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authorJean Delvare <khali@linux-fr.org>2008-07-14 16:38:21 -0400
committerJean Delvare <khali@mahadeva.delvare>2008-07-14 16:38:21 -0400
commit279e902445557897707d325182916a6e28ba80de (patch)
tree48f518f932b7a527ccd749f7e310d4fa92149c7e /drivers/i2c/busses
parent2e7437879897a4185bd84478a0451e5367dee7ed (diff)
i2c-nforce2: Add support for multiplexing on the Tyan S4985
Just like the Tyan S4882, the S4985 uses a multiplexer to give access to all 16 memory module SPD EEPROMs. This specific i2c-nforce2-s4985 driver adds support for this. It is heavily based on the older i2c-amd756-s4882 driver. As more mainboards will use multiplexer chips, we will have to find a way to support them without having to write a new specfic driver for each. The recent changes to the i2c subsystem should help us, and the new gpio subsystem might help, too. Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c/busses')
-rw-r--r--drivers/i2c/busses/Kconfig13
-rw-r--r--drivers/i2c/busses/Makefile1
-rw-r--r--drivers/i2c/busses/i2c-nforce2-s4985.c257
-rw-r--r--drivers/i2c/busses/i2c-nforce2.c16
4 files changed, 287 insertions, 0 deletions
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 48438cc5d0ca..00d76e13588f 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -315,6 +315,19 @@ config I2C_NFORCE2
315 This driver can also be built as a module. If so, the module 315 This driver can also be built as a module. If so, the module
316 will be called i2c-nforce2. 316 will be called i2c-nforce2.
317 317
318config I2C_NFORCE2_S4985
319 tristate "SMBus multiplexing on the Tyan S4985"
320 depends on I2C_NFORCE2 && EXPERIMENTAL
321 help
322 Enabling this option will add specific SMBus support for the Tyan
323 S4985 motherboard. On this 4-CPU board, the SMBus is multiplexed
324 over 4 different channels, where the various memory module EEPROMs
325 live. Saying yes here will give you access to these in addition
326 to the trunk.
327
328 This driver can also be built as a module. If so, the module
329 will be called i2c-nforce2-s4985.
330
318config I2C_OCORES 331config I2C_OCORES
319 tristate "OpenCores I2C Controller" 332 tristate "OpenCores I2C Controller"
320 depends on EXPERIMENTAL 333 depends on EXPERIMENTAL
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index e8c882a5ea66..8b0a8c257905 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
24obj-$(CONFIG_I2C_MPC) += i2c-mpc.o 24obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
25obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o 25obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
26obj-$(CONFIG_I2C_NFORCE2) += i2c-nforce2.o 26obj-$(CONFIG_I2C_NFORCE2) += i2c-nforce2.o
27obj-$(CONFIG_I2C_NFORCE2_S4985) += i2c-nforce2-s4985.o
27obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o 28obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o
28obj-$(CONFIG_I2C_OMAP) += i2c-omap.o 29obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
29obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o 30obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o
diff --git a/drivers/i2c/busses/i2c-nforce2-s4985.c b/drivers/i2c/busses/i2c-nforce2-s4985.c
new file mode 100644
index 000000000000..6a8995dfd0bb
--- /dev/null
+++ b/drivers/i2c/busses/i2c-nforce2-s4985.c
@@ -0,0 +1,257 @@
1/*
2 * i2c-nforce2-s4985.c - i2c-nforce2 extras for the Tyan S4985 motherboard
3 *
4 * Copyright (C) 2008 Jean Delvare <khali@linux-fr.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21/*
22 * We select the channels by sending commands to the Philips
23 * PCA9556 chip at I2C address 0x18. The main adapter is used for
24 * the non-multiplexed part of the bus, and 4 virtual adapters
25 * are defined for the multiplexed addresses: 0x50-0x53 (memory
26 * module EEPROM) located on channels 1-4. We define one virtual
27 * adapter per CPU, which corresponds to one multiplexed channel:
28 * CPU0: virtual adapter 1, channel 1
29 * CPU1: virtual adapter 2, channel 2
30 * CPU2: virtual adapter 3, channel 3
31 * CPU3: virtual adapter 4, channel 4
32 */
33
34#include <linux/module.h>
