1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Silicon Labs C2 port Linux support for Eurotech Duramar 2150
4  *
5  *  Copyright (c) 2008 Rodolfo Giometti <giometti@linux.it>
6  *  Copyright (c) 2008 Eurotech S.p.A. <info@eurotech.it>
7  */
8 
9 #include <linux/errno.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/delay.h>
14 #include <linux/io.h>
15 #include <linux/ioport.h>
16 #include <linux/c2port.h>
17 
18 #define DATA_PORT	0x325
19 #define DIR_PORT	0x326
20 #define    C2D		   (1 << 0)
21 #define    C2CK		   (1 << 1)
22 
23 static DEFINE_MUTEX(update_lock);
24 
25 /*
26  * C2 port operations
27  */
28 
duramar2150_c2port_access(struct c2port_device * dev,int status)29 static void duramar2150_c2port_access(struct c2port_device *dev, int status)
30 {
31 	u8 v;
32 
33 	mutex_lock(&update_lock);
34 
35 	v = inb(DIR_PORT);
36 
37 	/* 0 = input, 1 = output */
38 	if (status)
39 		outb(v | (C2D | C2CK), DIR_PORT);
40 	else
41 		/* When access is "off" is important that both lines are set
42 		 * as inputs or hi-impedance */
43 		outb(v & ~(C2D | C2CK), DIR_PORT);
44 
45 	mutex_unlock(&update_lock);
46 }
47 
duramar2150_c2port_c2d_dir(struct c2port_device * dev,int dir)48 static void duramar2150_c2port_c2d_dir(struct c2port_device *dev, int dir)
49 {
50 	u8 v;
51 
52 	mutex_lock(&update_lock);
53 
54 	v = inb(DIR_PORT);
55 
56 	if (dir)
57 		outb(v & ~C2D, DIR_PORT);
58 	else
59 		outb(v | C2D, DIR_PORT);
60 
61 	mutex_unlock(&update_lock);
62 }
63 
duramar2150_c2port_c2d_get(struct c2port_device * dev)64 static int duramar2150_c2port_c2d_get(struct c2port_device *dev)
65 {
66 	return inb(DATA_PORT) & C2D;
67 }
68 
duramar2150_c2port_c2d_set(struct c2port_device * dev,int status)69 static void duramar2150_c2port_c2d_set(struct c2port_device *dev, int status)
70 {
71 	u8 v;
72 
73 	mutex_lock(&update_lock);
74 
75 	v = inb(DATA_PORT);
76 
77 	if (status)
78 		outb(v | C2D, DATA_PORT);
79 	else
80 		outb(v & ~C2D, DATA_PORT);
81 
82 	mutex_unlock(&update_lock);
83 }
84 
duramar2150_c2port_c2ck_set(struct c2port_device * dev,int status)85 static void duramar2150_c2port_c2ck_set(struct c2port_device *dev, int status)
86 {
87 	u8 v;
88 
89 	mutex_lock(&update_lock);
90 
91 	v = inb(DATA_PORT);
92 
93 	if (status)
94 		outb(v | C2CK, DATA_PORT);
95 	else
96 		outb(v & ~C2CK, DATA_PORT);
97 
98 	mutex_unlock(&update_lock);
99 }
100 
101 static struct c2port_ops duramar2150_c2port_ops = {
102 	.block_size	= 512,	/* bytes */
103 	.blocks_num	= 30,	/* total flash size: 15360 bytes */
104 
105 	.access		= duramar2150_c2port_access,
106 	.c2d_dir	= duramar2150_c2port_c2d_dir,
107 	.c2d_get	= duramar2150_c2port_c2d_get,
108 	.c2d_set	= duramar2150_c2port_c2d_set,
109 	.c2ck_set	= duramar2150_c2port_c2ck_set,
110 };
111 
112 static struct c2port_device *duramar2150_c2port_dev;
113 
114 /*
115  * Module stuff
116  */
117 
duramar2150_c2port_init(void)118 static int __init duramar2150_c2port_init(void)
119 {
120 	struct resource *res;
121 	int ret = 0;
122 
123 	res = request_region(0x325, 2, "c2port");
124 	if (!res)
125 		return -EBUSY;
126 
127 	duramar2150_c2port_dev = c2port_device_register("uc",
128 					&duramar2150_c2port_ops, NULL);
129 	if (IS_ERR(duramar2150_c2port_dev)) {
130 		ret = PTR_ERR(duramar2150_c2port_dev);
131 		goto free_region;
132 	}
133 
134 	return 0;
135 
136 free_region:
137 	release_region(0x325, 2);
138 	return ret;
139 }
140 
duramar2150_c2port_exit(void)141 static void __exit duramar2150_c2port_exit(void)
142 {
143 	/* Setup the GPIOs as input by default (access = 0) */
144 	duramar2150_c2port_access(duramar2150_c2port_dev, 0);
145 
146 	c2port_device_unregister(duramar2150_c2port_dev);
147 
148 	release_region(0x325, 2);
149 }
150 
151 module_init(duramar2150_c2port_init);
152 module_exit(duramar2150_c2port_exit);
153 
154 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
155 MODULE_DESCRIPTION("Silicon Labs C2 port Linux support for Duramar 2150");
156 MODULE_LICENSE("GPL");
157