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
17#include <linux/kernel.h>
18#include <linux/ioport.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/delay.h>
22#include <linux/jiffies.h>
23#include <linux/init.h>
24#include <linux/interrupt.h>
25#include <linux/wait.h>
26#include <linux/isa.h>
27#include <linux/i2c.h>
28#include <linux/i2c-algo-pca.h>
29#include <linux/io.h>
30
31#include <asm/irq.h>
32
33#define DRIVER "i2c-pca-isa"
34#define IO_SIZE 4
35
36static unsigned long base;
37static int irq = -1;
38
39/* Data sheet recommends 59kHz for 100kHz operation due to variation
40 * in the actual clock rate */
41static int clock  = 59000;
42
43static struct i2c_adapter pca_isa_ops;
44static wait_queue_head_t pca_wait;
45
46static void pca_isa_writebyte(void *pd, int reg, int val)
47{
48#ifdef DEBUG_IO
49	static char *names[] = { "T/O", "DAT", "ADR", "CON" };
50	printk(KERN_DEBUG "*** write %s at %#lx <= %#04x\n", names[reg],
51	       base+reg, val);
52#endif
53	outb(val, base+reg);
54}
55
56static int pca_isa_readbyte(void *pd, int reg)
57{
58	int res = inb(base+reg);
59#ifdef DEBUG_IO
60	{
61		static char *names[] = { "STA", "DAT", "ADR", "CON" };
62		printk(KERN_DEBUG "*** read  %s => %#04x\n", names[reg], res);
63	}
64#endif
65	return res;
66}
67
68static int pca_isa_waitforcompletion(void *pd)
69{
70	unsigned long timeout;
71	long ret;
72
73	if (irq > -1) {
74		ret = wait_event_timeout(pca_wait,
75				pca_isa_readbyte(pd, I2C_PCA_CON)
76				& I2C_PCA_CON_SI, pca_isa_ops.timeout);
77	} else {
78		/* Do polling */
79		timeout = jiffies + pca_isa_ops.timeout;
80		do {
81			ret = time_before(jiffies, timeout);
82			if (pca_isa_readbyte(pd, I2C_PCA_CON)
83					& I2C_PCA_CON_SI)
84				break;
85			udelay(100);
86		} while (ret);
87	}
88
89	return ret > 0;
90}
91
92static void pca_isa_resetchip(void *pd)
93{
94	/* apparently only an external reset will do it. not a lot can be done */
95	printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
96}
97
98static irqreturn_t pca_handler(int this_irq, void *dev_id) {
99	wake_up(&pca_wait);
100	return IRQ_HANDLED;
101}
102
103static struct i2c_algo_pca_data pca_isa_data = {
104	/* .data intentionally left NULL, not needed with ISA */
105	.write_byte		= pca_isa_writebyte,
106	.read_byte		= pca_isa_readbyte,
107	.wait_for_completion	= pca_isa_waitforcompletion,
108	.reset_chip		= pca_isa_resetchip,
109};
110
111static struct i2c_adapter pca_isa_ops = {
112	.owner          = THIS_MODULE,
113	.algo_data	= &pca_isa_data,
114	.name		= "PCA9564/PCA9665 ISA Adapter",
115	.timeout	= HZ,
116};
117
118static int pca_isa_match(struct device *dev, unsigned int id)
119{
120	int match = base != 0;
121
122	if (match) {
123		if (irq <= -1)
124			dev_warn(dev, "Using polling mode (specify irq)\n");
125	} else
126		dev_err(dev, "Please specify I/O base\n");
127
128	return match;
129}
130
131static int pca_isa_probe(struct device *dev, unsigned int id)
132{
133	init_waitqueue_head(&pca_wait);
134
135	dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
136
137#ifdef CONFIG_PPC
138	if (check_legacy_ioport(base)) {
139		dev_err(dev, "I/O address %#08lx is not available\n", base);
140		goto out;
141	}
142#endif
143
144	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
145		dev_err(dev, "I/O address %#08lx is in use\n", base);
146		goto out;
147	}
148
149	if (irq > -1) {
150		if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
151			dev_err(dev, "Request irq%d failed\n", irq);
152			goto out_region;
153		}
154	}
155
156	pca_isa_data.i2c_clock = clock;
157	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
158		dev_err(dev, "Failed to add i2c bus\n");
159		goto out_irq;
160	}
161
162	return 0;
163
164 out_irq:
165	if (irq > -1)
166		free_irq(irq, &pca_isa_ops);
167 out_region:
168	release_region(base, IO_SIZE);
169 out:
170	return -ENODEV;
171}
172
173static int pca_isa_remove(struct device *dev, unsigned int id)
174{
175	i2c_del_adapter(&pca_isa_ops);
176
177	if (irq > -1) {
178		disable_irq(irq);
179		free_irq(irq, &pca_isa_ops);
180	}
181	release_region(base, IO_SIZE);
182
183	return 0;
184}
185
186static struct isa_driver pca_isa_driver = {
187	.match		= pca_isa_match,
188	.probe		= pca_isa_probe,
189	.remove		= pca_isa_remove,
190	.driver = {
191		.owner	= THIS_MODULE,
192		.name	= DRIVER,
193	}
194};
195
196static int __init pca_isa_init(void)
197{
198	return isa_register_driver(&pca_isa_driver, 1);
199}
200
201static void __exit pca_isa_exit(void)
202{
203	isa_unregister_driver(&pca_isa_driver);
204}
205
206MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
207MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
208MODULE_LICENSE("GPL");
209
210module_param(base, ulong, 0);
211MODULE_PARM_DESC(base, "I/O base address");
212
213module_param(irq, int, 0);
214MODULE_PARM_DESC(irq, "IRQ");
215module_param(clock, int, 0);
216MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
217		"For PCA9564: 330000,288000,217000,146000,"
218		"88000,59000,44000,36000\n"
219		"\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
220		"\t\t\t\tFast: 100100 - 400099\n"
221		"\t\t\t\tFast+: 400100 - 10000099\n"
222		"\t\t\t\tTurbo: Up to 1265800");
223
224module_init(pca_isa_init);
225module_exit(pca_isa_exit);
226