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, 639 insertions, 0 deletions

diff --git a/drivers/hwmon/max6697.c b/drivers/hwmon/max6697.c
new file mode 100644
index 000000000..c864093f0
--- /dev/null
+++ b/drivers/hwmon/max6697.c
@@ -0,0 +1,639 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2012 Guenter Roeck <linux@roeck-us.net>
+ *
+ * based on max1668.c
+ * Copyright (c) 2011 David George <david.george@ska.ac.za>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#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>
+
+enum chips { max6581, max6602, max6622, max6636, max6689, max6693, max6694,
+	     max6697, max6698, max6699 };
+
+/* Report local sensor as temp1 */
+
+static const u8 MAX6697_REG_TEMP[] = {
+			0x07, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x08 };
+static const u8 MAX6697_REG_TEMP_EXT[] = {
+			0x57, 0x09, 0x52, 0x53, 0x54, 0x55, 0x56, 0 };
+static const u8 MAX6697_REG_MAX[] = {
+			0x17, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x18 };
+static const u8 MAX6697_REG_CRIT[] = {
+			0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27 };
+
+#define MAX6697_REG_MIN			0x30
+/*
+ * Map device tree / internal register bit map to chip bit map.
+ * Applies to alert register and over-temperature register.
+ */
+
+#define MAX6697_EXTERNAL_MASK_DT	GENMASK(7, 1)
+#define MAX6697_LOCAL_MASK_DT		BIT(0)
+#define MAX6697_EXTERNAL_MASK_CHIP	GENMASK(6, 0)
+#define MAX6697_LOCAL_MASK_CHIP		BIT(7)
+
+/* alert - local channel is in bit 6 */
+#define MAX6697_ALERT_MAP_BITS(reg)	((((reg) & 0x7e) >> 1) | \
+				 (((reg) & 0x01) << 6) | ((reg) & 0x80))
+
+/* over-temperature - local channel is in bit 7 */
+#define MAX6697_OVERT_MAP_BITS(reg)	\
+	(FIELD_PREP(MAX6697_EXTERNAL_MASK_CHIP, FIELD_GET(MAX6697_EXTERNAL_MASK_DT, reg)) | \
+	 FIELD_PREP(MAX6697_LOCAL_MASK_CHIP, FIELD_GET(MAX6697_LOCAL_MASK_DT, reg)))
+
+#define MAX6697_REG_STAT_ALARM		0x44
+#define MAX6697_REG_STAT_CRIT		0x45
+#define MAX6697_REG_STAT_FAULT		0x46
+#define MAX6697_REG_STAT_MIN_ALARM	0x47
+
+#define MAX6697_REG_CONFIG		0x41
+#define MAX6581_CONF_EXTENDED		BIT(1)
+#define MAX6693_CONF_BETA		BIT(2)
+#define MAX6697_CONF_RESISTANCE		BIT(3)
+#define MAX6697_CONF_TIMEOUT		BIT(5)
+#define MAX6697_REG_ALERT_MASK		0x42
+#define MAX6697_REG_OVERT_MASK		0x43
+
+#define MAX6581_REG_RESISTANCE		0x4a
+#define MAX6581_REG_IDEALITY		0x4b
+#define MAX6581_REG_IDEALITY_SELECT	0x4c
+#define MAX6581_REG_OFFSET		0x4d
+#define MAX6581_REG_OFFSET_SELECT	0x4e
+#define MAX6581_OFFSET_MIN		-31750
+#define MAX6581_OFFSET_MAX		31750
+
+#define MAX6697_CONV_TIME		156	/* ms per channel, worst case */
+
+struct max6697_chip_data {
+	int channels;
+	u32 have_ext;
+	u32 have_crit;
+	u32 have_fault;
+	u8 valid_conf;
+};
+
+struct max6697_data {
+	struct regmap *regmap;
+
+	enum chips type;
+	const struct max6697_chip_data *chip;
+
+	int temp_offset;	/* in degrees C */
+
+#define MAX6697_TEMP_INPUT	0
+#define MAX6697_TEMP_EXT	1
+#define MAX6697_TEMP_MAX	2
+#define MAX6697_TEMP_CRIT	3
+	u32 alarms;
+};
+
+static const struct max6697_chip_data max6697_chip_data[] = {
+	[max6581] = {
+		.channels = 8,
+		.have_crit = 0xff,
+		.have_ext = 0x7f,
+		.have_fault = 0xfe,
+		.valid_conf = MAX6581_CONF_EXTENDED | MAX6697_CONF_TIMEOUT,
+	},
+	[max6602] = {
+		.channels = 5,
+		.have_crit = 0x12,
+		.have_ext = 0x02,
+		.have_fault = 0x1e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+	[max6622] = {
+		.channels = 5,
+		.have_crit = 0x12,
+		.have_ext = 0x02,
+		.have_fault = 0x1e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+	[max6636] = {
+		.channels = 7,
