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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* ------------------------------------------------------------------------- */
2/* i2c-elektor.c i2c-hw access for PCF8584 style isa bus adaptes */
3/* ------------------------------------------------------------------------- */
4/* Copyright (C) 1995-97 Simon G. Vogl
5 1998-99 Hans Berglund
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
20/* ------------------------------------------------------------------------- */
21
22/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even
23 Frodo Looijaard <frodol@dds.nl> */
24
25/* Partialy rewriten by Oleg I. Vdovikin for mmapped support of
26 for Alpha Processor Inc. UP-2000(+) boards */
27
28#include <linux/config.h>
29#include <linux/kernel.h>
30#include <linux/ioport.h>
31#include <linux/module.h>
32#include <linux/delay.h>
33#include <linux/slab.h>
34#include <linux/init.h>
35#include <linux/interrupt.h>
36#include <linux/pci.h>
37#include <linux/wait.h>
38
39#include <linux/i2c.h>
40#include <linux/i2c-algo-pcf.h>
41
42#include <asm/io.h>
43#include <asm/irq.h>
44
45#include "../algos/i2c-algo-pcf.h"
46
47#define DEFAULT_BASE 0x330
48
49static int base;
50static int irq;
51static int clock = 0x1c;
52static int own = 0x55;
53static int mmapped;
54
55/* vdovikin: removed static struct i2c_pcf_isa gpi; code -
56 this module in real supports only one device, due to missing arguments
57 in some functions, called from the algo-pcf module. Sometimes it's
58 need to be rewriten - but for now just remove this for simpler reading */
59
60static wait_queue_head_t pcf_wait;
61static int pcf_pending;
62static spinlock_t lock;
63
64/* ----- local functions ---------------------------------------------- */
65
66static void pcf_isa_setbyte(void *data, int ctl, int val)
67{
68 int address = ctl ? (base + 1) : base;
69
70 /* enable irq if any specified for serial operation */
71 if (ctl && irq && (val & I2C_PCF_ESO)) {
72 val |= I2C_PCF_ENI;
73 }
74
75 pr_debug("i2c-elektor: Write 0x%X 0x%02X\n", address, val & 255);
76
77 switch (mmapped) {
78 case 0: /* regular I/O */
79 outb(val, address);
80 break;
81 case 2: /* double mapped I/O needed for UP2000 board,
82 I don't know why this... */
83 writeb(val, (void *)address);
84 /* fall */
85 case 1: /* memory mapped I/O */
86 writeb(val, (void *)address);
87 break;
88 }
89}
90
91static int pcf_isa_getbyte(void *data, int ctl)
92{
93 int address = ctl ? (base + 1) : base;
94 int val = mmapped ? readb((void *)address) : inb(address);
95
96 pr_debug("i2c-elektor: Read 0x%X 0x%02X\n", address, val);
97
98 return (val);
99}
100
101static int pcf_isa_getown(void *data)
102{
103 return (own);
104}
105
106
107static int pcf_isa_getclock(void *data)
108{
109 return (clock);
110}
111
112static void pcf_isa_waitforpin(void) {
113 DEFINE_WAIT(wait);
114 int timeout = 2;
115 unsigned long flags;
116
117 if (irq > 0) {
118 spin_lock_irqsave(&lock, flags);
119 if (pcf_pending == 0) {
120 spin_unlock_irqrestore(&lock, flags);
121 prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
122 if (schedule_timeout(timeout*HZ)) {
123 spin_lock_irqsave(&lock, flags);
124 if (pcf_pending == 1) {
125 pcf_pending = 0;
126 }
127 spin_unlock_irqrestore(&lock, flags);
128 }
129 finish_wait(&pcf_wait, &wait);
130 } else {
131 pcf_pending = 0;
132 spin_unlock_irqrestore(&lock, flags);
133 }
134 } else {
135 udelay(100);
136 }
137}
138
139
140static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
141 spin_lock(&lock);
142 pcf_pending = 1;
143 spin_unlock(&lock);
144 wake_up_interruptible(&pcf_wait);
145 return IRQ_HANDLED;
146}
147
148
149static int pcf_isa_init(void)
150{
151 spin_lock_init(&lock);
152 if (!mmapped) {
153 if (!request_region(base, 2, "i2c (isa bus adapter)")) {
154 printk(KERN_ERR
155 "i2c-elektor: requested I/O region (0x%X:2) "
156 "is in use.\n", base);
157 return -ENODEV;
158 }
159 }
160 if (irq > 0) {
161 if (request_irq(irq, pcf_isa_handler, 0, "PCF8584", NULL) < 0) {
162 printk(KERN_ERR "i2c-elektor: Request irq%d failed\n", irq);
163 irq = 0;
164 } else
165 enable_irq(irq);
166 }
167 return 0;
168}
169
170/* ------------------------------------------------------------------------
171 * Encapsulate the above functions in the correct operations structure.
