
+#define CC2_RESP_EEPROM_W_MS		12
+#define CC2_STARTUP_TIME_US		1250
+
+#define CC2_RH_MAX			(100 * 1000U)
+
+#define CC2_CM_RETRIES			5
+
+struct cc2_rh_alarm_info {
+	bool low_alarm;
+	bool high_alarm;
+	bool low_alarm_visible;
+	bool high_alarm_visible;
+};
+
+struct cc2_data {
+	struct cc2_rh_alarm_info rh_alarm;
+	struct completion complete;
+	struct device *hwmon;
+	struct i2c_client *client;
+	struct regulator *regulator;
+	const char *name;
+	const char *label;
+	int irq_ready;
+	int irq_low;
+	int irq_high;
+	bool process_irqs;
+};
+
+/* %RH as a per cent mille from a register value */
+static long cc2_rh_convert(u16 data)
+{
+	unsigned long tmp = (data & CC2_RH_DATA_FIELD) * CC2_RH_MAX;
+
+	return tmp / ((1 << 14) - 1);
+}
+
+/* convert %RH to a register value */
+static u16 cc2_rh_to_reg(long data)
+{
+	return data * ((1 << 14) - 1) / CC2_RH_MAX;
+}
+
+/* temperature in milli degrees celsius from a register value */
+static long cc2_temp_convert(u16 data)
+{
+	unsigned long tmp = ((data >> 2) * 165 * 1000U) / ((1 << 14) - 1);
+
+	return tmp - 40 * 1000U;
+}
+
+static int cc2_enable(struct cc2_data *data)
+{
+	int ret;
+
+	/* exclusive regulator, check in case a disable failed */
+	if (regulator_is_enabled(data->regulator))
+		return 0;
+
+	/* clear any pending completion */
+	try_wait_for_completion(&data->complete);
+
+	ret = regulator_enable(data->regulator);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(CC2_STARTUP_TIME_US, CC2_STARTUP_TIME_US + 125);
+
+	data->process_irqs = true;
+
+	return 0;
+}
+
+static void cc2_disable(struct cc2_data *data)
+{
+	int err;
+
+	/* ignore alarms triggered by voltage toggling when powering up */
+	data->process_irqs = false;
+
+	/* exclusive regulator, check in case an enable failed */
+	if (regulator_is_enabled(data->regulator)) {
+		err = regulator_disable(data->regulator);
+		if (err)
+			dev_dbg(&data->client->dev, "Failed to disable device");
+	}
+}
+
+static int cc2_cmd_response_diagnostic(struct device *dev, u8 status)
+{
+	int resp;
+
+	if (FIELD_GET(CC2_STATUS_FIELD, status) != CC2_STATUS_CMD_MODE) {
+		dev_dbg(dev, "Command sent out of command window\n");
+		return -ETIMEDOUT;
+	}
+
+	resp = FIELD_GET(CC2_RESPONSE_FIELD, status);
+	switch (resp) {
+	case CC2_RESPONSE_ACK:
+		return 0;
+	case CC2_RESPONSE_BUSY:
+		return -EBUSY;
+	case CC2_RESPONSE_NACK:
+		if (resp & CC2_ERR_CORR_EEPROM)
+			dev_dbg(dev, "Command failed: corrected EEPROM\n");
+		if (resp & CC2_ERR_UNCORR_EEPROM)
+			dev_dbg(dev, "Command failed: uncorrected EEPROM\n");
+		if (resp & CC2_ERR_RAM_PARITY)
+			dev_dbg(dev, "Command failed: RAM parity\n");
+		if (resp & CC2_ERR_RAM_PARITY)
+			dev_dbg(dev, "Command failed: configuration error\n");
+		return -ENODATA;
+	default:
+		dev_dbg(dev, "Unknown command reply\n");
+		return -EINVAL;
+	}
+}
+
+static int cc2_read_command_status(struct i2c_client *client)
+{
+	u8 status;
+	int ret;
+
+	ret = i2c_master_recv(client, &status, 1);
+	if (ret != 1) {
+		ret = ret < 0 ? ret : -EIO;
+		return ret;
+	}
+
+	return cc2_cmd_response_diagnostic(&client->dev, status);
+}
+
+/*
+ * The command mode is only accessible after sending the START_CM command in the
+ * first 10 ms after power-up. Only in case the command window is missed,
+ * CC2_CM_RETRIES retries are attempted before giving up and returning an error.
