// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * A hwmon driver for the IBM System Director Active Energy Manager (AEM)
 * temperature/power/energy sensors and capping functionality.
 * Copyright (C) 2008 IBM
 *
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/ipmi.h>
#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/kdev_t.h>
#include <linux/spinlock.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/platform_device.h>
#include <linux/math64.h>
#include <linux/time.h>
#include <linux/err.h>

#define REFRESH_INTERVAL        (HZ)
#define IPMI_TIMEOUT            (30 * HZ)
#define DRVNAME                 "aem"

#define AEM_NETFN               0x2E

#define AEM_FIND_FW_CMD         0x80
#define AEM_ELEMENT_CMD         0x81
#define AEM_FW_INSTANCE_CMD     0x82

#define AEM_READ_ELEMENT_CFG    0x80
#define AEM_READ_BUFFER         0x81
#define AEM_READ_REGISTER       0x82
#define AEM_WRITE_REGISTER      0x83
#define AEM_SET_REG_MASK        0x84
#define AEM_CLEAR_REG_MASK      0x85
#define AEM_READ_ELEMENT_CFG2   0x86

#define AEM_CONTROL_ELEMENT     0
#define AEM_ENERGY_ELEMENT      1
#define AEM_CLOCK_ELEMENT       4
#define AEM_POWER_CAP_ELEMENT   7
#define AEM_EXHAUST_ELEMENT     9
#define AEM_POWER_ELEMENT       10

#define AEM_MODULE_TYPE_ID      0x0001

#define AEM2_NUM_ENERGY_REGS    2
#define AEM2_NUM_PCAP_REGS      6
#define AEM2_NUM_TEMP_REGS      2
#define AEM2_NUM_SENSORS        14

#define AEM1_NUM_ENERGY_REGS    1
#define AEM1_NUM_SENSORS        3

/* AEM 2.x has more energy registers */
#define AEM_NUM_ENERGY_REGS     AEM2_NUM_ENERGY_REGS
/* AEM 2.x needs more sensor files */
#define AEM_NUM_SENSORS         AEM2_NUM_SENSORS

#define POWER_CAP               0
#define POWER_CAP_MAX_HOTPLUG   1
#define POWER_CAP_MAX           2
#define POWER_CAP_MIN_WARNING   3
#define POWER_CAP_MIN           4
#define POWER_AUX               5

#define AEM_DEFAULT_POWER_INTERVAL 1000
#define AEM_MIN_POWER_INTERVAL  200
#define UJ_PER_MJ               1000L

static DEFINE_IDA(aem_ida);

static struct platform_driver aem_driver = {
        .driver = {
                .name = DRVNAME,
                .bus = &platform_bus_type,
        }
};

struct aem_ipmi_data {
        struct completion       read_complete;
        struct ipmi_addr        address;
        struct ipmi_user        *user;
        int                     interface;

        struct kernel_ipmi_msg  tx_message;
        long                    tx_msgid;

        void                    *rx_msg_data;
        unsigned short          rx_msg_len;
        unsigned char           rx_result;
        int                     rx_recv_type;

        struct device           *bmc_device;
};

struct aem_ro_sensor_template {
        char *label;
        ssize_t (*show)(struct device *dev,
                        struct device_attribute *devattr,
                        char *buf);
        int index;
};

struct aem_rw_sensor_template {
        char *label;
        ssize_t (*show)(struct device *dev,
                        struct device_attribute *devattr,
                        char *buf);
        ssize_t (*set)(struct device *dev,
                       struct device_attribute *devattr,
                       const char *buf, size_t count);
        int index;
};

struct aem_data {
        struct list_head        list;

        struct device           *hwmon_dev;
        struct platform_device  *pdev;
        struct mutex            lock;
        bool                    valid;
        unsigned long           last_updated;   /* In jiffies */
        u8                      ver_major;
        u8                      ver_minor;
        u8                      module_handle;
        int                     id;
        struct aem_ipmi_data    ipmi;

        /* Function and buffer to update sensors */
        void (*update)(struct aem_data *data);
        struct aem_read_sensor_resp *rs_resp;

