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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /drivers/platform/chrome/wilco_ec/telemetry.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'drivers/platform/chrome/wilco_ec/telemetry.c')
-rw-r--r--drivers/platform/chrome/wilco_ec/telemetry.c472
1 files changed, 472 insertions, 0 deletions
diff --git a/drivers/platform/chrome/wilco_ec/telemetry.c b/drivers/platform/chrome/wilco_ec/telemetry.c
new file mode 100644
index 000000000..60da7a29f
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/telemetry.c
@@ -0,0 +1,472 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Telemetry communication for Wilco EC
+ *
+ * Copyright 2019 Google LLC
+ *
+ * The Wilco Embedded Controller is able to send telemetry data
+ * which is useful for enterprise applications. A daemon running on
+ * the OS sends a command to the EC via a write() to a char device,
+ * and can read the response with a read(). The write() request is
+ * verified by the driver to ensure that it is performing only one
+ * of the allowlisted commands, and that no extraneous data is
+ * being transmitted to the EC. The response is passed directly
+ * back to the reader with no modification.
+ *
+ * The character device will appear as /dev/wilco_telemN, where N
+ * is some small non-negative integer, starting with 0. Only one
+ * process may have the file descriptor open at a time. The calling
+ * userspace program needs to keep the device file descriptor open
+ * between the calls to write() and read() in order to preserve the
+ * response. Up to 32 bytes will be available for reading.
+ *
+ * For testing purposes, try requesting the EC's firmware build
+ * date, by sending the WILCO_EC_TELEM_GET_VERSION command with
+ * argument index=3. i.e. write [0x38, 0x00, 0x03]
+ * to the device node. An ASCII string of the build date is
+ * returned.
+ */
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/platform_data/wilco-ec.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#define TELEM_DEV_NAME "wilco_telem"
+#define TELEM_CLASS_NAME TELEM_DEV_NAME
+#define DRV_NAME TELEM_DEV_NAME
+#define TELEM_DEV_NAME_FMT (TELEM_DEV_NAME "%d")
+static struct class telem_class = {
+ .owner = THIS_MODULE,
+ .name = TELEM_CLASS_NAME,
+};
+
+/* Keep track of all the device numbers used. */
+#define TELEM_MAX_DEV 128
+static int telem_major;
+static DEFINE_IDA(telem_ida);
+
+/* EC telemetry command codes */
+#define WILCO_EC_TELEM_GET_LOG 0x99
+#define WILCO_EC_TELEM_GET_VERSION 0x38
+#define WILCO_EC_TELEM_GET_FAN_INFO 0x2E
+#define WILCO_EC_TELEM_GET_DIAG_INFO 0xFA
+#define WILCO_EC_TELEM_GET_TEMP_INFO 0x95
+#define WILCO_EC_TELEM_GET_TEMP_READ 0x2C
+#define WILCO_EC_TELEM_GET_BATT_EXT_INFO 0x07
+#define WILCO_EC_TELEM_GET_BATT_PPID_INFO 0x8A
+
+#define TELEM_ARGS_SIZE_MAX 30
+
+/*
+ * The following telem_args_get_* structs are embedded within the |args| field
+ * of wilco_ec_telem_request.
+ */
+
+struct telem_args_get_log {
+ u8 log_type;
+ u8 log_index;
+} __packed;
+
+/*
+ * Get a piece of info about the EC firmware version:
+ * 0 = label
+ * 1 = svn_rev
+ * 2 = model_no
+ * 3 = build_date
+ * 4 = frio_version
+ */
+struct telem_args_get_version {
+ u8 index;
+} __packed;
+
+struct telem_args_get_fan_info {
+ u8 command;
+ u8 fan_number;
+ u8 arg;
+} __packed;
+
+struct telem_args_get_diag_info {
+ u8 type;
+ u8 sub_type;
+} __packed;
+
+struct telem_args_get_temp_info {
+ u8 command;
+ u8 index;
+ u8 field;
+ u8 zone;
+} __packed;
+
+struct telem_args_get_temp_read {
+ u8 sensor_index;
+} __packed;
+
+struct telem_args_get_batt_ext_info {
+ u8 var_args[5];
+} __packed;
+
+struct telem_args_get_batt_ppid_info {
+ u8 always1; /* Should always be 1 */
+} __packed;
+
+/**
+ * struct wilco_ec_telem_request - Telemetry command and arguments sent to EC.
