[PATCH v4 3/4] hwmon: smpro: Add Ampere's Altra smpro-hwmon driver

[Quan Nguyen <quan@os.amperecomputing.com>]

This commit adds support for Ampere SMpro hwmon driver. This driver
supports accessing various CPU sensors provided by the SMpro co-processor
including temperature, power, voltages, and current.

Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
---
Changes in v4:
  + Returned regmap_read() error code [Guenter]

Changes in v3:
  + Handled negative temperature value [Guenter]
  + Returned -ENODEV if Manufacturer ID is wrong [Guenter]
  + Refactored smpro_read_string() and smpro_temp_read() [Guenter]
  + Removed smpro_write() function [Guenter]
  + Added minor refactor changes [Quan]

Changes in v2:
  + Removed "virtual" sensors [Guenter]
  + Reported SOC_TDP as "Socket TDP" using max attributes [Guenter]
  + Corrected return error code when host is turn off [Guenter]
  + Reported MEM HOT Threshold for all DIMMs as temp*_crit [Guenter]
  + Removed license info as SPDX-License-Identifier existed [Guenter]
  + Added is_visible() support [Guenter]
  + Used HWMON_CHANNEL_INFO() macro and LABEL attributes [Guenter]
  + Made is_valid_id() return boolean [Guenter]
  + Returned -EPROBE_DEFER when smpro reg inaccessible [Guenter]
  + Removed unnecessary error message when dev register fail [Guenter]
  + Removed Socket TDP sensor [Quan]
  + Included sensor type and channel in labels [Quan]
  + Refactorized code to fix checkpatch.pl --strict complaint [Quan]

 drivers/hwmon/Kconfig       |   8 +
 drivers/hwmon/Makefile      |   1 +
 drivers/hwmon/smpro-hwmon.c | 491 ++++++++++++++++++++++++++++++++++++
 3 files changed, 500 insertions(+)
 create mode 100644 drivers/hwmon/smpro-hwmon.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 0ddc974b102e..ba4b5a911baf 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -67,6 +67,14 @@ config SENSORS_ABITUGURU3
 	  This driver can also be built as a module. If so, the module
 	  will be called abituguru3.
 