        /*
         * AEM 1.x sensors:
         * Available sensors:
         * Energy meter
         * Power meter
         *
         * AEM 2.x sensors:
         * Two energy meters
         * Two power meters
         * Two temperature sensors
         * Six power cap registers
         */

        /* sysfs attrs */
        struct sensor_device_attribute  sensors[AEM_NUM_SENSORS];

        /* energy use in mJ */
        u64                     energy[AEM_NUM_ENERGY_REGS];

        /* power sampling interval in ms */
        unsigned long           power_period[AEM_NUM_ENERGY_REGS];

        /* Everything past here is for AEM2 only */

        /* power caps in dW */
        u16                     pcap[AEM2_NUM_PCAP_REGS];

        /* exhaust temperature in C */
        u8                      temp[AEM2_NUM_TEMP_REGS];
};

/* Data structures returned by the AEM firmware */
struct aem_iana_id {
        u8                      bytes[3];
};
static struct aem_iana_id system_x_id = {
        .bytes = {0x4D, 0x4F, 0x00}
};

/* These are used to find AEM1 instances */
struct aem_find_firmware_req {
        struct aem_iana_id      id;
        u8                      rsvd;
        __be16                  index;
        __be16                  module_type_id;
} __packed;

struct aem_find_firmware_resp {
        struct aem_iana_id      id;
        u8                      num_instances;
} __packed;

/* These are used to find AEM2 instances */
struct aem_find_instance_req {
        struct aem_iana_id      id;
        u8                      instance_number;
        __be16                  module_type_id;
} __packed;

struct aem_find_instance_resp {
        struct aem_iana_id      id;
        u8                      num_instances;
        u8                      major;
        u8                      minor;
        u8                      module_handle;
        u16                     record_id;
} __packed;

/* These are used to query sensors */
struct aem_read_sensor_req {
        struct aem_iana_id      id;
        u8                      module_handle;
        u8                      element;
        u8                      subcommand;
        u8                      reg;
        u8                      rx_buf_size;
} __packed;

struct aem_read_sensor_resp {
        struct aem_iana_id      id;
        u8                      bytes[];
} __packed;

/* Data structures to talk to the IPMI layer */
struct aem_driver_data {
        struct list_head        aem_devices;
        struct ipmi_smi_watcher bmc_events;
        struct ipmi_user_hndl   ipmi_hndlrs;
};

static void aem_register_bmc(int iface, struct device *dev);
static void aem_bmc_gone(int iface);
static void aem_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);

static void aem_remove_sensors(struct aem_data *data);
static int aem1_find_sensors(struct aem_data *data);
static int aem2_find_sensors(struct aem_data *data);
static void update_aem1_sensors(struct aem_data *data);
static void update_aem2_sensors(struct aem_data *data);

static struct aem_driver_data driver_data = {
        .aem_devices = LIST_HEAD_INIT(driver_data.aem_devices),
        .bmc_events = {
                .owner = THIS_MODULE,
                .new_smi = aem_register_bmc,
                .smi_gone = aem_bmc_gone,
        },
        .ipmi_hndlrs = {
                .ipmi_recv_hndl = aem_msg_handler,
        },
};

/* Functions to talk to the IPMI layer */

/* Initialize IPMI address, message buffers and user data */
static int aem_init_ipmi_data(struct aem_ipmi_data *data, int iface,
                              struct device *bmc)
{
        int err;

        init_completion(&data->read_complete);
        data->bmc_device = bmc;

        /* Initialize IPMI address */
        data->address.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
        data->address.channel = IPMI_BMC_CHANNEL;
        data->address.data[0] = 0;
        data->interface = iface;

        /* Initialize message buffers */
        data->tx_msgid = 0;
        data->tx_message.netfn = AEM_NETFN;