+		.have_crit = 0x72,
+		.have_ext = 0x02,
+		.have_fault = 0x7e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+	[max6689] = {
+		.channels = 7,
+		.have_crit = 0x72,
+		.have_ext = 0x02,
+		.have_fault = 0x7e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+	[max6693] = {
+		.channels = 7,
+		.have_crit = 0x72,
+		.have_ext = 0x02,
+		.have_fault = 0x7e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6693_CONF_BETA |
+		  MAX6697_CONF_TIMEOUT,
+	},
+	[max6694] = {
+		.channels = 5,
+		.have_crit = 0x12,
+		.have_ext = 0x02,
+		.have_fault = 0x1e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6693_CONF_BETA |
+		  MAX6697_CONF_TIMEOUT,
+	},
+	[max6697] = {
+		.channels = 7,
+		.have_crit = 0x72,
+		.have_ext = 0x02,
+		.have_fault = 0x7e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+	[max6698] = {
+		.channels = 7,
+		.have_crit = 0x72,
+		.have_ext = 0x02,
+		.have_fault = 0x0e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+	[max6699] = {
+		.channels = 5,
+		.have_crit = 0x12,
+		.have_ext = 0x02,
+		.have_fault = 0x1e,
+		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
+	},
+};
+
+static int max6697_alarm_channel_map(int channel)
+{
+	switch (channel) {
+	case 0:
+		return 6;
+	case 7:
+		return 7;
+	default:
+		return channel - 1;
+	}
+}
+
+static int max6697_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	unsigned int offset_regs[2] = { MAX6581_REG_OFFSET_SELECT, MAX6581_REG_OFFSET };
+	unsigned int temp_regs[2] = { MAX6697_REG_TEMP[channel],
+				      MAX6697_REG_TEMP_EXT[channel] };
+	struct max6697_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	u8 regdata[2] = { };
+	u32 regval;
+	int ret;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		ret = regmap_multi_reg_read(regmap, temp_regs, regdata,
+					    data->chip->have_ext & BIT(channel) ? 2 : 1);
+		if (ret)
+			return ret;
+		*val = (((regdata[0] - data->temp_offset) << 3) | (regdata[1] >> 5)) * 125;
+		break;
+	case hwmon_temp_max:
+		ret = regmap_read(regmap, MAX6697_REG_MAX[channel], &regval);
+		if (ret)
+			return ret;
+		*val = ((int)regval - data->temp_offset) * 1000;
+		break;
+	case hwmon_temp_crit:
+		ret = regmap_read(regmap, MAX6697_REG_CRIT[channel], &regval);
+		if (ret)
+			return ret;
+		*val = ((int)regval - data->temp_offset) * 1000;
+		break;
+	case hwmon_temp_min:
+		ret = regmap_read(regmap, MAX6697_REG_MIN, &regval);
+		if (ret)
+			return ret;
+		*val = ((int)regval - data->temp_offset) * 1000;
+		break;
+	case hwmon_temp_offset:
+		ret = regmap_multi_reg_read(regmap, offset_regs, regdata, 2);
+		if (ret)
+			return ret;
+
+		if (!(regdata[0] & BIT(channel - 1)))
+			regdata[1] = 0;
+
+		*val = sign_extend32(regdata[1], 7) * 250;
+		break;
+	case hwmon_temp_fault:
+		ret = regmap_read(regmap, MAX6697_REG_STAT_FAULT, &regval);
+		if (ret)
+			return ret;
+		if (data->type == max6581)
+			*val = !!(regval & BIT(channel - 1));
+		else
+			*val = !!(regval & BIT(channel));
+		break;
+	case hwmon_temp_crit_alarm:
+		ret = regmap_read(regmap, MAX6697_REG_STAT_CRIT, &regval);
+		if (ret)
+			return ret;
+		/*
+		 * In the MAX6581 datasheet revision 0 to 3, the local channel
+		 * overtemperature status is reported in bit 6 of register 0x45,
+		 * and the overtemperature status for remote channel 7 is
+		 * reported in bit 7. In Revision 4 and later, the local channel
+		 * overtemperature status is reported in bit 7, and the remote
+		 * channel 7 overtemperature status is reported in bit 6. A real
+		 * chip was found to match the functionality documented in
+		 * Revision 4 and later.
