platform/chrome: wilco_ec: Add charging config driver

Add a device to control the charging algorithm used on Wilco devices,
which will be picked up by the drivers/power/supply/wilco-charger.c
driver. See Documentation/ABI/testing/sysfs-class-power-wilco for the
userspace interface and other info.
Signed-off-by: Nick Crews <ncrews@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/platform/chrome/wilco_ec/core.c

@@ -93,6 +93,16 @@ static int wilco_ec_probe(struct platform_device *pdev)
 		goto unregister_rtc;
 	}
 
+	/* Register child device to be found by charger config driver. */
+	ec->charger_pdev = platform_device_register_data(dev, "wilco-charger",
+							 PLATFORM_DEVID_AUTO,
+							 NULL, 0);
+	if (IS_ERR(ec->charger_pdev)) {
+		dev_err(dev, "Failed to create charger platform device\n");
+		ret = PTR_ERR(ec->charger_pdev);
+		goto remove_sysfs;
+	}
+
 	/* Register child device that will be found by the telemetry driver. */
 	ec->telem_pdev = platform_device_register_data(dev, "wilco_telem",
 						       PLATFORM_DEVID_AUTO,
@@ -100,11 +110,13 @@ static int wilco_ec_probe(struct platform_device *pdev)
 	if (IS_ERR(ec->telem_pdev)) {
 		dev_err(dev, "Failed to create telemetry platform device\n");
 		ret = PTR_ERR(ec->telem_pdev);
-		goto remove_sysfs;
+		goto unregister_charge_config;
 	}
 
 	return 0;
 
+unregister_charge_config:
+	platform_device_unregister(ec->charger_pdev);
 remove_sysfs:
 	wilco_ec_remove_sysfs(ec);
 unregister_rtc:
@@ -120,6 +132,7 @@ static int wilco_ec_remove(struct platform_device *pdev)
 {
 	struct wilco_ec_device *ec = platform_get_drvdata(pdev);
 
+	platform_device_unregister(ec->charger_pdev);
 	wilco_ec_remove_sysfs(ec);
 	platform_device_unregister(ec->telem_pdev);
 	platform_device_unregister(ec->rtc_pdev);

include/linux/platform_data/wilco-ec.h

@@ -29,6 +29,7 @@
  * @data_size: Size of the data buffer used for EC communication.
  * @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
  * @rtc_pdev: The child platform_device used by the RTC sub-driver.
+ * @charger_pdev: Child platform_device used by the charger config sub-driver.
  * @telem_pdev: The child platform_device used by the telemetry sub-driver.
  */
 struct wilco_ec_device {
@@ -41,6 +42,7 @@ struct wilco_ec_device {
 	size_t data_size;
 	struct platform_device *debugfs_pdev;
 	struct platform_device *rtc_pdev;
+	struct platform_device *charger_pdev;
 	struct platform_device *telem_pdev;
 };