Add code implementing HWMON adapter/compatibility layer to allow
expositing various sensors present on power supply devices via HWMON
subsystem. This is done in order to allow userspace to use single
ABI/library(libsensors) to access/manipulate all of the sensors of the
system.

Signed-off-by: Andrey Smirnov <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Cc: Chris Healy <[email protected]>
Cc: Cory Tusar <[email protected]>
Cc: Lucas Stach <[email protected]>
Cc: Fabio Estevam <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Sebastian Reichel <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
 drivers/power/supply/Kconfig              |  14 +
 drivers/power/supply/Makefile             |   1 +
 drivers/power/supply/power_supply_hwmon.c | 349 ++++++++++++++++++++++
 include/linux/power_supply.h              |   9 +
 4 files changed, 373 insertions(+)
 create mode 100644 drivers/power/supply/power_supply_hwmon.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index c614c8a196f3..0550cedb53c9 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -14,6 +14,20 @@ config POWER_SUPPLY_DEBUG
          Say Y here to enable debugging messages for power supply class
          and drivers.
 
+config POWER_SUPPLY_HWMON
+       bool
+       prompt "Expose power supply sensors as hwmon device"
+       depends on HWMON=y || HWMON=POWER_SUPPLY
+       default y
+       help
+         This options enables API that allows sensors found on a
+         power supply device (current, voltage, temperature) to be
+         exposed as a hwmon device.
+
+         Say 'Y' here if you want power supplies to
+         have hwmon sysfs interface too.
+
+
 config PDA_POWER
        tristate "Generic PDA/phone power driver"
        depends on !S390
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index c56803a9e4fe..0a87cfe49b21 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -6,6 +6,7 @@ power_supply-$(CONFIG_SYSFS)            += power_supply_sysfs.o
 power_supply-$(CONFIG_LEDS_TRIGGERS)   += power_supply_leds.o
 
 obj-$(CONFIG_POWER_SUPPLY)     += power_supply.o
+obj-$(CONFIG_POWER_SUPPLY_HWMON) += power_supply_hwmon.o
 obj-$(CONFIG_GENERIC_ADC_BATTERY)      += generic-adc-battery.o
 
