1 files changed, 144 insertions, 523 deletions

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 41dccced5026..39e611695053 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -5,461 +5,126 @@
  * Copyright (C) 2014 Google, Inc.
  */
 
-#include <linux/fs.h>
+#include <linux/kconfig.h>
 #include <linux/mfd/core.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
-#include <linux/pm.h>
+#include <linux/platform_data/cros_ec_chardev.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
 #include <linux/slab.h>
-#include <linux/uaccess.h>
-
-#include "cros_ec_dev.h"
 
 #define DRV_NAME "cros-ec-dev"
 
-/* Device variables */
-#define CROS_MAX_DEV 128
-static int ec_major;
-
 static struct class cros_class = {
 	.owner          = THIS_MODULE,
 	.name           = "chromeos",
 };
 
-/* Basic communication */
-static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
-{
-	struct ec_response_get_version *resp;
-	static const char * const current_image_name[] = {
-		"unknown", "read-only", "read-write", "invalid",
-	};
-	struct cros_ec_command *msg;
-	int ret;
-
-	msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
-	if (!msg)
-		return -ENOMEM;
-
-	msg->version = 0;
-	msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
-	msg->insize = sizeof(*resp);
-	msg->outsize = 0;
-
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
-	if (ret < 0)
-		goto exit;
-
-	if (msg->result != EC_RES_SUCCESS) {
-		snprintf(str, maxlen,
-			 "%s\nUnknown EC version: EC returned %d\n",
-			 CROS_EC_DEV_VERSION, msg->result);
-		ret = -EINVAL;
-		goto exit;
-	}
-
-	resp = (struct ec_response_get_version *)msg->data;
-	if (resp->current_image >= ARRAY_SIZE(current_image_name))
-		resp->current_image = 3; /* invalid */
-
-	snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
-		 resp->version_string_ro, resp->version_string_rw,
-		 current_image_name[resp->current_image]);
-
-	ret = 0;
-exit:
-	kfree(msg);
-	return ret;
-}
-
-static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
-{
-	struct cros_ec_command *msg;
-	int ret;
-
-	if (ec->features[0] == -1U && ec->features[1] == -1U) {
-		/* features bitmap not read yet */
-
-		msg = kmalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
-		if (!msg)
-			return -ENOMEM;
-
-		msg->version = 0;
-		msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
-		msg->insize = sizeof(ec->features);
-		msg->outsize = 0;
-
-		ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
-		if (ret < 0 || msg->result != EC_RES_SUCCESS) {
-			dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
-				 ret, msg->result);
-			memset(ec->features, 0, sizeof(ec->features));
-		} else {
-			memcpy(ec->features, msg->data, sizeof(ec->features));
-		}
-
-		dev_dbg(ec->dev, "EC features %08x %08x\n",
-			ec->features[0], ec->features[1]);
-
-		kfree(msg);
-	}
-
-	return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
-}
-
-/* Device file ops */
-static int ec_device_open(struct inode *inode, struct file *filp)
-{
-	struct cros_ec_dev *ec = container_of(inode->i_cdev,
-					      struct cros_ec_dev, cdev);
-	filp->private_data = ec;
-	nonseekable_open(inode, filp);
-	return 0;
-}
-
