[PATCH 4/6] hwmon: Add Delta TN48M CPLD HWMON driver

[Robert Marko <robert.marko@sartura.hr>]

Delta TN48M has a CPLD that also monitors the power supply
statuses.

These are useful to be presented to the users, so lets
add a driver for HWMON part of the CPLD.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
---
 drivers/hwmon/Kconfig       |  10 +++
 drivers/hwmon/Makefile      |   1 +
 drivers/hwmon/tn48m-hwmon.c | 148 ++++++++++++++++++++++++++++++++++++
 drivers/mfd/tn48m-cpld.c    |   3 +
 include/linux/mfd/tn48m.h   |   1 +
 5 files changed, 163 insertions(+)
 create mode 100644 drivers/hwmon/tn48m-hwmon.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 54f04e61fb83..89271dfeb775 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1924,6 +1924,16 @@ config SENSORS_TMP513
 	  This driver can also be built as a module. If so, the module
 	  will be called tmp513.
 
+config SENSORS_TN48M
+	tristate "Delta Networks TN48M switch CPLD HWMON driver"
+	depends on MFD_TN48M_CPLD
+	help
+	  If you say yes here you get support for Delta Networks TN48M
+	  CPLD.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called tn48m-hwmon.
+
 config SENSORS_VEXPRESS
 	tristate "Versatile Express"
 	depends on VEXPRESS_CONFIG
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index fe38e8a5c979..22e470057ffe 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -187,6 +187,7 @@ obj-$(CONFIG_SENSORS_TMP108)	+= tmp108.o
 obj-$(CONFIG_SENSORS_TMP401)	+= tmp401.o
 obj-$(CONFIG_SENSORS_TMP421)	+= tmp421.o
 obj-$(CONFIG_SENSORS_TMP513)	+= tmp513.o
+obj-$(CONFIG_SENSORS_TN48M)	+= tn48m-hwmon.o
 obj-$(CONFIG_SENSORS_VEXPRESS)	+= vexpress-hwmon.o
 obj-$(CONFIG_SENSORS_VIA_CPUTEMP)+= via-cputemp.o
 obj-$(CONFIG_SENSORS_VIA686A)	+= via686a.o
diff --git a/drivers/hwmon/tn48m-hwmon.c b/drivers/hwmon/tn48m-hwmon.c
new file mode 100644
index 000000000000..80fd18d74f1d
--- /dev/null
+++ b/drivers/hwmon/tn48m-hwmon.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Delta TN48M CPLD HWMON driver
+ *
+ * Copyright 2020 Sartura Ltd
+ *
+ * Author: Robert Marko <robert.marko@sartura.hr>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/tn48m.h>
+
+#define PSU1_PRESENT_MASK	BIT(0)
+#define PSU2_PRESENT_MASK	BIT(1)
+#define PSU1_POWERGOOD_MASK	BIT(2)
+#define PSU2_POWERGOOD_MASK	BIT(3)
+#define PSU1_ALERT_MASK		BIT(4)
+#define PSU2_ALERT_MASK		BIT(5)
+
+static int board_id_get(struct tn48m_data *data)
+{
+	unsigned int regval;
+
+	regmap_read(data->regmap, BOARD_ID, &regval);
+
+	switch (regval) {
+	case BOARD_ID_TN48M:
+		return BOARD_ID_TN48M;
+	case BOARD_ID_TN48M_P:
+		return BOARD_ID_TN48M_P;
+	default:
+		return -EINVAL;
+	}
+}
+
+static ssize_t psu_present_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
+	struct tn48m_data *data = dev_get_drvdata(dev);
+	unsigned int regval, status;
+
+	if (board_id_get(data) == BOARD_ID_TN48M_P) {
+		regmap_read(data->regmap, attr2->nr, &regval);
+
+		if (attr2->index == 1)
+			status = !FIELD_GET(PSU1_PRESENT_MASK, regval);
+		else
+			status = !FIELD_GET(PSU2_PRESENT_MASK, regval);
+	} else
+		status = 0;
+
+	return sprintf(buf, "%d\n", status);
+}
+
