subdev/volt/gpio.c

0001 /*
0002  * Copyright 2013 Red Hat Inc.
0003  *
0004  * Permission is hereby granted, free of charge, to any person obtaining a
0005  * copy of this software and associated documentation files (the "Software"),
0006  * to deal in the Software without restriction, including without limitation
0007  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0008  * and/or sell copies of the Software, and to permit persons to whom the
0009  * Software is furnished to do so, subject to the following conditions:
0010  *
0011  * The above copyright notice and this permission notice shall be included in
0012  * all copies or substantial portions of the Software.
0013  *
0014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0017  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
0018  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0019  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0020  * OTHER DEALINGS IN THE SOFTWARE.
0021  *
0022  * Authors: Ben Skeggs
0023  */
0024 #include <subdev/volt.h>
0025 #include <subdev/bios.h>
0026 #include <subdev/bios/gpio.h>
0027 #include <subdev/gpio.h>
0028 #include "priv.h"
0029
0030 static const u8 tags[] = {
0031     DCB_GPIO_VID0, DCB_GPIO_VID1, DCB_GPIO_VID2, DCB_GPIO_VID3,
0032     DCB_GPIO_VID4, DCB_GPIO_VID5, DCB_GPIO_VID6, DCB_GPIO_VID7,
0033 };
0034
0035 int
0036 nvkm_voltgpio_get(struct nvkm_volt *volt)
0037 {
0038     struct nvkm_gpio *gpio = volt->subdev.device->gpio;
0039     u8 vid = 0;
0040     int i;
0041
0042     for (i = 0; i < ARRAY_SIZE(tags); i++) {
0043         if (volt->vid_mask & (1 << i)) {
0044             int ret = nvkm_gpio_get(gpio, 0, tags[i], 0xff);
0045             if (ret < 0)
0046                 return ret;
0047             vid |= ret << i;
0048         }
0049     }
0050
0051     return vid;
0052 }
0053
0054 int
0055 nvkm_voltgpio_set(struct nvkm_volt *volt, u8 vid)
0056 {
0057     struct nvkm_gpio *gpio = volt->subdev.device->gpio;
0058     int i;
0059
0060     for (i = 0; i < ARRAY_SIZE(tags); i++, vid >>= 1) {
0061         if (volt->vid_mask & (1 << i)) {
0062             int ret = nvkm_gpio_set(gpio, 0, tags[i], 0xff, vid & 1);
0063             if (ret < 0)
0064                 return ret;
0065         }
0066     }
0067
0068     return 0;
0069 }
0070
0071 int
0072 nvkm_voltgpio_init(struct nvkm_volt *volt)
0073 {
0074     struct nvkm_subdev *subdev = &volt->subdev;
0075     struct nvkm_gpio *gpio = subdev->device->gpio;
0076     struct dcb_gpio_func func;
0077     int i;
0078
0079     /* check we have gpio function info for each vid bit.  on some
0080      * boards (ie. nvs295) the vid mask has more bits than there
0081      * are valid gpio functions... from traces, nvidia appear to
0082      * just touch the existing ones, so let's mask off the invalid
0083      * bits and continue with life
0084      */
0085     for (i = 0; i < ARRAY_SIZE(tags); i++) {
0086         if (volt->vid_mask & (1 << i)) {
0087             int ret = nvkm_gpio_find(gpio, 0, tags[i], 0xff, &func);
0088             if (ret) {
0089                 if (ret != -ENOENT)
0090                     return ret;
0091                 nvkm_debug(subdev, "VID bit %d has no GPIO\n", i);
0092                 volt->vid_mask &= ~(1 << i);
0093             }
0094         }
0095     }
0096
0097     return 0;
0098 }