-static int ec_device_release(struct inode *inode, struct file *filp)
-{
-	return 0;
-}
-
-static ssize_t ec_device_read(struct file *filp, char __user *buffer,
-			      size_t length, loff_t *offset)
-{
-	struct cros_ec_dev *ec = filp->private_data;
-	char msg[sizeof(struct ec_response_get_version) +
-		 sizeof(CROS_EC_DEV_VERSION)];
-	size_t count;
-	int ret;
-
-	if (*offset != 0)
-		return 0;
-
-	ret = ec_get_version(ec, msg, sizeof(msg));
-	if (ret)
-		return ret;
-
-	count = min(length, strlen(msg));
-
-	if (copy_to_user(buffer, msg, count))
-		return -EFAULT;
-
-	*offset = count;
-	return count;
-}
-
-/* Ioctls */
-static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
-{
-	long ret;
-	struct cros_ec_command u_cmd;
-	struct cros_ec_command *s_cmd;
-
-	if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
-		return -EFAULT;
-
-	if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
-	    (u_cmd.insize > EC_MAX_MSG_BYTES))
-		return -EINVAL;
-
-	s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
-			GFP_KERNEL);
-	if (!s_cmd)
-		return -ENOMEM;
-
-	if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
-		ret = -EFAULT;
-		goto exit;
-	}
-
-	if (u_cmd.outsize != s_cmd->outsize ||
-	    u_cmd.insize != s_cmd->insize) {
-		ret = -EINVAL;
-		goto exit;
-	}
-
-	s_cmd->command += ec->cmd_offset;
-	ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
-	/* Only copy data to userland if data was received. */
-	if (ret < 0)
-		goto exit;
-
-	if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
-		ret = -EFAULT;
-exit:
-	kfree(s_cmd);
-	return ret;
-}
-
-static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
-{
-	struct cros_ec_device *ec_dev = ec->ec_dev;
-	struct cros_ec_readmem s_mem = { };
-	long num;
-
-	/* Not every platform supports direct reads */
-	if (!ec_dev->cmd_readmem)
-		return -ENOTTY;
-
-	if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
-		return -EFAULT;
-
-	num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
-				  s_mem.buffer);
-	if (num <= 0)
-		return num;
-
-	if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
-		return -EFAULT;
-
-	return num;
-}
-
-static long ec_device_ioctl(struct file *filp, unsigned int cmd,
-			    unsigned long arg)
-{
-	struct cros_ec_dev *ec = filp->private_data;
-
-	if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
-		return -ENOTTY;
-
-	switch (cmd) {
-	case CROS_EC_DEV_IOCXCMD:
-		return ec_device_ioctl_xcmd(ec, (void __user *)arg);
-	case CROS_EC_DEV_IOCRDMEM:
-		return ec_device_ioctl_readmem(ec, (void __user *)arg);
-	}
-
-	return -ENOTTY;
-}
-
-/* Module initialization */
-static const struct file_operations fops = {
-	.open = ec_device_open,
-	.release = ec_device_release,
-	.read = ec_device_read,
-	.unlocked_ioctl = ec_device_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl = ec_device_ioctl,
-#endif
+/**
+ * cros_feature_to_name - CrOS feature id to name/short description.
+ * @id: The feature identifier.
+ * @name: Device name associated with the feature id.
+ * @desc: Short name that will be displayed.
+ */
+struct cros_feature_to_name {
+	unsigned int id;
+	const char *name;
+	const char *desc;
 };
 