+config SENSORS_SMPRO
+	tristate "Ampere's Altra SMpro hardware monitoring driver"
+	depends on MFD_SMPRO
+	help
+	  If you say yes here you get support for the thermal, voltage,
+	  current and power sensors of Ampere's Altra processor family SoC
+	  with SMpro co-processor.
+
 config SENSORS_AD7314
 	tristate "Analog Devices AD7314 and compatibles"
 	depends on SPI
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 59e78bc212cf..b25391f9c651 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -174,6 +174,7 @@ obj-$(CONFIG_SENSORS_SHT3x)	+= sht3x.o
 obj-$(CONFIG_SENSORS_SHTC1)	+= shtc1.o
 obj-$(CONFIG_SENSORS_SIS5595)	+= sis5595.o
 obj-$(CONFIG_SENSORS_SMM665)	+= smm665.o
+obj-$(CONFIG_SENSORS_SMPRO)	+= smpro-hwmon.o
 obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
 obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
diff --git a/drivers/hwmon/smpro-hwmon.c b/drivers/hwmon/smpro-hwmon.c
new file mode 100644
index 000000000000..1be3d98e73c7
--- /dev/null
+++ b/drivers/hwmon/smpro-hwmon.c
@@ -0,0 +1,491 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Ampere Computing SoC's SMPro Hardware Monitoring Driver
+ *
+ * Copyright (c) 2021, Ampere Computing LLC
+ */
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+/* Identification Registers */
+#define MANUFACTURER_ID_REG	0x02
+#define AMPERE_MANUFACTURER_ID	0xCD3A
+
+/* Logical Power Sensor Registers */
+#define SOC_TEMP		0x00
+#define SOC_VRD_TEMP		0x01
+#define DIMM_VRD_TEMP		0x02
+#define CORE_VRD_TEMP		0x03
+#define CH0_DIMM_TEMP		0x04
+#define CH1_DIMM_TEMP		0x05
+#define CH2_DIMM_TEMP		0x06
+#define CH3_DIMM_TEMP		0x07
+#define CH4_DIMM_TEMP		0x08
+#define CH5_DIMM_TEMP		0x09
+#define CH6_DIMM_TEMP		0x0A
+#define CH7_DIMM_TEMP		0x0B
+#define RCA_VRD_TEMP		0x0C
+
+#define CORE_VRD_PWR		0x10
+#define SOC_PWR			0x11
+#define DIMM_VRD1_PWR		0x12
+#define DIMM_VRD2_PWR		0x13
+#define CORE_VRD_PWR_MW		0x16
+#define SOC_PWR_MW		0x17
+#define DIMM_VRD1_PWR_MW	0x18
+#define DIMM_VRD2_PWR_MW	0x19
+#define RCA_VRD_PWR		0x1A
+#define RCA_VRD_PWR_MW		0x1B
+
+#define MEM_HOT_THRESHOLD	0x22
+#define SOC_VR_HOT_THRESHOLD	0x23
+#define CORE_VRD_VOLT		0x24
+#define SOC_VRD_VOLT		0x25
+#define DIMM_VRD1_VOLT		0x26
+#define DIMM_VRD2_VOLT		0x27
+#define RCA_VRD_VOLT		0x28
+
+#define CORE_VRD_CURR		0x29
+#define SOC_VRD_CURR		0x2A
+#define DIMM_VRD1_CURR		0x2B
+#define DIMM_VRD2_CURR		0x2C
+#define RCA_VRD_CURR		0x2D
+
+struct smpro_hwmon {
+	struct regmap *regmap;
+	u32 offset;
+};
+
+struct smpro_sensor {
+	const u8 reg;
+	const u8 reg_ext;
+	const char *label;
+};
+
+static const struct smpro_sensor temperature[] = {
+	{
+		.reg = SOC_TEMP,
+		.label = "temp1 SoC"
+	},
+	{
+		.reg = SOC_VRD_TEMP,
+		.reg_ext = SOC_VR_HOT_THRESHOLD,
+		.label = "temp2 SoC VRD"
+	},
+	{
+		.reg = DIMM_VRD_TEMP,
+		.label = "temp3 DIMM VRD"
+	},
+	{
+		.reg = CORE_VRD_TEMP,
+		.label = "temp4 CORE VRD"
+	},
+	{
+		.reg = CH0_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp5 CH0 DIMM"
+	},
+	{
+		.reg = CH1_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp6 CH1 DIMM"
+	},
+	{
+		.reg = CH2_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp7 CH2 DIMM"
+	},
+	{
+		.reg = CH3_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp8 CH3 DIMM"
+	},
+	{
+		.reg = CH4_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp9 CH4 DIMM"
+	},
+	{
+		.reg = CH5_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp10 CH5 DIMM"
+	},
+	{
+		.reg = CH6_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp11 CH6 DIMM"
+	},
+	{
+		.reg = CH7_DIMM_TEMP,
+		.reg_ext = MEM_HOT_THRESHOLD,
+		.label = "temp12 CH7 DIMM"
+	},
+	{
+		.reg = RCA_VRD_TEMP,
+		.label = "temp13 RCA VRD"
+	},
+};
+
+static const struct smpro_sensor voltage[] = {
+	{
+		.reg = CORE_VRD_VOLT,
+		.label = "vout0 CORE VRD"
+	},
+	{
+		.reg = SOC_VRD_VOLT,
+		.label = "vout1 SoC VRD"
+	},
+	{
+		.reg = DIMM_VRD1_VOLT,
+		.label = "vout2 DIMM VRD1"
+	},
+	{
+		.reg = DIMM_VRD2_VOLT,
+		.label = "vout3 DIMM VRD2"
+	},
+	{
+		.reg = RCA_VRD_VOLT,
+		.label = "vout4 RCA VRD"
+	},
+};
+
+static const struct smpro_sensor curr_sensor[] = {
+	{
+		.reg = CORE_VRD_CURR,
+		.label = "iout1 CORE VRD"
+	},
+	{
+		.reg = SOC_VRD_CURR,
+		.label = "iout2 SoC VRD"
+	},
+	{
+		.reg = DIMM_VRD1_CURR,
+		.label = "iout3 DIMM VRD1"
+	},
+	{
+		.reg = DIMM_VRD2_CURR,
+		.label = "iout4 DIMM VRD2"
+	},
+	{
+		.reg = RCA_VRD_CURR,
+		.label = "iout5 RCA VRD"
+	},
+};
+
+static const struct smpro_sensor power[] = {
+	{
+		.reg = CORE_VRD_PWR,
+		.reg_ext = CORE_VRD_PWR_MW,
+		.label = "power1 CORE VRD"
+	},
+	{
+		.reg = SOC_PWR,
+		.reg_ext = SOC_PWR_MW,
+		.label = "power2 SoC"
+	},
+	{
+		.reg = DIMM_VRD1_PWR,
+		.reg_ext = DIMM_VRD1_PWR_MW,
+		.label = "power3 DIMM VRD1"
+	},
+	{
+		.reg = DIMM_VRD2_PWR,
+		.reg_ext = DIMM_VRD2_PWR_MW,
+		.label = "power4 DIMM VRD2"
+	},
+	{
+		.reg = RCA_VRD_PWR,
+		.reg_ext = RCA_VRD_PWR_MW,
+		.label = "power5 RCA VRD"
+	},
+};
+
+static int smpro_read_temp(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct smpro_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		ret = regmap_read(hwmon->regmap, hwmon->offset + temperature[channel].reg, &value);
+		if (ret)
+			return ret;
+		break;
+	case hwmon_temp_crit:
+		ret = regmap_read(hwmon->regmap,
+				  hwmon->offset + temperature[channel].reg_ext, &value);
