[PATCH v3 2/2] hwmon: Add driver for Texas Instruments TMP464 and TMP468

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Add support for Texas Instruments TMP464 and TMP468 temperature sensor
ICs.

TI's TMP464 is an I2C temperature sensor chip. This chip is
similar to TI's TMP421 chip, but with 16bit-wide registers (instead
of 8bit-wide registers). The chip has one local sensor and four
remote sensors. TMP468 is similar to TMP464 but has one local and
eight remote sensors.

Originally-from: Agathe Porte <agathe.porte@xxxxxxxxx>
Cc: Agathe Porte <agathe.porte@xxxxxxxxx>
Cc: Krzysztof Adamski <krzysztof.adamski@xxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v3:
- Added support for TMP468
- Added support for various limits, temperature hysteresis, alarm attributes,
  and update interval
- Use regmap instead of local caching
- Use static chip configuration
- Unlock check if needed when loading driver, and lock it when unloading it
  - Call tmp464_init_client() before calling tmp464_probe_from_dt()
    since the latter changes registers, which requires the chip to be
    unlocked.
- Restore configuration register when unloading driver
- ti,n-factor is optional, so don't fail if the property is not present

Notes:
- Tested with real TMP468. Module tested for TMP464.
- I was not able to test with a system supporting devicetree;
  especially negative values for "ti,n-factor" need testing
  (and I wonder if of_property_read_s8() would be needed to
   support this properly).

 Documentation/hwmon/index.rst  |   1 +
 Documentation/hwmon/tmp464.rst |  73 ++++
 MAINTAINERS                    |   2 +
 drivers/hwmon/Kconfig          |  11 +
 drivers/hwmon/Makefile         |   1 +
 drivers/hwmon/tmp464.c         | 693 +++++++++++++++++++++++++++++++++
 6 files changed, 781 insertions(+)
 create mode 100644 Documentation/hwmon/tmp464.rst
 create mode 100644 drivers/hwmon/tmp464.c

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index df20022c741f..37590db85e65 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -193,6 +193,7 @@ Hardware Monitoring Kernel Drivers
    tmp108
    tmp401
    tmp421
+   tmp464
    tmp513
    tps23861
    tps40422
diff --git a/Documentation/hwmon/tmp464.rst b/Documentation/hwmon/tmp464.rst
new file mode 100644
index 000000000000..7596e7623d06
--- /dev/null
+++ b/Documentation/hwmon/tmp464.rst
@@ -0,0 +1,73 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver tmp464
+====================
+
+Supported chips:
+
+  * Texas Instruments TMP464
+
+    Prefix: 'tmp464'
+
+    Addresses scanned: I2C 0x48, 0x49, 0x4a and 0x4b
+
+    Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp464.html
+
+  * Texas Instruments TMP468
+
+    Prefix: 'tmp468'
+
+    Addresses scanned: I2C 0x48, 0x49, 0x4a and 0x4b
+
+    Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp468.html
+
+Authors:
+
+	Agathe Porte <agathe.porte@xxxxxxxxx>
+	Guenter Roeck <linux@xxxxxxxxxxxx>
+
+Description
+-----------
+
+This driver implements support for Texas Instruments TMP464 and TMP468
+temperature sensor chips. TMP464 provides one local and four remote
+sensors. TMP468 provides one local and eight remote sensors.
+Temperature is measured in degrees Celsius. The chips are wired over
+I2C/SMBus and specified over a temperature range of -40 to +125 degrees
+Celsius. Resolution for both the local and remote channels is 0.0625
+degree C.
+
+The chips support only temperature measurements. The driver exports
+temperature values, limits, and alarms via the following sysfs files:
+
+**temp[1-9]_input**
+
+**temp[1-9]_max**
+
+**temp[1-9]_max_hyst**
+
+**temp[1-9]_max_alarm**
+
+**temp[1-9]_crit**
+
+**temp[1-9]_crit_alarm**
+
+**temp[1-9]_crit_hyst**
+
+**temp[2-9]_offset**
+
+**temp[2-9]_fault**
+
+Each sensor can be individually disabled via Devicetree or from sysfs
+via:
+
+**temp[1-9]_enable**
+
+If labels were specified in Devicetree, additional sysfs files will
+be present:
+
+**temp[1-9]_label**
+
+The update interval is configurable with the following sysfs attribute.
+
+**update_interval**
diff --git a/MAINTAINERS b/MAINTAINERS
index f51bc7c7e439..9b51bf5ca3b8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19495,6 +19495,8 @@ M:	Guenter Roeck <linux@xxxxxxxxxxxx>
 L:	linux-hwmon@xxxxxxxxxxxxxxx
 S:	Maintained
 F:	Documentation/devicetree/bindings/hwmon/ti,tmp464.yaml
+F:	Documentation/hwmon/tmp464.rst
+F:	drivers/hwmon/tmp464.c
 