-static void cros_ec_class_release(struct device *dev)
-{
-	kfree(to_cros_ec_dev(dev));
-}
-
-static void cros_ec_sensors_register(struct cros_ec_dev *ec)
-{
-	/*
-	 * Issue a command to get the number of sensor reported.
-	 * Build an array of sensors driver and register them all.
-	 */
-	int ret, i, id, sensor_num;
-	struct mfd_cell *sensor_cells;
-	struct cros_ec_sensor_platform *sensor_platforms;
-	int sensor_type[MOTIONSENSE_TYPE_MAX];
-	struct ec_params_motion_sense *params;
-	struct ec_response_motion_sense *resp;
-	struct cros_ec_command *msg;
-
-	msg = kzalloc(sizeof(struct cros_ec_command) +
-		      max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
-	if (msg == NULL)
-		return;
-
-	msg->version = 2;
-	msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
-	msg->outsize = sizeof(*params);
-	msg->insize = sizeof(*resp);
-
-	params = (struct ec_params_motion_sense *)msg->data;
-	params->cmd = MOTIONSENSE_CMD_DUMP;
-
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
-	if (ret < 0 || msg->result != EC_RES_SUCCESS) {
-		dev_warn(ec->dev, "cannot get EC sensor information: %d/%d\n",
-			 ret, msg->result);
-		goto error;
-	}
-
-	resp = (struct ec_response_motion_sense *)msg->data;
-	sensor_num = resp->dump.sensor_count;
-	/*
-	 * Allocate 2 extra sensors if lid angle sensor and/or FIFO are needed.
-	 */
-	sensor_cells = kcalloc(sensor_num + 2, sizeof(struct mfd_cell),
-			       GFP_KERNEL);
-	if (sensor_cells == NULL)
-		goto error;
-
-	sensor_platforms = kcalloc(sensor_num,
-				   sizeof(struct cros_ec_sensor_platform),
-				   GFP_KERNEL);
-	if (sensor_platforms == NULL)
-		goto error_platforms;
-
-	memset(sensor_type, 0, sizeof(sensor_type));
-	id = 0;
-	for (i = 0; i < sensor_num; i++) {
-		params->cmd = MOTIONSENSE_CMD_INFO;
-		params->info.sensor_num = i;
-		ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
-		if (ret < 0 || msg->result != EC_RES_SUCCESS) {
-			dev_warn(ec->dev, "no info for EC sensor %d : %d/%d\n",
-				 i, ret, msg->result);
-			continue;
-		}
-		switch (resp->info.type) {
-		case MOTIONSENSE_TYPE_ACCEL:
-			sensor_cells[id].name = "cros-ec-accel";
-			break;
-		case MOTIONSENSE_TYPE_BARO:
-			sensor_cells[id].name = "cros-ec-baro";
-			break;
-		case MOTIONSENSE_TYPE_GYRO:
-			sensor_cells[id].name = "cros-ec-gyro";
-			break;
-		case MOTIONSENSE_TYPE_MAG:
-			sensor_cells[id].name = "cros-ec-mag";
-			break;
-		case MOTIONSENSE_TYPE_PROX:
-			sensor_cells[id].name = "cros-ec-prox";
-			break;
-		case MOTIONSENSE_TYPE_LIGHT:
-			sensor_cells[id].name = "cros-ec-light";
-			break;
-		case MOTIONSENSE_TYPE_ACTIVITY:
-			sensor_cells[id].name = "cros-ec-activity";
-			break;
-		default:
-			dev_warn(ec->dev, "unknown type %d\n", resp->info.type);
-			continue;
-		}
-		sensor_platforms[id].sensor_num = i;
-		sensor_cells[id].id = sensor_type[resp->info.type];
-		sensor_cells[id].platform_data = &sensor_platforms[id];
-		sensor_cells[id].pdata_size =
-			sizeof(struct cros_ec_sensor_platform);
-
-		sensor_type[resp->info.type]++;
-		id++;
-	}
-
-	if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
-		ec->has_kb_wake_angle = true;
-
-	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
-		sensor_cells[id].name = "cros-ec-ring";
-		id++;
-	}
-	if (cros_ec_check_features(ec,
-				EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {
-		sensor_cells[id].name = "cros-ec-lid-angle";
-		id++;
-	}
-
-	ret = mfd_add_devices(ec->dev, 0, sensor_cells, id,
-			      NULL, 0, NULL);
-	if (ret)
-		dev_err(ec->dev, "failed to add EC sensors\n");
-
-	kfree(sensor_platforms);
-error_platforms:
-	kfree(sensor_cells);
-error:
-	kfree(msg);
-}
-
-static struct cros_ec_sensor_platform sensor_platforms[] = {
-	{ .sensor_num = 0 },
-	{ .sensor_num = 1 }
+/**
+ * cros_feature_to_cells - CrOS feature id to mfd cells association.
+ * @id: The feature identifier.
+ * @mfd_cells: Pointer to the array of mfd cells that needs to be added.
+ * @num_cells: Number of mfd cells into the array.
+ */
+struct cros_feature_to_cells {
+	unsigned int id;
+	const struct mfd_cell *mfd_cells;
+	unsigned int num_cells;
 };
 
