Message-Id: <20210121134434.2782405-2-robert.marko@sartura.hr>
Date:   Thu, 21 Jan 2021 14:44:33 +0100
From:   Robert Marko <robert.marko@...tura.hr>
To:     jdelvare@...e.com, linux@...ck-us.net, robh+dt@...nel.org,
        linux-hwmon@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, corbet@....net,
        linux-doc@...r.kernel.org
Cc:     Robert Marko <robert.marko@...tura.hr>,
        Luka Perkov <luka.perkov@...tura.hr>
Subject: [PATCH v5 2/3] hwmon: add Texas Instruments TPS23861 driver

Add basic monitoring support as well as port on/off control for Texas
Instruments TPS23861 PoE PSE IC.

Signed-off-by: Robert Marko <robert.marko@...tura.hr>
Cc: Luka Perkov <luka.perkov@...tura.hr>
---
Changes in v4:
* Add documentation
* Correct of_property_read_u32() return check
* Drop useless and incorrect debugfs return check

Changes in v3:
* Leave only standard values in hwmon hwmon
* Drop custom sysfs entries
* Use debugfs to provide non standard debug information
* Add temperature label
* Use hwmon_in_enable to enable/disable ports

Changes in v2:
* Convert to devm_hwmon_device_register_with_info()
* Change license

 Documentation/hwmon/index.rst    |   1 +
 Documentation/hwmon/tps23861.rst |  41 +++
 drivers/hwmon/Kconfig            |  11 +
 drivers/hwmon/Makefile           |   1 +
 drivers/hwmon/tps23861.c         | 601 +++++++++++++++++++++++++++++++
 5 files changed, 655 insertions(+)
 create mode 100644 Documentation/hwmon/tps23861.rst
 create mode 100644 drivers/hwmon/tps23861.c

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index fcb870ce6286..2c94f0b524dd 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -178,6 +178,7 @@ Hardware Monitoring Kernel Drivers
    tmp401
    tmp421
    tmp513
+   tps23861
    tps40422
    tps53679
    twl4030-madc-hwmon
diff --git a/Documentation/hwmon/tps23861.rst b/Documentation/hwmon/tps23861.rst
new file mode 100644
index 000000000000..46d121ff3f31
--- /dev/null
+++ b/Documentation/hwmon/tps23861.rst
@@ -0,0 +1,41 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver tps23861
+======================
+
+Supported chips:
+  * Texas Instruments TPS23861
+
+    Prefix: 'tps23861'
+
+    Datasheet: https://www.ti.com/lit/gpn/tps23861
+
+Author: Robert Marko <robert.marko@...tura.hr>
+
+Description
+-----------
+
+This driver supports hardware monitoring for Texas Instruments TPS23861 PoE PSE.
+
+TPS23861 is a quad port IEEE802.3at PSE controller with optional I2C control
+and monitoring capabilities.
+
+TPS23861 offers three modes of operation: Auto, Semi-Auto and Manual.
+
+This driver only supports the Auto mode of operation providing monitoring
+as well as enabling/disabling the four ports.
+
+Sysfs entries
+-------------
+
+======================= =====================================================================
+in[0-3]_input		Voltage on ports [1-4]
+in[0-3]_label		"Port[1-4]"
+in4_input		IC input voltage
+in4_label		"Input"
+temp1_input		IC die temperature
+temp1_label		"Die"
+curr[1-4]_input		Current on ports [1-4]
+in[1-4]_label		"Port[1-4]"
+in[0-3]_enable		Enable/disable ports [1-4]
+======================= =====================================================================
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 1ecf697d8d99..e2a3aeed0628 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1136,6 +1136,17 @@ config SENSORS_TC654
 	  This driver can also be built as a module. If so, the module
 	  will be called tc654.
 
+config SENSORS_TPS23861
+	tristate "Texas Instruments TPS23861 PoE PSE"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for Texas Instruments
+	  TPS23861 802.3at PoE PSE chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called tps23861.