+		 */
+		*val = !!(regval & BIT(channel ? channel - 1 : 7));
+		break;
+	case hwmon_temp_max_alarm:
+		ret = regmap_read(regmap, MAX6697_REG_STAT_ALARM, &regval);
+		if (ret)
+			return ret;
+		*val = !!(regval & BIT(max6697_alarm_channel_map(channel)));
+		break;
+	case hwmon_temp_min_alarm:
+		ret = regmap_read(regmap, MAX6697_REG_STAT_MIN_ALARM, &regval);
+		if (ret)
+			return ret;
+		*val = !!(regval & BIT(max6697_alarm_channel_map(channel)));
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int max6697_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	struct max6697_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	int ret;
+
+	switch (attr) {
+	case hwmon_temp_max:
+		val = clamp_val(val, -1000000, 1000000);	/* prevent underflow */
+		val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
+		val = clamp_val(val, 0, data->type == max6581 ? 255 : 127);
+		return regmap_write(regmap, MAX6697_REG_MAX[channel], val);
+	case hwmon_temp_crit:
+		val = clamp_val(val, -1000000, 1000000);	/* prevent underflow */
+		val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
+		val = clamp_val(val, 0, data->type == max6581 ? 255 : 127);
+		return regmap_write(regmap, MAX6697_REG_CRIT[channel], val);
+	case hwmon_temp_min:
+		val = clamp_val(val, -1000000, 1000000);	/* prevent underflow */
+		val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
+		val = clamp_val(val, 0, 255);
+		return regmap_write(regmap, MAX6697_REG_MIN, val);
+	case hwmon_temp_offset:
+		val = clamp_val(val, MAX6581_OFFSET_MIN, MAX6581_OFFSET_MAX);
+		val = DIV_ROUND_CLOSEST(val, 250);
+		if (!val) {	/* disable this (and only this) channel */
+			ret = regmap_clear_bits(regmap, MAX6581_REG_OFFSET_SELECT,
+						BIT(channel - 1));
+		} else {
+			/* enable channel and update offset */
+			ret = regmap_set_bits(regmap, MAX6581_REG_OFFSET_SELECT,
+					      BIT(channel - 1));
+			if (ret)
+				return ret;
+			ret = regmap_write(regmap, MAX6581_REG_OFFSET, val);
+		}
+		return ret;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t max6697_is_visible(const void *_data, enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	const struct max6697_data *data = _data;
+	const struct max6697_chip_data *chip = data->chip;
+
+	if (channel >= chip->channels)
+		return 0;
+
+	switch (attr) {
+	case hwmon_temp_max:
+		return 0644;
+	case hwmon_temp_input:
+	case hwmon_temp_max_alarm:
+		return 0444;
+	case hwmon_temp_min:
+		if (data->type == max6581)
+			return channel ? 0444 : 0644;
+		break;
+	case hwmon_temp_min_alarm:
+		if (data->type == max6581)
+			return 0444;
+		break;
+	case hwmon_temp_crit:
+		if (chip->have_crit & BIT(channel))
+			return 0644;
+		break;
+	case hwmon_temp_crit_alarm:
+		if (chip->have_crit & BIT(channel))
+			return 0444;
+		break;
+	case hwmon_temp_fault:
+		if (chip->have_fault & BIT(channel))
+			return 0444;
