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
23static DEFINE_MUTEX(update_lock);
24
25/*
26 * C2 port operations
27 */
28
29static 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
48static 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
64static int duramar2150_c2port_c2d_get(struct c2port_device *dev)
65{
66	return inb(DATA_PORT) & C2D;
67}
68
69static 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
85static 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
101static 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
112static struct c2port_device *duramar2150_c2port_dev;
113
114/*
115 * Module stuff
116 */
117
118static 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
136free_region:
137	release_region(0x325, 2);
138	return ret;
139}
140
141static 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
151module_init(duramar2150_c2port_init);
152module_exit(duramar2150_c2port_exit);
153
154MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
155MODULE_DESCRIPTION("Silicon Labs C2 port Linux support for Duramar 2150");
156MODULE_LICENSE("GPL");
157