+
 config SENSORS_MENF21BMC_HWMON
 	tristate "MEN 14F021P00 BMC Hardware Monitoring"
 	depends on MFD_MENF21BMC
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 09a86c5e1d29..583ca5dbd838 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -144,6 +144,7 @@ obj-$(CONFIG_SENSORS_MAX31790)	+= max31790.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
 obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
 obj-$(CONFIG_SENSORS_TC654)	+= tc654.o
+obj-$(CONFIG_SENSORS_TPS23861)	+= tps23861.o
 obj-$(CONFIG_SENSORS_MLXREG_FAN) += mlxreg-fan.o
 obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
 obj-$(CONFIG_SENSORS_MR75203)	+= mr75203.o
diff --git a/drivers/hwmon/tps23861.c b/drivers/hwmon/tps23861.c
new file mode 100644
index 000000000000..c2484f15298b
--- /dev/null
+++ b/drivers/hwmon/tps23861.c
@@ -0,0 +1,601 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020 Sartura Ltd.
+ *
+ * Driver for the TI TPS23861 PoE PSE.
+ *
+ * Author: Robert Marko <robert.marko@...tura.hr>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#define TEMPERATURE			0x2c
+#define INPUT_VOLTAGE_LSB		0x2e
+#define INPUT_VOLTAGE_MSB		0x2f
+#define PORT_1_CURRENT_LSB		0x30
+#define PORT_1_CURRENT_MSB		0x31
+#define PORT_1_VOLTAGE_LSB		0x32
+#define PORT_1_VOLTAGE_MSB		0x33
+#define PORT_2_CURRENT_LSB		0x34
+#define PORT_2_CURRENT_MSB		0x35
+#define PORT_2_VOLTAGE_LSB		0x36
+#define PORT_2_VOLTAGE_MSB		0x37
+#define PORT_3_CURRENT_LSB		0x38
+#define PORT_3_CURRENT_MSB		0x39
+#define PORT_3_VOLTAGE_LSB		0x3a
+#define PORT_3_VOLTAGE_MSB		0x3b
+#define PORT_4_CURRENT_LSB		0x3c
+#define PORT_4_CURRENT_MSB		0x3d
+#define PORT_4_VOLTAGE_LSB		0x3e
+#define PORT_4_VOLTAGE_MSB		0x3f
+#define PORT_N_CURRENT_LSB_OFFSET	0x04
+#define PORT_N_VOLTAGE_LSB_OFFSET	0x04
+#define VOLTAGE_CURRENT_MASK		GENMASK(13, 0)
+#define PORT_1_RESISTANCE_LSB		0x60
+#define PORT_1_RESISTANCE_MSB		0x61
+#define PORT_2_RESISTANCE_LSB		0x62
+#define PORT_2_RESISTANCE_MSB		0x63
+#define PORT_3_RESISTANCE_LSB		0x64
+#define PORT_3_RESISTANCE_MSB		0x65
+#define PORT_4_RESISTANCE_LSB		0x66
+#define PORT_4_RESISTANCE_MSB		0x67
+#define PORT_N_RESISTANCE_LSB_OFFSET	0x02
+#define PORT_RESISTANCE_MASK		GENMASK(13, 0)
+#define PORT_RESISTANCE_RSN_MASK	GENMASK(15, 14)
+#define PORT_RESISTANCE_RSN_OTHER	0
+#define PORT_RESISTANCE_RSN_LOW		1
+#define PORT_RESISTANCE_RSN_OPEN	2
+#define PORT_RESISTANCE_RSN_SHORT	3
+#define PORT_1_STATUS			0x0c
+#define PORT_2_STATUS			0x0d
+#define PORT_3_STATUS			0x0e
+#define PORT_4_STATUS			0x0f
+#define PORT_STATUS_CLASS_MASK		GENMASK(7, 4)
+#define PORT_STATUS_DETECT_MASK		GENMASK(3, 0)
+#define PORT_CLASS_UNKNOWN		0
+#define PORT_CLASS_1			1
+#define PORT_CLASS_2			2
+#define PORT_CLASS_3			3
+#define PORT_CLASS_4			4
+#define PORT_CLASS_RESERVED		5
+#define PORT_CLASS_0			6
+#define PORT_CLASS_OVERCURRENT		7
+#define PORT_CLASS_MISMATCH		8
+#define PORT_DETECT_UNKNOWN		0
+#define PORT_DETECT_SHORT		1
+#define PORT_DETECT_RESERVED		2
