--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ChromeOS EC driver for charge control
+ *
+ */
+#include <acpi/battery.h>
+#include <linux/container_of.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#define EC_CHARGE_CONTROL_BEHAVIOURS (BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO) | \
+ BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE) | \
+ BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE))
+
+enum CROS_CHCTL_ATTR {
+ CROS_CHCTL_ATTR_START_THRESHOLD,
+ CROS_CHCTL_ATTR_END_THRESHOLD,
+ CROS_CHCTL_ATTR_CHARGE_BEHAVIOUR,
+ _CROS_CHCTL_ATTR_COUNT
+};
+
+/*
+ * Semantics of data *returned* from the EC API and Linux sysfs differ
+ * slightly, also the v1 API can not return any data.
+ * To match the expected sysfs API, data is never read back from the EC but
+ * cached in the driver.
+ *
+ * Changes to the EC bypassing the driver will not be reflected in sysfs.
+ * Any change to "charge_behaviour" will synchronize the EC with the driver state.
+ */
+
+struct cros_chctl_priv {
+ struct cros_ec_device *cros_ec;
+ struct acpi_battery_hook battery_hook;
+ struct power_supply *hooked_battery;
+ u8 cmd_version;
+
+ /* The callbacks need to access this priv structure.
+ * As neither the struct device nor power_supply are under the drivers
+ * control, embed the attributes within priv to use with container_of().
+ */
+ struct device_attribute device_attrs[_CROS_CHCTL_ATTR_COUNT];
+ struct attribute *attributes[_CROS_CHCTL_ATTR_COUNT];
+ struct attribute_group group;
+
+ enum power_supply_charge_behaviour current_behaviour;
+ u8 current_start_threshold, current_end_threshold;
+};
+
+static int cros_chctl_send_charge_control_cmd(struct cros_ec_device *cros_ec,
+ u8 cmd_version, struct ec_params_charge_control *req)
+{
+ static const u8 outsizes[] = {
+ [1] = offsetof(struct ec_params_charge_control, cmd),
+ [2] = sizeof(struct ec_params_charge_control),
+ [3] = sizeof(struct ec_params_charge_control),
+ };
+
+ struct {
+ struct cros_ec_command msg;
+ union {
+ struct ec_params_charge_control req;
+ struct ec_response_charge_control resp;
+ } __packed data;
+ } __packed buf = {
+ .msg = {
+ .command = EC_CMD_CHARGE_CONTROL,
+ .version = cmd_version,
+ .insize = 0,
+ .outsize = outsizes[cmd_version],
+ },
+ .data.req = *req,
+ };
+
+ return cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
+}
+
+static int cros_chctl_configure_ec(struct cros_chctl_priv *priv)
+{
+ struct ec_params_charge_control req = {};
+
+ req.cmd = EC_CHARGE_CONTROL_CMD_SET;
+
+ switch (priv->current_behaviour) {
+ case POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO:
+ req.mode = CHARGE_CONTROL_NORMAL;
+ break;
+ case POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE:
+ req.mode = CHARGE_CONTROL_IDLE;
+ break;
+ case POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE:
+ req.mode = CHARGE_CONTROL_DISCHARGE;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (priv->current_behaviour == POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO &&
+ !(priv->current_start_threshold == 0 && priv->current_end_threshold == 100)) {
+ req.sustain_soc.lower = priv->current_start_threshold;
+ req.sustain_soc.upper = priv->current_end_threshold;
+ } else {
+ /* Disable charging limits */
+ req.sustain_soc.lower = -1;
+ req.sustain_soc.upper = -1;
+ }
+
+ return cros_chctl_send_charge_control_cmd(priv->cros_ec, priv->cmd_version, &req);
+}
+
+static struct cros_chctl_priv *cros_chctl_attr_to_priv(struct attribute *attr,
+ enum CROS_CHCTL_ATTR idx)
+{
+ struct device_attribute *dev_attr = container_of(attr, struct device_attribute, attr);
+
+ return container_of(dev_attr, struct cros_chctl_priv, device_attrs[idx]);
+}
+
+static ssize_t cros_chctl_store_threshold(struct device *dev, struct cros_chctl_priv *priv,
+ int is_end_threshold, const char *buf, size_t count)
+{
+ int ret, val;
+
+ ret = kstrtoint(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+ if (val < 0 || val > 100)
+ return -EINVAL;
+
+ if (is_end_threshold) {
+ if (val <= priv->current_start_threshold)
+ return -EINVAL;
+ priv->current_end_threshold = val;
+ } else {
+ if (val >= priv->current_end_threshold)
+ return -EINVAL;
+ priv->current_start_threshold = val;
+ }
+
+ if (priv->current_behaviour == POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO) {
+ ret = cros_chctl_configure_ec(priv);
+ if (ret < 0)
+ return ret;
+ }
+
+ return count;
+}
+
+static ssize_t charge_control_start_threshold_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(&attr->attr,
+ CROS_CHCTL_ATTR_START_THRESHOLD);
+
+ return sysfs_emit(buf, "%u\n", (unsigned int)priv->current_start_threshold);
+}
+