 obj-$(CONFIG_PDA_POWER)                += pda_power.o
diff --git a/drivers/power/supply/power_supply_hwmon.c 
b/drivers/power/supply/power_supply_hwmon.c
new file mode 100644
index 000000000000..3451b997367d
--- /dev/null
+++ b/drivers/power/supply/power_supply_hwmon.c
@@ -0,0 +1,349 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  power_supply_hwmon.c - power supply hwmon support.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+
+struct power_supply_hwmon {
+       struct power_supply *psy;
+       unsigned long *props;
+};
+
+static int power_supply_hwmon_in_to_property(u32 attr)
+{
+       switch (attr) {
+       case hwmon_in_average:
+               return POWER_SUPPLY_PROP_VOLTAGE_AVG;
+       case hwmon_in_min:
+               return POWER_SUPPLY_PROP_VOLTAGE_MIN;
+       case hwmon_in_max:
+               return POWER_SUPPLY_PROP_VOLTAGE_MAX;
+       case hwmon_in_input:
+               return POWER_SUPPLY_PROP_VOLTAGE_NOW;
+       default:
+               return -EINVAL;
+       }
+}
+
+static int power_supply_hwmon_curr_to_property(u32 attr)
+{
+       switch (attr) {
+       case hwmon_curr_average:
+               return POWER_SUPPLY_PROP_CURRENT_AVG;
+       case hwmon_curr_max:
+               return POWER_SUPPLY_PROP_CURRENT_MAX;
+       case hwmon_curr_input:
+               return POWER_SUPPLY_PROP_CURRENT_NOW;
+       default:
+               return -EINVAL;
+       }
+}
+
+static int power_supply_hwmon_temp_to_property(u32 attr, int channel)
+{
+       if (channel) {
+               switch (attr) {
+               case hwmon_temp_input:
+                       return POWER_SUPPLY_PROP_TEMP_AMBIENT;
+               case hwmon_temp_min_alarm:
+                       return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN;
+               case hwmon_temp_max_alarm:
+                       return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX;
+               default:
+                       break;
+               }
+       } else {
+               switch (attr) {
+               case hwmon_temp_input:
+                       return POWER_SUPPLY_PROP_TEMP;
+               case hwmon_temp_max:
+                       return POWER_SUPPLY_PROP_TEMP_MAX;
+               case hwmon_temp_min:
+                       return POWER_SUPPLY_PROP_TEMP_MIN;
+               case hwmon_temp_min_alarm:
+                       return POWER_SUPPLY_PROP_TEMP_ALERT_MIN;
+               case hwmon_temp_max_alarm:
+                       return POWER_SUPPLY_PROP_TEMP_ALERT_MAX;
+               default:
+                       break;
+               }
+       }
+
+       return -EINVAL;
+}
+
+static int
+power_supply_hwmon_to_property(enum hwmon_sensor_types type,
+                              u32 attr, int channel)
+{
+       switch (type) {
+       case hwmon_in:
+               return power_supply_hwmon_in_to_property(attr);
+       case hwmon_curr:
+               return power_supply_hwmon_curr_to_property(attr);
+       case hwmon_temp:
+               return power_supply_hwmon_temp_to_property(attr, channel);
+       default:
+               return -EINVAL;
+       }
+}
+
+static bool power_supply_hwmon_is_a_label(enum hwmon_sensor_types type,
+                                          u32 attr)
+{
+       return type == hwmon_temp && attr == hwmon_temp_label;
+}
+
+static bool power_supply_hwmon_is_writable(enum hwmon_sensor_types type,
+                                          u32 attr)
+{
+       switch (type) {
+       case hwmon_in:
+               return attr == hwmon_in_min ||
+                      attr == hwmon_in_max;
+       case hwmon_curr:
+               return attr == hwmon_curr_max;
+       case hwmon_temp:
+               return attr == hwmon_temp_max ||
+                      attr == hwmon_temp_min ||
+                      attr == hwmon_temp_min_alarm ||
+                      attr == hwmon_temp_max_alarm;
+       default:
+               return false;
+       }
+}
+
+static umode_t power_supply_hwmon_is_visible(const void *data,
+                                            enum hwmon_sensor_types type,
+                                            u32 attr, int channel)
+{
+       const struct power_supply_hwmon *psyhw = data;
+       int prop;
+
+
+       if (power_supply_hwmon_is_a_label(type, attr))
+               return 0444;
+
+       prop = power_supply_hwmon_to_property(type, attr, channel);
+       if (prop < 0 || !test_bit(prop, psyhw->props))
+               return 0;
+
+       if (power_supply_property_is_writeable(psyhw->psy, prop) > 0 &&
+           power_supply_hwmon_is_writable(type, attr))
+               return 0644;
+
+       return 0444;
+}
+
+static int power_supply_hwmon_read_string(struct device *dev,
+                                         enum hwmon_sensor_types type,
+                                         u32 attr, int channel,
+                                         const char **str)
+{
+       *str = channel ? "temp" : "temp ambient";
+       return 0;
+}
+
+static int
+power_supply_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+                       u32 attr, int channel, long *val)
+{
+       struct power_supply_hwmon *psyhw = dev_get_drvdata(dev);
+       struct power_supply *psy = psyhw->psy;
+       union power_supply_propval pspval;
+       int ret, prop;
+
+       prop = power_supply_hwmon_to_property(type, attr, channel);
+       if (prop < 0)
+               return prop;
+
+       ret  = power_supply_get_property(psy, prop, &pspval);
+       if (ret)
+               return ret;
+
+       switch (type) {
+       /*
+        * Both voltage and current is reported in units of
+        * microvolts/microamps, so we need to adjust it to
+        * milliamps(volts)
+        */
+       case hwmon_curr:
+       case hwmon_in:
+               pspval.intval = DIV_ROUND_CLOSEST(pspval.intval, 1000);
+               break;
+       /*
+        * Temp needs to be converted from 1/10 C to milli-C
+        */
+       case hwmon_temp:
+               if (check_mul_overflow(pspval.intval, 100,
+                                      &pspval.intval))