        /* Create IPMI messaging interface user */
        err = ipmi_create_user(data->interface, &driver_data.ipmi_hndlrs,
                               data, &data->user);
        if (err < 0) {
                dev_err(bmc,
                        "Unable to register user with IPMI interface %d\n",
                        data->interface);
                return err;
        }

        return 0;
}

/* Send an IPMI command */
static int aem_send_message(struct aem_ipmi_data *data)
{
        int err;

        err = ipmi_validate_addr(&data->address, sizeof(data->address));
        if (err)
                goto out;

        data->tx_msgid++;
        err = ipmi_request_settime(data->user, &data->address, data->tx_msgid,
                                   &data->tx_message, data, 0, 0, 0);
        if (err)
                goto out1;

        return 0;
out1:
        dev_err(data->bmc_device, "request_settime=%x\n", err);
        return err;
out:
        dev_err(data->bmc_device, "validate_addr=%x\n", err);
        return err;
}

/* Dispatch IPMI messages to callers */
static void aem_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
{
        unsigned short rx_len;
        struct aem_ipmi_data *data = user_msg_data;

        if (msg->msgid != data->tx_msgid) {
                dev_err(data->bmc_device,
                        "Mismatch between received msgid (%02x) and transmitted msgid (%02x)!\n",
                        (int)msg->msgid,
                        (int)data->tx_msgid);
                ipmi_free_recv_msg(msg);
                return;
        }

        data->rx_recv_type = msg->recv_type;
        if (msg->msg.data_len > 0)
                data->rx_result = msg->msg.data[0];
        else
                data->rx_result = IPMI_UNKNOWN_ERR_COMPLETION_CODE;

        if (msg->msg.data_len > 1) {
                rx_len = msg->msg.data_len - 1;
                if (data->rx_msg_len < rx_len)
                        rx_len = data->rx_msg_len;
                data->rx_msg_len = rx_len;
                memcpy(data->rx_msg_data, msg->msg.data + 1, data->rx_msg_len);
        } else
                data->rx_msg_len = 0;

        ipmi_free_recv_msg(msg);
        complete(&data->read_complete);
}

/* Sensor support functions */

/* Read a sensor value; must be called with data->lock held */
static int aem_read_sensor(struct aem_data *data, u8 elt, u8 reg,
                           void *buf, size_t size)
{
        int rs_size;
        struct aem_read_sensor_req rs_req;
        /* Use preallocated rx buffer */
        struct aem_read_sensor_resp *rs_resp = data->rs_resp;
        struct aem_ipmi_data *ipmi = &data->ipmi;

        /* AEM registers are 1, 2, 4 or 8 bytes */
        switch (size) {
        case 1:
        case 2:
        case 4:
        case 8:
                break;
        default:
                return -EINVAL;
        }

        rs_req.id = system_x_id;
        rs_req.module_handle = data->module_handle;
        rs_req.element = elt;
        rs_req.subcommand = AEM_READ_REGISTER;
        rs_req.reg = reg;
        rs_req.rx_buf_size = size;

        ipmi->tx_message.cmd = AEM_ELEMENT_CMD;
        ipmi->tx_message.data = (char *)&rs_req;
        ipmi->tx_message.data_len = sizeof(rs_req);

        rs_size = sizeof(*rs_resp) + size;
        ipmi->rx_msg_data = rs_resp;
        ipmi->rx_msg_len = rs_size;

        aem_send_message(ipmi);

        if (!wait_for_completion_timeout(&ipmi->read_complete, IPMI_TIMEOUT))
                return -ETIMEDOUT;

        if (ipmi->rx_result || ipmi->rx_msg_len != rs_size ||
            memcmp(&rs_resp->id, &system_x_id, sizeof(system_x_id)))
                return -ENOENT;

        switch (size) {
        case 1: {
                u8 *x = buf;
                *x = rs_resp->bytes[0];
                break;
        }
        case 2: {
                u16 *x = buf;
                *x = be16_to_cpup((__be16 *)rs_resp->bytes);
                break;
        }
        case 4: {
                u32 *x = buf;
                *x = be32_to_cpup((__be32 *)rs_resp->bytes);
                break;
        }
        case 8: {
                u64 *x = buf;
                *x = be64_to_cpup((__be64 *)rs_resp->bytes);
                break;
        }
        }

        return 0;
}

/* Update AEM energy registers */
static void update_aem_energy_one(struct aem_data *data, int which)
{
        aem_read_sensor(data, AEM_ENERGY_ELEMENT, which,
                        &data->energy[which], 8);
}

static void update_aem_energy(struct aem_data *data)
{
        update_aem_energy_one(data, 0);
        if (data->ver_major < 2)
                return;
        update_aem_energy_one(data, 1);
}

