This patch adds battery gauge driver for Acer Iconia Tab A500 device.
The battery gauge function is provided via the Embedded Controller,
which is found on the Acer A500.
Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/power/supply/Kconfig | 6 +
drivers/power/supply/Makefile | 1 +
drivers/power/supply/acer_a500_battery.c | 297 +++++++++++++++++++++++
3 files changed, 304 insertions(+)
create mode 100644 drivers/power/supply/acer_a500_battery.c
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index eec646c568b7..bc493173ddbc 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -774,4 +774,10 @@ config RN5T618_POWER
This driver can also be built as a module. If so, the module will be
called rn5t618_power.
+config BATTERY_ACER_A500
+ tristate "Acer Iconia Tab A500 battery driver"
+ depends on MFD_ACER_A500_EC
+ help
+ Say Y to include support for Acer Iconia Tab A500 battery fuel gauge.
+
endif # POWER_SUPPLY
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index dd4b86318cd9..0607a3d64c0f 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -98,3 +98,4 @@ obj-$(CONFIG_CHARGER_BD70528) += bd70528-charger.o
obj-$(CONFIG_CHARGER_BD99954) += bd99954-charger.o
obj-$(CONFIG_CHARGER_WILCO) += wilco-charger.o
obj-$(CONFIG_RN5T618_POWER) += rn5t618_power.o
+obj-$(CONFIG_BATTERY_ACER_A500) += acer_a500_battery.o
diff --git a/drivers/power/supply/acer_a500_battery.c b/drivers/power/supply/acer_a500_battery.c
new file mode 100644
index 000000000000..93135933c8af
--- /dev/null
+++ b/drivers/power/supply/acer_a500_battery.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Battery driver for Acer Iconia Tab A500.
+ *
+ * Copyright 2020 GRATE-driver project.
+ *
+ * Based on downstream driver from Acer Inc.
+ * Based on NVIDIA Gas Gauge driver for SBS Compliant Batteries.
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+enum {
+ REG_CAPACITY,
+ REG_VOLTAGE,
+ REG_CURRENT,
+ REG_DESIGN_CAPACITY,
+ REG_TEMPERATURE,
+};
+
+#define EC_DATA(_reg, _psp) { \
+ .psp = POWER_SUPPLY_PROP_ ## _psp, \
+ .reg = _reg, \
+}
+
+static const struct battery_register {
+ enum power_supply_property psp;
+ unsigned int reg;
+} ec_data[] = {
+ [REG_CAPACITY] = EC_DATA(0x00, CAPACITY),
+ [REG_VOLTAGE] = EC_DATA(0x01, VOLTAGE_NOW),
+ [REG_CURRENT] = EC_DATA(0x03, CURRENT_NOW),
+ [REG_DESIGN_CAPACITY] = EC_DATA(0x08, CHARGE_FULL_DESIGN),
+ [REG_TEMPERATURE] = EC_DATA(0x0a, TEMP),
+};
+
+static const enum power_supply_property a500_battery_properties[] = {
+ POWER_SUPPLY_PROP_CAPACITY,
+ POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+ POWER_SUPPLY_PROP_CURRENT_NOW,
+ POWER_SUPPLY_PROP_PRESENT,
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_TECHNOLOGY,
+ POWER_SUPPLY_PROP_TEMP,
+ POWER_SUPPLY_PROP_VOLTAGE_NOW,
+};
+
+struct a500_battery {
+ struct delayed_work poll_work;
+ struct power_supply *psy;
+ struct regmap *rmap;
+ unsigned int capacity;
+};
+
+static bool a500_battery_update_capacity(struct a500_battery *bat)
+{
+ unsigned int capacity;
+ int err;
+
+ err = regmap_read(bat->rmap, ec_data[REG_CAPACITY].reg, &capacity);
+ if (err)
+ return false;
+
+ /* capacity can be >100% even if max value is 100% */
+ capacity = min(capacity, 100u);
+
+ if (bat->capacity != capacity) {
+ bat->capacity = capacity;
+ return true;
+ }
+
+ return false;
+}
+
+static int a500_battery_get_status(struct a500_battery *bat)
+{
+ if (bat->capacity < 100) {
+ if (power_supply_am_i_supplied(bat->psy))
+ return POWER_SUPPLY_STATUS_CHARGING;
+ else
+ return POWER_SUPPLY_STATUS_DISCHARGING;
+ }
+
+ return POWER_SUPPLY_STATUS_FULL;
+}
+
+static void a500_battery_unit_adjustment(struct device *dev,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ const unsigned int base_unit_conversion = 1000;
+ const unsigned int temp_kelvin_to_celsius = 2731;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+ case POWER_SUPPLY_PROP_CURRENT_NOW:
+ case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+ val->intval *= base_unit_conversion;
+ break;
+
+ case POWER_SUPPLY_PROP_TEMP:
+ val->intval -= temp_kelvin_to_celsius;
+ break;
+
+ case POWER_SUPPLY_PROP_PRESENT:
+ val->intval = !!val->intval;
+ break;
+
+ default:
+ dev_dbg(dev,
+ "%s: no need for unit conversion %d\n", __func__, psp);
+ }
+}
+
+static int a500_battery_get_ec_data_index(struct device *dev,
+ enum power_supply_property psp)
+{
+ unsigned int i;
+
+ /*
+ * DESIGN_CAPACITY register always returns a non-zero value if
+ * battery is connected and zero if disconnected, hence we'll use
+ * it for judging the battery presence.
