cros_ec: Allow reading the battery-charge state

Add a function to read this information from the EC. It is useful for
determining whether the battery has enough charge to boot.
Signed-off-by: NSimon Glass <sjg@chromium.org>

drivers/misc/cros_ec.c

@@ -1661,6 +1661,23 @@ int cros_ec_get_switches(struct udevice *dev)
 	return ret;
 }
 
+int cros_ec_read_batt_charge(struct udevice *dev, uint *chargep)
+{
+	struct ec_params_charge_state req;
+	struct ec_response_charge_state resp;
+	int ret;
+
+	req.cmd = CHARGE_STATE_CMD_GET_STATE;
+	ret = ec_command(dev, EC_CMD_CHARGE_STATE, 0, &req, sizeof(req),
+			 &resp, sizeof(resp));
+	if (ret)
+		return log_msg_ret("read", ret);
+
+	*chargep = resp.get_state.batt_state_of_charge;
+
+	return 0;
+}
+
 UCLASS_DRIVER(cros_ec) = {
 	.id		= UCLASS_CROS_EC,
 	.name		= "cros-ec",

include/cros_ec.h

@@ -652,4 +652,12 @@ int cros_ec_vstore_read(struct udevice *dev, int slot, uint8_t *data);
 int cros_ec_vstore_write(struct udevice *dev, int slot, const uint8_t *data,
 			 size_t size);
 
+/**
+ * cros_ec_read_batt_charge() - Read the battery-charge state
+ *
+ * @dev: CROS-EC device
+ * @chargep: Return battery-charge state as a percentage
+ */
+int cros_ec_read_batt_charge(struct udevice *dev, uint *chargep);
+
 #endif