+ */
+static int cc2_command_mode_start(struct cc2_data *data)
+{
+	unsigned long timeout;
+	int i, ret;
+
+	for (i = 0; i < CC2_CM_RETRIES; i++) {
+		ret = cc2_enable(data);
+		if (ret < 0)
+			return ret;
+
+		ret = i2c_smbus_write_word_data(data->client, CC2_START_CM, 0);
+		if (ret < 0)
+			return ret;
+
+		if (data->irq_ready > 0) {
+			timeout = usecs_to_jiffies(2 * CC2_RESP_START_CM_US);
+			ret = wait_for_completion_timeout(&data->complete,
+							  timeout);
+			if (!ret)
+				return -ETIMEDOUT;
+		} else {
+			usleep_range(CC2_RESP_START_CM_US,
+				     2 * CC2_RESP_START_CM_US);
+		}
+		ret = cc2_read_command_status(data->client);
+		if (ret != -ETIMEDOUT || i == CC2_CM_RETRIES)
+			break;
+
+		/* command window missed, prepare for a retry */
+		cc2_disable(data);
+		msleep(CC2_POWER_CYCLE_MS);
+	}
+
+	return ret;
+}
+
+/* Sending a Start_NOM command finishes the command mode immediately with no
+ * reply and the device enters normal operation mode
+ */
+static int cc2_command_mode_finish(struct cc2_data *data)
+{
+	int ret;
+
+	ret = i2c_smbus_write_word_data(data->client, CC2_START_NOM, 0);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int cc2_write_reg(struct cc2_data *data, u8 reg, u16 val)
+{
+	unsigned long timeout;
+	int ret;
+
+	ret = cc2_command_mode_start(data);
+	if (ret < 0)
+		goto disable;
+
+	cpu_to_be16s(&val);
+	ret = i2c_smbus_write_word_data(data->client, reg, val);
+	if (ret < 0)
+		goto disable;
+
+	if (data->irq_ready > 0) {
+		timeout = msecs_to_jiffies(2 * CC2_RESP_EEPROM_W_MS);
+		ret = wait_for_completion_timeout(&data->complete, timeout);
+		if (!ret) {
+			ret = -ETIMEDOUT;
+			goto disable;
+		}
+	} else {
+		msleep(CC2_RESP_EEPROM_W_MS);
+	}
+
+	ret = cc2_read_command_status(data->client);
+
+disable:
+	cc2_disable(data);
+
+	return ret;
+}
+
+static int cc2_read_reg(struct cc2_data *data, u8 reg, u16 *val)
+{
+	u8 buf[CC2_EEPROM_DATA_LEN];
+	unsigned long timeout;
+	int ret;
+
+	ret = cc2_command_mode_start(data);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_word_data(data->client, reg, 0);
+	if (ret < 0)
+		return ret;
+
+	if (data->irq_ready > 0) {
+		timeout = usecs_to_jiffies(2 * CC2_RESP_EEPROM_R_US);
+		ret = wait_for_completion_timeout(&data->complete, timeout);
+		if (!ret)
+			return -ETIMEDOUT;
+
+	} else {
+		usleep_range(CC2_RESP_EEPROM_R_US, CC2_RESP_EEPROM_R_US + 10);
+	}
+	ret = i2c_master_recv(data->client, buf, CC2_EEPROM_DATA_LEN);
+	if (ret != CC2_EEPROM_DATA_LEN)
+		return ret < 0 ? ret : -EIO;
+
+	*val = be16_to_cpup((__be16 *)&buf[1]);
+
+	return cc2_read_command_status(data->client);
+}
+
+static int cc2_get_reg_val(struct cc2_data *data, u8 reg, long *val)
+{
+	u16 reg_val;
+	int ret;
+
+	ret = cc2_read_reg(data, reg, &reg_val);
+	if (!ret)
+		*val = cc2_rh_convert(reg_val);
+
+	cc2_disable(data);
+
+	return ret;
+}
+
+static int cc2_data_fetch(struct i2c_client *client,
+			  enum hwmon_sensor_types type, long *val)
+{
+	u8 data[CC2_MEASUREMENT_DATA_LEN];
+	u8 status;
+	int ret;
+
+	ret = i2c_master_recv(client, data, CC2_MEASUREMENT_DATA_LEN);
+	if (ret != CC2_MEASUREMENT_DATA_LEN) {
+		ret = ret < 0 ? ret : -EIO;
+		return ret;
+	}
+	status = FIELD_GET(CC2_STATUS_FIELD, data[0]);
+	if (status == CC2_STATUS_STALE_DATA)
+		return -EBUSY;
+
+	if (status != CC2_STATUS_VALID_DATA)
+		return -EIO;
+
+	switch (type) {
+	case hwmon_humidity:
+		*val = cc2_rh_convert(be16_to_cpup((__be16 *)&data[0]));
+		break;
+	case hwmon_temp:
+		*val = cc2_temp_convert(be16_to_cpup((__be16 *)&data[2]));
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int cc2_read_measurement(struct cc2_data *data,
+				enum hwmon_sensor_types type, long *val)
+{
+	unsigned long timeout;
+	int ret;
+
+	if (data->irq_ready > 0) {
+		timeout = msecs_to_jiffies(CC2_STARTUP_TO_DATA_MS * 2);
+		ret = wait_for_completion_timeout(&data->complete, timeout);
+		if (!ret)
+			return -ETIMEDOUT;
+
+	} else {
+		msleep(CC2_STARTUP_TO_DATA_MS);
+	}
+
+	ret = cc2_data_fetch(data->client, type, val);
+
+	return ret;
+}
+
+/*
+ * A measurement requires enabling the device, waiting for the automatic
+ * measurement to finish, reading the measurement data and disabling the device
+ * again.