+		if (ret)
+			return ret;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	*val = sign_extend32(value, 8) * 1000;
+	return 0;
+}
+
+static int smpro_read_in(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct smpro_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	switch (attr) {
+	case hwmon_in_input:
+		ret = regmap_read(hwmon->regmap, hwmon->offset + voltage[channel].reg, &value);
+		if (ret < 0)
+			return ret;
+		/* 15-bit value in 1mV */
+		*val = value & 0x7fff;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int smpro_read_curr(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct smpro_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	switch (attr) {
+	case hwmon_curr_input:
+		ret = regmap_read(hwmon->regmap, hwmon->offset + curr_sensor[channel].reg, &value);
+		if (ret < 0)
+			return ret;
+		/* Scale reported by the hardware is 1mA */
+		*val = value & 0x7fff;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int smpro_read_power(struct device *dev, u32 attr, int channel, long *val_pwr)
+{
+	struct smpro_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int val = 0, val_mw = 0;
+	int ret;
+
+	switch (attr) {
+	case hwmon_power_input:
+		ret = regmap_read(hwmon->regmap, hwmon->offset + power[channel].reg, &val);
+		if (ret)
+			return ret;
+
+		ret = regmap_read(hwmon->regmap, hwmon->offset + power[channel].reg_ext, &val_mw);
+		if (ret)
+			return ret;
+
+		*val_pwr = val * 1000000 + val_mw * 1000;
+		return 0;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int smpro_read(struct device *dev, enum hwmon_sensor_types type,
+		      u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return smpro_read_temp(dev, attr, channel, val);
+	case hwmon_in:
+		return smpro_read_in(dev, attr, channel, val);
+	case hwmon_power:
+		return smpro_read_power(dev, attr, channel, val);
+	case hwmon_curr:
+		return smpro_read_curr(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int smpro_read_string(struct device *dev, enum hwmon_sensor_types type,
+			     u32 attr, int channel, const char **str)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_label:
+			*str = temperature[channel].label;
+			return 0;
+		default:
+			break;
+		}
+		break;
+
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_label:
+			*str = voltage[channel].label;
+			return 0;
+		default:
+			break;
+		}
+		break;
+
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_label:
+			*str = curr_sensor[channel].label;
+			return 0;
+		default:
+			break;
+		}
+		break;
+
+	case hwmon_power:
+		switch (attr) {
+		case hwmon_power_label:
+			*str = power[channel].label;
+			return 0;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static umode_t smpro_is_visible(const void *data, enum hwmon_sensor_types type,
+				u32 attr, int channel)
+{
+	const struct smpro_hwmon *hwmon = data;
+	unsigned int value;
+	int ret;
+
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+		case hwmon_temp_label:
+		case hwmon_temp_crit:
+			ret = regmap_read(hwmon->regmap,
+					  hwmon->offset + temperature[channel].reg, &value);
+			if (ret || value == 0xFFFF)
+				return 0;
+		break;
+		}
+	default:
+		break;
+	}
+
+	return 0444;
+}
+
+static const struct hwmon_channel_info *smpro_info[] = {
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT,
+			   HWMON_T_INPUT | HWMON_T_LABEL),
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL,
+			   HWMON_I_INPUT | HWMON_I_LABEL),
+	HWMON_CHANNEL_INFO(power,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_LABEL,
+			   HWMON_P_INPUT | HWMON_P_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,
+			   HWMON_C_INPUT | HWMON_C_LABEL),
+	NULL
+};
+
+static const struct hwmon_ops smpro_hwmon_ops = {
+	.is_visible = smpro_is_visible,
+	.read = smpro_read,
+	.read_string = smpro_read_string,
+};
+
+static const struct hwmon_chip_info smpro_chip_info = {
+	.ops = &smpro_hwmon_ops,
+	.info = smpro_info,
+};
+
+static int smpro_hwmon_probe(struct platform_device *pdev)
+{
+	struct smpro_hwmon *hwmon;
+	struct device *hwmon_dev;
+	unsigned int val;
+	int ret;
+
+	hwmon = devm_kzalloc(&pdev->dev, sizeof(struct smpro_hwmon), GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+
+	hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!hwmon->regmap)
+		return -ENODEV;
+
+	ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset);
+	if (ret)
+		return -EINVAL;
+
+	/* Check for valid ID */
+	ret = regmap_read(hwmon->regmap, MANUFACTURER_ID_REG, &val);
+	if (ret)
+		return ret;
+
+	if (val != AMPERE_MANUFACTURER_ID)
+		return -ENODEV;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, "smpro_hwmon",
+							 hwmon, &smpro_chip_info, NULL);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct of_device_id smpro_hwmon_of_match[] = {
+	{ .compatible = "ampere,ac01-hwmon" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, smpro_hwmon_of_match);
+
+static struct platform_driver smpro_hwmon_driver = {
+	.probe		= smpro_hwmon_probe,
+	.driver = {
+		.name	= "smpro-hwmon",
+		.of_match_table = smpro_hwmon_of_match,
+	},
+};
+
+module_platform_driver(smpro_hwmon_driver);
+
+MODULE_AUTHOR("Thu Nguyen <thu@os.amperecomputing.com>");
+MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
+MODULE_DESCRIPTION("Ampere Altra SMPro hwmon driver");
+MODULE_LICENSE("GPL v2");
-- 
2.28.0