+		break;
+	case hwmon_temp_offset:
+		if (data->type == max6581 && channel)
+			return 0644;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static const struct hwmon_channel_info * const max6697_info[] = {
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET,
+			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_FAULT | HWMON_T_OFFSET),
+	NULL
+};
+
+static const struct hwmon_ops max6697_hwmon_ops = {
+	.is_visible = max6697_is_visible,
+	.read = max6697_read,
+	.write = max6697_write,
+};
+
+static const struct hwmon_chip_info max6697_chip_info = {
+	.ops = &max6697_hwmon_ops,
+	.info = max6697_info,
+};
+
+static int max6697_config_of(struct device_node *node, struct max6697_data *data)
+{
+	const struct max6697_chip_data *chip = data->chip;
+	struct regmap *regmap = data->regmap;
+	int ret, confreg;
+	u32 vals[2];
+
+	confreg = 0;
+	if (of_property_read_bool(node, "smbus-timeout-disable") &&
+	    (chip->valid_conf & MAX6697_CONF_TIMEOUT)) {
+		confreg |= MAX6697_CONF_TIMEOUT;
+	}
+	if (of_property_read_bool(node, "extended-range-enable") &&
+	    (chip->valid_conf & MAX6581_CONF_EXTENDED)) {
+		confreg |= MAX6581_CONF_EXTENDED;
+		data->temp_offset = 64;
+	}
+	if (of_property_read_bool(node, "beta-compensation-enable") &&
+	    (chip->valid_conf & MAX6693_CONF_BETA)) {
+		confreg |= MAX6693_CONF_BETA;
+	}
+
+	if (of_property_read_u32(node, "alert-mask", vals))
+		vals[0] = 0;
+	ret = regmap_write(regmap, MAX6697_REG_ALERT_MASK,
+			   MAX6697_ALERT_MAP_BITS(vals[0]));
+	if (ret)
+		return ret;
+
+	if (of_property_read_u32(node, "over-temperature-mask", vals))
+		vals[0] = 0;
+	ret = regmap_write(regmap, MAX6697_REG_OVERT_MASK,
+			   MAX6697_OVERT_MAP_BITS(vals[0]));
+	if (ret)
+		return ret;
+
+	if (data->type != max6581) {
+		if (of_property_read_bool(node, "resistance-cancellation") &&
+		    chip->valid_conf & MAX6697_CONF_RESISTANCE) {
+			confreg |= MAX6697_CONF_RESISTANCE;
+		}
+	} else {
+		if (of_property_read_u32(node, "resistance-cancellation", &vals[0])) {
+			if (of_property_read_bool(node, "resistance-cancellation"))
+				vals[0] = 0xfe;
+			else
+				vals[0] = 0;
+		}
+
+		vals[0] &= 0xfe;
+		ret = regmap_write(regmap, MAX6581_REG_RESISTANCE, vals[0] >> 1);
+		if (ret < 0)
+			return ret;
+
+		if (of_property_read_u32_array(node, "transistor-ideality", vals, 2)) {
+			vals[0] = 0;
+			vals[1] = 0;
+		}
+
+		ret = regmap_write(regmap, MAX6581_REG_IDEALITY, vals[1]);
+		if (ret < 0)
+			return ret;
+		ret = regmap_write(regmap, MAX6581_REG_IDEALITY_SELECT,
+				   (vals[0] & 0xfe) >> 1);
+		if (ret < 0)
+			return ret;
+	}
+	return regmap_write(regmap, MAX6697_REG_CONFIG, confreg);
+}
+
+static int max6697_init_chip(struct device_node *np, struct max6697_data *data)
+{
+	unsigned int reg;
+	int ret;
+
+	/*
+	 * Don't touch configuration if there is no devicetree configuration.
