xref: /openbmc/linux/drivers/pcmcia/max1600.c (revision bebdf98a)
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