+                       return -EOVERFLOW;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       *val = pspval.intval;
+
+       return 0;
+}
+
+static int
+power_supply_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
+                        u32 attr, int channel, long val)
+{
+       struct power_supply_hwmon *psyhw = dev_get_drvdata(dev);
+       struct power_supply *psy = psyhw->psy;
+       union power_supply_propval pspval;
+       int prop;
+
+       prop = power_supply_hwmon_to_property(type, attr, channel);
+       if (prop < 0)
+               return prop;
+
+       pspval.intval = val;
+
+       switch (type) {
+       /*
+        * Both voltage and current is reported in units of
+        * microvolts/microamps, so we need to adjust it to
+        * milliamps(volts)
+        */
+       case hwmon_curr:
+       case hwmon_in:
+               if (check_mul_overflow(pspval.intval, 1000,
+                                      &pspval.intval))
+                       return -EOVERFLOW;
+               break;
+       /*
+        * Temp needs to be converted from 1/10 C to milli-C
+        */
+       case hwmon_temp:
+               pspval.intval = DIV_ROUND_CLOSEST(pspval.intval, 100);
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return power_supply_set_property(psy, prop, &pspval);
+}
+
+static const struct hwmon_ops power_supply_hwmon_ops = {
+       .is_visible     = power_supply_hwmon_is_visible,
+       .read           = power_supply_hwmon_read,
+       .write          = power_supply_hwmon_write,
+       .read_string    = power_supply_hwmon_read_string,
+};
+
+static const struct hwmon_channel_info *power_supply_hwmon_info[] = {
+       HWMON_CHANNEL_INFO(temp,
+                          HWMON_T_LABEL     |
+                          HWMON_T_INPUT     |
+                          HWMON_T_MAX       |
+                          HWMON_T_MIN       |
+                          HWMON_T_MIN_ALARM |
+                          HWMON_T_MIN_ALARM,
+
+                          HWMON_T_LABEL     |
+                          HWMON_T_INPUT     |
+                          HWMON_T_MIN_ALARM |
+                          HWMON_T_LABEL     |
+                          HWMON_T_MAX_ALARM),
+
+       HWMON_CHANNEL_INFO(curr,
+                          HWMON_C_AVERAGE |
+                          HWMON_C_MAX     |
+                          HWMON_C_INPUT),
+
+       HWMON_CHANNEL_INFO(in,
+                          HWMON_I_AVERAGE |
+                          HWMON_I_MIN     |
+                          HWMON_I_MAX     |
+                          HWMON_I_INPUT),
+       NULL
+};
+
+static const struct hwmon_chip_info power_supply_hwmon_chip_info = {
+       .ops = &power_supply_hwmon_ops,
+       .info = power_supply_hwmon_info,
+};
+
+static void power_supply_hwmon_bitmap_free(void *data)
+{
+       bitmap_free(data);
+}
+
+int devm_power_supply_add_hwmon_sysfs(struct power_supply *psy)
+{
+       const struct power_supply_desc *desc = psy->desc;
+       struct power_supply_hwmon *psyhw;
+       struct device *dev = &psy->dev;
+       struct device *hwmon;
+       int ret, i;
+
+       if (!devres_open_group(dev, NULL, GFP_KERNEL))
+               return -ENOMEM;
+
+       psyhw = devm_kzalloc(dev, sizeof(*psyhw), GFP_KERNEL);
+       if (!psyhw) {
+               ret = -ENOMEM;
+               goto error;
+       }
+
+       psyhw->psy = psy;
+       psyhw->props = bitmap_zalloc(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG + 1,
+                                    GFP_KERNEL);
+       if (!psyhw->props) {
+               ret = -ENOMEM;
+               goto error;
+       }
+
+       ret = devm_add_action(dev, power_supply_hwmon_bitmap_free,
+                             psyhw->props);
+       if (ret)
+               goto error;
+
+       for (i = 0; i < desc->num_properties; i++) {
+               const enum power_supply_property prop = desc->properties[i];
+
+               switch (prop) {
+               case POWER_SUPPLY_PROP_CURRENT_AVG:
+               case POWER_SUPPLY_PROP_CURRENT_MAX:
+               case POWER_SUPPLY_PROP_CURRENT_NOW:
+               case POWER_SUPPLY_PROP_TEMP:
+               case POWER_SUPPLY_PROP_TEMP_MAX:
+               case POWER_SUPPLY_PROP_TEMP_MIN:
+               case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+               case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+               case POWER_SUPPLY_PROP_TEMP_AMBIENT:
+               case POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN:
+               case POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX:
+               case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+               case POWER_SUPPLY_PROP_VOLTAGE_MIN:
+               case POWER_SUPPLY_PROP_VOLTAGE_MAX:
+               case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+                       set_bit(prop, psyhw->props);
+                       break;
+               default:
+                       break;
+               }
+       }
+
+       hwmon = devm_hwmon_device_register_with_info(dev, psy->desc->name,
+                                               psyhw,
+                                               &power_supply_hwmon_chip_info,
+                                               NULL);
+       ret = PTR_ERR_OR_ZERO(hwmon);
+       if (ret)
+               goto error;
+
+       devres_remove_group(dev, NULL);
+       return 0;
+error:
+       devres_release_group(dev, NULL);
+       return ret;
+}
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index bdab14c7ca4d..39343bc4a3f8 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -475,4 +475,13 @@ static inline bool power_supply_is_watt_property(enum 
power_supply_property psp)
        return 0;
 }
 
+#ifdef CONFIG_POWER_SUPPLY_HWMON
+int devm_power_supply_add_hwmon_sysfs(struct power_supply *psy);
+#else
+static int devm_power_supply_add_hwmon_sysfs(struct power_supply *psy)
+{
+       return 0;
+}
+#endif
+
 #endif /* __LINUX_POWER_SUPPLY_H__ */
-- 
2.21.0

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