/* Update all AEM1 sensors */
static void update_aem1_sensors(struct aem_data *data)
{
        mutex_lock(&data->lock);
        if (time_before(jiffies, data->last_updated + REFRESH_INTERVAL) &&
            data->valid)
                goto out;

        update_aem_energy(data);
out:
        mutex_unlock(&data->lock);
}

/* Update all AEM2 sensors */
static void update_aem2_sensors(struct aem_data *data)
{
        int i;

        mutex_lock(&data->lock);
        if (time_before(jiffies, data->last_updated + REFRESH_INTERVAL) &&
            data->valid)
                goto out;

        update_aem_energy(data);
        aem_read_sensor(data, AEM_EXHAUST_ELEMENT, 0, &data->temp[0], 1);
        aem_read_sensor(data, AEM_EXHAUST_ELEMENT, 1, &data->temp[1], 1);

        for (i = POWER_CAP; i <= POWER_AUX; i++)
                aem_read_sensor(data, AEM_POWER_CAP_ELEMENT, i,
                                &data->pcap[i], 2);
out:
        mutex_unlock(&data->lock);
}

/* Delete an AEM instance */
static void aem_delete(struct aem_data *data)
{
        list_del(&data->list);
        aem_remove_sensors(data);
        kfree(data->rs_resp);
        hwmon_device_unregister(data->hwmon_dev);
        ipmi_destroy_user(data->ipmi.user);
        platform_set_drvdata(data->pdev, NULL);
        platform_device_unregister(data->pdev);
        ida_free(&aem_ida, data->id);
        kfree(data);
}

/* Probe functions for AEM1 devices */

/* Retrieve version and module handle for an AEM1 instance */
static int aem_find_aem1_count(struct aem_ipmi_data *data)
{
        struct aem_find_firmware_req    ff_req;
        struct aem_find_firmware_resp   ff_resp;

        ff_req.id = system_x_id;
        ff_req.index = 0;
        ff_req.module_type_id = cpu_to_be16(AEM_MODULE_TYPE_ID);

        data->tx_message.cmd = AEM_FIND_FW_CMD;
        data->tx_message.data = (char *)&ff_req;
        data->tx_message.data_len = sizeof(ff_req);

        data->rx_msg_data = &ff_resp;
        data->rx_msg_len = sizeof(ff_resp);

        aem_send_message(data);

        if (!wait_for_completion_timeout(&data->read_complete, IPMI_TIMEOUT))
                return -ETIMEDOUT;

        if (data->rx_result || data->rx_msg_len != sizeof(ff_resp) ||
            memcmp(&ff_resp.id, &system_x_id, sizeof(system_x_id)))
                return -ENOENT;

        return ff_resp.num_instances;
}

/* Find and initialize one AEM1 instance */
static int aem_init_aem1_inst(struct aem_ipmi_data *probe, u8 module_handle)
{
        struct aem_data *data;
        int i;
        int res = -ENOMEM;

        data = kzalloc_obj(*data);
        if (!data)
                return res;
        mutex_init(&data->lock);

        /* Copy instance data */
        data->ver_major = 1;
        data->ver_minor = 0;
        data->module_handle = module_handle;
        for (i = 0; i < AEM1_NUM_ENERGY_REGS; i++)
                data->power_period[i] = AEM_DEFAULT_POWER_INTERVAL;

        /* Create sub-device for this fw instance */
        data->id = ida_alloc(&aem_ida, GFP_KERNEL);
        if (data->id < 0)
                goto id_err;

        data->pdev = platform_device_alloc(DRVNAME, data->id);
        if (!data->pdev)
                goto dev_err;
        data->pdev->dev.driver = &aem_driver.driver;

        res = platform_device_add(data->pdev);
        if (res)
                goto dev_add_err;

        platform_set_drvdata(data->pdev, data);

        /* Set up IPMI interface */
        res = aem_init_ipmi_data(&data->ipmi, probe->interface,
                                 probe->bmc_device);
        if (res)
                goto ipmi_err;

