aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-pca-isa.c
blob: f80df9ae50541936925752804e632f901dcd4d3f (plain) (blame)
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
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
/*
 *  i2c-pca-isa.c driver for PCA9564 on ISA boards
 *    Copyright (C) 2004 Arcom Control Systems
 *    Copyright (C) 2008 Pengutronix
 *
 *  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/init.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/isa.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pca.h>

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

#define DRIVER "i2c-pca-isa"
#define IO_SIZE 4

static unsigned long base;
static int irq = -1;

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

static wait_queue_head_t pca_wait;

static void pca_isa_writebyte(void *pd, 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(void *pd, 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_waitforcompletion(void *pd)
{
	int ret = 0;

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

static void pca_isa_resetchip(void *pd)
{
	/* apparently only an external reset will do it. not a lot can be done */
	printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
}

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 = {
	/* .data intentionally left NULL, not needed with ISA */
	.write_byte		= pca_isa_writebyte,
	.read_byte		= pca_isa_readbyte,
	.wait_for_completion	= pca_isa_waitforcompletion,
	.reset_chip		= pca_isa_resetchip,
};

static struct i2c_adapter pca_isa_ops = {
	.owner          = THIS_MODULE,
	.id		= I2C_HW_A_ISA,
	.algo_data	= &pca_isa_data,
	.name		= "PCA9564 ISA Adapter",
	.timeout	= 100,
};

static int __devinit pca_isa_match(struct device *dev, unsigned int id)
{
	int match = base != 0;

	if (match) {
		if (irq <= -1)
			dev_warn(dev, "Using polling mode (specify irq)\n");
	} else
		dev_err(dev, "Please specify I/O base\n");

	return match;
}

static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
{
	init_waitqueue_head(&pca_wait);

	dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);

#ifdef CONFIG_PPC_MERGE
	if (check_legacy_ioport(base)) {
		dev_err(dev, "I/O address %#08lx is not available\n", base);
		goto out;
	}
#endif

	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
		dev_err(dev, "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) {
			dev_err(dev, "Request irq%d failed\n", irq);
			goto out_region;
		}
	}

	pca_isa_data.i2c_clock = clock;
	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
		dev_err(dev, "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 int __devexit pca_isa_remove(struct device *dev, unsigned int id)
{
	i2c_del_adapter(&pca_isa_ops);

	if (irq > -1) {
		disable_irq(irq);
		free_irq(irq, &pca_isa_ops);
	}
	release_region(base, IO_SIZE);

	return 0;
}

static struct isa_driver pca_isa_driver = {
	.match		= pca_isa_match,
	.probe		= pca_isa_probe,
	.remove		= __devexit_p(pca_isa_remove),
	.driver = {
		.owner	= THIS_MODULE,
		.name	= DRIVER,
	}
};

static int __init pca_isa_init(void)
{
	return isa_register_driver(&pca_isa_driver, 1);
}

static void __exit pca_isa_exit(void)
{
	isa_unregister_driver(&pca_isa_driver);
}

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_init(pca_isa_init);
module_exit(pca_isa_exit);