// SPDX-License-Identifier: GPL-2.0
/*
 * Regulator event over netlink
 *
 * Author: Naresh Solanki <Naresh.Solanki@9elements.com>
 */

#include <regulator/regulator.h>
#include <net/netlink.h>
#include <net/genetlink.h>
#include <linux/atomic.h>

#include "regnl.h"

static atomic_t reg_event_seqnum = ATOMIC_INIT(0);

static const struct genl_multicast_group reg_event_mcgrps[] = {
        { .name = REG_GENL_MCAST_GROUP_NAME, },
};

static struct genl_family reg_event_genl_family __ro_after_init = {
        .module = THIS_MODULE,
        .name = REG_GENL_FAMILY_NAME,
        .version = REG_GENL_VERSION,
        .maxattr = REG_GENL_ATTR_MAX,
        .mcgrps = reg_event_mcgrps,
        .n_mcgrps = ARRAY_SIZE(reg_event_mcgrps),
};

int reg_generate_netlink_event(const char *reg_name, u64 event)
{
        struct sk_buff *skb;
        struct nlattr *attr;
        struct reg_genl_event *edata;
        void *msg_header;
        int size;

        /* allocate memory */
        size = nla_total_size(sizeof(struct reg_genl_event)) +
            nla_total_size(0);

        skb = genlmsg_new(size, GFP_ATOMIC);
        if (!skb)
                return -ENOMEM;

        /* add the genetlink message header */
        msg_header = genlmsg_put(skb, 0, atomic_inc_return(&reg_event_seqnum),
                                 &reg_event_genl_family, 0, REG_GENL_CMD_EVENT);
        if (!msg_header) {
                nlmsg_free(skb);
                return -ENOMEM;
        }

        /* fill the data */
        attr = nla_reserve(skb, REG_GENL_ATTR_EVENT, sizeof(struct reg_genl_event));
        if (!attr) {
                nlmsg_free(skb);
                return -EINVAL;
        }

        edata = nla_data(attr);
        memset(edata, 0, sizeof(struct reg_genl_event));

        strscpy(edata->reg_name, reg_name, sizeof(edata->reg_name));
        edata->event = event;

        /* send multicast genetlink message */
        genlmsg_end(skb, msg_header);
        size = genlmsg_multicast(&reg_event_genl_family, skb, 0, 0, GFP_ATOMIC);

        return size;
}

static int __init reg_event_genetlink_init(void)
{
        return genl_register_family(&reg_event_genl_family);
}

static int __init reg_event_init(void)
{
        int error;

        /* create genetlink for acpi event */
        error = reg_event_genetlink_init();
        if (error)
                pr_warn("Failed to create genetlink family for reg event\n");

        return 0;
}

fs_initcall(reg_event_init);