summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-powermac.c
blob: a508cb962d244e89b4addc108f2c159212639364 (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
/*
    i2c Support for Apple SMU Controller

    Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
                       <benh@kernel.crashing.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <asm/prom.h>
#include <asm/pmac_low_i2c.h>

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
MODULE_LICENSE("GPL");

/*
 * SMBUS-type transfer entrypoint
 */
static s32 i2c_powermac_smbus_xfer(	struct i2c_adapter*	adap,
					u16			addr,
					unsigned short		flags,
					char			read_write,
					u8			command,
					int			size,
					union i2c_smbus_data*	data)
{
	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
	int			rc = 0;
	int			read = (read_write == I2C_SMBUS_READ);
	int			addrdir = (addr << 1) | read;
	u8			local[2];

	rc = pmac_i2c_open(bus, 0);
	if (rc)
		return rc;

	switch (size) {
        case I2C_SMBUS_QUICK:
		rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
		if (rc)
			goto bail;
		rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
	    	break;
        case I2C_SMBUS_BYTE:
		rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
		if (rc)
			goto bail;
		rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
	    	break;
        case I2C_SMBUS_BYTE_DATA:
		rc = pmac_i2c_setmode(bus, read ?
				      pmac_i2c_mode_combined :
				      pmac_i2c_mode_stdsub);
		if (rc)
			goto bail;
		rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
	    	break;
        case I2C_SMBUS_WORD_DATA:
		rc = pmac_i2c_setmode(bus, read ?
				      pmac_i2c_mode_combined :
				      pmac_i2c_mode_stdsub);
		if (rc)
			goto bail;
		if (!read) {
			local[0] = data->word & 0xff;
			local[1] = (data->word >> 8) & 0xff;
		}
		rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
		if (rc == 0 && read) {
			data->word = ((u16)local[1]) << 8;
			data->word |= local[0];
		}
	    	break;

	/* Note that these are broken vs. the expected smbus API where
	 * on reads, the lenght is actually returned from the function,
	 * but I think the current API makes no sense and I don't want
	 * any driver that I haven't verified for correctness to go
	 * anywhere near a pmac i2c bus anyway ...
	 *
	 * I'm also not completely sure what kind of phases to do between
	 * the actual command and the data (what I am _supposed_ to do that
	 * is). For now, I assume writes are a single stream and reads have
	 * a repeat start/addr phase (but not stop in between)
	 */
        case I2C_SMBUS_BLOCK_DATA:
		rc = pmac_i2c_setmode(bus, read ?
				      pmac_i2c_mode_combined :
				      pmac_i2c_mode_stdsub);
		if (rc)
			goto bail;
		rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
				   data->block[0] + 1);

		break;
	case I2C_SMBUS_I2C_BLOCK_DATA:
		rc = pmac_i2c_setmode(bus, read ?
				      pmac_i2c_mode_combined :
				      pmac_i2c_mode_stdsub);
		if (rc)
			goto bail;
		rc = pmac_i2c_xfer(bus, addrdir, 1, command,
				   read ? data->block : &data->block[1],
				   data->block[0]);
		break;

        default:
	    	rc = -EINVAL;
	}
 bail:
	pmac_i2c_close(bus);
	return rc;
}

/*
 * Generic i2c master transfer entrypoint. This driver only support single
 * messages (for "lame i2c" transfers). Anything else should use the smbus
 * entry point
 */
static int i2c_powermac_master_xfer(	struct i2c_adapter *adap,
					struct i2c_msg *msgs,
					int num)
{
	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
	int			rc = 0;
	int			read;
	int			addrdir;

	if (msgs->flags & I2C_M_TEN)
		return -EINVAL;
	read = (msgs->flags & I2C_M_RD) != 0;
	addrdir = (msgs->addr << 1) | read;
	if (msgs->flags & I2C_M_REV_DIR_ADDR)
		addrdir ^= 1;

	rc = pmac_i2c_open(bus, 0);
	if (rc)
		return rc;
	rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
	if (rc)
		goto bail;
	rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 bail:
	pmac_i2c_close(bus);
	return rc < 0 ? rc : 1;
}

static u32 i2c_powermac_func(struct i2c_adapter * adapter)
{
	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
		I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
}

/* For now, we only handle smbus */
static const struct i2c_algorithm i2c_powermac_algorithm = {
	.smbus_xfer	= i2c_powermac_smbus_xfer,
	.master_xfer	= i2c_powermac_master_xfer,
	.functionality	= i2c_powermac_func,
};


static int i2c_powermac_remove(struct device *dev)
{
	struct i2c_adapter	*adapter = dev_get_drvdata(dev);
	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adapter);
	int			rc;

	rc = i2c_del_adapter(adapter);
	pmac_i2c_detach_adapter(bus, adapter);
	i2c_set_adapdata(adapter, NULL);
	/* We aren't that prepared to deal with this... */
	if (rc)
		printk("i2c-powermac.c: Failed to remove bus %s !\n",
		       adapter->name);
	dev_set_drvdata(dev, NULL);
	kfree(adapter);

	return 0;
}


static int i2c_powermac_probe(struct device *dev)
{
	struct pmac_i2c_bus *bus = dev->platform_data;
	struct device_node *parent = NULL;
	struct i2c_adapter *adapter;
	char name[32];
	const char *basename;
	int rc;

	if (bus == NULL)
		return -EINVAL;

	/* Ok, now we need to make up a name for the interface that will
	 * match what we used to do in the past, that is basically the
	 * controller's parent device node for keywest. PMU didn't have a
	 * naming convention and SMU has a different one
	 */
	switch(pmac_i2c_get_type(bus)) {
	case pmac_i2c_bus_keywest:
		parent = of_get_parent(pmac_i2c_get_controller(bus));
		if (parent == NULL)
			return -EINVAL;
		basename = parent->name;
		break;
	case pmac_i2c_bus_pmu:
		basename = "pmu";
		break;
	case pmac_i2c_bus_smu:
		/* This is not what we used to do but I'm fixing drivers at
		 * the same time as this change
		 */
		basename = "smu";
		break;
	default:
		return -EINVAL;
	}
	snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
	of_node_put(parent);

	adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
	if (adapter == NULL) {
		printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
		return -ENOMEM;
	}
	dev_set_drvdata(dev, adapter);
	strcpy(adapter->name, name);
	adapter->algo = &i2c_powermac_algorithm;
	i2c_set_adapdata(adapter, bus);
	adapter->dev.parent = dev;
	pmac_i2c_attach_adapter(bus, adapter);
	rc = i2c_add_adapter(adapter);
	if (rc) {
		printk(KERN_ERR "i2c-powermac: Adapter %s registration "
		       "failed\n", name);
		i2c_set_adapdata(adapter, NULL);
		pmac_i2c_detach_adapter(bus, adapter);
	}

	printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
	return rc;
}


static struct device_driver i2c_powermac_driver = {
	.name = "i2c-powermac",
	.bus = &platform_bus_type,
	.probe = i2c_powermac_probe,
	.remove = i2c_powermac_remove,
};

static int __init i2c_powermac_init(void)
{
	driver_register(&i2c_powermac_driver);
	return 0;
}


static void __exit i2c_powermac_cleanup(void)
{
	driver_unregister(&i2c_powermac_driver);
}

module_init(i2c_powermac_init);
module_exit(i2c_powermac_cleanup);