 TMP513 HARDWARE MONITOR DRIVER
 M:	Eric Tremblay <etremblay@xxxxxxxxxxxxxxxxxxxx>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 8df25f1079ba..b84932fd0c13 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1979,6 +1979,17 @@ config SENSORS_TMP421
 	  This driver can also be built as a module. If so, the module
 	  will be called tmp421.
 
+config SENSORS_TMP464
+	tristate "Texas Instruments TMP464 and compatible"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for Texas Instruments TMP464
+	  and TMP468 temperature sensor chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called tmp464.
+
 config SENSORS_TMP513
 	tristate "Texas Instruments TMP513 and compatibles"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 185f946d698b..a1f2d6686227 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -194,6 +194,7 @@ obj-$(CONFIG_SENSORS_TMP103)	+= tmp103.o
 obj-$(CONFIG_SENSORS_TMP108)	+= tmp108.o
 obj-$(CONFIG_SENSORS_TMP401)	+= tmp401.o
 obj-$(CONFIG_SENSORS_TMP421)	+= tmp421.o
+obj-$(CONFIG_SENSORS_TMP464)	+= tmp464.o
 obj-$(CONFIG_SENSORS_TMP513)	+= tmp513.o
 obj-$(CONFIG_SENSORS_VEXPRESS)	+= vexpress-hwmon.o
 obj-$(CONFIG_SENSORS_VIA_CPUTEMP)+= via-cputemp.o
diff --git a/drivers/hwmon/tmp464.c b/drivers/hwmon/tmp464.c
new file mode 100644
index 000000000000..098c53c65393
--- /dev/null
+++ b/drivers/hwmon/tmp464.c
@@ -0,0 +1,693 @@
+// 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@xxxxxxxxx>
+ * Preliminary support by:
+ * Lionel Pouliquen <lionel.lp.pouliquen@xxxxxxxxx>
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.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[] = {
+	{ "tmp464", TMP464_NUM_CHANNELS },
+	{ "tmp468", 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;
+	struct mutex update_lock;
+	int channels;
+	s16 config_orig;
+	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);
+	struct regmap *regmap = data->regmap;
+	unsigned int status;
+	int err;
+
+	switch (attr) {
+	case hwmon_chip_update_interval:
+		err = regmap_read(regmap, TMP464_CONFIG_REG, &status);
+		if (err)
+			return err;
+		status = (status & TMP464_CONFIG_CONVERSION_RATE_MASK) >>
+					TMP464_CONFIG_CONVERSION_RATE_B0;
+		*val = 125 << (7 - status);
+		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 regval, regval2;
+	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:
+		err = regmap_read(regmap, TMP464_REMOTE_OPEN_REG, &regval);
+		if (err < 0)
+			break;
+		*val = !!(regval & BIT(channel + 7));
+		break;
+	case hwmon_temp_max_hyst:
+		mutex_lock(&data->update_lock);
+		err = regmap_read(regmap, TMP464_THERM_LIMIT[channel], &regval);
+		if (err < 0)
+			goto unlock_max;
+		err = regmap_read(regmap, TMP464_TEMP_HYST_REG, &regval2);
+		if (err < 0)
+			goto unlock_max;
+		regval -= regval2;
+		*val = temp_from_reg(regval);
+unlock_max:
+		mutex_unlock(&data->update_lock);
+		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:
+		mutex_lock(&data->update_lock);
+		err = regmap_read(regmap, TMP464_THERM2_LIMIT[channel], &regval);
+		if (err < 0)
+			goto unlock_crit;
+		err = regmap_read(regmap, TMP464_TEMP_HYST_REG, &regval2);
+		if (err < 0)
+			goto unlock_crit;
+		regval -= regval2;
+		*val = temp_from_reg(regval);
+unlock_crit:
+		mutex_unlock(&data->update_lock);
+		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)
+			return -ENODATA;
+		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:
+		return -EOPNOTSUPP;
+	}