        /* Register with hwmon */
        data->hwmon_dev = hwmon_device_register(&data->pdev->dev);
        if (IS_ERR(data->hwmon_dev)) {
                dev_err(&data->pdev->dev,
                        "Unable to register hwmon device for IPMI interface %d\n",
                        probe->interface);
                res = PTR_ERR(data->hwmon_dev);
                goto hwmon_reg_err;
        }

        data->update = update_aem1_sensors;
        data->rs_resp = kzalloc(sizeof(*(data->rs_resp)) + 8, GFP_KERNEL);
        if (!data->rs_resp) {
                res = -ENOMEM;
                goto alloc_resp_err;
        }

        /* Find sensors */
        res = aem1_find_sensors(data);
        if (res)
                goto sensor_err;

        /* Add to our list of AEM devices */
        list_add_tail(&data->list, &driver_data.aem_devices);

        dev_info(data->ipmi.bmc_device, "Found AEM v%d.%d at 0x%X\n",
                 data->ver_major, data->ver_minor,
                 data->module_handle);
        return 0;

sensor_err:
        kfree(data->rs_resp);
alloc_resp_err:
        hwmon_device_unregister(data->hwmon_dev);
hwmon_reg_err:
        ipmi_destroy_user(data->ipmi.user);
ipmi_err:
        platform_set_drvdata(data->pdev, NULL);
        platform_device_del(data->pdev);
dev_add_err:
        platform_device_put(data->pdev);
dev_err:
        ida_free(&aem_ida, data->id);
id_err:
        kfree(data);

        return res;
}

/* Find and initialize all AEM1 instances */
static void aem_init_aem1(struct aem_ipmi_data *probe)
{
        int num, i, err;

        num = aem_find_aem1_count(probe);
        for (i = 0; i < num; i++) {
                err = aem_init_aem1_inst(probe, i);
                if (err) {
                        dev_err(probe->bmc_device,
                                "Error %d initializing AEM1 0x%X\n",
                                err, i);
                }
        }
}

/* Probe functions for AEM2 devices */

/* Retrieve version and module handle for an AEM2 instance */
static int aem_find_aem2(struct aem_ipmi_data *data,
                            struct aem_find_instance_resp *fi_resp,
                            int instance_num)
{
        struct aem_find_instance_req fi_req;

        fi_req.id = system_x_id;
        fi_req.instance_number = instance_num;
        fi_req.module_type_id = cpu_to_be16(AEM_MODULE_TYPE_ID);

        data->tx_message.cmd = AEM_FW_INSTANCE_CMD;
        data->tx_message.data = (char *)&fi_req;
        data->tx_message.data_len = sizeof(fi_req);

        data->rx_msg_data = fi_resp;
        data->rx_msg_len = sizeof(*fi_resp);

        aem_send_message(data);

        if (!wait_for_completion_timeout(&data->read_complete, IPMI_TIMEOUT))
                return -ETIMEDOUT;

        if (data->rx_result || data->rx_msg_len != sizeof(*fi_resp) ||
            memcmp(&fi_resp->id, &system_x_id, sizeof(system_x_id)) ||
            fi_resp->num_instances <= instance_num)
                return -ENOENT;

        return 0;
}

/* Find and initialize one AEM2 instance */
static int aem_init_aem2_inst(struct aem_ipmi_data *probe,
                              struct aem_find_instance_resp *fi_resp)
{
        struct aem_data *data;
        int i;
        int res = -ENOMEM;

        data = kzalloc_obj(*data);
        if (!data)
                return res;
        mutex_init(&data->lock);

        /* Copy instance data */
        data->ver_major = fi_resp->major;
        data->ver_minor = fi_resp->minor;
        data->module_handle = fi_resp->module_handle;
        for (i = 0; i < AEM2_NUM_ENERGY_REGS; i++)
                data->power_period[i] = AEM_DEFAULT_POWER_INTERVAL;