+#define PORT_DETECT_RESISTANCE_LOW	3
+#define PORT_DETECT_RESISTANCE_OK	4
+#define PORT_DETECT_RESISTANCE_HIGH	5
+#define PORT_DETECT_OPEN_CIRCUIT	6
+#define PORT_DETECT_RESERVED_2		7
+#define PORT_DETECT_MOSFET_FAULT	8
+#define PORT_DETECT_LEGACY		9
+/* Measurment beyond clamp voltage */
+#define PORT_DETECT_CAPACITANCE_INVALID_BEYOND	10
+/* Insufficient voltage delta */
+#define PORT_DETECT_CAPACITANCE_INVALID_DELTA	11
+#define PORT_DETECT_CAPACITANCE_OUT_OF_RANGE	12
+#define POE_PLUS			0x40
+#define OPERATING_MODE			0x12
+#define OPERATING_MODE_OFF		0
+#define OPERATING_MODE_MANUAL		1
+#define OPERATING_MODE_SEMI		2
+#define OPERATING_MODE_AUTO		3
+#define OPERATING_MODE_PORT_1_MASK	GENMASK(1, 0)
+#define OPERATING_MODE_PORT_2_MASK	GENMASK(3, 2)
+#define OPERATING_MODE_PORT_3_MASK	GENMASK(5, 4)
+#define OPERATING_MODE_PORT_4_MASK	GENMASK(7, 6)
+
+#define DETECT_CLASS_RESTART		0x18
+#define POWER_ENABLE			0x19
+#define TPS23861_NUM_PORTS		4
+
+#define TEMPERATURE_LSB			652 /* 0.652 degrees Celsius */
+#define VOLTAGE_LSB			3662 /* 3.662 mV */
+#define SHUNT_RESISTOR_DEFAULT		255000 /* 255 mOhm */
+#define CURRENT_LSB_255			62260 /* 62.260 uA */
+#define CURRENT_LSB_250			61039 /* 61.039 uA */
+#define RESISTANCE_LSB			110966 /* 11.0966 Ohm*/
+#define RESISTANCE_LSB_LOW		157216 /* 15.7216 Ohm*/
+
+struct tps23861_data {
+	struct regmap *regmap;
+	u32 shunt_resistor;
+	struct i2c_client *client;
+	struct dentry *debugfs_dir;
+};
+
+static struct regmap_config tps23861_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int tps23861_read_temp(struct tps23861_data *data, long *val)
+{
+	unsigned int regval;
+	int err;
+
+	err = regmap_read(data->regmap, TEMPERATURE, &regval);
+	if (err < 0)
+		return err;
+
+	*val = (regval * TEMPERATURE_LSB) - 20000;
+
+	return 0;
+}
+
+static int tps23861_read_voltage(struct tps23861_data *data, int channel,
+				 long *val)
+{
+	unsigned int regval;
+	int err;
+
+	if (channel < TPS23861_NUM_PORTS) {
+		err = regmap_bulk_read(data->regmap,
+				       PORT_1_VOLTAGE_LSB + channel * PORT_N_VOLTAGE_LSB_OFFSET,
+				       &regval, 2);
+	} else {
+		err = regmap_bulk_read(data->regmap,
+				       INPUT_VOLTAGE_LSB,
+				       &regval, 2);
+	}
+	if (err < 0)
+		return err;
+
+	*val = (FIELD_GET(VOLTAGE_CURRENT_MASK, regval) * VOLTAGE_LSB) / 1000;
+
+	return 0;
+}
+
+static int tps23861_read_current(struct tps23861_data *data, int channel,
+				 long *val)
+{
+	unsigned int current_lsb;
+	unsigned int regval;
+	int err;
+
+	if (data->shunt_resistor == SHUNT_RESISTOR_DEFAULT)
+		current_lsb = CURRENT_LSB_255;
+	else
+		current_lsb = CURRENT_LSB_250;
+
+	err = regmap_bulk_read(data->regmap,
+			       PORT_1_CURRENT_LSB + channel * PORT_N_CURRENT_LSB_OFFSET,
+			       &regval, 2);
+	if (err < 0)
+		return err;
+
+	*val = (FIELD_GET(VOLTAGE_CURRENT_MASK, regval) * current_lsb) / 1000000;
+
+	return 0;
+}
+
+static int tps23861_port_disable(struct tps23861_data *data, int channel)
+{
+	unsigned int regval = 0;