35#include <linux/kernel.h>
36#include <linux/slab.h>
37#include <linux/init.h>
38#include <linux/i2c.h>
39#include <linux/mutex.h>
40
41extern struct i2c_adapter *nforce2_smbus;
42
43static struct i2c_adapter *s4985_adapter;
44static struct i2c_algorithm *s4985_algo;
45
46/* Wrapper access functions for multiplexed SMBus */
47static DEFINE_MUTEX(nforce2_lock);
48
49static s32 nforce2_access_virt0(struct i2c_adapter *adap, u16 addr,
50 unsigned short flags, char read_write,
51 u8 command, int size,
52 union i2c_smbus_data *data)
53{
54 int error;
55
56 /* We exclude the multiplexed addresses */
57 if ((addr & 0xfc) == 0x50 || (addr & 0xfc) == 0x30
58 || addr == 0x18)
59 return -ENXIO;
60
61 mutex_lock(&nforce2_lock);
62 error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write,
63 command, size, data);
64 mutex_unlock(&nforce2_lock);
65
66 return error;
67}
68
69/* We remember the last used channels combination so as to only switch
70 channels when it is really needed. This greatly reduces the SMBus
71 overhead, but also assumes that nobody will be writing to the PCA9556
72 in our back. */
73static u8 last_channels;
74
75static inline s32 nforce2_access_channel(struct i2c_adapter *adap, u16 addr,
76 unsigned short flags, char read_write,
77 u8 command, int size,
78 union i2c_smbus_data *data,
79 u8 channels)
80{
81 int error;
82
83 /* We exclude the non-multiplexed addresses */
84 if ((addr & 0xfc) != 0x50 && (addr & 0xfc) != 0x30)
85 return -ENXIO;
86
87 mutex_lock(&nforce2_lock);
88 if (last_channels != channels) {
89 union i2c_smbus_data mplxdata;
90 mplxdata.byte = channels;
91
92 error = nforce2_smbus->algo->smbus_xfer(adap, 0x18, 0,
93 I2C_SMBUS_WRITE, 0x01,
94 I2C_SMBUS_BYTE_DATA,
95 &mplxdata);
96 if (error)
97 goto UNLOCK;
98 last_channels = channels;
99 }
100 error = nforce2_smbus->algo->smbus_xfer(adap, addr, flags, read_write,
101 command, size, data);
102
103UNLOCK:
104 mutex_unlock(&nforce2_lock);
105 return error;
106}
107
108static s32 nforce2_access_virt1(struct i2c_adapter *adap, u16 addr,
109 unsigned short flags, char read_write,
110 u8 command, int size,
111 union i2c_smbus_data *data)
112{
113 /* CPU0: channel 1 enabled */
114 return nforce2_access_channel(adap, addr, flags, read_write, command,
115 size, data, 0x02);
116}
117
118static s32 nforce2_access_virt2(struct i2c_adapter *adap, u16 addr,
119 unsigned short flags, char read_write,
120 u8 command, int size,
121 union i2c_smbus_data *data)
122{
123 /* CPU1: channel 2 enabled */
124 return nforce2_access_channel(adap, addr, flags, read_write, command,
125 size, data, 0x04);
126}
127
128static s32 nforce2_access_virt3(struct i2c_adapter *adap, u16 addr,
129 unsigned short flags, char read_write,
130 u8 command, int size,
131 union i2c_smbus_data *data)
132{
133 /* CPU2: channel 3 enabled */
134 return nforce2_access_channel(adap, addr, flags, read_write, command,
135 size, data, 0x08);
136}
137
138static s32 nforce2_access_virt4(struct i2c_adapter *adap, u16 addr,
139 unsigned short flags, char read_write,
140 u8 command, int size,
141 union i2c_smbus_data *data)
142{
143 /* CPU3: channel 4 enabled */
144 return nforce2_access_channel(adap, addr, flags, read_write, command,
145 size, data, 0x10);
146}
147
148static int __init nforce2_s4985_init(void)
149{
150 int i, error;
151 union i2c_smbus_data ioconfig;
152
153 /* Unregister physical bus */
154 if (!nforce2_smbus)
155 return -ENODEV;
156 error = i2c_del_adapter(nforce2_smbus);
157 if (error) {
158 dev_err(&nforce2_smbus->dev, "Physical bus removal failed\n");
159 goto ERROR0;
160 }
161
162 printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4985\n");
163 /* Define the 5 virtual adapters and algorithms structures */
164 s4985_adapter = kzalloc(5 * sizeof(struct i2c_adapter), GFP_KERNEL);
165 if (!s4985_adapter) {
166 error = -ENOMEM;
167 goto ERROR1;
168 }
169 s4985_algo = kzalloc(5 * sizeof(struct i2c_algorithm), GFP_KERNEL);
170 if (!s4985_algo) {
171 error = -ENOMEM;
172 goto ERROR2;
173 }
174
175 /* Fill in the new structures */
176 s4985_algo[0] = *(nforce2_smbus->algo);
177 s4985_algo[0].smbus_xfer = nforce2_access_virt0;