        /* Create sub-device for this fw instance */
        data->id = ida_alloc(&aem_ida, GFP_KERNEL);
        if (data->id < 0)
                goto id_err;

        data->pdev = platform_device_alloc(DRVNAME, data->id);
        if (!data->pdev)
                goto dev_err;
        data->pdev->dev.driver = &aem_driver.driver;

        res = platform_device_add(data->pdev);
        if (res)
                goto dev_add_err;

        platform_set_drvdata(data->pdev, data);

        /* Set up IPMI interface */
        res = aem_init_ipmi_data(&data->ipmi, probe->interface,
                                 probe->bmc_device);
        if (res)
                goto ipmi_err;

        /* Register with hwmon */
        data->hwmon_dev = hwmon_device_register(&data->pdev->dev);
        if (IS_ERR(data->hwmon_dev)) {
                dev_err(&data->pdev->dev,
                        "Unable to register hwmon device for IPMI interface %d\n",
                        probe->interface);
                res = PTR_ERR(data->hwmon_dev);
                goto hwmon_reg_err;
        }

        data->update = update_aem2_sensors;
        data->rs_resp = kzalloc(sizeof(*(data->rs_resp)) + 8, GFP_KERNEL);
        if (!data->rs_resp) {
                res = -ENOMEM;
                goto alloc_resp_err;
        }

        /* Find sensors */
        res = aem2_find_sensors(data);
        if (res)
                goto sensor_err;

        /* Add to our list of AEM devices */
        list_add_tail(&data->list, &driver_data.aem_devices);

        dev_info(data->ipmi.bmc_device, "Found AEM v%d.%d at 0x%X\n",
                 data->ver_major, data->ver_minor,
                 data->module_handle);
        return 0;

sensor_err:
        kfree(data->rs_resp);
alloc_resp_err:
        hwmon_device_unregister(data->hwmon_dev);
hwmon_reg_err:
        ipmi_destroy_user(data->ipmi.user);
ipmi_err:
        platform_set_drvdata(data->pdev, NULL);
        platform_device_del(data->pdev);
dev_add_err:
        platform_device_put(data->pdev);
dev_err:
        ida_free(&aem_ida, data->id);
id_err:
        kfree(data);

        return res;
}

/* Find and initialize all AEM2 instances */
static void aem_init_aem2(struct aem_ipmi_data *probe)
{
        struct aem_find_instance_resp fi_resp;
        int err;
        int i = 0;

        while (!aem_find_aem2(probe, &fi_resp, i)) {
                if (fi_resp.major != 2) {
                        dev_err(probe->bmc_device,
                                "Unknown AEM v%d; please report this to the maintainer.\n",
                                fi_resp.major);
                        i++;
                        continue;
                }
                err = aem_init_aem2_inst(probe, &fi_resp);
                if (err) {
                        dev_err(probe->bmc_device,
                                "Error %d initializing AEM2 0x%X\n",
                                err, fi_resp.module_handle);
                }
                i++;
        }
}

/* Probe a BMC for AEM firmware instances */
static void aem_register_bmc(int iface, struct device *dev)
{
        struct aem_ipmi_data probe;

        if (aem_init_ipmi_data(&probe, iface, dev))
                return;

        /* Ignore probe errors; they won't cause problems */
        aem_init_aem1(&probe);
        aem_init_aem2(&probe);

        ipmi_destroy_user(probe.user);
}

/* Handle BMC deletion */
static void aem_bmc_gone(int iface)
{
        struct aem_data *p1, *next1;

        list_for_each_entry_safe(p1, next1, &driver_data.aem_devices, list)
                if (p1->ipmi.interface == iface)
                        aem_delete(p1);
}

/* sysfs support functions */

/* AEM device name */
static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
                         char *buf)
{
        struct aem_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%s%d\n", DRVNAME, data->ver_major);
}
static SENSOR_DEVICE_ATTR_RO(name, name, 0);

/* AEM device version */
static ssize_t version_show(struct device *dev,
                            struct device_attribute *devattr, char *buf)
{
        struct aem_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%d.%d\n", data->ver_major, data->ver_minor);
}
static SENSOR_DEVICE_ATTR_RO(version, version, 0);