-static const struct mfd_cell cros_ec_accel_legacy_cells[] = {
+static const struct cros_feature_to_name cros_mcu_devices[] = {
 	{
-		.name = "cros-ec-accel-legacy",
-		.platform_data = &sensor_platforms[0],
-		.pdata_size = sizeof(struct cros_ec_sensor_platform),
+		.id	= EC_FEATURE_FINGERPRINT,
+		.name	= CROS_EC_DEV_FP_NAME,
+		.desc	= "Fingerprint",
 	},
 	{
-		.name = "cros-ec-accel-legacy",
-		.platform_data = &sensor_platforms[1],
-		.pdata_size = sizeof(struct cros_ec_sensor_platform),
-	}
+		.id	= EC_FEATURE_ISH,
+		.name	= CROS_EC_DEV_ISH_NAME,
+		.desc	= "Integrated Sensor Hub",
+	},
+	{
+		.id	= EC_FEATURE_SCP,
+		.name	= CROS_EC_DEV_SCP_NAME,
+		.desc	= "System Control Processor",
+	},
+	{
+		.id	= EC_FEATURE_TOUCHPAD,
+		.name	= CROS_EC_DEV_TP_NAME,
+		.desc	= "Touchpad",
+	},
 };
 
-static void cros_ec_accel_legacy_register(struct cros_ec_dev *ec)
-{
-	struct cros_ec_device *ec_dev = ec->ec_dev;
-	u8 status;
-	int ret;
-
-	/*
-	 * ECs that need legacy support are the main EC, directly connected to
-	 * the AP.
-	 */
-	if (ec->cmd_offset != 0)
-		return;
-
-	/*
-	 * Check if EC supports direct memory reads and if EC has
-	 * accelerometers.
-	 */
-	if (ec_dev->cmd_readmem) {
-		ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS, 1,
-					  &status);
-		if (ret < 0) {
-			dev_warn(ec->dev, "EC direct read error.\n");
-			return;
-		}
-
-		/* Check if EC has accelerometers. */
-		if (!(status & EC_MEMMAP_ACC_STATUS_PRESENCE_BIT)) {
-			dev_info(ec->dev, "EC does not have accelerometers.\n");
-			return;
-		}
-	}
-
-	/*
-	 * The device may still support accelerometers:
-	 * it would be an older ARM based device that do not suppor the
-	 * EC_CMD_GET_FEATURES command.
-	 *
-	 * Register 2 accelerometers, we will fail in the IIO driver if there
-	 * are no sensors.
-	 */
-	ret = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
-			      cros_ec_accel_legacy_cells,
-			      ARRAY_SIZE(cros_ec_accel_legacy_cells),
-			      NULL, 0, NULL);
-	if (ret)
-		dev_err(ec_dev->dev, "failed to add EC sensors\n");
-}
-
 static const struct mfd_cell cros_ec_cec_cells[] = {
-	{ .name = "cros-ec-cec" }
+	{ .name = "cros-ec-cec", },
 };
 
 static const struct mfd_cell cros_ec_rtc_cells[] = {
-	{ .name = "cros-ec-rtc" }
+	{ .name = "cros-ec-rtc", },
+};
+
+static const struct mfd_cell cros_ec_sensorhub_cells[] = {
+	{ .name = "cros-ec-sensorhub", },
 };
 
 static const struct mfd_cell cros_usbpd_charger_cells[] = {
-	{ .name = "cros-usbpd-charger" },
-	{ .name = "cros-usbpd-logger" },
+	{ .name = "cros-usbpd-charger", },
+	{ .name = "cros-usbpd-logger", },
+};
+
+static const struct mfd_cell cros_usbpd_notify_cells[] = {
+	{ .name = "cros-usbpd-notify", },
+};
+
+static const struct cros_feature_to_cells cros_subdevices[] = {
+	{
+		.id		= EC_FEATURE_CEC,
+		.mfd_cells	= cros_ec_cec_cells,
+		.num_cells	= ARRAY_SIZE(cros_ec_cec_cells),
+	},
+	{
+		.id		= EC_FEATURE_RTC,
+		.mfd_cells	= cros_ec_rtc_cells,
+		.num_cells	= ARRAY_SIZE(cros_ec_rtc_cells),
+	},
+	{
+		.id		= EC_FEATURE_USB_PD,
+		.mfd_cells	= cros_usbpd_charger_cells,
+		.num_cells	= ARRAY_SIZE(cros_usbpd_charger_cells),
+	},
 };
 
 static const struct mfd_cell cros_ec_platform_cells[] = {
-	{ .name = "cros-ec-debugfs" },
-	{ .name = "cros-ec-lightbar" },
-	{ .name = "cros-ec-sysfs" },
+	{ .name = "cros-ec-chardev", },
+	{ .name = "cros-ec-debugfs", },
+	{ .name = "cros-ec-lightbar", },
+	{ .name = "cros-ec-sysfs", },
 };
 
 static const struct mfd_cell cros_ec_vbc_cells[] = {
-	{ .name = "cros-ec-vbc" }
+	{ .name = "cros-ec-vbc", }
 };
 
