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Message-ID: <206ad774-bf6f-aed3-81a7-3d9c8f80a69e@roeck-us.net>
Date: Wed, 26 Jul 2023 09:14:59 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Carsten Spieß <mail@...sten-spiess.de>,
Jean Delvare <jdelvare@...e.com>,
Jonathan Corbet <corbet@....net>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Magnus Damm <magnus.damm@...il.com>
Cc: linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH 1/2] hwmon: (isl28022) new driver for ISL28022 power
monitor
On 7/26/23 08:22, Carsten Spieß wrote:
> Driver for Renesas ISL28022 power monitor with I2C interface.
> The device monitors voltage, current via shunt resistor
> and calculated power.
>
> Signed-off-by: Carsten Spieß <mail@...sten-spiess.de>
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/isl28022.rst | 56 +++++
> MAINTAINERS | 7 +
> drivers/hwmon/Kconfig | 11 +
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/isl28022.c | 405 +++++++++++++++++++++++++++++++
> 6 files changed, 481 insertions(+)
> create mode 100644 Documentation/hwmon/isl28022.rst
> create mode 100644 drivers/hwmon/isl28022.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index d11924667f76..c9548fc5c40e 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -90,6 +90,7 @@ Hardware Monitoring Kernel Drivers
> ir35221
> ir38064
> ir36021
> + isl28022
> isl68137
> it87
> jc42
> diff --git a/Documentation/hwmon/isl28022.rst b/Documentation/hwmon/isl28022.rst
> new file mode 100644
> index 000000000000..84c27ddcd33e
> --- /dev/null
> +++ b/Documentation/hwmon/isl28022.rst
> @@ -0,0 +1,56 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver isl28022
> +======================
> +
> +Supported chips:
> +
> + * Renesas ISL28022
> +
> + Prefix: 'isl28022'
> +
> + Addresses scanned: none
> +
> + Datasheet: Publicly available at the Renesas website
> +
> + https://www.renesas.com/us/en/www/doc/datasheet/isl28022.pdf
> +
> +Author:
> + Carsten Spieß <mail@...sten-spiess.de>
> +
> +Description
> +-----------
> +
> +The ISL28022 is a power monitor with I2C interface. The device monitors
> +voltage, current via shunt resistor and calculated power.
> +
> +Usage Notes
> +-----------
> +
> +This driver does not auto-detect devices. You will have to instantiate the
> +device explicitly. Please see Documentation/i2c/instantiating-devices.rst for
> +details.
> +
> +The shunt value in micro-ohms, shunt gain and averaging can be set
> +via device tree at compile-time.
At _compile-time_ ?
> +Please refer to the Documentation/devicetree/bindings/hwmon/isl,isl28022.yaml
> +for bindings if the device tree is used.
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported. All attributes are read-only.
> +
> +======================= =======================================================
> +in0_input shunt voltage (micro Volt)
No. You must not change the ABI like that.
> +in1_input bus voltage (milli Volt)
> +
> +curr1_input current (milli Ampere)
> +power1_input power (micro Watt)
> +
> +note current and power attributes are supported only when
> + shunt value is configured via device tree
No. Use a reasonable default if there are no devicetree properties.
> +
> + shunt voltage is in micro Volt, not milli Volt,
> + to get useful values
I'd argue that shunt voltage is all but useless, but if you want to have it supported
it _has_ to be in mV.
Why not support limit attributes ?
> +======================= =======================================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7abb5710e1bb..c61aa688cd11 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11072,6 +11072,13 @@ S: Maintained
> F: Documentation/filesystems/isofs.rst
> F: fs/isofs/
>
> +ISL28022 HARDWARE MONITORING DRIVER
> +M: Carsten Spieß <mail@...sten-spiess.de>
> +L: linux-hwmon@...r.kernel.org
> +S: Maintained
> +F: Documentation/hwmon/isl28022.rst
> +F: drivers/hwmon/isl28022.c
> +
> IT87 HARDWARE MONITORING DRIVER
> M: Jean Delvare <jdelvare@...e.com>
> L: linux-hwmon@...r.kernel.org
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 2913299c2c9e..3049c519e6ac 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -800,6 +800,17 @@ config SENSORS_CORETEMP
> sensor inside your CPU. Most of the family 6 CPUs
> are supported. Check Documentation/hwmon/coretemp.rst for details.
