Message-ID: <6a620f7c-af06-61db-feec-66814fdbae7e@os.amperecomputing.com>
Date:   Thu, 15 Apr 2021 11:13:22 +0700
From:   Quan Nguyen <quan@...amperecomputing.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Joel Stanley <joel@....id.au>, Andrew Jeffery <andrew@...id.au>,
        Jean Delvare <jdelvare@...e.com>,
        Rob Herring <robh+dt@...nel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Jonathan Corbet <corbet@....net>, linux-hwmon@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-aspeed@...ts.ozlabs.org,
        openbmc@...ts.ozlabs.org,
        Open Source Submission <patches@...erecomputing.com>,
        Phong Vo <phong@...amperecomputing.com>,
        "Thang Q . Nguyen" <thang@...amperecomputing.com>
Subject: Re: [PATCH v3 3/4] hwmon: smpro: Add Ampere's Altra smpro-hwmon
 driver

On 14/04/2021 19:33, Guenter Roeck wrote:
> On Fri, Apr 09, 2021 at 10:13:31AM +0700, Quan Nguyen wrote:
>> 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@...amperecomputing.com>
>> ---
> 
> Change log goes here. You are making it difficult to review your patches.
> 
Will add changelog here in next version.

>>   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..a3389fcbad82
>> --- /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 -EPROBE_DEFER;
> 
> This is unacceptable. regmap_read() could return various errors.
> An error here might mean that the chip is simply not there, or that
> there is some other problem with, say, the i2c controller driver.
> The function might, for all we know, even return -ENOMEM.
> 
> If this is supposed to mean that the chip is not yet ready, some other
> and more specific solution will be needed. -EPROBE_DEFER means that
> some other driver needs to be loaded first, not "chip is not ready,
> try again later".
> 
> Thanks,
> Guenter
> 

Thanks to this clarification and will return regmap_read() return value, 
ie: "return ret" in next version.

>> +
>> +	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@...amperecomputing.com>");
>> +MODULE_AUTHOR("Quan Nguyen <quan@...amperecomputing.com>");
>> +MODULE_DESCRIPTION("Ampere Altra SMPro hwmon driver");
>> +MODULE_LICENSE("GPL v2");

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