+static void cros_ec_class_release(struct device *dev)
+{
+	kfree(to_cros_ec_dev(dev));
+}
+
 static int ec_device_probe(struct platform_device *pdev)
 {
 	int retval = -ENOMEM;
@@ -467,6 +132,7 @@ static int ec_device_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 	struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
+	int i;
 
 	if (!ec)
 		return retval;
@@ -478,57 +144,27 @@ static int ec_device_probe(struct platform_device *pdev)
 	ec->features[0] = -1U; /* Not cached yet */
 	ec->features[1] = -1U; /* Not cached yet */
 	device_initialize(&ec->class_dev);
-	cdev_init(&ec->cdev, &fops);
-
-	/* Check whether this is actually a Fingerprint MCU rather than an EC */
-	if (cros_ec_check_features(ec, EC_FEATURE_FINGERPRINT)) {
-		dev_info(dev, "CrOS Fingerprint MCU detected.\n");
-		/*
-		 * Help userspace differentiating ECs from FP MCU,
-		 * regardless of the probing order.
-		 */
-		ec_platform->ec_name = CROS_EC_DEV_FP_NAME;
-	}
-
-	/*
-	 * Check whether this is actually an Integrated Sensor Hub (ISH)
-	 * rather than an EC.
-	 */
-	if (cros_ec_check_features(ec, EC_FEATURE_ISH)) {
-		dev_info(dev, "CrOS ISH MCU detected.\n");
-		/*
-		 * Help userspace differentiating ECs from ISH MCU,
-		 * regardless of the probing order.
-		 */
-		ec_platform->ec_name = CROS_EC_DEV_ISH_NAME;
-	}
-
-	/* Check whether this is actually a Touchpad MCU rather than an EC */
-	if (cros_ec_check_features(ec, EC_FEATURE_TOUCHPAD)) {
-		dev_info(dev, "CrOS Touchpad MCU detected.\n");
-		/*
-		 * Help userspace differentiating ECs from TP MCU,
-		 * regardless of the probing order.
-		 */
-		ec_platform->ec_name = CROS_EC_DEV_TP_NAME;
-	}
 
-	/* Check whether this is actually a SCP rather than an EC. */
-	if (cros_ec_check_features(ec, EC_FEATURE_SCP)) {
-		dev_info(dev, "CrOS SCP MCU detected.\n");
+	for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
 		/*
-		 * Help userspace differentiating ECs from SCP,
-		 * regardless of the probing order.
+		 * Check whether this is actually a dedicated MCU rather
+		 * than an standard EC.
 		 */
-		ec_platform->ec_name = CROS_EC_DEV_SCP_NAME;
+		if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
+			dev_info(dev, "CrOS %s MCU detected\n",
+				 cros_mcu_devices[i].desc);
+			/*
+			 * Help userspace differentiating ECs from other MCU,
+			 * regardless of the probing order.
+			 */
+			ec_platform->ec_name = cros_mcu_devices[i].name;
+			break;
+		}
 	}
 
 	/*
 	 * Add the class device
-	 * Link to the character device for creating the /dev entry
-	 * in devtmpfs.
 	 */
-	ec->class_dev.devt = MKDEV(ec_major, pdev->id);
 	ec->class_dev.class = &cros_class;
 	ec->class_dev.parent = dev;
 	ec->class_dev.release = cros_ec_class_release;
@@ -539,60 +175,60 @@ static int ec_device_probe(struct platform_device *pdev)
 		goto failed;
 	}
 
-	/* check whether this EC is a sensor hub. */
-	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
-		cros_ec_sensors_register(ec);
-	else
-		/* Workaroud for older EC firmware */
-		cros_ec_accel_legacy_register(ec);
-
-	/* Check whether this EC instance has CEC host command support */
-	if (cros_ec_check_features(ec, EC_FEATURE_CEC)) {
-		retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
-					 cros_ec_cec_cells,
-					 ARRAY_SIZE(cros_ec_cec_cells),
-					 NULL, 0, NULL);
-		if (retval)
-			dev_err(ec->dev,
-				"failed to add cros-ec-cec device: %d\n",
-				retval);
-	}
+	retval = device_add(&ec->class_dev);
+	if (retval)
+		goto failed;
 
-	/* Check whether this EC instance has RTC host command support */
-	if (cros_ec_check_features(ec, EC_FEATURE_RTC)) {
-		retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
-					 cros_ec_rtc_cells,
-					 ARRAY_SIZE(cros_ec_rtc_cells),
-					 NULL, 0, NULL);
+	/* check whether this EC is a sensor hub. */
+	if (cros_ec_get_sensor_count(ec) > 0) {
+		retval = mfd_add_hotplug_devices(ec->dev,
+				cros_ec_sensorhub_cells,
+				ARRAY_SIZE(cros_ec_sensorhub_cells));
 		if (retval)
-			dev_err(ec->dev,
-				"failed to add cros-ec-rtc device: %d\n",
-				retval);
+			dev_err(ec->dev, "failed to add %s subdevice: %d\n",
+				cros_ec_sensorhub_cells->name, retval);
 	}
 