>
> +config SENSORS_ISL28022
> + tristate "Renesas ISL28022"
> + depends on I2C
> + select REGMAP_I2C
> + help
> + If you say yes here you get support for ISL28022 power monitor.
> + Check Documentation/hwmon/isl28022.rst for details.
> +
> + This driver can also be built as a module. If so, the module
> + will be called isl28022.
> +
> config SENSORS_IT87
> tristate "ITE IT87xx and compatibles"
> depends on !PPC
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index ff6bfd109c72..4046fed7f48d 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -98,6 +98,7 @@ obj-$(CONFIG_SENSORS_INA2XX) += ina2xx.o
> obj-$(CONFIG_SENSORS_INA238) += ina238.o
> obj-$(CONFIG_SENSORS_INA3221) += ina3221.o
> obj-$(CONFIG_SENSORS_INTEL_M10_BMC_HWMON) += intel-m10-bmc-hwmon.o
> +obj-$(CONFIG_SENSORS_ISL28022) += isl28022.o
> obj-$(CONFIG_SENSORS_IT87) += it87.o
> obj-$(CONFIG_SENSORS_JC42) += jc42.o
> obj-$(CONFIG_SENSORS_K8TEMP) += k8temp.o
> diff --git a/drivers/hwmon/isl28022.c b/drivers/hwmon/isl28022.c
> new file mode 100644
> index 000000000000..67cf47c31600
> --- /dev/null
> +++ b/drivers/hwmon/isl28022.c
> @@ -0,0 +1,405 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * isl28022.c - driver for Renesas ISL28022 power monitor chip
> + * monitoring
> + * Copyright (c) 2023 Carsten Spieß <mail@...sten-spiess.de>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/i2c.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/err.h>
> +#include <linux/of_device.h>
> +#include <linux/of.h>
> +#include <linux/regmap.h>
> +#include <linux/util_macros.h>
> +#include <linux/regulator/consumer.h>
> +
> +/* ISL28022 registers */
> +#define ISL28022_REG_CONFIG 0x00
> +#define ISL28022_REG_SHUNT 0x01
> +#define ISL28022_REG_BUS 0x02
> +#define ISL28022_REG_POWER 0x03
> +#define ISL28022_REG_CURRENT 0x04
> +#define ISL28022_REG_CALIB 0x05
> +#define ISL28022_REG_SHUNT_THR 0x06
> +#define ISL28022_REG_BUS_THR 0x07
> +#define ISL28022_REG_INT 0x08
> +#define ISL28022_REG_AUX 0x09
> +#define ISL28022_REG_MAX ISL28022_REG_AUX
> +
> +/* ISL28022 config flags */
> +/* mode flags */
> +#define ISL28022_MODE_SHIFT 0
> +#define ISL28022_MODE_MASK 0x0007
> +
> +#define ISL28022_MODE_PWR_DOWN 0x0
> +#define ISL28022_MODE_TRG_S 0x1
> +#define ISL28022_MODE_TRG_B 0x2
> +#define ISL28022_MODE_TRG_SB 0x3
> +#define ISL28022_MODE_ADC_OFF 0x4
> +#define ISL28022_MODE_CONT_S 0x5
> +#define ISL28022_MODE_CONT_B 0x6
> +#define ISL28022_MODE_CONT_SB 0x7
> +
> +/* shunt ADC settings */
> +#define ISL28022_SADC_SHIFT 3
> +#define ISL28022_SADC_MASK 0x0078
> +
> +#define ISL28022_BADC_SHIFT 7
> +#define ISL28022_BADC_MASK 0x0780
> +
> +#define ISL28022_ADC_12 0x0 /* 12 bit ADC */
> +#define ISL28022_ADC_13 0x1 /* 13 bit ADC */
> +#define ISL28022_ADC_14 0x2 /* 14 bit ADC */
