summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-elektor.c
blob: 140426db28df19bac1a3eb4b1782798049dcb065 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
// SPDX-License-Identifier: GPL-2.0-or-later
/* ------------------------------------------------------------------------- */
/* i2c-elektor.c i2c-hw access for PCF8584 style isa bus adaptes             */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-97 Simon G. Vogl
                   1998-99 Hans Berglund

 */
/* ------------------------------------------------------------------------- */

/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even
   Frodo Looijaard <frodol@dds.nl> */

/* Partially rewriten by Oleg I. Vdovikin for mmapped support of
   for Alpha Processor Inc. UP-2000(+) boards */

#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/wait.h>

#include <linux/isa.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pcf.h>
#include <linux/io.h>

#include <asm/irq.h>

#include "../algos/i2c-algo-pcf.h"

#define DEFAULT_BASE 0x330

static int base;
static u8 __iomem *base_iomem;

static int irq;
static int clock  = 0x1c;
static int own    = 0x55;
static int mmapped;

/* vdovikin: removed static struct i2c_pcf_isa gpi; code -
  this module in real supports only one device, due to missing arguments
  in some functions, called from the algo-pcf module. Sometimes it's
  need to be rewriten - but for now just remove this for simpler reading */

static wait_queue_head_t pcf_wait;
static int pcf_pending;
static spinlock_t lock;

static struct i2c_adapter pcf_isa_ops;

/* ----- local functions ----------------------------------------------	*/

static void pcf_isa_setbyte(void *data, int ctl, int val)
{
	u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;

	/* enable irq if any specified for serial operation */
	if (ctl && irq && (val & I2C_PCF_ESO)) {
		val |= I2C_PCF_ENI;
	}

	pr_debug("%s: Write %p 0x%02X\n", pcf_isa_ops.name, address, val);
	iowrite8(val, address);
#ifdef __alpha__
	/* API UP2000 needs some hardware fudging to make the write stick */
	iowrite8(val, address);
#endif
}

static int pcf_isa_getbyte(void *data, int ctl)
{
	u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
	int val = ioread8(address);

	pr_debug("%s: Read %p 0x%02X\n", pcf_isa_ops.name, address, val);
	return (val);
}

static int pcf_isa_getown(void *data)
{
	return (own);
}


static int pcf_isa_getclock(void *data)
{
	return (clock);
}

static void pcf_isa_waitforpin(void *data)
{
	DEFINE_WAIT(wait);
	int timeout = 2;
	unsigned long flags;

	if (irq > 0) {
		spin_lock_irqsave(&lock, flags);
		if (pcf_pending == 0) {
			spin_unlock_irqrestore(&lock, flags);
			prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
			if (schedule_timeout(timeout*HZ)) {
				spin_lock_irqsave(&lock, flags);
				if (pcf_pending == 1) {
					pcf_pending = 0;
				}
				spin_unlock_irqrestore(&lock, flags);
			}
			finish_wait(&pcf_wait, &wait);
		} else {
			pcf_pending = 0;
			spin_unlock_irqrestore(&lock, flags);
		}
	} else {
		udelay(100);
	}
}


static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id) {
	spin_lock(&lock);
	pcf_pending = 1;
	spin_unlock(&lock);
	wake_up_interruptible(&pcf_wait);
	return IRQ_HANDLED;
}


static int pcf_isa_init(void)
{
	spin_lock_init(&lock);
	if (!mmapped) {
		if (!request_region(base, 2, pcf_isa_ops.name)) {
			printk(KERN_ERR "%s: requested I/O region (%#x:2) is "
			       "in use\n", pcf_isa_ops.name, base);
			return -ENODEV;
		}
		base_iomem = ioport_map(base, 2);
		if (!base_iomem) {
			printk(KERN_ERR "%s: remap of I/O region %#x failed\n",
			       pcf_isa_ops.name, base);
			release_region(base, 2);
			return -ENODEV;
		}
	} else {
		if (!request_mem_region(base, 2, pcf_isa_ops.name)) {
			printk(KERN_ERR "%s: requested memory region (%#x:2) "
			       "is in use\n", pcf_isa_ops.name, base);
			return -ENODEV;
		}
		base_iomem = ioremap(base, 2);
		if (base_iomem == NULL) {
			printk(KERN_ERR "%s: remap of memory region %#x "
			       "failed\n", pcf_isa_ops.name, base);
			release_mem_region(base, 2);
			return -ENODEV;
		}
	}
	pr_debug("%s: registers %#x remapped to %p\n", pcf_isa_ops.name, base,
		 base_iomem);

	if (irq > 0) {
		if (request_irq(irq, pcf_isa_handler, 0, pcf_isa_ops.name,
				NULL) < 0) {
			printk(KERN_ERR "%s: Request irq%d failed\n",
			       pcf_isa_ops.name, irq);
			irq = 0;
		} else
			enable_irq(irq);
	}
	return 0;
}