+	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 regmap *regmap, 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));
+
+	return regmap_update_bits(regmap, TMP464_CONFIG_REG,
+				  TMP464_CONFIG_CONVERSION_RATE_MASK,
+				  rate << TMP464_CONFIG_CONVERSION_RATE_B0);
+}
+
+static int tmp464_chip_write(struct device *dev, u32 attr, int channel, long val)
+{
+	struct tmp464_data *data = dev_get_drvdata(dev);
+
+	switch (attr) {
+	case hwmon_chip_update_interval:
+		return tmp464_set_convrate(data->regmap, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int tmp464_temp_write(struct device *dev, u32 attr, int channel, long val)
+{
+	struct tmp464_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	unsigned int regval;
+	int err = 0;
+
+	switch (attr) {
+	case hwmon_temp_max_hyst:
+		mutex_lock(&data->update_lock);
+		err = regmap_read(regmap, TMP464_THERM_LIMIT[0], &regval);
+		if (err < 0)
+			goto unlock;
+		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);
+unlock:
+		mutex_unlock(&data->update_lock);
+		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:
+		mutex_lock(&data->update_lock);
+		data->channel[channel].enabled = !!val;
+		err = tmp464_enable_channels(data);
+		mutex_unlock(&data->update_lock);
+		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)
+{
+	switch (type) {
+	case hwmon_chip:
+		return tmp464_chip_write(dev, attr, channel, val);
+	case hwmon_temp:
+		return tmp464_temp_write(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+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;
+
+	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 val;
+	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", &val);
+	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 (val > 127 || val < -128) {
+			dev_err(dev, "n-factor for channel %d invalid (%d)\n",
+				channel, val);
+			return -EINVAL;
+		}
+		err = regmap_write(regmap, TMP464_N_FACTOR_REG(channel), val);
+		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;
+	struct device_node *child;
+	int err;
+
+	for_each_child_of_node(np, child) {
+		if (strcmp(child->name, "channel"))
+			continue;
+
+		err = tmp464_probe_child_from_dt(dev, child, data);
+		if (err) {
+			of_node_put(child);
+			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 *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_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_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_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_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_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_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_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_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),
+	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_RBTREE,
+	.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;
+
+	mutex_init(&data->update_lock);
+
+	if (dev->of_node)
+		data->channels = (int)(unsigned long)of_device_get_match_data(&client->dev);
+	else
+		data->channels = i2c_match_id(tmp464_id, client)->driver_data;
+
+	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_new = tmp464_probe,
+	.id_table = tmp464_id,
+	.detect = tmp464_detect,
+	.address_list = normal_i2c,
+};
+
+module_i2c_driver(tmp464_driver);
+
+MODULE_AUTHOR("Agathe Porte <agathe.porte@xxxxxxxxx>");
+MODULE_DESCRIPTION("Texas Instruments TMP464 temperature sensor driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1




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