+ * @command: One of WILCO_EC_TELEM_GET_* command codes.
+ * @reserved: Must be 0.
+ * @args: The first N bytes are one of telem_args_get_* structs, the rest is 0.
+ */
+struct wilco_ec_telem_request {
+ u8 command;
+ u8 reserved;
+ union {
+ u8 buf[TELEM_ARGS_SIZE_MAX];
+ struct telem_args_get_log get_log;
+ struct telem_args_get_version get_version;
+ struct telem_args_get_fan_info get_fan_info;
+ struct telem_args_get_diag_info get_diag_info;
+ struct telem_args_get_temp_info get_temp_info;
+ struct telem_args_get_temp_read get_temp_read;
+ struct telem_args_get_batt_ext_info get_batt_ext_info;
+ struct telem_args_get_batt_ppid_info get_batt_ppid_info;
+ } args;
+} __packed;
+
+/**
+ * check_telem_request() - Ensure that a request from userspace is valid.
+ * @rq: Request buffer copied from userspace.
+ * @size: Number of bytes copied from userspace.
+ *
+ * Return: 0 if valid, -EINVAL if bad command or reserved byte is non-zero,
+ * -EMSGSIZE if the request is too long.
+ *
+ * We do not want to allow userspace to send arbitrary telemetry commands to
+ * the EC. Therefore we check to ensure that
+ * 1. The request follows the format of struct wilco_ec_telem_request.
+ * 2. The supplied command code is one of the allowlisted commands.
+ * 3. The request only contains the necessary data for the header and arguments.
+ */
+static int check_telem_request(struct wilco_ec_telem_request *rq,
+ size_t size)
+{
+ size_t max_size = offsetof(struct wilco_ec_telem_request, args);
+
+ if (rq->reserved)
+ return -EINVAL;
+
+ switch (rq->command) {
+ case WILCO_EC_TELEM_GET_LOG:
+ max_size += sizeof(rq->args.get_log);
+ break;
+ case WILCO_EC_TELEM_GET_VERSION:
+ max_size += sizeof(rq->args.get_version);
+ break;
+ case WILCO_EC_TELEM_GET_FAN_INFO:
+ max_size += sizeof(rq->args.get_fan_info);
+ break;
+ case WILCO_EC_TELEM_GET_DIAG_INFO:
+ max_size += sizeof(rq->args.get_diag_info);
+ break;
+ case WILCO_EC_TELEM_GET_TEMP_INFO:
+ max_size += sizeof(rq->args.get_temp_info);
+ break;
+ case WILCO_EC_TELEM_GET_TEMP_READ:
+ max_size += sizeof(rq->args.get_temp_read);
+ break;
+ case WILCO_EC_TELEM_GET_BATT_EXT_INFO:
+ max_size += sizeof(rq->args.get_batt_ext_info);
+ break;
+ case WILCO_EC_TELEM_GET_BATT_PPID_INFO:
+ if (rq->args.get_batt_ppid_info.always1 != 1)
+ return -EINVAL;
+
+ max_size += sizeof(rq->args.get_batt_ppid_info);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return (size <= max_size) ? 0 : -EMSGSIZE;
+}
+
+/**
+ * struct telem_device_data - Data for a Wilco EC device that queries telemetry.
+ * @cdev: Char dev that userspace reads and polls from.
+ * @dev: Device associated with the %cdev.
+ * @ec: Wilco EC that we will be communicating with using the mailbox interface.
+ * @available: Boolean of if the device can be opened.
+ */
+struct telem_device_data {
+ struct device dev;
+ struct cdev cdev;
+ struct wilco_ec_device *ec;
+ atomic_t available;
+};
+
+#define TELEM_RESPONSE_SIZE EC_MAILBOX_DATA_SIZE
+
+/**
+ * struct telem_session_data - Data that exists between open() and release().
+ * @dev_data: Pointer to get back to the device data and EC.
+ * @request: Command and arguments sent to EC.
