drivers/gpu/drm/nouveau/nvkm/subdev/volt/gpio.c

   1 /*
   2  * Copyright 2013 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
  23  */
  24 #include <subdev/volt.h>
  25 #include <subdev/bios.h>
  26 #include <subdev/bios/gpio.h>
  27 #include <subdev/gpio.h>
  28
  29 static const u8 tags[] = {
  30         DCB_GPIO_VID0, DCB_GPIO_VID1, DCB_GPIO_VID2, DCB_GPIO_VID3,
  31         DCB_GPIO_VID4, DCB_GPIO_VID5, DCB_GPIO_VID6, DCB_GPIO_VID7,
  32 };
  33
  34 int
  35 nvkm_voltgpio_get(struct nvkm_volt *volt)
  36 {
  37         struct nvkm_gpio *gpio = nvkm_gpio(volt);
  38         u8 vid = 0;
  39         int i;
  40
  41         for (i = 0; i < ARRAY_SIZE(tags); i++) {
  42                 if (volt->vid_mask & (1 << i)) {
  43                         int ret = gpio->get(gpio, 0, tags[i], 0xff);
  44                         if (ret < 0)
  45                                 return ret;
  46                         vid |= ret << i;
  47                 }
  48         }
  49
  50         return vid;
  51 }
  52
  53 int
  54 nvkm_voltgpio_set(struct nvkm_volt *volt, u8 vid)
  55 {
  56         struct nvkm_gpio *gpio = nvkm_gpio(volt);
  57         int i;
  58
  59         for (i = 0; i < ARRAY_SIZE(tags); i++, vid >>= 1) {
  60                 if (volt->vid_mask & (1 << i)) {
  61                         int ret = gpio->set(gpio, 0, tags[i], 0xff, vid & 1);
  62                         if (ret < 0)
  63                                 return ret;
  64                 }
  65         }
  66
  67         return 0;
  68 }
  69
  70 int
  71 nvkm_voltgpio_init(struct nvkm_volt *volt)
  72 {
  73         struct nvkm_gpio *gpio = nvkm_gpio(volt);
  74         struct dcb_gpio_func func;
  75         int i;
  76
  77         /* check we have gpio function info for each vid bit.  on some
  78          * boards (ie. nvs295) the vid mask has more bits than there
  79          * are valid gpio functions... from traces, nvidia appear to
  80          * just touch the existing ones, so let's mask off the invalid
  81          * bits and continue with life
  82          */
  83         for (i = 0; i < ARRAY_SIZE(tags); i++) {
  84                 if (volt->vid_mask & (1 << i)) {
  85                         int ret = gpio->find(gpio, 0, tags[i], 0xff, &func);
  86                         if (ret) {
  87                                 if (ret != -ENOENT)
  88                                         return ret;
  89                                 nv_debug(volt, "VID bit %d has no GPIO\n", i);
  90                                 volt->vid_mask &= ~(1 << i);
  91                         }
  92                 }
  93         }
  94
  95         return 0;
  96 }