1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * MAX1600 PCMCIA power switch library
4 *
5 * Copyright (C) 2016 Russell King
6 */
7 #include <linux/device.h>
8 #include <linux/module.h>
9 #include <linux/gpio/consumer.h>
10 #include <linux/slab.h>
11 #include "max1600.h"
12
13 static const char *max1600_gpio_name[2][MAX1600_GPIO_MAX] = {
14 { "a0vcc", "a1vcc", "a0vpp", "a1vpp" },
15 { "b0vcc", "b1vcc", "b0vpp", "b1vpp" },
16 };
17
max1600_init(struct device * dev,struct max1600 ** ptr,unsigned int channel,unsigned int code)18 int max1600_init(struct device *dev, struct max1600 **ptr,
19 unsigned int channel, unsigned int code)
20 {
21 struct max1600 *m;
22 int chan;
23 int i;
24
25 switch (channel) {
26 case MAX1600_CHAN_A:
27 chan = 0;
28 break;
29 case MAX1600_CHAN_B:
30 chan = 1;
31 break;
32 default:
33 return -EINVAL;
34 }
35
36 if (code != MAX1600_CODE_LOW && code != MAX1600_CODE_HIGH)
37 return -EINVAL;
38
39 m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL);
40 if (!m)
41 return -ENOMEM;
42
43 m->dev = dev;
44 m->code = code;
45
46 for (i = 0; i < MAX1600_GPIO_MAX; i++) {
47 const char *name;
48
49 name = max1600_gpio_name[chan][i];
50 if (i != MAX1600_GPIO_0VPP) {
51 m->gpio[i] = devm_gpiod_get(dev, name, GPIOD_OUT_LOW);
52 } else {
53 m->gpio[i] = devm_gpiod_get_optional(dev, name,
54 GPIOD_OUT_LOW);
55 if (!m->gpio[i])
56 break;
57 }
58 if (IS_ERR(m->gpio[i]))
59 return PTR_ERR(m->gpio[i]);
60 }
61
62 *ptr = m;
63
64 return 0;
65 }
66 EXPORT_SYMBOL_GPL(max1600_init);
67
max1600_configure(struct max1600 * m,unsigned int vcc,unsigned int vpp)68 int max1600_configure(struct max1600 *m, unsigned int vcc, unsigned int vpp)
69 {
70 DECLARE_BITMAP(values, MAX1600_GPIO_MAX) = { 0, };
71 int n = MAX1600_GPIO_0VPP;
72
73 if (m->gpio[MAX1600_GPIO_0VPP]) {
74 if (vpp == 0) {
75 __assign_bit(MAX1600_GPIO_0VPP, values, 0);
76 __assign_bit(MAX1600_GPIO_1VPP, values, 0);
77 } else if (vpp == 120) {
78 __assign_bit(MAX1600_GPIO_0VPP, values, 0);
79 __assign_bit(MAX1600_GPIO_1VPP, values, 1);
80 } else if (vpp == vcc) {
81 __assign_bit(MAX1600_GPIO_0VPP, values, 1);
82 __assign_bit(MAX1600_GPIO_1VPP, values, 0);
83 } else {
84 dev_err(m->dev, "unrecognised Vpp %u.%uV\n",
85 vpp / 10, vpp % 10);
86 return -EINVAL;
87 }
88 n = MAX1600_GPIO_MAX;
89 } else if (vpp != vcc && vpp != 0) {
90 dev_err(m->dev, "no VPP control\n");
91 return -EINVAL;
92 }
93
94 if (vcc == 0) {
95 __assign_bit(MAX1600_GPIO_0VCC, values, 0);
96 __assign_bit(MAX1600_GPIO_1VCC, values, 0);
97 } else if (vcc == 33) { /* VY */
98 __assign_bit(MAX1600_GPIO_0VCC, values, 1);
99 __assign_bit(MAX1600_GPIO_1VCC, values, 0);
100 } else if (vcc == 50) { /* VX */
101 __assign_bit(MAX1600_GPIO_0VCC, values, 0);
102 __assign_bit(MAX1600_GPIO_1VCC, values, 1);
103 } else {
104 dev_err(m->dev, "unrecognised Vcc %u.%uV\n",
105 vcc / 10, vcc % 10);
106 return -EINVAL;
107 }
108
109 if (m->code == MAX1600_CODE_HIGH) {
110 /*
111 * Cirrus mode appears to be the same as Intel mode,
112 * except the VCC pins are inverted.
113 */
114 __change_bit(MAX1600_GPIO_0VCC, values);
115 __change_bit(MAX1600_GPIO_1VCC, values);
116 }
117
118 return gpiod_set_array_value_cansleep(n, m->gpio, NULL, values);
119 }
120 EXPORT_SYMBOL_GPL(max1600_configure);
121
122 MODULE_LICENSE("GPL v2");
123