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/config.h>
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/slab.h>
27 #include <linux/init.h>
28 #include <linux/interrupt.h>
29 #include <linux/pci.h>
30 #include <linux/wait.h>
31
32 #include <linux/i2c.h>
33 #include <linux/i2c-algo-pca.h>
34
35 #include <asm/io.h>
36 #include <asm/irq.h>
37
38 #include "../algos/i2c-algo-pca.h"
39
40 #define IO_SIZE 4
41
42 #undef DEBUG_IO
43 //#define DEBUG_IO
44
45 static unsigned long base = 0x330;
46 static int irq = 10;
47
48 /* Data sheet recommends 59kHz for 100kHz operation due to variation
49 * in the actual clock rate */
50 static int clock = I2C_PCA_CON_59kHz;
51
52 static int own = 0x55;
53
54 static wait_queue_head_t pca_wait;
55
56 static int pca_isa_getown(struct i2c_algo_pca_data *adap)
57 {
58 return (own);
59 }
60
61 static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
62 {
63 return (clock);
64 }
65
66 static void
67 pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
68 {
69 #ifdef DEBUG_IO
70 static char *names[] = { "T/O", "DAT", "ADR", "CON" };
71 printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
72 #endif
73 outb(val, base+reg);
74 }
75
76 static int
77 pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
78 {
79 int res = inb(base+reg);
80 #ifdef DEBUG_IO
81 {
82 static char *names[] = { "STA", "DAT", "ADR", "CON" };
83 printk("*** read %s => %#04x\n", names[reg], res);
84 }
85 #endif
86 return res;
87 }
88
89 static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
90 {
91 int ret = 0;
92
93 if (irq > -1) {
94 ret = wait_event_interruptible(pca_wait,
95 pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI);
96 } else {
97 while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
98 udelay(100);
99 }
100 return ret;
101 }
102
103 static irqreturn_t pca_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
104 wake_up_interruptible(&pca_wait);
105 return IRQ_HANDLED;
106 }
107
108 static struct i2c_algo_pca_data pca_isa_data = {
109 .get_own = pca_isa_getown,
110 .get_clock = pca_isa_getclock,
111 .write_byte = pca_isa_writebyte,
112 .read_byte = pca_isa_readbyte,
113 .wait_for_interrupt = pca_isa_waitforinterrupt,
114 };
115
116 static struct i2c_adapter pca_isa_ops = {
117 .owner = THIS_MODULE,
118 .id = I2C_HW_A_ISA,
119 .algo_data = &pca_isa_data,
120 .name = "PCA9564 ISA Adapter",
121 };
122
123 static int __init pca_isa_init(void)
124 {
125
126 init_waitqueue_head(&pca_wait);
127
128 printk(KERN_INFO "i2c-pca-isa: i/o base %#08lx. irq %d\n", base, irq);
129
130 if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
131 printk(KERN_ERR "i2c-pca-isa: I/O address %#08lx is in use.\n", base);
132 goto out;
133 }
134
135 if (irq > -1) {
136 if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
137 printk(KERN_ERR "i2c-pca-isa: Request irq%d failed\n", irq);
138 goto out_region;
139 }
140 }
141
142 if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
143 printk(KERN_ERR "i2c-pca-isa: Failed to add i2c bus\n");
144 goto out_irq;
145 }
146
147 return 0;
148
149 out_irq:
150 if (irq > -1)
151 free_irq(irq, &pca_isa_ops);
152 out_region:
153 release_region(base, IO_SIZE);
154 out:
155 return -ENODEV;
156 }
157
158 static void pca_isa_exit(void)
159 {
160 i2c_pca_del_bus(&pca_isa_ops);
161
162 if (irq > 0) {
163 disable_irq(irq);
164 free_irq(irq, &pca_isa_ops);
165 }
166 release_region(base, IO_SIZE);
167 }
168
169 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
170 MODULE_DESCRIPTION("ISA base PCA9564 driver");
171 MODULE_LICENSE("GPL");
172
173 module_param(base, ulong, 0);
174 MODULE_PARM_DESC(base, "I/O base address");
175
176 module_param(irq, int, 0);
177 MODULE_PARM_DESC(irq, "IRQ");
178 module_param(clock, int, 0);
179 MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
180
181 module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */
182
183 module_init(pca_isa_init);
184 module_exit(pca_isa_exit);
185
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