/* ------------------------------------------------------------------------
 * Encapsulate the above functions in the correct operations structure.
 * This is only done when more than one hardware adapter is supported.
 */
static struct i2c_algo_pcf_data pcf_isa_data = {
	.setpcf	    = pcf_isa_setbyte,
	.getpcf	    = pcf_isa_getbyte,
	.getown	    = pcf_isa_getown,
	.getclock   = pcf_isa_getclock,
	.waitforpin = pcf_isa_waitforpin,
};

static struct i2c_adapter pcf_isa_ops = {
	.owner		= THIS_MODULE,
	.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
	.algo_data	= &pcf_isa_data,
	.name		= "i2c-elektor",
};

static int elektor_match(struct device *dev, unsigned int id)
{
#ifdef __alpha__
	/* check to see we have memory mapped PCF8584 connected to the
	Cypress cy82c693 PCI-ISA bridge as on UP2000 board */
	if (base == 0) {
		struct pci_dev *cy693_dev;

		cy693_dev = pci_get_device(PCI_VENDOR_ID_CONTAQ,
					   PCI_DEVICE_ID_CONTAQ_82C693, NULL);
		if (cy693_dev) {
			unsigned char config;
			/* yeap, we've found cypress, let's check config */
			if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {

				dev_dbg(dev, "found cy82c693, config "
					"register 0x47 = 0x%02x\n", config);

				/* UP2000 board has this register set to 0xe1,
				   but the most significant bit as seems can be
				   reset during the proper initialisation
				   sequence if guys from API decides to do that
				   (so, we can even enable Tsunami Pchip
				   window for the upper 1 Gb) */

				/* so just check for ROMCS at 0xe0000,
				   ROMCS enabled for writes
				   and external XD Bus buffer in use. */
				if ((config & 0x7f) == 0x61) {
					/* seems to be UP2000 like board */
					base = 0xe0000;
					mmapped = 1;
					/* UP2000 drives ISA with
					   8.25 MHz (PCI/4) clock
					   (this can be read from cypress) */
					clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
					dev_info(dev, "found API UP2000 like "
						 "board, will probe PCF8584 "
						 "later\n");
				}
			}
			pci_dev_put(cy693_dev);
		}
	}
#endif

	/* sanity checks for mmapped I/O */
	if (mmapped && base < 0xc8000) {
		dev_err(dev, "incorrect base address (%#x) specified "
		       "for mmapped I/O\n", base);
		return 0;
	}

	if (base == 0) {
		base = DEFAULT_BASE;
	}
	return 1;
}

static int elektor_probe(struct device *dev, unsigned int id)
{
	init_waitqueue_head(&pcf_wait);
	if (pcf_isa_init())
		return -ENODEV;
	pcf_isa_ops.dev.parent = dev;
	if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
		goto fail;

	dev_info(dev, "found device at %#x\n", base);

	return 0;

 fail:
	if (irq > 0) {
		disable_irq(irq);
		free_irq(irq, NULL);
	}

	if (!mmapped) {
		ioport_unmap(base_iomem);
		release_region(base, 2);
	} else {
		iounmap(base_iomem);
		release_mem_region(base, 2);
	}
	return -ENODEV;
}

static int elektor_remove(struct device *dev, unsigned int id)
{
	i2c_del_adapter(&pcf_isa_ops);

	if (irq > 0) {
		disable_irq(irq);
		free_irq(irq, NULL);
	}

	if (!mmapped) {
		ioport_unmap(base_iomem);
		release_region(base, 2);
	} else {
		iounmap(base_iomem);
		release_mem_region(base, 2);
	}

	return 0;
}

static struct isa_driver i2c_elektor_driver = {
	.match		= elektor_match,
	.probe		= elektor_probe,
	.remove		= elektor_remove,
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "i2c-elektor",
	},
};

MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
MODULE_LICENSE("GPL");

module_param_hw(base, int, ioport_or_iomem, 0);
module_param_hw(irq, int, irq, 0);
module_param(clock, int, 0);
module_param(own, int, 0);
module_param_hw(mmapped, int, other, 0);
module_isa_driver(i2c_elektor_driver, 1);