+static ssize_t charge_control_start_threshold_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(&attr->attr,
+ CROS_CHCTL_ATTR_START_THRESHOLD);
+
+ return cros_chctl_store_threshold(dev, priv, 0, buf, count);
+}
+
+static ssize_t charge_control_end_threshold_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(&attr->attr,
+ CROS_CHCTL_ATTR_END_THRESHOLD);
+
+ return sysfs_emit(buf, "%u\n", (unsigned int)priv->current_end_threshold);
+}
+
+static ssize_t charge_control_end_threshold_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(&attr->attr,
+ CROS_CHCTL_ATTR_END_THRESHOLD);
+
+ return cros_chctl_store_threshold(dev, priv, 1, buf, count);
+}
+
+static ssize_t charge_behaviour_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(&attr->attr,
+ CROS_CHCTL_ATTR_CHARGE_BEHAVIOUR);
+
+ return power_supply_charge_behaviour_show(dev, EC_CHARGE_CONTROL_BEHAVIOURS,
+ priv->current_behaviour, buf);
+}
+
+static ssize_t charge_behaviour_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(&attr->attr,
+ CROS_CHCTL_ATTR_CHARGE_BEHAVIOUR);
+ enum power_supply_charge_behaviour behaviour;
+ int ret;
+
+ behaviour = power_supply_charge_behaviour_parse(EC_CHARGE_CONTROL_BEHAVIOURS, buf);
+ if (behaviour < 0)
+ return behaviour;
+
+ priv->current_behaviour = behaviour;
+
+ ret = cros_chctl_configure_ec(priv);
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static umode_t cros_chtl_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+ struct cros_chctl_priv *priv = cros_chctl_attr_to_priv(attr, n);
+
+ if (priv->cmd_version < 2) {
+ if (n == CROS_CHCTL_ATTR_START_THRESHOLD)
+ return 0;
+ if (n == CROS_CHCTL_ATTR_END_THRESHOLD)
+ return 0;
+ }
+
+ return attr->mode;
+}
+
+static int cros_chctl_add_battery(struct power_supply *battery, struct acpi_battery_hook *hook)
+{
+ struct cros_chctl_priv *priv = container_of(hook, struct cros_chctl_priv, battery_hook);
+
+ if (priv->hooked_battery)
+ return 0;
+
+ priv->hooked_battery = battery;
+ return device_add_group(&battery->dev, &priv->group);
+}
+
+static int cros_chctl_remove_battery(struct power_supply *battery, struct acpi_battery_hook *hook)
+{
+ struct cros_chctl_priv *priv = container_of(hook, struct cros_chctl_priv, battery_hook);
+
+ if (priv->hooked_battery == battery) {
+ device_remove_group(&battery->dev, &priv->group);
+ priv->hooked_battery = NULL;
+ }
+
+ return 0;
+}
+
+static int cros_chctl_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
+ struct cros_ec_device *cros_ec = ec_dev->ec_dev;
+ struct cros_chctl_priv *priv;
+ size_t i;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ ret = cros_ec_get_cmd_versions(cros_ec, EC_CMD_CHARGE_CONTROL);
+ if (ret < 0)
+ return ret;
+ else if (ret & EC_VER_MASK(3))
+ priv->cmd_version = 3;
+ else if (ret & EC_VER_MASK(2))
+ priv->cmd_version = 2;
+ else if (ret & EC_VER_MASK(1))
+ priv->cmd_version = 1;
+ else
+ return -ENODEV;
+
+ dev_dbg(dev, "Command version: %u\n", (unsigned int)priv->cmd_version);
+
+ priv->cros_ec = cros_ec;
+ priv->device_attrs[CROS_CHCTL_ATTR_START_THRESHOLD] =
+ (struct device_attribute)__ATTR_RW(charge_control_start_threshold);
+ priv->device_attrs[CROS_CHCTL_ATTR_END_THRESHOLD] =
+ (struct device_attribute)__ATTR_RW(charge_control_end_threshold);
+ priv->device_attrs[CROS_CHCTL_ATTR_CHARGE_BEHAVIOUR] =
+ (struct device_attribute)__ATTR_RW(charge_behaviour);
+ for (i = 0; i < _CROS_CHCTL_ATTR_COUNT; i++) {
+ sysfs_attr_init(&priv->device_attrs[i].attr);
+ priv->attributes[i] = &priv->device_attrs[i].attr;
+ }
+ priv->attributes[_CROS_CHCTL_ATTR_COUNT] = NULL;
+ priv->group.is_visible = cros_chtl_attr_is_visible;
+ priv->group.attrs = priv->attributes;
+
+ priv->battery_hook.name = dev_name(dev);
+ priv->battery_hook.add_battery = cros_chctl_add_battery;
+ priv->battery_hook.remove_battery = cros_chctl_remove_battery;
+
+ priv->current_behaviour = POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO;
+ priv->current_start_threshold = 0;
+ priv->current_end_threshold = 100;
+
+ /* Bring EC into well-known state */
+ ret = cros_chctl_configure_ec(priv);
+ if (ret < 0)
+ return ret;
+
+ return devm_battery_hook_register(dev, &priv->battery_hook);
+}
+
+static const struct platform_device_id cros_chctl_id[] = {
+ { "cros-charge-control", 0 },
+ {}
+};
+
+static struct platform_driver cros_chctl_driver = {
+ .driver.name = "cros-charge-control",
+ .probe = cros_chctl_probe,
+ .id_table = cros_chctl_id,
+};
+module_platform_driver(cros_chctl_driver);
+
+MODULE_DEVICE_TABLE(platform, cros_chctl_id);
+MODULE_DESCRIPTION("ChromeOS EC charge control");
+MODULE_LICENSE("GPL");
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