LXR linux/drivers/staging/most/hdm-dim2/dim2

   1/*
   2 * dim2_sysfs.c - MediaLB sysfs information
   3 *
   4 * Copyright (C) 2015, Microchip Technology Germany II GmbH & Co. KG
   5 *
   6 * This program is distributed in the hope that it will be useful,
   7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9 * GNU General Public License for more details.
  10 *
  11 * This file is licensed under GPLv2.
  12 */
  13
  14/* Author: Andrey Shvetsov <andrey.shvetsov@k2l.de> */
  15
  16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18#include <linux/kernel.h>
  19#include "dim2_sysfs.h"
  20
  21struct bus_attr {
  22        struct attribute attr;
  23        ssize_t (*show)(struct medialb_bus *bus, char *buf);
  24        ssize_t (*store)(struct medialb_bus *bus, const char *buf,
  25                         size_t count);
  26};
  27
  28static ssize_t state_show(struct medialb_bus *bus, char *buf)
  29{
  30        bool state = dim2_sysfs_get_state_cb();
  31
  32        return sprintf(buf, "%s\n", state ? "locked" : "");
  33}
  34
  35static struct bus_attr state_attr = __ATTR_RO(state);
  36
  37static struct attribute *bus_default_attrs[] = {
  38        &state_attr.attr,
  39        NULL,
  40};
  41
  42static const struct attribute_group bus_attr_group = {
  43        .attrs = bus_default_attrs,
  44};
  45
  46static void bus_kobj_release(struct kobject *kobj)
  47{
  48}
  49
  50static ssize_t bus_kobj_attr_show(struct kobject *kobj, struct attribute *attr,
  51                                  char *buf)
  52{
  53        struct medialb_bus *bus =
  54                container_of(kobj, struct medialb_bus, kobj_group);
  55        struct bus_attr *xattr = container_of(attr, struct bus_attr, attr);
  56
  57        if (!xattr->show)
  58                return -EIO;
  59
  60        return xattr->show(bus, buf);
  61}
  62
  63static ssize_t bus_kobj_attr_store(struct kobject *kobj, struct attribute *attr,
  64                                   const char *buf, size_t count)
  65{
  66        struct medialb_bus *bus =
  67                container_of(kobj, struct medialb_bus, kobj_group);
  68        struct bus_attr *xattr = container_of(attr, struct bus_attr, attr);
  69
  70        if (!xattr->store)
  71                return -EIO;
  72
  73        return xattr->store(bus, buf, count);
  74}
  75
  76static struct sysfs_ops const bus_kobj_sysfs_ops = {
  77        .show = bus_kobj_attr_show,
  78        .store = bus_kobj_attr_store,
  79};
  80
  81static struct kobj_type bus_ktype = {
  82        .release = bus_kobj_release,
  83        .sysfs_ops = &bus_kobj_sysfs_ops,
  84};
  85
  86int dim2_sysfs_probe(struct medialb_bus *bus, struct kobject *parent_kobj)
  87{
  88        int err;
  89
  90        kobject_init(&bus->kobj_group, &bus_ktype);
  91        err = kobject_add(&bus->kobj_group, parent_kobj, "bus");
  92        if (err) {
  93                pr_err("kobject_add() failed: %d\n", err);
  94                goto err_kobject_add;
  95        }
  96
  97        err = sysfs_create_group(&bus->kobj_group, &bus_attr_group);
  98        if (err) {
  99                pr_err("sysfs_create_group() failed: %d\n", err);
 100                goto err_create_group;
 101        }
 102
 103        return 0;
 104
 105err_create_group:
 106        kobject_put(&bus->kobj_group);
 107
 108err_kobject_add:
 109        return err;
 110}
 111
 112void dim2_sysfs_destroy(struct medialb_bus *bus)
 113{
 114        kobject_put(&bus->kobj_group);
 115}
 116