> +#define ISL28022_ADC_15 0x3 /* 15 bit ADC */
> +#define ISL28022_ADC_15_1 0x8 /* 15 bit ADC, 1 sample */
> +#define ISL28022_ADC_15_2 0x9 /* 15 bit ADC, 2 samples */
> +#define ISL28022_ADC_15_4 0xA /* 15 bit ADC, 4 samples */
> +#define ISL28022_ADC_15_8 0xB /* 15 bit ADC, 8 samples */
> +#define ISL28022_ADC_15_16 0xC /* 15 bit ADC, 16 samples */
> +#define ISL28022_ADC_15_32 0xD /* 15 bit ADC, 32 samples */
> +#define ISL28022_ADC_15_64 0xE /* 15 bit ADC, 64 samples */
> +#define ISL28022_ADC_15_128 0xF /* 15 bit ADC, 128 samples */
> +
> +/* shunt voltage range */
> +#define ISL28022_PG_SHIFT 11
> +#define ISL28022_PG_MASK 0x1800
> +
> +#define ISL28022_PG_40 0x0 /* +/-40 mV */
> +#define ISL28022_PG_80 0x1 /* +/-80 mV */
> +#define ISL28022_PG_160 0x2 /* +/-160 mV */
> +#define ISL28022_PG_320 0x3 /* +/-3200 mV */
> +
> +/* bus voltage range */
> +#define ISL28022_BRNG_SHIFT 13
> +#define ISL28022_BRNG_MASK 0x6000
> +
> +#define ISL28022_BRNG_16 0x0 /* 16 V */
> +#define ISL28022_BRNG_32 0x1 /* 32 V */
> +#define ISL28022_BRNG_60 0x3 /* 60 V */
> +
> +/* reset */
> +#define ISL28022_RESET 0x8000
> +
> +struct isl28022_data {
> + struct i2c_client *client;
> + struct regmap *regmap;
> + u32 shunt;
> + u32 gain;
> + u32 average;
> + u16 config;
> + u16 calib;
> +};
> +
> +static int isl28022_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + struct isl28022_data *data = dev_get_drvdata(dev);
> + unsigned int regval;
> + int err;
> +
> + switch (type) {
> + case hwmon_in:
> + switch (attr) {
> + case hwmon_in_input:
> + err = regmap_read(data->regmap,
> + ISL28022_REG_SHUNT + channel, ®val);
That never reads REG_BUS.
> + if (err < 0)
> + return err;
> + *val = (channel == 0) ?
> + (long)((s16)((u16)regval)) * 10 :
> + (long)(((u16)regval) & 0xFFFC);
I don't think the sign extensions are correct based on the datasheet.
This will have to use sign_extend.
> + break;
> + default:
> + return -EINVAL;
> + }
> + break;
> + case hwmon_curr:
> + switch (attr) {
> + case hwmon_curr_input:
> + err = regmap_read(data->regmap,
> + ISL28022_REG_CURRENT, ®val);
> + if (err < 0)
> + return err;
> + if (!data->shunt)
> + return -EINVAL;
Getting an error message each time the "sensors" command is executed ?
Unacceptable.
> + *val = ((long)regval * 10000L * (long)data->gain) /
> + (long)(8 * data->shunt);
> + break;
> + default:
> + return -EINVAL;
> + }
> + break;
> + case hwmon_power:
> + switch (attr) {
> + case hwmon_power_input:
> + err = regmap_read(data->regmap,
> + ISL28022_REG_POWER, ®val);
> + if (err < 0)
> + return err;
> + if (!data->shunt)
> + return -EINVAL;
Unacceptable.
> + *val = ((long)regval * 409600000L * (long)data->gain) /
> + (long)(8 * data->shunt);
I don't think this was checked for overflows.
