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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-04 20:46:27 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-04 20:46:27 -0400
commit8d41f0e8d51742aba5bbcab9acb5238a8578c917 (patch)
treec69e7ffaf2a8598283422d20643154a298d08293 /Documentation
parent8bc8493063f938c932819958a7b5a0d56046bc96 (diff)
parent5b68790cd5e2879067bcbc45b01eeb6081e7d731 (diff)
Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6
* 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6: (44 commits) i2c-s3c2410: Fix bug in releasing driver i2c-s3c2410: Fix I2C SDA to SCL setup time i2c: New i2c-tiny-usb bus driver i2c: Documentation update i2c: SPIN_LOCK_UNLOCKED cleanup i2c: Obsolete i2c-ixp2000, i2c-ixp4xx and scx200_i2c i2c: New Simtec I2C bus driver i2c: Bitbanging I2C bus driver using the GPIO API Use menuconfig objects - I2C i2c: Restore i2c_smbus_read_block_data i2c-pxa: Clean transaction stop i2c-algo-bit: Improve debugging i2c-algo-bit: Implement a 50/50 SCL duty cycle i2c-omap: Switch to static adapter numbering i2c: Blackfin Two Wire Interface driver i2c-algo-sgi: Comment and whitespace cleanups i2c: Make i2c_del_driver a void function i2c: Move i2c-isa-only exported symbol declarations i2c: Document i2c_new_device() i2c: Add i2c_new_probed_device() ... Fixed trivial conflict in Documentation/feature-removal-schedule.txt manually. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/feature-removal-schedule.txt21
-rw-r--r--Documentation/i2c/busses/i2c-nforce22
-rw-r--r--Documentation/i2c/porting-clients18
-rw-r--r--Documentation/i2c/summary29
-rw-r--r--Documentation/i2c/writing-clients415
5 files changed, 181 insertions, 304 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 1a9e600a73a8..7d252dbe7d17 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -190,18 +190,10 @@ Who: Jean Delvare <khali@linux-fr.org>
190 190
191--------------------------- 191---------------------------
192 192
193What: i2c_adapter.dev 193What: i2c_adapter.list
194 i2c_adapter.list
195When: July 2007 194When: July 2007
196Why: Superfluous, given i2c_adapter.class_dev: 195Why: Superfluous, this list duplicates the one maintained by the driver
197 * The "dev" was a stand-in for the physical device node that legacy 196 core.
198 drivers would not have; but now it's almost always present. Any
199 remaining legacy drivers must upgrade (they now trigger warnings).
200 * The "list" duplicates class device children.
201 The delay in removing this is so upgraded lm_sensors and libsensors
202 can get deployed. (Removal causes minor changes in the sysfs layout,
203 notably the location of the adapter type name and parenting the i2c
204 client hardware directly from their controller.)
205Who: Jean Delvare <khali@linux-fr.org>, 197Who: Jean Delvare <khali@linux-fr.org>,
206 David Brownell <dbrownell@users.sourceforge.net> 198 David Brownell <dbrownell@users.sourceforge.net>
207 199
@@ -331,3 +323,10 @@ Who: Cornelia Huck <cornelia.huck@de.ibm.com>
331 323
332--------------------------- 324---------------------------
333 325
326What: i2c-ixp2000, i2c-ixp4xx and scx200_i2c drivers
327When: September 2007
328Why: Obsolete. The new i2c-gpio driver replaces all hardware-specific
329 I2C-over-GPIO drivers.
330Who: Jean Delvare <khali@linux-fr.org>
331
332---------------------------
diff --git a/Documentation/i2c/busses/i2c-nforce2 b/Documentation/i2c/busses/i2c-nforce2
index 7f61fbc03f7f..fae3495bcbaf 100644
--- a/Documentation/i2c/busses/i2c-nforce2
+++ b/Documentation/i2c/busses/i2c-nforce2
@@ -9,6 +9,8 @@ Supported adapters:
9 * nForce4 MCP-04 10de:0034 9 * nForce4 MCP-04 10de:0034
10 * nForce4 MCP51 10de:0264 10 * nForce4 MCP51 10de:0264
11 * nForce4 MCP55 10de:0368 11 * nForce4 MCP55 10de:0368
12 * nForce4 MCP61 10de:03EB
13 * nForce4 MCP65 10de:0446
12 14
13Datasheet: not publicly available, but seems to be similar to the 15Datasheet: not publicly available, but seems to be similar to the