/* Display power use */
static ssize_t aem_show_power(struct device *dev,
                              struct device_attribute *devattr,
                              char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct aem_data *data = dev_get_drvdata(dev);
        u64 before, after, delta, time;
        signed long leftover;

        mutex_lock(&data->lock);
        update_aem_energy_one(data, attr->index);
        time = ktime_get_ns();
        before = data->energy[attr->index];

        leftover = schedule_timeout_interruptible(
                        msecs_to_jiffies(data->power_period[attr->index])
                   );
        if (leftover) {
                mutex_unlock(&data->lock);
                return 0;
        }

        update_aem_energy_one(data, attr->index);
        time = ktime_get_ns() - time;
        after = data->energy[attr->index];
        mutex_unlock(&data->lock);

        delta = (after - before) * UJ_PER_MJ;

        return sprintf(buf, "%llu\n",
                (unsigned long long)div64_u64(delta * NSEC_PER_SEC, time));
}

/* Display energy use */
static ssize_t aem_show_energy(struct device *dev,
                               struct device_attribute *devattr,
                               char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct aem_data *a = dev_get_drvdata(dev);
        mutex_lock(&a->lock);
        update_aem_energy_one(a, attr->index);
        mutex_unlock(&a->lock);

        return sprintf(buf, "%llu\n",
                        (unsigned long long)a->energy[attr->index] * 1000);
}

/* Display power interval registers */
static ssize_t aem_show_power_period(struct device *dev,
                                     struct device_attribute *devattr,
                                     char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct aem_data *a = dev_get_drvdata(dev);
        a->update(a);

        return sprintf(buf, "%lu\n", a->power_period[attr->index]);
}

/* Set power interval registers */
static ssize_t aem_set_power_period(struct device *dev,
                                    struct device_attribute *devattr,
                                    const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct aem_data *a = dev_get_drvdata(dev);
        unsigned long temp;
        int res;

        res = kstrtoul(buf, 10, &temp);
        if (res)
                return res;

        if (temp < AEM_MIN_POWER_INTERVAL)
                return -EINVAL;

        mutex_lock(&a->lock);
        a->power_period[attr->index] = temp;
        mutex_unlock(&a->lock);

        return count;
}

/* Discover sensors on an AEM device */
static int aem_register_sensors(struct aem_data *data,
                                const struct aem_ro_sensor_template *ro,
                                const struct aem_rw_sensor_template *rw)
{
        struct device *dev = &data->pdev->dev;
        struct sensor_device_attribute *sensors = data->sensors;
        int err;

        /* Set up read-only sensors */
        while (ro->label) {
                sysfs_attr_init(&sensors->dev_attr.attr);
                sensors->dev_attr.attr.name = ro->label;
                sensors->dev_attr.attr.mode = 0444;
                sensors->dev_attr.show = ro->show;
                sensors->index = ro->index;

                err = device_create_file(dev, &sensors->dev_attr);
                if (err) {
                        sensors->dev_attr.attr.name = NULL;
                        goto error;
                }
                sensors++;
                ro++;
        }

        /* Set up read-write sensors */
        while (rw->label) {
                sysfs_attr_init(&sensors->dev_attr.attr);
                sensors->dev_attr.attr.name = rw->label;
                sensors->dev_attr.attr.mode = 0644;
                sensors->dev_attr.show = rw->show;
                sensors->dev_attr.store = rw->set;
                sensors->index = rw->index;

                err = device_create_file(dev, &sensors->dev_attr);
                if (err) {
                        sensors->dev_attr.attr.name = NULL;
                        goto error;
                }
                sensors++;
                rw++;
        }

        err = device_create_file(dev, &sensor_dev_attr_name.dev_attr);
        if (err)
                goto error;
        err = device_create_file(dev, &sensor_dev_attr_version.dev_attr);
        return err;

error:
        aem_remove_sensors(data);
        return err;
}

/* sysfs support functions for AEM2 sensors */

/* Display temperature use */
static ssize_t aem2_show_temp(struct device *dev,
                              struct device_attribute *devattr,
                              char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct aem_data *a = dev_get_drvdata(dev);
        a->update(a);

        return sprintf(buf, "%u\n", a->temp[attr->index] * 1000);
}

/* Display power-capping registers */
static ssize_t aem2_show_pcap_value(struct device *dev,
                                    struct device_attribute *devattr,
                                    char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
        struct aem_data *a = dev_get_drvdata(dev);
        a->update(a);