+	 * If that is the case, use the current chip configuration.
+	 */
+	if (!np) {
+		struct regmap *regmap = data->regmap;
+
+		ret = regmap_read(regmap, MAX6697_REG_CONFIG, &reg);
+		if (ret < 0)
+			return ret;
+		if (data->type == max6581) {
+			if (reg & MAX6581_CONF_EXTENDED)
+				data->temp_offset = 64;
+			ret = regmap_read(regmap, MAX6581_REG_RESISTANCE, &reg);
+		}
+	} else {
+		ret = max6697_config_of(np, data);
+	}
+
+	return ret;
+}
+
+static bool max6697_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case 0x00 ... 0x09:	/* temperature high bytes */
+	case 0x44 ... 0x47:	/* status */
+	case 0x51 ... 0x58:	/* temperature low bytes */
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool max6697_writeable_reg(struct device *dev, unsigned int reg)
+{
+	return reg != 0x0a && reg != 0x0f && !max6697_volatile_reg(dev, reg);
+}
+
+static const struct regmap_config max6697_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x58,
+	.writeable_reg = max6697_writeable_reg,
+	.volatile_reg = max6697_volatile_reg,
+	.cache_type = REGCACHE_MAPLE,
+};
+
+static int max6697_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct max6697_data *data;
+	struct device *hwmon_dev;
+	struct regmap *regmap;
+	int err;
+
+	regmap = devm_regmap_init_i2c(client, &max6697_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	data = devm_kzalloc(dev, sizeof(struct max6697_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->regmap = regmap;
+	data->type = (uintptr_t)i2c_get_match_data(client);
+	data->chip = &max6697_chip_data[data->type];
+
+	err = max6697_init_chip(client->dev.of_node, data);
+	if (err)
+		return err;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
+							 &max6697_chip_info, NULL);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id max6697_id[] = {
+	{ .name = "max6581", .driver_data = max6581 },
+	{ .name = "max6602", .driver_data = max6602 },
+	{ .name = "max6622", .driver_data = max6622 },
+	{ .name = "max6636", .driver_data = max6636 },
+	{ .name = "max6689", .driver_data = max6689 },
+	{ .name = "max6693", .driver_data = max6693 },
+	{ .name = "max6694", .driver_data = max6694 },
+	{ .name = "max6697", .driver_data = max6697 },
+	{ .name = "max6698", .driver_data = max6698 },
+	{ .name = "max6699", .driver_data = max6699 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max6697_id);
+
+static const struct of_device_id __maybe_unused max6697_of_match[] = {
+	{
+		.compatible = "maxim,max6581",
+		.data = (void *)max6581
+	},
+	{
+		.compatible = "maxim,max6602",
+		.data = (void *)max6602
+	},
+	{
+		.compatible = "maxim,max6622",
+		.data = (void *)max6622
+	},
+	{
+		.compatible = "maxim,max6636",
+		.data = (void *)max6636
+	},
+	{
+		.compatible = "maxim,max6689",
+		.data = (void *)max6689
+	},
+	{
+		.compatible = "maxim,max6693",
+		.data = (void *)max6693
+	},
+	{
+		.compatible = "maxim,max6694",
+		.data = (void *)max6694
+	},
+	{
+		.compatible = "maxim,max6697",
+		.data = (void *)max6697
+	},
+	{
+		.compatible = "maxim,max6698",
+		.data = (void *)max6698
+	},
+	{
+		.compatible = "maxim,max6699",
+		.data = (void *)max6699
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, max6697_of_match);
+
+static struct i2c_driver max6697_driver = {
+	.driver = {
+		.name	= "max6697",
+		.of_match_table = of_match_ptr(max6697_of_match),
+	},
+	.probe = max6697_probe,
+	.id_table = max6697_id,
+};
+
+module_i2c_driver(max6697_driver);
+
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("MAX6697 temperature sensor driver");
+MODULE_LICENSE("GPL");