14 AMD-8111 SMBus 2.0 adapter. 16 AMD-8111 SMBus 2.0 adapter.
diff --git a/Documentation/i2c/porting-clients b/Documentation/i2c/porting-clients
index ca272b263a92..7bf82c08f6ca 100644
--- a/Documentation/i2c/porting-clients
+++ b/Documentation/i2c/porting-clients
@@ -1,4 +1,4 @@
1Revision 6, 2005-11-20 1Revision 7, 2007-04-19
2Jean Delvare <khali@linux-fr.org> 2Jean Delvare <khali@linux-fr.org>
3Greg KH <greg@kroah.com> 3Greg KH <greg@kroah.com>
4 4
@@ -20,6 +20,10 @@ yours for best results.
20 20
21Technical changes: 21Technical changes:
22 22
23* [Driver type] Any driver that was relying on i2c-isa has to be
24 converted to a proper isa, platform or pci driver. This is not
25 covered by this guide.
26
23* [Includes] Get rid of "version.h" and <linux/i2c-proc.h>. 27* [Includes] Get rid of "version.h" and <linux/i2c-proc.h>.
24 Includes typically look like that: 28 Includes typically look like that:
25 #include <linux/module.h> 29 #include <linux/module.h>
@@ -27,12 +31,10 @@ Technical changes:
27 #include <linux/slab.h> 31 #include <linux/slab.h>
28 #include <linux/jiffies.h> 32 #include <linux/jiffies.h>
29 #include <linux/i2c.h> 33 #include <linux/i2c.h>
30 #include <linux/i2c-isa.h> /* for ISA drivers */
31 #include <linux/hwmon.h> /* for hardware monitoring drivers */ 34 #include <linux/hwmon.h> /* for hardware monitoring drivers */
32 #include <linux/hwmon-sysfs.h> 35 #include <linux/hwmon-sysfs.h>
33 #include <linux/hwmon-vid.h> /* if you need VRM support */ 36 #include <linux/hwmon-vid.h> /* if you need VRM support */
34 #include <linux/err.h> /* for class registration */ 37 #include <linux/err.h> /* for class registration */
35 #include <asm/io.h> /* if you have I/O operations */
36 Please respect this inclusion order. Some extra headers may be 38 Please respect this inclusion order. Some extra headers may be
37 required for a given driver (e.g. "lm75.h"). 39 required for a given driver (e.g. "lm75.h").
38 40
@@ -69,20 +71,16 @@ Technical changes:
69 sensors mailing list <lm-sensors@lm-sensors.org> by providing a 71 sensors mailing list <lm-sensors@lm-sensors.org> by providing a
70 patch to the Documentation/hwmon/sysfs-interface file. 72 patch to the Documentation/hwmon/sysfs-interface file.
71 73
72* [Attach] For I2C drivers, the attach function should make sure 74* [Attach] The attach function should make sure that the adapter's
73 that the adapter's class has I2C_CLASS_HWMON (or whatever class is 75 class has I2C_CLASS_HWMON (or whatever class is suitable for your
74 suitable for your driver), using the following construct: 76 driver), using the following construct:
75 if (!(adapter->class & I2C_CLASS_HWMON)) 77 if (!(adapter->class & I2C_CLASS_HWMON))
76 return 0; 78 return 0;
77 ISA-only drivers of course don't need this.
78 Call i2c_probe() instead of i2c_detect(). 79 Call i2c_probe() instead of i2c_detect().
79 80
80* [Detect] As mentioned earlier, the flags parameter is gone. 81* [Detect] As mentioned earlier, the flags parameter is gone.
81 The type_name and client_name strings are replaced by a single 82 The type_name and client_name strings are replaced by a single
82 name string, which will be filled with a lowercase, short string. 83 name string, which will be filled with a lowercase, short string.
83 In i2c-only drivers, drop the i2c_is_isa_adapter check, it's
84 useless. Same for isa-only drivers, as the test would always be
85 true. Only hybrid drivers (which are quite rare) still need it.
86 The labels used for error paths are reduced to the number needed. 84 The labels used for error paths are reduced to the number needed.
