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 = volt->subdev.device->gpio;
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 = nvkm_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 = volt->subdev.device->gpio;
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 = nvkm_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_subdev *subdev = &volt->subdev;
74 	struct nvkm_gpio *gpio = subdev->device->gpio;
75 	struct dcb_gpio_func func;
76 	int i;
77 
78 	/* check we have gpio function info for each vid bit.  on some
79 	 * boards (ie. nvs295) the vid mask has more bits than there
80 	 * are valid gpio functions... from traces, nvidia appear to
81 	 * just touch the existing ones, so let's mask off the invalid
82 	 * bits and continue with life
83 	 */
84 	for (i = 0; i < ARRAY_SIZE(tags); i++) {
85 		if (volt->vid_mask & (1 << i)) {
86 			int ret = nvkm_gpio_find(gpio, 0, tags[i], 0xff, &func);
87 			if (ret) {
88 				if (ret != -ENOENT)
89 					return ret;
90 				nvkm_debug(subdev, "VID bit %d has no GPIO\n", i);
91 				volt->vid_mask &= ~(1 << i);
92 			}
93 		}
94 	}
95 
96 	return 0;
97 }
98