+	int err;
+
+	regval |= BIT(channel + 4);
+	err = regmap_write(data->regmap, POWER_ENABLE, regval);
+
+	return err;
+}
+
+static int tps23861_port_enable(struct tps23861_data *data, int channel)
+{
+	unsigned int regval = 0;
+	int err;
+
+	regval |= BIT(channel);
+	regval |= BIT(channel + 4);
+	err = regmap_write(data->regmap, DETECT_CLASS_RESTART, regval);
+
+	return err;
+}
+
+static umode_t tps23861_is_visible(const void *data, enum hwmon_sensor_types type,
+				   u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+		case hwmon_temp_label:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+		case hwmon_in_label:
+			return 0444;
+		case hwmon_in_enable:
+			return 0200;
+		default:
+			return 0;
+		}
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+		case hwmon_curr_label:
+			return 0444;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static int tps23861_write(struct device *dev, enum hwmon_sensor_types type,
+			  u32 attr, int channel, long val)
+{
+	struct tps23861_data *data = dev_get_drvdata(dev);
+	int err;
+
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_enable:
+			if (val == 0)
+				err = tps23861_port_disable(data, channel);
+			else if (val == 1)
+				err = tps23861_port_enable(data, channel);
+			else
+				err = -EINVAL;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return err;
+}
+
+static int tps23861_read(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long *val)
+{
+	struct tps23861_data *data = dev_get_drvdata(dev);
+	int err;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+			err = tps23861_read_temp(data, val);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_input:
+			err = tps23861_read_voltage(data, channel, val);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+			err = tps23861_read_current(data, channel, val);
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return err;
+}
+
+static const char * const tps23861_port_label[] = {
+	"Port1",
+	"Port2",
+	"Port3",
+	"Port4",
+	"Input",
+};
+
+static int tps23861_read_string(struct device *dev,
+				enum hwmon_sensor_types type,
+				u32 attr, int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_in:
+	case hwmon_curr:
+		*str = tps23861_port_label[channel];
+		break;
+	case hwmon_temp:
+		*str = "Die";
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_channel_info *tps23861_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_ENABLE | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL),
+	HWMON_CHANNEL_INFO(curr,
+			   HWMON_C_INPUT | HWMON_C_LABEL,
+			   HWMON_C_INPUT | HWMON_C_LABEL,
+			   HWMON_C_INPUT | HWMON_C_LABEL,
+			   HWMON_C_INPUT | HWMON_C_LABEL),
+	NULL
+};
+
+static const struct hwmon_ops tps23861_hwmon_ops = {
+	.is_visible = tps23861_is_visible,
+	.write = tps23861_write,
+	.read = tps23861_read,
+	.read_string = tps23861_read_string,
+};
+
+static const struct hwmon_chip_info tps23861_chip_info = {
+	.ops = &tps23861_hwmon_ops,
+	.info = tps23861_info,
+};
+