        return sprintf(buf, "%u\n", a->pcap[attr->index] * 100000);
}

/* Remove sensors attached to an AEM device */
static void aem_remove_sensors(struct aem_data *data)
{
        int i;

        for (i = 0; i < AEM_NUM_SENSORS; i++) {
                if (!data->sensors[i].dev_attr.attr.name)
                        continue;
                device_remove_file(&data->pdev->dev,
                                   &data->sensors[i].dev_attr);
        }

        device_remove_file(&data->pdev->dev,
                           &sensor_dev_attr_name.dev_attr);
        device_remove_file(&data->pdev->dev,
                           &sensor_dev_attr_version.dev_attr);
}

/* Sensor probe functions */

/* Description of AEM1 sensors */
static const struct aem_ro_sensor_template aem1_ro_sensors[] = {
{"energy1_input",  aem_show_energy, 0},
{"power1_average", aem_show_power,  0},
{NULL,             NULL,            0},
};

static const struct aem_rw_sensor_template aem1_rw_sensors[] = {
{"power1_average_interval", aem_show_power_period, aem_set_power_period, 0},
{NULL,                      NULL,                  NULL,                 0},
};

/* Description of AEM2 sensors */
static const struct aem_ro_sensor_template aem2_ro_sensors[] = {
{"energy1_input",         aem_show_energy,      0},
{"energy2_input",         aem_show_energy,      1},
{"power1_average",        aem_show_power,       0},
{"power2_average",        aem_show_power,       1},
{"temp1_input",           aem2_show_temp,       0},
{"temp2_input",           aem2_show_temp,       1},

{"power4_average",        aem2_show_pcap_value, POWER_CAP_MAX_HOTPLUG},
{"power5_average",        aem2_show_pcap_value, POWER_CAP_MAX},
{"power6_average",        aem2_show_pcap_value, POWER_CAP_MIN_WARNING},
{"power7_average",        aem2_show_pcap_value, POWER_CAP_MIN},

{"power3_average",        aem2_show_pcap_value, POWER_AUX},
{"power_cap",             aem2_show_pcap_value, POWER_CAP},
{NULL,                    NULL,                 0},
};

static const struct aem_rw_sensor_template aem2_rw_sensors[] = {
{"power1_average_interval", aem_show_power_period, aem_set_power_period, 0},
{"power2_average_interval", aem_show_power_period, aem_set_power_period, 1},
{NULL,                      NULL,                  NULL,                 0},
};

/* Set up AEM1 sensor attrs */
static int aem1_find_sensors(struct aem_data *data)
{
        return aem_register_sensors(data, aem1_ro_sensors, aem1_rw_sensors);
}

/* Set up AEM2 sensor attrs */
static int aem2_find_sensors(struct aem_data *data)
{
        return aem_register_sensors(data, aem2_ro_sensors, aem2_rw_sensors);
}

/* Module init/exit routines */

static int __init aem_init(void)
{
        int res;

        res = driver_register(&aem_driver.driver);
        if (res) {
                pr_err("Can't register aem driver\n");
                return res;
        }

        res = ipmi_smi_watcher_register(&driver_data.bmc_events);
        if (res)
                goto ipmi_reg_err;
        return 0;

ipmi_reg_err:
        driver_unregister(&aem_driver.driver);
        return res;

}

static void __exit aem_exit(void)
{
        struct aem_data *p1, *next1;

        ipmi_smi_watcher_unregister(&driver_data.bmc_events);
        driver_unregister(&aem_driver.driver);
        list_for_each_entry_safe(p1, next1, &driver_data.aem_devices, list)
                aem_delete(p1);
}

MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
MODULE_DESCRIPTION("IBM AEM power/temp/energy sensor driver");
MODULE_LICENSE("GPL");

module_init(aem_init);
module_exit(aem_exit);

MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3350-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3550-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3650-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3655-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMSystemx3755-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBM3850M2/x3950M2-*");
MODULE_ALIAS("dmi:bvnIBM:*:pnIBMBladeHC10-*");