tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * i2c-pca-isa.c driver for PCA9564 on ISA boards
3 * Copyright (C) 2004 Arcom Control Systems
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19
20#include <linux/kernel.h>
21#include <linux/ioport.h>
22#include <linux/module.h>
23#include <linux/moduleparam.h>
24#include <linux/delay.h>
25#include <linux/slab.h>
26#include <linux/init.h>
27#include <linux/interrupt.h>
28#include <linux/pci.h>
29#include <linux/wait.h>
30
31#include <linux/i2c.h>
32#include <linux/i2c-algo-pca.h>
33
34#include <asm/io.h>
35#include <asm/irq.h>
36
37#include "../algos/i2c-algo-pca.h"
38
39#define IO_SIZE 4
40
41#undef DEBUG_IO
42//#define DEBUG_IO
43
44static unsigned long base = 0x330;
45static int irq = 10;
46
47/* Data sheet recommends 59kHz for 100kHz operation due to variation
48 * in the actual clock rate */
49static int clock = I2C_PCA_CON_59kHz;
50
51static int own = 0x55;
52
53static wait_queue_head_t pca_wait;
54
55static int pca_isa_getown(struct i2c_algo_pca_data *adap)
56{
57 return (own);
58}
59
60static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
61{
62 return (clock);
63}
64
65static void
66pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
67{
68#ifdef DEBUG_IO
69 static char *names[] = { "T/O", "DAT", "ADR", "CON" };
70 printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
71#endif
72 outb(val, base+reg);
73}
74
75static int
76pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
77{
78 int res = inb(base+reg);
79#ifdef DEBUG_IO
80 {
81 static char *names[] = { "STA", "DAT", "ADR", "CON" };
82 printk("*** read %s => %#04x\n", names[reg], res);
83 }
84#endif
85 return res;
86}
87
88static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
89{
90 int ret = 0;
91
92 if (irq > -1) {
93 ret = wait_event_interruptible(pca_wait,
94 pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI);
95 } else {
96 while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
97 udelay(100);
98 }
99 return ret;
100}
101
102static irqreturn_t pca_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
103 wake_up_interruptible(&pca_wait);
104 return IRQ_HANDLED;
105}
106
107static struct i2c_algo_pca_data pca_isa_data = {
108 .get_own = pca_isa_getown,
109 .get_clock = pca_isa_getclock,
110 .write_byte = pca_isa_writebyte,
111 .read_byte = pca_isa_readbyte,
112 .wait_for_interrupt = pca_isa_waitforinterrupt,
113};
114
115static struct i2c_adapter pca_isa_ops = {
116 .owner = THIS_MODULE,
117 .id = I2C_HW_A_ISA,
118 .algo_data = &pca_isa_data,
119 .name = "PCA9564 ISA Adapter",
120};
121
122static int __init pca_isa_init(void)
123{
124
125 init_waitqueue_head(&pca_wait);
126
127 printk(KERN_INFO "i2c-pca-isa: i/o base %#08lx. irq %d\n", base, irq);
128
129 if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
130 printk(KERN_ERR "i2c-pca-isa: I/O address %#08lx is in use.\n", base);
131 goto out;
132 }
133
134 if (irq > -1) {
135 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
136 printk(KERN_ERR "i2c-pca-isa: Request irq%d failed\n", irq);
137 goto out_region;
138 }
139 }
140
141 if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
142 printk(KERN_ERR "i2c-pca-isa: Failed to add i2c bus\n");
143 goto out_irq;
144 }
145
146 return 0;
147
148 out_irq:
149 if (irq > -1)
150 free_irq(irq, &pca_isa_ops);
151 out_region:
152 release_region(base, IO_SIZE);
153 out:
154 return -ENODEV;
155}
156
157static void pca_isa_exit(void)
158{
159 i2c_pca_del_bus(&pca_isa_ops);
160
161 if (irq > 0) {
162 disable_irq(irq);
163 free_irq(irq, &pca_isa_ops);
164 }
165 release_region(base, IO_SIZE);
166}
167
168MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
169MODULE_DESCRIPTION("ISA base PCA9564 driver");
170MODULE_LICENSE("GPL");
171
172module_param(base, ulong, 0);
173MODULE_PARM_DESC(base, "I/O base address");
174
175module_param(irq, int, 0);
176MODULE_PARM_DESC(irq, "IRQ");
177module_param(clock, int, 0);
178MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
179
180module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */
181
182module_init(pca_isa_init);
183module_exit(pca_isa_exit);