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
  26 static void
  27 nvkm_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
  35 void
  36 nvkm_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
  45 void
  46 nvkm_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
  54 int
  55 nvkm_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
  69 void
  70 nvkm_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
  76 void
  77 nvkm_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
  83 void
  84 nvkm_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
  95 void
  96 nvkm_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
 108 int
 109 nvkm_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 }