+ */
+static int cc2_measurement(struct cc2_data *data, enum hwmon_sensor_types type,
+			   long *val)
+{
+	int ret;
+
+	ret = cc2_enable(data);
+	if (ret)
+		return ret;
+
+	ret = cc2_read_measurement(data, type, val);
+
+	cc2_disable(data);
+
+	return ret;
+}
+
+/*
+ * In order to check alarm status, the corresponding ALARM_OFF (hysteresis)
+ * register must be read and a new measurement must be carried out to trigger
+ * the alarm signals. Given that the device carries out a measurement after
+ * exiting the command mode, there is no need to force two power-up sequences.
+ * Instead, a NOM command is sent and the device is disabled after the
+ * measurement is read.
+ */
+static int cc2_read_hyst_and_measure(struct cc2_data *data, u8 reg,
+				     long *hyst, long *measurement)
+{
+	u16 reg_val;
+	int ret;
+
+	ret = cc2_read_reg(data, reg, &reg_val);
+	if (ret)
+		goto disable;
+
+	*hyst = cc2_rh_convert(reg_val);
+
+	ret = cc2_command_mode_finish(data);
+	if (ret)
+		goto disable;
+
+	ret = cc2_read_measurement(data, hwmon_humidity, measurement);
+
+disable:
+	cc2_disable(data);
+
+	return ret;
+}
+
+static umode_t cc2_is_visible(const void *data, enum hwmon_sensor_types type,
+			      u32 attr, int channel)
+{
+	const struct cc2_data *cc2 = data;
+
+	switch (type) {
+	case hwmon_humidity:
+		switch (attr) {
+		case hwmon_humidity_input:
+			return 0444;
+		case hwmon_humidity_label:
+			return cc2->label ? 0444 : 0;
+		case hwmon_humidity_min_alarm:
+			return cc2->rh_alarm.low_alarm_visible ? 0444 : 0;
+		case hwmon_humidity_max_alarm:
+			return cc2->rh_alarm.high_alarm_visible ? 0444 : 0;
+		case hwmon_humidity_min:
+		case hwmon_humidity_min_hyst:
+			return cc2->rh_alarm.low_alarm_visible ? 0644 : 0;
+		case hwmon_humidity_max:
+		case hwmon_humidity_max_hyst:
+			return cc2->rh_alarm.high_alarm_visible ? 0644 : 0;
+		default:
+			return 0;
+		}
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			return 0444;
+		case hwmon_temp_label:
+			return cc2->label ? 0444 : 0;
+		default:
+			return 0;
+		}
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static irqreturn_t cc2_ready_interrupt(int irq, void *data)
+{
+	struct cc2_data *cc2 = data;
+
+	if (cc2->process_irqs)
+		complete(&cc2->complete);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t cc2_low_interrupt(int irq, void *data)
+{
+	struct cc2_data *cc2 = data;
+
+	if (cc2->process_irqs) {
+		hwmon_notify_event(cc2->hwmon, hwmon_humidity,
+				   hwmon_humidity_min_alarm, 0);
+		cc2->rh_alarm.low_alarm = true;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t cc2_high_interrupt(int irq, void *data)
+{
+	struct cc2_data *cc2 = data;
+
+	if (cc2->process_irqs) {
+		hwmon_notify_event(cc2->hwmon, hwmon_humidity,
+				   hwmon_humidity_max_alarm, 0);
+		cc2->rh_alarm.high_alarm = true;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int cc2_humidity_min_alarm_status(struct cc2_data *data, long *val)
+{
+	long measurement, min_hyst;
+	int ret;
+
+	ret = cc2_read_hyst_and_measure(data, CC2_R_ALARM_L_OFF, &min_hyst,
+					&measurement);
+	if (ret < 0)
+		return ret;
+
+	if (data->rh_alarm.low_alarm) {
+		*val = (measurement < min_hyst) ? 1 : 0;
+		data->rh_alarm.low_alarm = *val;
+	} else {
+		*val = 0;
+	}
+
