summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-pca-isa.c
blob: 6b03e0d0a8e325f12046ffa79234cfc5cd13127f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
/*
 *  i2c-pca-isa.c driver for PCA9564 on ISA boards
 *    Copyright (C) 2004 Arcom Control Systems
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/wait.h>

#include <linux/i2c.h>
#include <linux/i2c-algo-pca.h>

#include <asm/io.h>
#include <asm/irq.h>

#include "../algos/i2c-algo-pca.h"

#define IO_SIZE 4

#undef DEBUG_IO
//#define DEBUG_IO

static unsigned long base   = 0x330;
static int irq 	  = 10;

/* Data sheet recommends 59kHz for 100kHz operation due to variation
 * in the actual clock rate */
static int clock  = I2C_PCA_CON_59kHz;

static int own    = 0x55;

static wait_queue_head_t pca_wait;

static int pca_isa_getown(struct i2c_algo_pca_data *adap)
{
	return (own);
}

static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
{
	return (clock);
}

static void
pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
{
#ifdef DEBUG_IO
	static char *names[] = { "T/O", "DAT", "ADR", "CON" };
	printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
#endif
	outb(val, base+reg);
}

static int
pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
{
	int res = inb(base+reg);
#ifdef DEBUG_IO
	{
		static char *names[] = { "STA", "DAT", "ADR", "CON" };	
		printk("*** read  %s => %#04x\n", names[reg], res);
	}
#endif
	return res;
}

static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
{
	int ret = 0;

	if (irq > -1) {
		ret = wait_event_interruptible(pca_wait,
					       pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI);
	} else {
		while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0) 
			udelay(100);
	}
	return ret;
}

static irqreturn_t pca_handler(int this_irq, void *dev_id) {
	wake_up_interruptible(&pca_wait);
	return IRQ_HANDLED;
}

static struct i2c_algo_pca_data pca_isa_data = {
	.get_own		= pca_isa_getown,
	.get_clock		= pca_isa_getclock,
	.write_byte		= pca_isa_writebyte,
	.read_byte		= pca_isa_readbyte,
	.wait_for_interrupt	= pca_isa_waitforinterrupt,
};

static struct i2c_adapter pca_isa_ops = {
	.owner          = THIS_MODULE,
	.id		= I2C_HW_A_ISA,
	.algo_data	= &pca_isa_data,
	.name		= "PCA9564 ISA Adapter",
};

static int __init pca_isa_init(void)
{

	init_waitqueue_head(&pca_wait);

	printk(KERN_INFO "i2c-pca-isa: i/o base %#08lx. irq %d\n", base, irq);

	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
		printk(KERN_ERR "i2c-pca-isa: I/O address %#08lx is in use.\n", base);
		goto out;
	}

	if (irq > -1) {
		if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
			printk(KERN_ERR "i2c-pca-isa: Request irq%d failed\n", irq);
			goto out_region;
		}
	}

	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
		printk(KERN_ERR "i2c-pca-isa: Failed to add i2c bus\n");
		goto out_irq;
	}

	return 0;

 out_irq:
	if (irq > -1)
		free_irq(irq, &pca_isa_ops);
 out_region:
	release_region(base, IO_SIZE);
 out:
	return -ENODEV;
}

static void pca_isa_exit(void)
{
	i2c_del_adapter(&pca_isa_ops);

	if (irq > 0) {
		disable_irq(irq);
		free_irq(irq, &pca_isa_ops);
	}
	release_region(base, IO_SIZE);
}

MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
MODULE_DESCRIPTION("ISA base PCA9564 driver");
MODULE_LICENSE("GPL");

module_param(base, ulong, 0);
MODULE_PARM_DESC(base, "I/O base address");

module_param(irq, int, 0);
MODULE_PARM_DESC(irq, "IRQ");
module_param(clock, int, 0);
MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");

module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */

module_init(pca_isa_init);
module_exit(pca_isa_exit);
OpenPOWER on IntegriCloud