+static char *tps23861_port_operating_mode(struct tps23861_data *data, int port)
+{
+	unsigned int regval;
+	int mode;
+
+	regmap_read(data->regmap, OPERATING_MODE, &regval);
+
+	switch (port) {
+	case 1:
+		mode = FIELD_GET(OPERATING_MODE_PORT_1_MASK, regval);
+		break;
+	case 2:
+		mode = FIELD_GET(OPERATING_MODE_PORT_2_MASK, regval);
+		break;
+	case 3:
+		mode = FIELD_GET(OPERATING_MODE_PORT_3_MASK, regval);
+		break;
+	case 4:
+		mode = FIELD_GET(OPERATING_MODE_PORT_4_MASK, regval);
+		break;
+	default:
+		mode = -EINVAL;
+	}
+
+	switch (mode) {
+	case OPERATING_MODE_OFF:
+		return "Off";
+	case OPERATING_MODE_MANUAL:
+		return "Manual";
+	case OPERATING_MODE_SEMI:
+		return "Semi-Auto";
+	case OPERATING_MODE_AUTO:
+		return "Auto";
+	default:
+		return "Invalid";
+	}
+}
+
+static char *tps23861_port_detect_status(struct tps23861_data *data, int port)
+{
+	unsigned int regval;
+
+	regmap_read(data->regmap,
+		    PORT_1_STATUS + (port - 1),
+		    &regval);
+
+	switch (FIELD_GET(PORT_STATUS_DETECT_MASK, regval)) {
+	case PORT_DETECT_UNKNOWN:
+		return "Unknown device";
+	case PORT_DETECT_SHORT:
+		return "Short circuit";
+	case PORT_DETECT_RESISTANCE_LOW:
+		return "Too low resistance";
+	case PORT_DETECT_RESISTANCE_OK:
+		return "Valid resistance";
+	case PORT_DETECT_RESISTANCE_HIGH:
+		return "Too high resistance";
+	case PORT_DETECT_OPEN_CIRCUIT:
+		return "Open circuit";
+	case PORT_DETECT_MOSFET_FAULT:
+		return "MOSFET fault";
+	case PORT_DETECT_LEGACY:
+		return "Legacy device";
+	case PORT_DETECT_CAPACITANCE_INVALID_BEYOND:
+		return "Invalid capacitance, beyond clamp voltage";
+	case PORT_DETECT_CAPACITANCE_INVALID_DELTA:
+		return "Invalid capacitance, insufficient voltage delta";
+	case PORT_DETECT_CAPACITANCE_OUT_OF_RANGE:
+		return "Valid capacitance, outside of legacy range";
+	case PORT_DETECT_RESERVED:
+	case PORT_DETECT_RESERVED_2:
+	default:
+		return "Invalid";
+	}
+}
+
+static char *tps23861_port_class_status(struct tps23861_data *data, int port)
+{
+	unsigned int regval;
+
+	regmap_read(data->regmap,
+		    PORT_1_STATUS + (port - 1),
+		    &regval);
+
+	switch (FIELD_GET(PORT_STATUS_CLASS_MASK, regval)) {
+	case PORT_CLASS_UNKNOWN:
+		return "Unknown";
+	case PORT_CLASS_RESERVED:
+	case PORT_CLASS_0:
+		return "0";
+	case PORT_CLASS_1:
+		return "1";
+	case PORT_CLASS_2:
+		return "2";
+	case PORT_CLASS_3:
+		return "3";
+	case PORT_CLASS_4:
+		return "4";
+	case PORT_CLASS_OVERCURRENT:
+		return "Overcurrent";
+	case PORT_CLASS_MISMATCH:
+		return "Mismatch";
+	default:
+		return "Invalid";
+	}
+}
+
+static char *tps23861_port_poe_plus_status(struct tps23861_data *data, int port)
+{
+	unsigned int regval;
+
+	regmap_read(data->regmap, POE_PLUS, &regval);
+
+	if (BIT(port + 3) & regval)
+		return "Yes";
+	else
+		return "No";
+}
+
+static int tps23861_port_resistance(struct tps23861_data *data, int port)
+{
+	u16 regval;
+
+	regmap_bulk_read(data->regmap,
+			 PORT_1_RESISTANCE_LSB + PORT_N_RESISTANCE_LSB_OFFSET * (port - 1),