87 It is advised that the labels are given descriptive names such as 85 It is advised that the labels are given descriptive names such as
88 exit and exit_free. Don't forget to properly set err before 86 exit and exit_free. Don't forget to properly set err before
diff --git a/Documentation/i2c/summary b/Documentation/i2c/summary
index 41dde8776791..aea60bf7e8f0 100644
--- a/Documentation/i2c/summary
+++ b/Documentation/i2c/summary
@@ -4,17 +4,23 @@ I2C and SMBus
4============= 4=============
5 5
6I2C (pronounce: I squared C) is a protocol developed by Philips. It is a 6I2C (pronounce: I squared C) is a protocol developed by Philips. It is a
7slow two-wire protocol (10-400 kHz), but it suffices for many types of 7slow two-wire protocol (variable speed, up to 400 kHz), with a high speed
8devices. 8extension (3.4 MHz). It provides an inexpensive bus for connecting many
9types of devices with infrequent or low bandwidth communications needs.
10I2C is widely used with embedded systems. Some systems use variants that
11don't meet branding requirements, and so are not advertised as being I2C.
9 12
10SMBus (System Management Bus) is a subset of the I2C protocol. Many 13SMBus (System Management Bus) is based on the I2C protocol, and is mostly
11modern mainboards have a System Management Bus. There are a lot of 14a subset of I2C protocols and signaling. Many I2C devices will work on an
12devices which can be connected to a SMBus; the most notable are modern 15SMBus, but some SMBus protocols add semantics beyond what is required to
13memory chips with EEPROM memories and chips for hardware monitoring. 16achieve I2C branding. Modern PC mainboards rely on SMBus. The most common
17devices connected through SMBus are RAM modules configured using I2C EEPROMs,
18and hardware monitoring chips.
14 19
15Because the SMBus is just a special case of the generalized I2C bus, we 20Because the SMBus is mostly a subset of the generalized I2C bus, we can
16can simulate the SMBus protocol on plain I2C busses. The reverse is 21use its protocols on many I2C systems. However, there are systems that don't
17regretfully impossible. 22meet both SMBus and I2C electrical constraints; and others which can't
23implement all the common SMBus protocol semantics or messages.
18 24
19 25
20Terminology 26Terminology
@@ -29,6 +35,7 @@ When we talk about I2C, we use the following terms:
29An Algorithm driver contains general code that can be used for a whole class 35An Algorithm driver contains general code that can be used for a whole class
30of I2C adapters. Each specific adapter driver depends on one algorithm 36of I2C adapters. Each specific adapter driver depends on one algorithm
31driver. 37driver.
38
32A Driver driver (yes, this sounds ridiculous, sorry) contains the general 39A Driver driver (yes, this sounds ridiculous, sorry) contains the general
33code to access some type of device. Each detected device gets its own 40code to access some type of device. Each detected device gets its own
34data in the Client structure. Usually, Driver and Client are more closely 41data in the Client structure. Usually, Driver and Client are more closely
@@ -40,6 +47,10 @@ a separate Adapter and Algorithm driver), and drivers for your I2C devices
40in this package. See the lm_sensors project http://www.lm-sensors.nu 47in this package. See the lm_sensors project http://www.lm-sensors.nu
41for device drivers. 48for device drivers.
42 49
50At this time, Linux only operates I2C (or SMBus) in master mode; you can't
51use these APIs to make a Linux system behave as a slave/device, either to
52speak a custom protocol or to emulate some other device.
53
43 54
44Included Bus Drivers 55Included Bus Drivers
45==================== 56====================
diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index fbcff96f4ca1..3d8d36b0ad12 100644
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -1,5 +1,5 @@
1This is a small guide for those who want to write kernel drivers for I2C 1This is a small guide for those who want to write kernel drivers for I2C
2or SMBus devices. 2or SMBus devices, using Linux as the protocol host/master (not slave).
3 3
4To set up a driver, you need to do several things. Some are optional, and 4To set up a driver, you need to do several things. Some are optional, and
5some things can be done slightly or completely different. Use this as a 5some things can be done slightly or completely different. Use this as a
@@ -29,8 +29,16 @@ static struct i2c_driver foo_driver = {
29 .driver = { 29 .driver = {
30 .name = "foo", 30 .name = "foo",
31 }, 31 },
32
33 /* iff driver uses driver model ("new style") binding model: */
34 .probe = foo_probe,
35 .remove = foo_remove,
36
37 /* else, driver uses "legacy" binding model: */
32 .attach_adapter = foo_attach_adapter, 38 .attach_adapter = foo_attach_adapter,
33 .detach_client = foo_detach_client, 39 .detach_client = foo_detach_client,
40
41 /* these may be used regardless of the driver binding model */
34 .shutdown = foo_shutdown, /* optional */ 42 .shutdown = foo_shutdown, /* optional */
35 .suspend = foo_suspend, /* optional */ 43 .suspend = foo_suspend, /* optional */
36 .resume = foo_resume, /* optional */ 44 .resume = foo_resume, /* optional */
@@ -40,7 +48,8 @@ static struct i2c_driver foo_driver = {
40The name field is the driver name, and must not contain spaces. It 48The name field is the driver name, and must not contain spaces. It
41should match the module name (if the driver can be compiled as a module), 49should match the module name (if the driver can be compiled as a module),
42although you can use MODULE_ALIAS (passing "foo" in this example) to add 50although you can use MODULE_ALIAS (passing "foo" in this example) to add
43another name for the module. 51another name for the module. If the driver name doesn't match the module
52name, the module won't be automatically loaded (hotplug/coldplug).