> + break;
> + default:
> + return -EINVAL;
> + }
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static umode_t isl28022_is_visible(const void *data, enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + switch (type) {
> + case hwmon_in:
> + switch (attr) {
> + case hwmon_in_input:
> + return 0444;
> + }
> + break;
> + case hwmon_curr:
> + switch (attr) {
> + case hwmon_curr_input:
> + return 0444;
> + }
> + break;
> + case hwmon_power:
> + switch (attr) {
> + case hwmon_power_input:
> + return 0444;
> + }
> + break;
> + default:
> + break;
> + }
> + return 0;
> +}
> +
> +static const struct hwmon_channel_info *isl28022_info[] = {
> + HWMON_CHANNEL_INFO(in,
> + HWMON_I_INPUT, /* channel 0: shunt voltage (µV) */
> + HWMON_I_INPUT), /* channel 1: bus voltage (mV) */
> + NULL
> +};
> +
> +static const struct hwmon_channel_info *isl28022_info_shunt[] = {
> + HWMON_CHANNEL_INFO(in,
> + HWMON_I_INPUT, /* channel 0: shunt voltage (µV) */
> + HWMON_I_INPUT), /* channel 1: bus voltage (mV) */
> + HWMON_CHANNEL_INFO(curr,
> + HWMON_C_INPUT), /* channel 1: current (mA) */
> + HWMON_CHANNEL_INFO(power,
> + HWMON_P_INPUT), /* channel 1: power (µW) */
> + NULL
> +};
> +
> +static const struct hwmon_ops isl28022_hwmon_ops = {
> + .is_visible = isl28022_is_visible,
> + .read = isl28022_read,
> +};
> +
> +static const struct hwmon_chip_info isl28022_chip_info = {
> + .ops = &isl28022_hwmon_ops,
> + .info = isl28022_info,
> +};
> +
> +static const struct hwmon_chip_info isl28022_chip_info_shunt = {
> + .ops = &isl28022_hwmon_ops,
> + .info = isl28022_info_shunt,
> +};
> +
> +static bool isl28022_is_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case ISL28022_REG_CONFIG:
> + case ISL28022_REG_CALIB:
> + case ISL28022_REG_SHUNT_THR:
> + case ISL28022_REG_BUS_THR:
> + case ISL28022_REG_INT:
> + case ISL28022_REG_AUX:
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static bool isl28022_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case ISL28022_REG_CONFIG:
> + case ISL28022_REG_SHUNT:
> + case ISL28022_REG_BUS:
> + case ISL28022_REG_POWER:
> + case ISL28022_REG_CURRENT:
> + case ISL28022_REG_INT:
> + case ISL28022_REG_AUX:
> + return true;
> + }
> + return true;
> +}
> +
> +static const struct regmap_config isl28022_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 16,
> + .max_register = ISL28022_REG_MAX,
> + .writeable_reg = isl28022_is_writeable_reg,
> + .volatile_reg = isl28022_is_volatile_reg,
> + .val_format_endian = REGMAP_ENDIAN_BIG,
> + .cache_type = REGCACHE_RBTREE,
> + .use_single_read = true,
> + .use_single_write = true,
> +};
> +
> +static const struct i2c_device_id isl28022_ids[] = {
> + { "isl28022", 0},
> + { /* LIST END */ }
> +};
> +MODULE_DEVICE_TABLE(i2c, isl28022_ids);
> +
> +static int isl28022_config(struct device *dev)
> +{
> + struct isl28022_data *data = dev_get_drvdata(dev);
> +
> + if (!dev || !data)
> + return -EINVAL;
How would this ever happen ?
