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

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

On Fri, Apr 30, 2021 at 3:12 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 4/30/21 5:35 AM, Robert Marko wrote:
> > 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,
>
> Literally none of those attributes are standard hwmon attributes.
> I don't know what this is, but it is not a hardware monitoring driver.

Yes, I agree that it does not expose any of the standard attributes, but these
are the only ones the CPLD exposes.

I don't know where else to put them, MFD driver did not seem logical to me.
>
> > +     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);
>
> Please use devm_hwmon_device_register_with_info() to register hwmon devices.
> Of course, that only makes sense for actual hardware monitoring drivers
> which do support standard attributes.

Yes, devm_hwmon_device_register_with_info() made no sense without any of the
standard attributes.

Robert
>
> > +     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;
> >
>


-- 
Robert Marko
Staff Embedded Linux Engineer
Sartura Ltd.
Lendavska ulica 16a
10000 Zagreb, Croatia
Email: robert.marko@sartura.hr
Web: www.sartura.hr