44 53
45All other fields are for call-back functions which will be explained 54All other fields are for call-back functions which will be explained
46below. 55below.
@@ -65,16 +74,13 @@ An example structure is below.
65 74
66 struct foo_data { 75 struct foo_data {
67 struct i2c_client client; 76 struct i2c_client client;
68 struct semaphore lock; /* For ISA access in `sensors' drivers. */
69 int sysctl_id; /* To keep the /proc directory entry for
70 `sensors' drivers. */
71 enum chips type; /* To keep the chips type for `sensors' drivers. */ 77 enum chips type; /* To keep the chips type for `sensors' drivers. */
72 78
73 /* Because the i2c bus is slow, it is often useful to cache the read 79 /* Because the i2c bus is slow, it is often useful to cache the read
74 information of a chip for some time (for example, 1 or 2 seconds). 80 information of a chip for some time (for example, 1 or 2 seconds).
75 It depends of course on the device whether this is really worthwhile 81 It depends of course on the device whether this is really worthwhile
76 or even sensible. */ 82 or even sensible. */
77 struct semaphore update_lock; /* When we are reading lots of information, 83 struct mutex update_lock; /* When we are reading lots of information,
78 another process should not update the 84 another process should not update the
79 below information */ 85 below information */
80 char valid; /* != 0 if the following fields are valid. */ 86 char valid; /* != 0 if the following fields are valid. */
@@ -95,8 +101,7 @@ some obscure clients). But we need generic reading and writing routines.
95I have found it useful to define foo_read and foo_write function for this. 101I have found it useful to define foo_read and foo_write function for this.
96For some cases, it will be easier to call the i2c functions directly, 102For some cases, it will be easier to call the i2c functions directly,
97but many chips have some kind of register-value idea that can easily 103but many chips have some kind of register-value idea that can easily
98be encapsulated. Also, some chips have both ISA and I2C interfaces, and 104be encapsulated.
99it useful to abstract from this (only for `sensors' drivers).
100 105
101The below functions are simple examples, and should not be copied 106The below functions are simple examples, and should not be copied
102literally. 107literally.
@@ -119,28 +124,101 @@ literally.
119 return i2c_smbus_write_word_data(client,reg,value); 124 return i2c_smbus_write_word_data(client,reg,value);
120 } 125 }
121 126
122For sensors code, you may have to cope with ISA registers too. Something
123like the below often works. Note the locking!
124
125 int foo_read_value(struct i2c_client *client, u8 reg)
126 {
127 int res;
128 if (i2c_is_isa_client(client)) {
129 down(&(((struct foo_data *) (client->data)) -> lock));
130 outb_p(reg,client->addr + FOO_ADDR_REG_OFFSET);
131 res = inb_p(client->addr + FOO_DATA_REG_OFFSET);
132 up(&(((struct foo_data *) (client->data)) -> lock));
133 return res;
134 } else
135 return i2c_smbus_read_byte_data(client,reg);
136 }
137
138Writing is done the same way.
139
140 127
141Probing and attaching 128Probing and attaching
142===================== 129=====================
143 130
131The Linux I2C stack was originally written to support access to hardware
132monitoring chips on PC motherboards, and thus it embeds some assumptions
133that are more appropriate to SMBus (and PCs) than to I2C. One of these
134assumptions is that most adapters and devices drivers support the SMBUS_QUICK
135protocol to probe device presence. Another is that devices and their drivers
136can be sufficiently configured using only such probe primitives.
137
138As Linux and its I2C stack became more widely used in embedded systems
139and complex components such as DVB adapters, those assumptions became more
140problematic. Drivers for I2C devices that issue interrupts need more (and
141different) configuration information, as do drivers handling chip variants
142that can't be distinguished by protocol probing, or which need some board
143specific information to operate correctly.
