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}