-	/* Check whether this EC instance has the PD charge manager */
-	if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
-		retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
-					 cros_usbpd_charger_cells,
-					 ARRAY_SIZE(cros_usbpd_charger_cells),
-					 NULL, 0, NULL);
-		if (retval)
-			dev_err(ec->dev,
-				"failed to add cros-usbpd-charger device: %d\n",
-				retval);
+	/*
+	 * The following subdevices can be detected by sending the
+	 * EC_FEATURE_GET_CMD Embedded Controller device.
+	 */
+	for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
+		if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
+			retval = mfd_add_hotplug_devices(ec->dev,
+						cros_subdevices[i].mfd_cells,
+						cros_subdevices[i].num_cells);
+			if (retval)
+				dev_err(ec->dev,
+					"failed to add %s subdevice: %d\n",
+					cros_subdevices[i].mfd_cells->name,
+					retval);
+		}
 	}
 
-	/* We can now add the sysfs class, we know which parameter to show */
-	retval = cdev_device_add(&ec->cdev, &ec->class_dev);
-	if (retval) {
-		dev_err(dev, "cdev_device_add failed => %d\n", retval);
-		goto failed;
+	/*
+	 * The PD notifier driver cell is separate since it only needs to be
+	 * explicitly added on platforms that don't have the PD notifier ACPI
+	 * device entry defined.
+	 */
+	if (IS_ENABLED(CONFIG_OF)) {
+		if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
+			retval = mfd_add_hotplug_devices(ec->dev,
+					cros_usbpd_notify_cells,
+					ARRAY_SIZE(cros_usbpd_notify_cells));
+			if (retval)
+				dev_err(ec->dev,
+					"failed to add PD notify devices: %d\n",
+					retval);
+		}
 	}
 
-	retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
-				 cros_ec_platform_cells,
-				 ARRAY_SIZE(cros_ec_platform_cells),
-				 NULL, 0, NULL);
+	/*
+	 * The following subdevices cannot be detected by sending the
+	 * EC_FEATURE_GET_CMD to the Embedded Controller device.
+	 */
+	retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
+					 ARRAY_SIZE(cros_ec_platform_cells));
 	if (retval)
 		dev_warn(ec->dev,
 			 "failed to add cros-ec platform devices: %d\n",
@@ -601,10 +237,8 @@ static int ec_device_probe(struct platform_device *pdev)
 	/* Check whether this EC instance has a VBC NVRAM */
 	node = ec->ec_dev->dev->of_node;
 	if (of_property_read_bool(node, "google,has-vbc-nvram")) {
-		retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
-					 cros_ec_vbc_cells,
-					 ARRAY_SIZE(cros_ec_vbc_cells),
-					 NULL, 0, NULL);
+		retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
+						ARRAY_SIZE(cros_ec_vbc_cells));
 		if (retval)
 			dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 				 retval);
@@ -622,7 +256,6 @@ static int ec_device_remove(struct platform_device *pdev)
 	struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 
 	mfd_remove_devices(ec->dev);
-	cdev_del(&ec->cdev);
 	device_unregister(&ec->class_dev);
 	return 0;
 }
@@ -645,7 +278,6 @@ static struct platform_driver cros_ec_dev_driver = {
 static int __init cros_ec_dev_init(void)
 {
 	int ret;
-	dev_t dev = 0;
 
 	ret  = class_register(&cros_class);
 	if (ret) {
@@ -653,14 +285,6 @@ static int __init cros_ec_dev_init(void)
 		return ret;
 	}
 
-	/* Get a range of minor numbers (starting with 0) to work with */
-	ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
-	if (ret < 0) {
-		pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
-		goto failed_chrdevreg;
-	}
-	ec_major = MAJOR(dev);
-
 	/* Register the driver */
 	ret = platform_driver_register(&cros_ec_dev_driver);
 	if (ret < 0) {
@@ -670,8 +294,6 @@ static int __init cros_ec_dev_init(void)
 	return 0;
 
 failed_devreg:
-	unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
-failed_chrdevreg:
 	class_unregister(&cros_class);
 	return ret;
 }
@@ -679,7 +301,6 @@ failed_chrdevreg:
 static void __exit cros_ec_dev_exit(void)
 {
 	platform_driver_unregister(&cros_ec_dev_driver);
-	unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
 	class_unregister(&cros_class);
 }