172 * This is only done when more than one hardware adapter is supported.
173 */
174static struct i2c_algo_pcf_data pcf_isa_data = {
175 .setpcf = pcf_isa_setbyte,
176 .getpcf = pcf_isa_getbyte,
177 .getown = pcf_isa_getown,
178 .getclock = pcf_isa_getclock,
179 .waitforpin = pcf_isa_waitforpin,
180 .udelay = 10,
181 .mdelay = 10,
182 .timeout = 100,
183};
184
185static struct i2c_adapter pcf_isa_ops = {
186 .owner = THIS_MODULE,
187 .class = I2C_CLASS_HWMON,
188 .id = I2C_HW_P_ELEK,
189 .algo_data = &pcf_isa_data,
190 .name = "PCF8584 ISA adapter",
191};
192
193static int __init i2c_pcfisa_init(void)
194{
195#ifdef __alpha__
196 /* check to see we have memory mapped PCF8584 connected to the
197 Cypress cy82c693 PCI-ISA bridge as on UP2000 board */
198 if (base == 0) {
199 struct pci_dev *cy693_dev;
200
201 cy693_dev = pci_get_device(PCI_VENDOR_ID_CONTAQ,
202 PCI_DEVICE_ID_CONTAQ_82C693, NULL);
203 if (cy693_dev) {
204 char config;
205 /* yeap, we've found cypress, let's check config */
206 if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {
207
208 pr_debug("i2c-elektor: found cy82c693, config register 0x47 = 0x%02x.\n", config);
209
210 /* UP2000 board has this register set to 0xe1,
211 but the most significant bit as seems can be
212 reset during the proper initialisation
213 sequence if guys from API decides to do that
214 (so, we can even enable Tsunami Pchip
215 window for the upper 1 Gb) */
216
217 /* so just check for ROMCS at 0xe0000,
218 ROMCS enabled for writes
219 and external XD Bus buffer in use. */
220 if ((config & 0x7f) == 0x61) {
221 /* seems to be UP2000 like board */
222 base = 0xe0000;
223 /* I don't know why we need to
224 write twice */
225 mmapped = 2;
226 /* UP2000 drives ISA with
227 8.25 MHz (PCI/4) clock
228 (this can be read from cypress) */
229 clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
230 printk(KERN_INFO "i2c-elektor: found API UP2000 like board, will probe PCF8584 later.\n");
231 }
232 }
233 pci_dev_put(cy693_dev);
234 }
235 }
236#endif
237
238 /* sanity checks for mmapped I/O */
239 if (mmapped && base < 0xc8000) {
240 printk(KERN_ERR "i2c-elektor: incorrect base address (0x%0X) specified for mmapped I/O.\n", base);
241 return -ENODEV;
242 }
243
244 printk(KERN_INFO "i2c-elektor: i2c pcf8584-isa adapter driver\n");
245
246 if (base == 0) {
247 base = DEFAULT_BASE;
248 }
249
250 init_waitqueue_head(&pcf_wait);
251 if (pcf_isa_init())
252 return -ENODEV;
253 if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
254 goto fail;
255
256 printk(KERN_ERR "i2c-elektor: found device at %#x.\n", base);
257
258 return 0;
259
260 fail:
261 if (irq > 0) {
262 disable_irq(irq);
263 free_irq(irq, NULL);
264 }
265
266 if (!mmapped)
267 release_region(base , 2);
268 return -ENODEV;
269}
270
271static void i2c_pcfisa_exit(void)
272{
273 i2c_pcf_del_bus(&pcf_isa_ops);
274
275 if (irq > 0) {
276 disable_irq(irq);
277 free_irq(irq, NULL);
278 }
279
280 if (!mmapped)
281 release_region(base , 2);
282}
283
284MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
285MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
286MODULE_LICENSE("GPL");
287
288module_param(base, int, 0);
289module_param(irq, int, 0);
290module_param(clock, int, 0);
291module_param(own, int, 0);
292module_param(mmapped, int, 0);
293
294module_init(i2c_pcfisa_init);
295module_exit(i2c_pcfisa_exit);