> + ;
> + data->config = (ISL28022_MODE_CONT_SB << ISL28022_MODE_SHIFT) |
> + (ISL28022_BRNG_60 << ISL28022_BRNG_SHIFT);
> +
> + switch (data->gain) {
> + case 1:
> + data->config |= (ISL28022_PG_40 << ISL28022_PG_SHIFT);
> + break;
> + case 2:
> + data->config |= (ISL28022_PG_80 << ISL28022_PG_SHIFT);
> + break;
> + case 4:
> + data->config |= (ISL28022_PG_160 << ISL28022_PG_SHIFT);
> + break;
> + default:
> + data->config |= (ISL28022_PG_320 << ISL28022_PG_SHIFT);
> + data->gain = 8;
> + break;
> + }
> +
> + data->calib = data->shunt ? 0x8000 / data->gain : 0;
> +
> + switch (data->average) {
> + case 128:
> + data->config |= (ISL28022_ADC_15_128 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_128 << ISL28022_BADC_SHIFT);
> + break;
> + case 64:
> + data->config |= (ISL28022_ADC_15_64 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_64 << ISL28022_BADC_SHIFT);
> + break;
> + case 32:
> + data->config |= (ISL28022_ADC_15_32 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_32 << ISL28022_BADC_SHIFT);
> + break;
> + case 16:
> + data->config |= (ISL28022_ADC_15_16 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_16 << ISL28022_BADC_SHIFT);
> + break;
> + case 8:
> + data->config |= (ISL28022_ADC_15_8 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_8 << ISL28022_BADC_SHIFT);
> + break;
> + case 4:
> + data->config |= (ISL28022_ADC_15_4 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_4 << ISL28022_BADC_SHIFT);
> + break;
> + case 2:
> + data->config |= (ISL28022_ADC_15_2 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_2 << ISL28022_BADC_SHIFT);
> + break;
> + case 1:
> + data->config |= (ISL28022_ADC_15_1 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15_1 << ISL28022_BADC_SHIFT);
> + break;
> + default:
> + data->config |= (ISL28022_ADC_15 << ISL28022_SADC_SHIFT) |
> + (ISL28022_ADC_15 << ISL28022_BADC_SHIFT);
> + data->average = 0;
> + break;
> + }
> +
> + regmap_write(data->regmap, ISL28022_REG_CONFIG, data->config);
> + regmap_write(data->regmap, ISL28022_REG_CALIB, data->calib);
Error checking needed.
> +
> + return 0;
> +}
> +
> +static int isl28022_probe(struct i2c_client *client)
> +{
> + struct device *dev = &client->dev;
> + struct device *hwmon_dev;
> + struct isl28022_data *data;
> + int status;
> +
> + if (!i2c_check_functionality(client->adapter,
> + I2C_FUNC_SMBUS_BYTE_DATA |
> + I2C_FUNC_SMBUS_WORD_DATA))
> + return -EIO;
This is not an IO error. Return -ENODEV as most other drivers do.
> +
> + data = devm_kzalloc(dev, sizeof(struct isl28022_data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->client = client;
> +
> + of_property_read_u32(dev->of_node, "shunt-resistor-micro-ohms", &data->shunt);
> + of_property_read_u32(dev->of_node, "shunt-gain", &data->gain);
> + of_property_read_u32(dev->of_node, "average", &data->average);
Check for errors and provide defaults if properties are not set.
Also please use device_property_read_u32() to enable use from non-devicetree
systems.
> +
> + data->regmap = devm_regmap_init_i2c(client, &isl28022_regmap_config);
> + if (IS_ERR(data->regmap))
> + return PTR_ERR(data->regmap);
> +
> + hwmon_dev = devm_hwmon_device_register_with_info(dev, "isl28022_hwmon",
> + data, data->shunt ?
> + &isl28022_chip_info_shunt :
> + &isl28022_chip_info, NULL);
> + if (IS_ERR(hwmon_dev))
> + return PTR_ERR(hwmon_dev);
> +
> + status = isl28022_config(hwmon_dev);
> + if (status)
> + return status;
That has to happen before the call to devm_hwmon_device_register_with_info()
to avoid race conditions.
> +
> + dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id __maybe_unused isl28022_of_match[] = {
> + { .compatible = "renesas,isl28022"},
> + { /* LIST END */ }
> +};
> +MODULE_DEVICE_TABLE(of, isl28022_of_match);
> +
> +static struct i2c_driver isl28022_driver = {
> + .class = I2C_CLASS_HWMON,
> + .driver = {
> + .name = "isl28022",
> + .of_match_table = of_match_ptr(isl28022_of_match),
Drop of_match_ptr()
> + },
> + .probe_new = isl28022_probe,
> + .id_table = isl28022_ids,
> +};
> +
> +module_i2c_driver(isl28022_driver);
> +
> +MODULE_AUTHOR("Carsten Spiess <mail@...sten-spiess.de>");
> +MODULE_DESCRIPTION("ISL28022 driver");
> +MODULE_LICENSE("GPL");
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