144
145Accordingly, the I2C stack now has two models for associating I2C devices
146with their drivers: the original "legacy" model, and a newer one that's
147fully compatible with the Linux 2.6 driver model. These models do not mix,
148since the "legacy" model requires drivers to create "i2c_client" device
149objects after SMBus style probing, while the Linux driver model expects
150drivers to be given such device objects in their probe() routines.
151
152
153Standard Driver Model Binding ("New Style")
154-------------------------------------------
155
156System infrastructure, typically board-specific initialization code or
157boot firmware, reports what I2C devices exist. For example, there may be
158a table, in the kernel or from the boot loader, identifying I2C devices
159and linking them to board-specific configuration information about IRQs
160and other wiring artifacts, chip type, and so on. That could be used to
161create i2c_client objects for each I2C device.
162
163I2C device drivers using this binding model work just like any other
164kind of driver in Linux: they provide a probe() method to bind to
165those devices, and a remove() method to unbind.
166
167 static int foo_probe(struct i2c_client *client);
168 static int foo_remove(struct i2c_client *client);
169
170Remember that the i2c_driver does not create those client handles. The
171handle may be used during foo_probe(). If foo_probe() reports success
172(zero not a negative status code) it may save the handle and use it until
173foo_remove() returns. That binding model is used by most Linux drivers.
174
175Drivers match devices when i2c_client.driver_name and the driver name are
176the same; this approach is used in several other busses that don't have
177device typing support in the hardware. The driver and module name should
178match, so hotplug/coldplug mechanisms will modprobe the driver.
179
180
181Device Creation (Standard driver model)
182---------------------------------------
183
184If you know for a fact that an I2C device is connected to a given I2C bus,
185you can instantiate that device by simply filling an i2c_board_info
186structure with the device address and driver name, and calling
187i2c_new_device(). This will create the device, then the driver core will
188take care of finding the right driver and will call its probe() method.
189If a driver supports different device types, you can specify the type you
190want using the type field. You can also specify an IRQ and platform data
191if needed.
192
193Sometimes you know that a device is connected to a given I2C bus, but you
194don't know the exact address it uses. This happens on TV adapters for
195example, where the same driver supports dozens of slightly different
196models, and I2C device addresses change from one model to the next. In
197that case, you can use the i2c_new_probed_device() variant, which is
198similar to i2c_new_device(), except that it takes an additional list of
199possible I2C addresses to probe. A device is created for the first
200responsive address in the list. If you expect more than one device to be
201present in the address range, simply call i2c_new_probed_device() that
202many times.
203
204The call to i2c_new_device() or i2c_new_probed_device() typically happens
205in the I2C bus driver. You may want to save the returned i2c_client
206reference for later use.
207
208
209Device Deletion (Standard driver model)
210---------------------------------------
211
212Each I2C device which has been created using i2c_new_device() or
213i2c_new_probed_device() can be unregistered by calling
214i2c_unregister_device(). If you don't call it explicitly, it will be
215called automatically before the underlying I2C bus itself is removed, as a
216device can't survive its parent in the device driver model.
217
218
219Legacy Driver Binding Model
220---------------------------
221
144Most i2c devices can be present on several i2c addresses; for some this 222Most i2c devices can be present on several i2c addresses; for some this
145is determined in hardware (by soldering some chip pins to Vcc or Ground), 223is determined in hardware (by soldering some chip pins to Vcc or Ground),
146for others this can be changed in software (by writing to specific client 224for others this can be changed in software (by writing to specific client
@@ -157,13 +235,9 @@ detection algorithm.
157You do not have to use this parameter interface; but don't try to use 235You do not have to use this parameter interface; but don't try to use
158function i2c_probe() if you don't. 236function i2c_probe() if you don't.
159 237
160NOTE: If you want to write a `sensors' driver, the interface is slightly
161 different! See below.
162
163 238
164 239Probing classes (Legacy model)
165Probing classes 240------------------------------
166---------------
167 241
168All parameters are given as lists of unsigned 16-bit integers. Lists are 242All parameters are given as lists of unsigned 16-bit integers. Lists are
169terminated by I2C_CLIENT_END. 243terminated by I2C_CLIENT_END.
@@ -210,8 +284,8 @@ Note that you *have* to call the defined variable `normal_i2c',
210without any prefix! 284without any prefix!
