xref: /openbmc/linux/drivers/i2c/busses/i2c-pca-isa.c (revision 22246614)
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/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/wait.h>
29 #include <linux/isa.h>
30 #include <linux/i2c.h>
31 #include <linux/i2c-algo-pca.h>
32 
33 #include <asm/io.h>
34 #include <asm/irq.h>
35 
36 #define DRIVER "i2c-pca-isa"
37 #define IO_SIZE 4
38 
39 static unsigned long base   = 0x330;
40 static int irq 	  = 10;
41 
42 /* Data sheet recommends 59kHz for 100kHz operation due to variation
43  * in the actual clock rate */
44 static int clock  = I2C_PCA_CON_59kHz;
45 
46 static wait_queue_head_t pca_wait;
47 
48 static void pca_isa_writebyte(void *pd, int reg, int val)
49 {
50 #ifdef DEBUG_IO
51 	static char *names[] = { "T/O", "DAT", "ADR", "CON" };
52 	printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
53 #endif
54 	outb(val, base+reg);
55 }
56 
57 static int pca_isa_readbyte(void *pd, int reg)
58 {
59 	int res = inb(base+reg);
60 #ifdef DEBUG_IO
61 	{
62 		static char *names[] = { "STA", "DAT", "ADR", "CON" };
63 		printk("*** read  %s => %#04x\n", names[reg], res);
64 	}
65 #endif
66 	return res;
67 }
68 
69 static int pca_isa_waitforcompletion(void *pd)
70 {
71 	int ret = 0;
72 
73 	if (irq > -1) {
74 		ret = wait_event_interruptible(pca_wait,
75 					       pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
76 	} else {
77 		while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
78 			udelay(100);
79 	}
80 	return ret;
81 }
82 
83 static void pca_isa_resetchip(void *pd)
84 {
85 	/* apparently only an external reset will do it. not a lot can be done */
86 	printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
87 }
88 
89 static irqreturn_t pca_handler(int this_irq, void *dev_id) {
90 	wake_up_interruptible(&pca_wait);
91 	return IRQ_HANDLED;
92 }
93 
94 static struct i2c_algo_pca_data pca_isa_data = {
95 	/* .data intentionally left NULL, not needed with ISA */
96 	.write_byte		= pca_isa_writebyte,
97 	.read_byte		= pca_isa_readbyte,
98 	.wait_for_completion	= pca_isa_waitforcompletion,
99 	.reset_chip		= pca_isa_resetchip,
100 };
101 
102 static struct i2c_adapter pca_isa_ops = {
103 	.owner          = THIS_MODULE,
104 	.id		= I2C_HW_A_ISA,
105 	.algo_data	= &pca_isa_data,
106 	.name		= "PCA9564 ISA Adapter",
107 	.timeout	= 100,
108 };
109 
110 static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
111 {
112 	init_waitqueue_head(&pca_wait);
113 
114 	dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
115 
116 #ifdef CONFIG_PPC_MERGE
117 	if (check_legacy_ioport(base)) {
118 		dev_err(dev, "I/O address %#08lx is not available\n", base);
119 		goto out;
120 	}
121 #endif
122 
123 	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
124 		dev_err(dev, "I/O address %#08lx is in use\n", base);
125 		goto out;
126 	}
127 
128 	if (irq > -1) {
129 		if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
130 			dev_err(dev, "Request irq%d failed\n", irq);
131 			goto out_region;
132 		}
133 	}
134 
135 	pca_isa_data.i2c_clock = clock;
136 	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
137 		dev_err(dev, "Failed to add i2c bus\n");
138 		goto out_irq;
139 	}
140 
141 	return 0;
142 
143  out_irq:
144 	if (irq > -1)
145 		free_irq(irq, &pca_isa_ops);
146  out_region:
147 	release_region(base, IO_SIZE);
148  out:
149 	return -ENODEV;
150 }
151 
152 static int __devexit pca_isa_remove(struct device *dev, unsigned int id)
153 {
154 	i2c_del_adapter(&pca_isa_ops);
155 
156 	if (irq > 0) {
157 		disable_irq(irq);
158 		free_irq(irq, &pca_isa_ops);
159 	}
160 	release_region(base, IO_SIZE);
161 
162 	return 0;
163 }
164 
165 static struct isa_driver pca_isa_driver = {
166 	.probe		= pca_isa_probe,
167 	.remove		= __devexit_p(pca_isa_remove),
168 	.driver = {
169 		.owner	= THIS_MODULE,
170 		.name	= DRIVER,
171 	}
172 };
173 
174 static int __init pca_isa_init(void)
175 {
176 	return isa_register_driver(&pca_isa_driver, 1);
177 }
178 
179 static void __exit pca_isa_exit(void)
180 {
181 	isa_unregister_driver(&pca_isa_driver);
182 }
183 
184 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
185 MODULE_DESCRIPTION("ISA base PCA9564 driver");
186 MODULE_LICENSE("GPL");
187 
188 module_param(base, ulong, 0);
189 MODULE_PARM_DESC(base, "I/O base address");
190 
191 module_param(irq, int, 0);
192 MODULE_PARM_DESC(irq, "IRQ");
193 module_param(clock, int, 0);
194 MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
195 
196 module_init(pca_isa_init);
197 module_exit(pca_isa_exit);
198