+ * @response: Response buffer of data from EC.
+ * @has_msg: Is there data available to read from a previous write?
+ */
+struct telem_session_data {
+ struct telem_device_data *dev_data;
+ struct wilco_ec_telem_request request;
+ u8 response[TELEM_RESPONSE_SIZE];
+ bool has_msg;
+};
+
+/**
+ * telem_open() - Callback for when the device node is opened.
+ * @inode: inode for this char device node.
+ * @filp: file for this char device node.
+ *
+ * We need to ensure that after writing a command to the device,
+ * the same userspace process reads the corresponding result.
+ * Therefore, we increment a refcount on opening the device, so that
+ * only one process can communicate with the EC at a time.
+ *
+ * Return: 0 on success, or negative error code on failure.
+ */
+static int telem_open(struct inode *inode, struct file *filp)
+{
+ struct telem_device_data *dev_data;
+ struct telem_session_data *sess_data;
+
+ /* Ensure device isn't already open */
+ dev_data = container_of(inode->i_cdev, struct telem_device_data, cdev);
+ if (atomic_cmpxchg(&dev_data->available, 1, 0) == 0)
+ return -EBUSY;
+
+ get_device(&dev_data->dev);
+
+ sess_data = kzalloc(sizeof(*sess_data), GFP_KERNEL);
+ if (!sess_data) {
+ atomic_set(&dev_data->available, 1);
+ return -ENOMEM;
+ }
+ sess_data->dev_data = dev_data;
+ sess_data->has_msg = false;
+
+ stream_open(inode, filp);
+ filp->private_data = sess_data;
+
+ return 0;
+}
+
+static ssize_t telem_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *pos)
+{
+ struct telem_session_data *sess_data = filp->private_data;
+ struct wilco_ec_message msg = {};
+ int ret;
+
+ if (count > sizeof(sess_data->request))
+ return -EMSGSIZE;
+ memset(&sess_data->request, 0, sizeof(sess_data->request));
+ if (copy_from_user(&sess_data->request, buf, count))
+ return -EFAULT;
+ ret = check_telem_request(&sess_data->request, count);
+ if (ret < 0)
+ return ret;
+
+ memset(sess_data->response, 0, sizeof(sess_data->response));
+ msg.type = WILCO_EC_MSG_TELEMETRY;
+ msg.request_data = &sess_data->request;
+ msg.request_size = sizeof(sess_data->request);
+ msg.response_data = sess_data->response;
+ msg.response_size = sizeof(sess_data->response);
+
+ ret = wilco_ec_mailbox(sess_data->dev_data->ec, &msg);
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(sess_data->response))
+ return -EMSGSIZE;
+
+ sess_data->has_msg = true;
+
+ return count;
+}
+
+static ssize_t telem_read(struct file *filp, char __user *buf, size_t count,
+ loff_t *pos)
+{
+ struct telem_session_data *sess_data = filp->private_data;
+
+ if (!sess_data->has_msg)
+ return -ENODATA;
+ if (count > sizeof(sess_data->response))
+ return -EINVAL;
+
+ if (copy_to_user(buf, sess_data->response, count))
+ return -EFAULT;
+
+ sess_data->has_msg = false;
+
+ return count;
+}
+
+static int telem_release(struct inode *inode, struct file *filp)
+{
+ struct telem_session_data *sess_data = filp->private_data;
+
+ atomic_set(&sess_data->dev_data->available, 1);
+ put_device(&sess_data->dev_data->dev);
+ kfree(sess_data);
+
+ return 0;
+}
+
+static const struct file_operations telem_fops = {
+ .open = telem_open,
+ .write = telem_write,
+ .read = telem_read,
+ .release = telem_release,
+ .llseek = no_llseek,
+ .owner = THIS_MODULE,
+};
+
+/**
+ * telem_device_free() - Callback to free the telem_device_data structure.
+ * @d: The device embedded in our device data, which we have been ref counting.
+ *
+ * Once all open file descriptors are closed and the device has been removed,
+ * the refcount of the device will fall to 0 and this will be called.