211 285
212 286
213Attaching to an adapter 287Attaching to an adapter (Legacy model)
214----------------------- 288--------------------------------------
215 289
216Whenever a new adapter is inserted, or for all adapters if the driver is 290Whenever a new adapter is inserted, or for all adapters if the driver is
217being registered, the callback attach_adapter() is called. Now is the 291being registered, the callback attach_adapter() is called. Now is the
@@ -237,17 +311,13 @@ them (unless a `force' parameter was used). In addition, addresses that
237are already in use (by some other registered client) are skipped. 311are already in use (by some other registered client) are skipped.
238 312
239 313
240The detect client function 314The detect client function (Legacy model)
241-------------------------- 315-----------------------------------------
242 316
243The detect client function is called by i2c_probe. The `kind' parameter 317The detect client function is called by i2c_probe. The `kind' parameter
244contains -1 for a probed detection, 0 for a forced detection, or a positive 318contains -1 for a probed detection, 0 for a forced detection, or a positive
245number for a forced detection with a chip type forced. 319number for a forced detection with a chip type forced.
246 320
247Below, some things are only needed if this is a `sensors' driver. Those
248parts are between /* SENSORS ONLY START */ and /* SENSORS ONLY END */
249markers.
250
251Returning an error different from -ENODEV in a detect function will cause 321Returning an error different from -ENODEV in a detect function will cause
252the detection to stop: other addresses and adapters won't be scanned. 322the detection to stop: other addresses and adapters won't be scanned.
253This should only be done on fatal or internal errors, such as a memory 323This should only be done on fatal or internal errors, such as a memory
@@ -256,64 +326,20 @@ shortage or i2c_attach_client failing.
256For now, you can ignore the `flags' parameter. It is there for future use. 326For now, you can ignore the `flags' parameter. It is there for future use.
257 327
258 int foo_detect_client(struct i2c_adapter *adapter, int address, 328 int foo_detect_client(struct i2c_adapter *adapter, int address,
259 unsigned short flags, int kind) 329 int kind)
260 { 330 {
261 int err = 0; 331 int err = 0;
262 int i; 332 int i;
263 struct i2c_client *new_client; 333 struct i2c_client *client;
264 struct foo_data *data; 334 struct foo_data *data;
265 const char *client_name = ""; /* For non-`sensors' drivers, put the real 335 const char *name = "";
266 name here! */
267 336
268 /* Let's see whether this adapter can support what we need. 337 /* Let's see whether this adapter can support what we need.
269 Please substitute the things you need here! 338 Please substitute the things you need here! */
270 For `sensors' drivers, add `! is_isa &&' to the if statement */
271 if (!i2c_check_functionality(adapter,I2C_FUNC_SMBUS_WORD_DATA | 339 if (!i2c_check_functionality(adapter,I2C_FUNC_SMBUS_WORD_DATA |
272 I2C_FUNC_SMBUS_WRITE_BYTE)) 340 I2C_FUNC_SMBUS_WRITE_BYTE))
273 goto ERROR0; 341 goto ERROR0;
274 342
275 /* SENSORS ONLY START */
276 const char *type_name = "";
277 int is_isa = i2c_is_isa_adapter(adapter);
278
279 /* Do this only if the chip can additionally be found on the ISA bus
280 (hybrid chip). */
281
282 if (is_isa) {
283
284 /* Discard immediately if this ISA range is already used */
285 /* FIXME: never use check_region(), only request_region() */
286 if (check_region(address,FOO_EXTENT))
287 goto ERROR0;
288
289 /* Probe whether there is anything on this address.
290 Some example code is below, but you will have to adapt this
291 for your own driver */
292
293 if (kind < 0) /* Only if no force parameter was used */ {
294 /* We may need long timeouts at least for some chips. */
295 #define REALLY_SLOW_IO
296 i = inb_p(address + 1);
297 if (inb_p(address + 2) != i)
298 goto ERROR0;
299 if (inb_p(address + 3) != i)
300 goto ERROR0;
301 if (inb_p(address + 7) != i)
302 goto ERROR0;
303 #undef REALLY_SLOW_IO
304
305 /* Let's just hope nothing breaks here */
306 i = inb_p(address + 5) & 0x7f;
307 outb_p(~i & 0x7f,address+5);
308 if ((inb_p(address + 5) & 0x7f) != (~i & 0x7f)) {
309 outb_p(i,address+5);
310 return 0;
311 }
312 }
313 }
314
315 /* SENSORS ONLY END */
316
317 /* OK. For now, we presume we have a valid client. We now create the 343 /* OK. For now, we presume we have a valid client. We now create the
318 client structure, even though we cannot fill it completely yet. 344 client structure, even though we cannot fill it completely yet.