+	return 0;
+}
+
+static int cc2_humidity_max_alarm_status(struct cc2_data *data, long *val)
+{
+	long measurement, max_hyst;
+	int ret;
+
+	ret = cc2_read_hyst_and_measure(data, CC2_R_ALARM_H_OFF, &max_hyst,
+					&measurement);
+	if (ret < 0)
+		return ret;
+
+	if (data->rh_alarm.high_alarm) {
+		*val = (measurement > max_hyst) ? 1 : 0;
+		data->rh_alarm.high_alarm = *val;
+	} else {
+		*val = 0;
+	}
+
+	return 0;
+}
+
+static int cc2_read_string(struct device *dev, enum hwmon_sensor_types type,
+			   u32 attr, int channel, const char **str)
+{
+	struct cc2_data *data = dev_get_drvdata(dev);
+
+	*str = data->label;
+
+	return 0;
+}
+
+static int cc2_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+		    int channel, long *val)
+{
+	struct cc2_data *data = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_temp:
+		return cc2_measurement(data, type, val);
+	case hwmon_humidity:
+		switch (attr) {
+		case hwmon_humidity_input:
+			return cc2_measurement(data, type, val);
+		case hwmon_humidity_min:
+			return cc2_get_reg_val(data, CC2_R_ALARM_L_ON, val);
+		case hwmon_humidity_min_hyst:
+			return cc2_get_reg_val(data, CC2_R_ALARM_L_OFF, val);
+		case hwmon_humidity_max:
+			return cc2_get_reg_val(data, CC2_R_ALARM_H_ON, val);
+		case hwmon_humidity_max_hyst:
+			return cc2_get_reg_val(data, CC2_R_ALARM_H_OFF, val);
+		case hwmon_humidity_min_alarm:
+			return cc2_humidity_min_alarm_status(data, val);
+		case hwmon_humidity_max_alarm:
+			return cc2_humidity_max_alarm_status(data, val);
+		default:
+			return -EOPNOTSUPP;
+		}
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int cc2_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+		     int channel, long val)
+{
+	struct cc2_data *data = dev_get_drvdata(dev);
+	u16 arg;
+	u8 cmd;
+
+	if (type != hwmon_humidity)
+		return -EOPNOTSUPP;
+
+	if (val < 0 || val > CC2_RH_MAX)
+		return -EINVAL;
+
+	switch (attr) {
+	case hwmon_humidity_min:
+		cmd = CC2_W_ALARM_L_ON;
+		arg = cc2_rh_to_reg(val);
+		return cc2_write_reg(data, cmd, arg);
+	case hwmon_humidity_min_hyst:
+		cmd = CC2_W_ALARM_L_OFF;
+		arg = cc2_rh_to_reg(val);
+		return cc2_write_reg(data, cmd, arg);
+	case hwmon_humidity_max:
+		cmd = CC2_W_ALARM_H_ON;
+		arg = cc2_rh_to_reg(val);
+		return cc2_write_reg(data, cmd, arg);
+	case hwmon_humidity_max_hyst:
+		cmd = CC2_W_ALARM_H_OFF;
+		arg = cc2_rh_to_reg(val);
+		return cc2_write_reg(data, cmd, arg);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int cc2_request_ready_irq(struct cc2_data *data, struct device *dev)
+{
+	int ret = 0;
+
+	data->irq_ready = fwnode_irq_get_byname(dev_fwnode(dev), "ready");
+	if (data->irq_ready > 0) {
+		init_completion(&data->complete);
+		ret = devm_request_threaded_irq(dev, data->irq_ready, NULL,
+						cc2_ready_interrupt,
+						IRQF_ONESHOT |
+						IRQF_TRIGGER_RISING,
+						dev_name(dev), data);
+	}
+
+	return ret;
+}
+
+static int cc2_request_alarm_irqs(struct cc2_data *data, struct device *dev)
+{
+	int ret = 0;
+
+	data->irq_low = fwnode_irq_get_byname(dev_fwnode(dev), "low");
+	if (data->irq_low > 0) {
+		ret = devm_request_threaded_irq(dev, data->irq_low, NULL,
+						cc2_low_interrupt,
+						IRQF_ONESHOT |
+						IRQF_TRIGGER_RISING,
+						dev_name(dev), data);
+		if (ret)