+ */
+static void telem_device_free(struct device *d)
+{
+ struct telem_device_data *dev_data;
+
+ dev_data = container_of(d, struct telem_device_data, dev);
+ kfree(dev_data);
+}
+
+/**
+ * telem_device_probe() - Callback when creating a new device.
+ * @pdev: platform device that we will be receiving telems from.
+ *
+ * This finds a free minor number for the device, allocates and initializes
+ * some device data, and creates a new device and char dev node.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+static int telem_device_probe(struct platform_device *pdev)
+{
+ struct telem_device_data *dev_data;
+ int error, minor;
+
+ /* Get the next available device number */
+ minor = ida_alloc_max(&telem_ida, TELEM_MAX_DEV-1, GFP_KERNEL);
+ if (minor < 0) {
+ error = minor;
+ dev_err(&pdev->dev, "Failed to find minor number: %d\n", error);
+ return error;
+ }
+
+ dev_data = kzalloc(sizeof(*dev_data), GFP_KERNEL);
+ if (!dev_data) {
+ ida_simple_remove(&telem_ida, minor);
+ return -ENOMEM;
+ }
+
+ /* Initialize the device data */
+ dev_data->ec = dev_get_platdata(&pdev->dev);
+ atomic_set(&dev_data->available, 1);
+ platform_set_drvdata(pdev, dev_data);
+
+ /* Initialize the device */
+ dev_data->dev.devt = MKDEV(telem_major, minor);
+ dev_data->dev.class = &telem_class;
+ dev_data->dev.release = telem_device_free;
+ dev_set_name(&dev_data->dev, TELEM_DEV_NAME_FMT, minor);
+ device_initialize(&dev_data->dev);
+
+ /* Initialize the character device and add it to userspace */;
+ cdev_init(&dev_data->cdev, &telem_fops);
+ error = cdev_device_add(&dev_data->cdev, &dev_data->dev);
+ if (error) {
+ put_device(&dev_data->dev);
+ ida_simple_remove(&telem_ida, minor);
+ return error;
+ }
+
+ return 0;
+}
+
+static int telem_device_remove(struct platform_device *pdev)
+{
+ struct telem_device_data *dev_data = platform_get_drvdata(pdev);
+
+ cdev_device_del(&dev_data->cdev, &dev_data->dev);
+ ida_simple_remove(&telem_ida, MINOR(dev_data->dev.devt));
+ put_device(&dev_data->dev);
+
+ return 0;
+}
+
+static struct platform_driver telem_driver = {
+ .probe = telem_device_probe,
+ .remove = telem_device_remove,
+ .driver = {
+ .name = DRV_NAME,
+ },
+};
+
+static int __init telem_module_init(void)
+{
+ dev_t dev_num = 0;
+ int ret;
+
+ ret = class_register(&telem_class);
+ if (ret) {
+ pr_err(DRV_NAME ": Failed registering class: %d\n", ret);
+ return ret;
+ }
+
+ /* Request the kernel for device numbers, starting with minor=0 */
+ ret = alloc_chrdev_region(&dev_num, 0, TELEM_MAX_DEV, TELEM_DEV_NAME);
+ if (ret) {
+ pr_err(DRV_NAME ": Failed allocating dev numbers: %d\n", ret);
+ goto destroy_class;
+ }
+ telem_major = MAJOR(dev_num);
+
+ ret = platform_driver_register(&telem_driver);
+ if (ret < 0) {
+ pr_err(DRV_NAME ": Failed registering driver: %d\n", ret);
+ goto unregister_region;
+ }
+
+ return 0;
+
+unregister_region:
+ unregister_chrdev_region(MKDEV(telem_major, 0), TELEM_MAX_DEV);
+destroy_class:
+ class_unregister(&telem_class);
+ ida_destroy(&telem_ida);
+ return ret;
+}
+
+static void __exit telem_module_exit(void)
+{
+ platform_driver_unregister(&telem_driver);
+ unregister_chrdev_region(MKDEV(telem_major, 0), TELEM_MAX_DEV);
+ class_unregister(&telem_class);
+ ida_destroy(&telem_ida);
+}
+
+module_init(telem_module_init);
+module_exit(telem_module_exit);
+
+MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
+MODULE_DESCRIPTION("Wilco EC telemetry driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);