LXR linux/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/pad.c

   1/*
   2 * Copyright 2015 Red Hat Inc.
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice shall be included in
  12 * all copies or substantial portions of the Software.
  13 *
  14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20 * OTHER DEALINGS IN THE SOFTWARE.
  21 *
  22 * Authors: Ben Skeggs <bskeggs@redhat.com>
  23 */
  24#include "pad.h"
  25
  26static void
  27nvkm_i2c_pad_mode_locked(struct nvkm_i2c_pad *pad, enum nvkm_i2c_pad_mode mode)
  28{
  29        PAD_TRACE(pad, "-> %s", (mode == NVKM_I2C_PAD_AUX) ? "aux" :
  30                              (mode == NVKM_I2C_PAD_I2C) ? "i2c" : "off");
  31        if (pad->func->mode)
  32                pad->func->mode(pad, mode);
  33}
  34
  35void
  36nvkm_i2c_pad_mode(struct nvkm_i2c_pad *pad, enum nvkm_i2c_pad_mode mode)
  37{
  38        PAD_TRACE(pad, "mode %d", mode);
  39        mutex_lock(&pad->mutex);
  40        nvkm_i2c_pad_mode_locked(pad, mode);
  41        pad->mode = mode;
  42        mutex_unlock(&pad->mutex);
  43}
  44
  45void
  46nvkm_i2c_pad_release(struct nvkm_i2c_pad *pad)
  47{
  48        PAD_TRACE(pad, "release");
  49        if (pad->mode == NVKM_I2C_PAD_OFF)
  50                nvkm_i2c_pad_mode_locked(pad, pad->mode);
  51        mutex_unlock(&pad->mutex);
  52}
  53
  54int
  55nvkm_i2c_pad_acquire(struct nvkm_i2c_pad *pad, enum nvkm_i2c_pad_mode mode)
  56{
  57        PAD_TRACE(pad, "acquire");
  58        mutex_lock(&pad->mutex);
  59        if (pad->mode != mode) {
  60                if (pad->mode != NVKM_I2C_PAD_OFF) {
  61                        mutex_unlock(&pad->mutex);
  62                        return -EBUSY;
  63                }
  64                nvkm_i2c_pad_mode_locked(pad, mode);
  65        }
  66        return 0;
  67}
  68
  69void
  70nvkm_i2c_pad_fini(struct nvkm_i2c_pad *pad)
  71{
  72        PAD_TRACE(pad, "fini");
  73        nvkm_i2c_pad_mode_locked(pad, NVKM_I2C_PAD_OFF);
  74}
  75
  76void
  77nvkm_i2c_pad_init(struct nvkm_i2c_pad *pad)
  78{
  79        PAD_TRACE(pad, "init");
  80        nvkm_i2c_pad_mode_locked(pad, pad->mode);
  81}
  82
  83void
  84nvkm_i2c_pad_del(struct nvkm_i2c_pad **ppad)
  85{
  86        struct nvkm_i2c_pad *pad = *ppad;
  87        if (pad) {
  88                PAD_TRACE(pad, "dtor");
  89                list_del(&pad->head);
  90                kfree(pad);
  91                pad = NULL;
  92        }
  93}
  94
  95void
  96nvkm_i2c_pad_ctor(const struct nvkm_i2c_pad_func *func, struct nvkm_i2c *i2c,
  97                  int id, struct nvkm_i2c_pad *pad)
  98{
  99        pad->func = func;
 100        pad->i2c = i2c;
 101        pad->id = id;
 102        pad->mode = NVKM_I2C_PAD_OFF;
 103        mutex_init(&pad->mutex);
 104        list_add_tail(&pad->head, &i2c->pad);
 105        PAD_TRACE(pad, "ctor");
 106}
 107
 108int
 109nvkm_i2c_pad_new_(const struct nvkm_i2c_pad_func *func, struct nvkm_i2c *i2c,
 110                  int id, struct nvkm_i2c_pad **ppad)
 111{
 112        if (!(*ppad = kzalloc(sizeof(**ppad), GFP_KERNEL)))
 113                return -ENOMEM;
 114        nvkm_i2c_pad_ctor(func, i2c, id, *ppad);
 115        return 0;
 116}
 117