319 But it allows us to access several i2c functions safely */ 345 But it allows us to access several i2c functions safely */
@@ -323,13 +349,12 @@ For now, you can ignore the `flags' parameter. It is there for future use.
323 goto ERROR0; 349 goto ERROR0;
324 } 350 }
325 351
326 new_client = &data->client; 352 client = &data->client;
327 i2c_set_clientdata(new_client, data); 353 i2c_set_clientdata(client, data);
328 354
329 new_client->addr = address; 355 client->addr = address;
330 new_client->adapter = adapter; 356 client->adapter = adapter;
331 new_client->driver = &foo_driver; 357 client->driver = &foo_driver;
332 new_client->flags = 0;
333 358
334 /* Now, we do the remaining detection. If no `force' parameter is used. */ 359 /* Now, we do the remaining detection. If no `force' parameter is used. */
335 360
@@ -337,19 +362,17 @@ For now, you can ignore the `flags' parameter. It is there for future use.
337 parameter was used. */ 362 parameter was used. */
338 if (kind < 0) { 363 if (kind < 0) {
339 /* The below is of course bogus */ 364 /* The below is of course bogus */
340 if (foo_read(new_client,FOO_REG_GENERIC) != FOO_GENERIC_VALUE) 365 if (foo_read(client, FOO_REG_GENERIC) != FOO_GENERIC_VALUE)
341 goto ERROR1; 366 goto ERROR1;
342 } 367 }
343 368
344 /* SENSORS ONLY START */
345
346 /* Next, specific detection. This is especially important for `sensors' 369 /* Next, specific detection. This is especially important for `sensors'
347 devices. */ 370 devices. */
348 371
349 /* Determine the chip type. Not needed if a `force_CHIPTYPE' parameter 372 /* Determine the chip type. Not needed if a `force_CHIPTYPE' parameter
350 was used. */ 373 was used. */
351 if (kind <= 0) { 374 if (kind <= 0) {
352 i = foo_read(new_client,FOO_REG_CHIPTYPE); 375 i = foo_read(client, FOO_REG_CHIPTYPE);
353 if (i == FOO_TYPE_1) 376 if (i == FOO_TYPE_1)
354 kind = chip1; /* As defined in the enum */ 377 kind = chip1; /* As defined in the enum */
355 else if (i == FOO_TYPE_2) 378 else if (i == FOO_TYPE_2)
@@ -363,63 +386,31 @@ For now, you can ignore the `flags' parameter. It is there for future use.
363 386
364 /* Now set the type and chip names */ 387 /* Now set the type and chip names */
365 if (kind == chip1) { 388 if (kind == chip1) {
366 type_name = "chip1"; /* For /proc entry */ 389 name = "chip1";
367 client_name = "CHIP 1";
368 } else if (kind == chip2) { 390 } else if (kind == chip2) {
369 type_name = "chip2"; /* For /proc entry */ 391 name = "chip2";
370 client_name = "CHIP 2";
371 } 392 }
372 393
373 /* Reserve the ISA region */
374 if (is_isa)
375 request_region(address,FOO_EXTENT,type_name);
376
377 /* SENSORS ONLY END */
378
379 /* Fill in the remaining client fields. */ 394 /* Fill in the remaining client fields. */
380 strcpy(new_client->name,client_name); 395 strlcpy(client->name, name, I2C_NAME_SIZE);
381
382 /* SENSORS ONLY BEGIN */
383 data->type = kind; 396 data->type = kind;
384 /* SENSORS ONLY END */ 397 mutex_init(&data->update_lock); /* Only if you use this field */
385
386 data->valid = 0; /* Only if you use this field */
387 init_MUTEX(&data->update_lock); /* Only if you use this field */
388 398
389 /* Any other initializations in data must be done here too. */ 399 /* Any other initializations in data must be done here too. */
390 400
391 /* Tell the i2c layer a new client has arrived */
392 if ((err = i2c_attach_client(new_client)))
393 goto ERROR3;
394
395 /* SENSORS ONLY BEGIN */
396 /* Register a new directory entry with module sensors. See below for
397 the `template' structure. */
398 if ((i = i2c_register_entry(new_client, type_name,
399 foo_dir_table_template,THIS_MODULE)) < 0) {
400 err = i;
401 goto ERROR4;
402 }
403 data->sysctl_id = i;
404
405 /* SENSORS ONLY END */
406
407 /* This function can write default values to the client registers, if 401 /* This function can write default values to the client registers, if
408 needed. */ 402 needed. */
409 foo_init_client(new_client); 403 foo_init_client(client);
404
405 /* Tell the i2c layer a new client has arrived */
406 if ((err = i2c_attach_client(client)))
407 goto ERROR1;
408
410 return 0; 409 return 0;
411 410
412 /* OK, this is not exactly good programming practice, usually. But it is 411 /* OK, this is not exactly good programming practice, usually. But it is
413 very code-efficient in this case. */ 412 very code-efficient in this case. */
414 413
415 ERROR4:
416 i2c_detach_client(new_client);
417 ERROR3:
418 ERROR2:
419 /* SENSORS ONLY START */
420 if (is_isa)
421 release_region(address,FOO_EXTENT);
422 /* SENSORS ONLY END */
423 ERROR1: 414 ERROR1:
424 kfree(data); 415 kfree(data);
425 ERROR0: 416 ERROR0:
@@ -427,8 +418,8 @@ For now, you can ignore the `flags' parameter. It is there for future use.