+static ssize_t psu_pg_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
+	struct tn48m_data *data = dev_get_drvdata(dev);
+	unsigned int regval, status;
+
+	regmap_read(data->regmap, attr2->nr, &regval);
+
+	if (attr2->index == 1)
+		status = FIELD_GET(PSU1_POWERGOOD_MASK, regval);
+	else
+		status = FIELD_GET(PSU2_POWERGOOD_MASK, regval);
+
+	return sprintf(buf, "%d\n", status);
+}
+
+static ssize_t psu_alert_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
+	struct tn48m_data *data = dev_get_drvdata(dev);
+	unsigned int regval, status;
+
+	if (board_id_get(data) == BOARD_ID_TN48M_P) {
+		regmap_read(data->regmap, attr2->nr, &regval);
+
+		if (attr2->index == 1)
+			status = !FIELD_GET(PSU1_ALERT_MASK, regval);
+		else
+			status = !FIELD_GET(PSU2_ALERT_MASK, regval);
+	} else
+		status = 0;
+
+	return sprintf(buf, "%d\n", status);
+}
+
+static SENSOR_DEVICE_ATTR_2_RO(psu1_present, psu_present, PSU_STATUS, 1);
+static SENSOR_DEVICE_ATTR_2_RO(psu2_present, psu_present, PSU_STATUS, 2);
+static SENSOR_DEVICE_ATTR_2_RO(psu1_pg, psu_pg, PSU_STATUS, 1);
+static SENSOR_DEVICE_ATTR_2_RO(psu2_pg, psu_pg, PSU_STATUS, 2);
+static SENSOR_DEVICE_ATTR_2_RO(psu1_alert, psu_alert, PSU_STATUS, 1);
+static SENSOR_DEVICE_ATTR_2_RO(psu2_alert, psu_alert, PSU_STATUS, 2);
+
+static struct attribute *tn48m_hwmon_attrs[] = {
+	&sensor_dev_attr_psu1_present.dev_attr.attr,
+	&sensor_dev_attr_psu2_present.dev_attr.attr,
+	&sensor_dev_attr_psu1_pg.dev_attr.attr,
+	&sensor_dev_attr_psu2_pg.dev_attr.attr,
+	&sensor_dev_attr_psu1_alert.dev_attr.attr,
+	&sensor_dev_attr_psu2_alert.dev_attr.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(tn48m_hwmon);
+
+static int tn48m_hwmon_probe(struct platform_device *pdev)
+{
+	struct tn48m_data *data = dev_get_drvdata(pdev->dev.parent);
+	struct device *hwmon_dev;
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev,
+							   "tn48m_hwmon",
+							   data,
+							   tn48m_hwmon_groups);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct platform_device_id tn48m_hwmon_id_table[] = {
+	{ "delta,tn48m-hwmon", },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, tn48m_hwmon_id_table);
+
+static struct platform_driver tn48m_hwmon_driver = {
+	.driver = {
+		.name = "tn48m-hwmon",
+	},
+	.probe = tn48m_hwmon_probe,
+	.id_table = tn48m_hwmon_id_table,
+};
+module_platform_driver(tn48m_hwmon_driver);
+
+MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
+MODULE_DESCRIPTION("Delta TN48M CPLD HWMON driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mfd/tn48m-cpld.c b/drivers/mfd/tn48m-cpld.c
index f22a15ddd22d..4d837aca01e7 100644
--- a/drivers/mfd/tn48m-cpld.c
+++ b/drivers/mfd/tn48m-cpld.c
@@ -20,6 +20,9 @@
 static const struct mfd_cell tn48m_cell[] = {
 	{
 		.name = "delta,tn48m-gpio",
+	},
+	{
+		.name = "delta,tn48m-hwmon",
 	}
 };
 
diff --git a/include/linux/mfd/tn48m.h b/include/linux/mfd/tn48m.h
index 9cc2b04c8d69..eb2cfc3a5db7 100644
--- a/include/linux/mfd/tn48m.h
+++ b/include/linux/mfd/tn48m.h
@@ -22,6 +22,7 @@
 #define SFP_TX_DISABLE		0x31
 #define SFP_PRESENT		0x3a
 #define SFP_LOS			0x40
+#define PSU_STATUS		0xa
 
 struct tn48m_data {
 	struct device *dev;
-- 
2.31.1