1/*
2 *  i2c-pca-isa.c driver for PCA9564 on ISA boards
3 *    Copyright (C) 2004 Arcom Control Systems
4 *    Copyright (C) 2008 Pengutronix
5 *
6 *  This program is free software; you can redistribute it and/or modify
7 *  it under the terms of the GNU General Public License as published by
8 *  the Free Software Foundation; either version 2 of the License, or
9 *  (at your option) any later version.
10 *
11 *  This program is distributed in the hope that it will be useful,
12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *  GNU General Public License for more details.
15 *
16 *  You should have received a copy of the GNU General Public License
17 *  along with this program; if not, write to the Free Software
18 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include <linux/kernel.h>
22#include <linux/ioport.h>
23#include <linux/module.h>
24#include <linux/moduleparam.h>
25#include <linux/delay.h>
26#include <linux/jiffies.h>
27#include <linux/init.h>
28#include <linux/interrupt.h>
29#include <linux/wait.h>
30#include <linux/isa.h>
31#include <linux/i2c.h>
32#include <linux/i2c-algo-pca.h>
33#include <linux/io.h>
34
35#include <asm/irq.h>
36
37#define DRIVER "i2c-pca-isa"
38#define IO_SIZE 4
39
40static unsigned long base;
41static int irq = -1;
42
43/* Data sheet recommends 59kHz for 100kHz operation due to variation
44 * in the actual clock rate */
45static int clock  = 59000;
46
47static struct i2c_adapter pca_isa_ops;
48static wait_queue_head_t pca_wait;
49
50static void pca_isa_writebyte(void *pd, int reg, int val)
51{
52#ifdef DEBUG_IO
53	static char *names[] = { "T/O", "DAT", "ADR", "CON" };
54	printk(KERN_DEBUG "*** write %s at %#lx <= %#04x\n", names[reg],
55	       base+reg, val);
56#endif
57	outb(val, base+reg);
58}
59
60static int pca_isa_readbyte(void *pd, int reg)
61{
62	int res = inb(base+reg);
63#ifdef DEBUG_IO
64	{
65		static char *names[] = { "STA", "DAT", "ADR", "CON" };
66		printk(KERN_DEBUG "*** read  %s => %#04x\n", names[reg], res);
67	}
68#endif
69	return res;
70}
71
72static int pca_isa_waitforcompletion(void *pd)
73{
74	unsigned long timeout;
75	long ret;
76
77	if (irq > -1) {
78		ret = wait_event_timeout(pca_wait,
79				pca_isa_readbyte(pd, I2C_PCA_CON)
80				& I2C_PCA_CON_SI, pca_isa_ops.timeout);
81	} else {
82		/* Do polling */
83		timeout = jiffies + pca_isa_ops.timeout;
84		do {
85			ret = time_before(jiffies, timeout);
86			if (pca_isa_readbyte(pd, I2C_PCA_CON)
87					& I2C_PCA_CON_SI)
88				break;
89			udelay(100);
90		} while (ret);
91	}
92
93	return ret > 0;
94}
95
96static void pca_isa_resetchip(void *pd)
97{
98	/* apparently only an external reset will do it. not a lot can be done */
99	printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
100}
101
102static irqreturn_t pca_handler(int this_irq, void *dev_id) {
103	wake_up(&pca_wait);
104	return IRQ_HANDLED;
105}
106
107static struct i2c_algo_pca_data pca_isa_data = {
108	/* .data intentionally left NULL, not needed with ISA */
109	.write_byte		= pca_isa_writebyte,
110	.read_byte		= pca_isa_readbyte,
111	.wait_for_completion	= pca_isa_waitforcompletion,
112	.reset_chip		= pca_isa_resetchip,
113};
114
115static struct i2c_adapter pca_isa_ops = {
116	.owner          = THIS_MODULE,
117	.algo_data	= &pca_isa_data,
118	.name		= "PCA9564/PCA9665 ISA Adapter",
119	.timeout	= HZ,
120};
121
122static int __devinit pca_isa_match(struct device *dev, unsigned int id)
123{
124	int match = base != 0;
125
126	if (match) {
127		if (irq <= -1)
128			dev_warn(dev, "Using polling mode (specify irq)\n");
129	} else
130		dev_err(dev, "Please specify I/O base\n");
131
132	return match;
133}
134
135static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
136{
137	init_waitqueue_head(&pca_wait);
138
139	dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
140
141#ifdef CONFIG_PPC
142	if (check_legacy_ioport(base)) {
143		dev_err(dev, "I/O address %#08lx is not available\n", base);
144		goto out;
145	}
146#endif
147
148	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
149		dev_err(dev, "I/O address %#08lx is in use\n", base);
150		goto out;
151	}
152
153	if (irq > -1) {
154		if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
155			dev_err(dev, "Request irq%d failed\n", irq);
156			goto out_region;
157		}
158	}
159
160	pca_isa_data.i2c_clock = clock;
161	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
162		dev_err(dev, "Failed to add i2c bus\n");
163		goto out_irq;
164	}
165
166	return 0;
167
168 out_irq:
169	if (irq > -1)
170		free_irq(irq, &pca_isa_ops);
171 out_region:
172	release_region(base, IO_SIZE);
173 out:
174	return -ENODEV;
175}
176
177static int __devexit pca_isa_remove(struct device *dev, unsigned int id)
178{
179	i2c_del_adapter(&pca_isa_ops);
180
181	if (irq > -1) {
182		disable_irq(irq);
183		free_irq(irq, &pca_isa_ops);
184	}
185	release_region(base, IO_SIZE);
186
187	return 0;
188}
189
190static struct isa_driver pca_isa_driver = {
191	.match		= pca_isa_match,
192	.probe		= pca_isa_probe,
193	.remove		= __devexit_p(pca_isa_remove),
194	.driver = {
195		.owner	= THIS_MODULE,
196		.name	= DRIVER,
197	}
198};
199
200static int __init pca_isa_init(void)
201{
202	return isa_register_driver(&pca_isa_driver, 1);
203}
204
205static void __exit pca_isa_exit(void)
206{
207	isa_unregister_driver(&pca_isa_driver);
208}
209
210MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
211MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
212MODULE_LICENSE("GPL");
213
214module_param(base, ulong, 0);
215MODULE_PARM_DESC(base, "I/O base address");
216
217module_param(irq, int, 0);
218MODULE_PARM_DESC(irq, "IRQ");
219module_param(clock, int, 0);
220MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
221		"For PCA9564: 330000,288000,217000,146000,"
222		"88000,59000,44000,36000\n"
223		"\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
224		"\t\t\t\tFast: 100100 - 400099\n"
225		"\t\t\t\tFast+: 400100 - 10000099\n"
226		"\t\t\t\tTurbo: Up to 1265800");
227
228module_init(pca_isa_init);
229module_exit(pca_isa_exit);
230