+			return ret;
+
+		data->rh_alarm.low_alarm_visible = true;
+	}
+
+	data->irq_high = fwnode_irq_get_byname(dev_fwnode(dev), "high");
+	if (data->irq_high > 0) {
+		ret = devm_request_threaded_irq(dev, data->irq_high, NULL,
+						cc2_high_interrupt,
+						IRQF_ONESHOT |
+						IRQF_TRIGGER_RISING,
+						dev_name(dev), data);
+		if (ret)
+			return ret;
+
+		data->rh_alarm.high_alarm_visible = true;
+	}
+
+	return ret;
+}
+
+static const struct hwmon_channel_info *cc2_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT | HWMON_H_LABEL |
+			   HWMON_H_MIN | HWMON_H_MAX |
+			   HWMON_H_MIN_HYST | HWMON_H_MAX_HYST |
+			   HWMON_H_MIN_ALARM | HWMON_H_MAX_ALARM),
+	NULL
+};
+
+static const struct hwmon_ops cc2_hwmon_ops = {
+	.is_visible = cc2_is_visible,
+	.read = cc2_read,
+	.read_string = cc2_read_string,
+	.write = cc2_write,
+};
+
+static const struct hwmon_chip_info cc2_chip_info = {
+	.ops = &cc2_hwmon_ops,
+	.info = cc2_info,
+};
+
+static int cc2_probe(struct i2c_client *client)
+{
+	struct cc2_data *data;
+	struct device *dev = &client->dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -EOPNOTSUPP;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, data);
+
+	data->client = client;
+
+	data->regulator = devm_regulator_get_exclusive(dev, "vdd");
+	if (IS_ERR(data->regulator))
+		return dev_err_probe(dev, PTR_ERR(data->regulator),
+				     "Failed to get regulator\n");
+
+	device_property_read_string(dev, "label", &data->label);
+
+	ret = cc2_request_ready_irq(data, dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request ready irq\n");
+
+	ret = cc2_request_alarm_irqs(data, dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request alarm irqs\n");
+
+	data->hwmon = devm_hwmon_device_register_with_info(dev, client->name,
+							   data, &cc2_chip_info,
+							   NULL);
+	if (IS_ERR(data->hwmon))
+		return dev_err_probe(dev, PTR_ERR(data->hwmon),
+				     "Failed to register hwmon device\n");
+
+	return 0;
+}
+
+static void cc2_remove(struct i2c_client *client)
+{
+	struct cc2_data *data = i2c_get_clientdata(client);
+
+	cc2_disable(data);
+}
+
+static const struct i2c_device_id cc2_id[] = {
+	{ .name = "cc2d23" },
+	{ .name = "cc2d23s" },
+	{ .name = "cc2d25" },
+	{ .name = "cc2d25s" },
+	{ .name = "cc2d33" },
+	{ .name = "cc2d33s" },
+	{ .name = "cc2d35" },
+	{ .name = "cc2d35s" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, cc2_id);
+
+static const struct of_device_id cc2_of_match[] = {
+	{ .compatible = "amphenol,cc2d23" },
+	{ .compatible = "amphenol,cc2d23s" },
+	{ .compatible = "amphenol,cc2d25" },
+	{ .compatible = "amphenol,cc2d25s" },
+	{ .compatible = "amphenol,cc2d33" },
+	{ .compatible = "amphenol,cc2d33s" },
+	{ .compatible = "amphenol,cc2d35" },
+	{ .compatible = "amphenol,cc2d35s" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, cc2_of_match);
+
+static struct i2c_driver cc2_driver = {
+	.driver = {
+		.name	= "cc2d23",
+		.of_match_table = cc2_of_match,
+	},
+	.probe		= cc2_probe,
+	.remove		= cc2_remove,
+	.id_table = cc2_id,
+};
+module_i2c_driver(cc2_driver);
+
+MODULE_AUTHOR("Javier Carrasco <javier.carrasco.cruz@gamil.com>");
+MODULE_DESCRIPTION("Amphenol ChipCap 2 humidity and temperature sensor driver");
+MODULE_LICENSE("GPL");