+ */
+ if (psp == POWER_SUPPLY_PROP_PRESENT)
+ psp = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;
+
+ for (i = 0; i < ARRAY_SIZE(ec_data); i++)
+ if (psp == ec_data[i].psp)
+ return i;
+
+ dev_dbg(dev, "%s: invalid property %u\n", __func__, psp);
+
+ return -EINVAL;
+}
+
+static int a500_battery_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct a500_battery *bat = power_supply_get_drvdata(psy);
+ struct device *dev = psy->dev.parent;
+ int ret = 0;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_STATUS:
+ val->intval = a500_battery_get_status(bat);
+ break;
+
+ case POWER_SUPPLY_PROP_TECHNOLOGY:
+ val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+ break;
+
+ case POWER_SUPPLY_PROP_CAPACITY:
+ a500_battery_update_capacity(bat);
+ val->intval = bat->capacity;
+ break;
+
+ case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+ case POWER_SUPPLY_PROP_CURRENT_NOW:
+ case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+ case POWER_SUPPLY_PROP_PRESENT:
+ case POWER_SUPPLY_PROP_TEMP:
+ ret = a500_battery_get_ec_data_index(dev, psp);
+ if (ret < 0)
+ break;
+
+ ret = regmap_read(bat->rmap, ec_data[ret].reg, &val->intval);
+ break;
+
+ default:
+ dev_err(dev, "%s: invalid property %u\n", __func__, psp);
+ return -EINVAL;
+ }
+
+ if (!ret) {
+ /* convert units to match requirements of power supply class */
+ a500_battery_unit_adjustment(dev, psp, val);
+ }
+
+ dev_dbg(dev, "%s: property = %d, value = %x\n",
+ __func__, psp, val->intval);
+
+ /* return NODATA for properties if battery not presents */
+ if (ret)
+ return -ENODATA;
+
+ return 0;
+}
+
+static void a500_battery_poll_work(struct work_struct *work)
+{
+ struct a500_battery *bat;
+ bool capacity_changed;
+
+ bat = container_of(work, struct a500_battery, poll_work.work);
+ capacity_changed = a500_battery_update_capacity(bat);
+
+ if (capacity_changed)
+ power_supply_changed(bat->psy);
+
+ /* continuously send uevent notification */
+ schedule_delayed_work(&bat->poll_work, 30 * HZ);
+}
+
+static const struct power_supply_desc a500_battery_desc = {
+ .name = "ec-battery",
+ .type = POWER_SUPPLY_TYPE_BATTERY,
+ .properties = a500_battery_properties,
+ .get_property = a500_battery_get_property,
+ .num_properties = ARRAY_SIZE(a500_battery_properties),
+ .external_power_changed = power_supply_changed,
+};
+
+static int a500_battery_probe(struct platform_device *pdev)
+{
+ struct power_supply_config psy_cfg = {};
+ struct a500_battery *bat;
+
+ bat = devm_kzalloc(&pdev->dev, sizeof(*bat), GFP_KERNEL);
+ if (!bat)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, bat);
+
+ psy_cfg.of_node = pdev->dev.parent->of_node;
+ psy_cfg.drv_data = bat;
+
+ bat->rmap = dev_get_regmap(pdev->dev.parent, "KB930");
+ if (!bat->rmap)
+ return -EINVAL;
+
+ bat->psy = devm_power_supply_register_no_ws(&pdev->dev,
+ &a500_battery_desc,
+ &psy_cfg);
+ if (IS_ERR(bat->psy))
+ return dev_err_probe(&pdev->dev, PTR_ERR(bat->psy),
+ "failed to register battery\n");
+
+ INIT_DELAYED_WORK(&bat->poll_work, a500_battery_poll_work);
+ schedule_delayed_work(&bat->poll_work, HZ);
+
+ return 0;
+}
+
+static int a500_battery_remove(struct platform_device *pdev)
+{
+ struct a500_battery *bat = dev_get_drvdata(&pdev->dev);
+
+ cancel_delayed_work_sync(&bat->poll_work);
+
+ return 0;
+}
+
+static int __maybe_unused a500_battery_suspend(struct device *dev)
+{
+ struct a500_battery *bat = dev_get_drvdata(dev);
+
+ cancel_delayed_work_sync(&bat->poll_work);
+
+ return 0;
+}
+
+static int __maybe_unused a500_battery_resume(struct device *dev)
+{
+ struct a500_battery *bat = dev_get_drvdata(dev);
+
+ schedule_delayed_work(&bat->poll_work, HZ);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(a500_battery_pm_ops,
+ a500_battery_suspend, a500_battery_resume);
+
+static struct platform_driver a500_battery_driver = {
+ .driver = {
+ .name = "acer-a500-iconia-battery",
+ .pm = &a500_battery_pm_ops,
+ },
+ .probe = a500_battery_probe,
+ .remove = a500_battery_remove,
+};
+module_platform_driver(a500_battery_driver);
+
+MODULE_DESCRIPTION("Battery gauge driver for Acer Iconia Tab A500");
+MODULE_AUTHOR("Dmitry Osipenko <digetx@xxxxxxxxx>");
+MODULE_ALIAS("platform:acer-a500-iconia-battery");
+MODULE_LICENSE("GPL");
--
2.27.0