+			 &regval,
+			 2);
+
+	switch (FIELD_GET(PORT_RESISTANCE_RSN_MASK, regval)) {
+	case PORT_RESISTANCE_RSN_OTHER:
+		return (FIELD_GET(PORT_RESISTANCE_MASK, regval) * RESISTANCE_LSB) / 10000;
+	case PORT_RESISTANCE_RSN_LOW:
+		return (FIELD_GET(PORT_RESISTANCE_MASK, regval) * RESISTANCE_LSB_LOW) / 10000;
+	case PORT_RESISTANCE_RSN_SHORT:
+	case PORT_RESISTANCE_RSN_OPEN:
+	default:
+		return 0;
+	}
+}
+
+static int tps23861_port_status_show(struct seq_file *s, void *data)
+{
+	struct tps23861_data *priv = s->private;
+	int i;
+
+	for (i = 1; i < TPS23861_NUM_PORTS + 1; i++) {
+		seq_printf(s, "Port: \t\t%d\n", i);
+		seq_printf(s, "Operating mode: %s\n", tps23861_port_operating_mode(priv, i));
+		seq_printf(s, "Detected: \t%s\n", tps23861_port_detect_status(priv, i));
+		seq_printf(s, "Class: \t\t%s\n", tps23861_port_class_status(priv, i));
+		seq_printf(s, "PoE Plus: \t%s\n", tps23861_port_poe_plus_status(priv, i));
+		seq_printf(s, "Resistance: \t%d\n", tps23861_port_resistance(priv, i));
+		seq_putc(s, '\n');
+	}
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(tps23861_port_status);
+
+static void tps23861_init_debugfs(struct tps23861_data *data)
+{
+	data->debugfs_dir = debugfs_create_dir(data->client->name, NULL);
+
+	debugfs_create_file("port_status",
+			    0400,
+			    data->debugfs_dir,
+			    data,
+			    &tps23861_port_status_fops);
+}
+
+static int tps23861_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct tps23861_data *data;
+	struct device *hwmon_dev;
+	u32 shunt_resistor;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	i2c_set_clientdata(client, data);
+
+	data->regmap = devm_regmap_init_i2c(client, &tps23861_regmap_config);
+	if (IS_ERR(data->regmap)) {
+		dev_err(dev, "failed to allocate register map\n");
+		return PTR_ERR(data->regmap);
+	}
+
+	if (!of_property_read_u32(dev->of_node, "shunt-resistor-micro-ohms", &shunt_resistor))
+		data->shunt_resistor = shunt_resistor;
+	else
+		data->shunt_resistor = SHUNT_RESISTOR_DEFAULT;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data, &tps23861_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	tps23861_init_debugfs(data);
+
+	return 0;
+}
+
+static int tps23861_remove(struct i2c_client *client)
+{
+	struct tps23861_data *data = i2c_get_clientdata(client);
+
+	debugfs_remove_recursive(data->debugfs_dir);
+
+	return 0;
+}
+
+static const struct of_device_id __maybe_unused tps23861_of_match[] = {
+	{ .compatible = "ti,tps23861", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, tps23861_of_match);
+
+static struct i2c_driver tps23861_driver = {
+	.probe_new		= tps23861_probe,
+	.remove			= tps23861_remove,
+	.driver = {
+		.name		= "tps23861",
+		.of_match_table	= of_match_ptr(tps23861_of_match),
+	},
+};
+module_i2c_driver(tps23861_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Marko <robert.marko@...tura.hr>");
+MODULE_DESCRIPTION("TI TPS23861 PoE PSE");
-- 
2.29.2

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