178 s4985_adapter[0] = *nforce2_smbus;
179 s4985_adapter[0].algo = s4985_algo;
180 s4985_adapter[0].dev.parent = nforce2_smbus->dev.parent;
181 for (i = 1; i < 5; i++) {
182 s4985_algo[i] = *(nforce2_smbus->algo);
183 s4985_adapter[i] = *nforce2_smbus;
184 snprintf(s4985_adapter[i].name, sizeof(s4985_adapter[i].name),
185 "SMBus nForce2 adapter (CPU%d)", i - 1);
186 s4985_adapter[i].algo = s4985_algo + i;
187 s4985_adapter[i].dev.parent = nforce2_smbus->dev.parent;
188 }
189 s4985_algo[1].smbus_xfer = nforce2_access_virt1;
190 s4985_algo[2].smbus_xfer = nforce2_access_virt2;
191 s4985_algo[3].smbus_xfer = nforce2_access_virt3;
192 s4985_algo[4].smbus_xfer = nforce2_access_virt4;
193
194 /* Configure the PCA9556 multiplexer */
195 ioconfig.byte = 0x00; /* All I/O to output mode */
196 error = nforce2_smbus->algo->smbus_xfer(nforce2_smbus, 0x18, 0,
197 I2C_SMBUS_WRITE, 0x03,
198 I2C_SMBUS_BYTE_DATA, &ioconfig);
199 if (error) {
200 dev_err(&nforce2_smbus->dev, "PCA9556 configuration failed\n");
201 error = -EIO;
202 goto ERROR3;
203 }
204
205 /* Register virtual adapters */
206 for (i = 0; i < 5; i++) {
207 error = i2c_add_adapter(s4985_adapter + i);
208 if (error) {
209 dev_err(&nforce2_smbus->dev,
210 "Virtual adapter %d registration "
211 "failed, module not inserted\n", i);
212 for (i--; i >= 0; i--)
213 i2c_del_adapter(s4985_adapter + i);
214 goto ERROR3;
215 }
216 }
217
218 return 0;
219
220ERROR3:
221 kfree(s4985_algo);
222 s4985_algo = NULL;
223ERROR2:
224 kfree(s4985_adapter);
225 s4985_adapter = NULL;
226ERROR1:
227 /* Restore physical bus */
228 i2c_add_adapter(nforce2_smbus);
229ERROR0:
230 return error;
231}
232
233static void __exit nforce2_s4985_exit(void)
234{
235 if (s4985_adapter) {
236 int i;
237
238 for (i = 0; i < 5; i++)
239 i2c_del_adapter(s4985_adapter+i);
240 kfree(s4985_adapter);
241 s4985_adapter = NULL;
242 }
243 kfree(s4985_algo);
244 s4985_algo = NULL;
245
246 /* Restore physical bus */
247 if (i2c_add_adapter(nforce2_smbus))
248 dev_err(&nforce2_smbus->dev, "Physical bus restoration "
249 "failed\n");
250}
251
252MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
253MODULE_DESCRIPTION("S4985 SMBus multiplexing");
254MODULE_LICENSE("GPL");
255
256module_init(nforce2_s4985_init);
257module_exit(nforce2_s4985_exit);
diff --git a/drivers/i2c/busses/i2c-nforce2.c b/drivers/i2c/busses/i2c-nforce2.c
index 43c9f8df9509..f95efff9b3d1 100644
--- a/drivers/i2c/busses/i2c-nforce2.c
+++ b/drivers/i2c/busses/i2c-nforce2.c
@@ -124,6 +124,20 @@ static struct dmi_system_id __devinitdata nforce2_dmi_blacklist2[] = {
124 124
125static struct pci_driver nforce2_driver; 125static struct pci_driver nforce2_driver;
126 126
127/* For multiplexing support, we need a global reference to the 1st
128 SMBus channel */
129#if defined CONFIG_I2C_NFORCE2_S4985 || defined CONFIG_I2C_NFORCE2_S4985_MODULE
130struct i2c_adapter *nforce2_smbus;
131EXPORT_SYMBOL_GPL(nforce2_smbus);
132
133static void nforce2_set_reference(struct i2c_adapter *adap)
134{
135 nforce2_smbus = adap;
136}
137#else
138static inline void nforce2_set_reference(struct i2c_adapter *adap) { }
139#endif
140
127static void nforce2_abort(struct i2c_adapter *adap) 141static void nforce2_abort(struct i2c_adapter *adap)
128{ 142{
129 struct nforce2_smbus *smbus = adap->algo_data; 143 struct nforce2_smbus *smbus = adap->algo_data;
@@ -398,6 +412,7 @@ static int __devinit nforce2_probe(struct pci_dev *dev, const struct pci_device_
398 return -ENODEV; 412 return -ENODEV;
399 } 413 }
400 414
415 nforce2_set_reference(&smbuses[0].adapter);
401 return 0; 416 return 0;
402} 417}
403 418
@@ -406,6 +421,7 @@ static void __devexit nforce2_remove(struct pci_dev *dev)
406{ 421{
407 struct nforce2_smbus *smbuses = (void*) pci_get_drvdata(dev); 422 struct nforce2_smbus *smbuses = (void*) pci_get_drvdata(dev);
408 423
424 nforce2_set_reference(NULL);
409 if (smbuses[0].base) { 425 if (smbuses[0].base) {
410 i2c_del_adapter(&smbuses[0].adapter); 426 i2c_del_adapter(&smbuses[0].adapter);
411 release_region(smbuses[0].base, smbuses[0].size); 427 release_region(smbuses[0].base, smbuses[0].size);