427 } 418 }
428 419
429 420
430Removing the client 421Removing the client (Legacy model)
431=================== 422==================================
432 423
433The detach_client call back function is called when a client should be 424The detach_client call back function is called when a client should be
434removed. It may actually fail, but only when panicking. This code is 425removed. It may actually fail, but only when panicking. This code is
@@ -436,22 +427,12 @@ much simpler than the attachment code, fortunately!
436 427
437 int foo_detach_client(struct i2c_client *client) 428 int foo_detach_client(struct i2c_client *client)
438 { 429 {
439 int err,i; 430 int err;
440
441 /* SENSORS ONLY START */
442 /* Deregister with the `i2c-proc' module. */
443 i2c_deregister_entry(((struct lm78_data *)(client->data))->sysctl_id);
444 /* SENSORS ONLY END */
445 431
446 /* Try to detach the client from i2c space */ 432 /* Try to detach the client from i2c space */
447 if ((err = i2c_detach_client(client))) 433 if ((err = i2c_detach_client(client)))
448 return err; 434 return err;
449 435
450 /* HYBRID SENSORS CHIP ONLY START */
451 if i2c_is_isa_client(client)
452 release_region(client->addr,LM78_EXTENT);
453 /* HYBRID SENSORS CHIP ONLY END */
454
455 kfree(i2c_get_clientdata(client)); 436 kfree(i2c_get_clientdata(client));
456 return 0; 437 return 0;
457 } 438 }
@@ -464,45 +445,34 @@ When the kernel is booted, or when your foo driver module is inserted,
464you have to do some initializing. Fortunately, just attaching (registering) 445you have to do some initializing. Fortunately, just attaching (registering)
465the driver module is usually enough. 446the driver module is usually enough.
466 447
467 /* Keep track of how far we got in the initialization process. If several
468 things have to initialized, and we fail halfway, only those things
469 have to be cleaned up! */
470 static int __initdata foo_initialized = 0;
471
472 static int __init foo_init(void) 448 static int __init foo_init(void)
473 { 449 {
474 int res; 450 int res;
475 printk("foo version %s (%s)\n",FOO_VERSION,FOO_DATE);
476 451
477 if ((res = i2c_add_driver(&foo_driver))) { 452 if ((res = i2c_add_driver(&foo_driver))) {
478 printk("foo: Driver registration failed, module not inserted.\n"); 453 printk("foo: Driver registration failed, module not inserted.\n");
479 foo_cleanup();
480 return res; 454 return res;
481 } 455 }
482 foo_initialized ++;
483 return 0; 456 return 0;
484 } 457 }
485 458
486 void foo_cleanup(void) 459 static void __exit foo_cleanup(void)
487 { 460 {
488 if (foo_initialized == 1) { 461 i2c_del_driver(&foo_driver);
489 if ((res = i2c_del_driver(&foo_driver))) {
490 printk("foo: Driver registration failed, module not removed.\n");
491 return;
492 }
493 foo_initialized --;
494 }
495 } 462 }
496 463
497 /* Substitute your own name and email address */ 464 /* Substitute your own name and email address */
498 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>" 465 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"
499 MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices"); 466 MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices");
500 467
468 /* a few non-GPL license types are also allowed */
469 MODULE_LICENSE("GPL");
470
501 module_init(foo_init); 471 module_init(foo_init);
502 module_exit(foo_cleanup); 472 module_exit(foo_cleanup);
503 473
504Note that some functions are marked by `__init', and some data structures 474Note that some functions are marked by `__init', and some data structures
505by `__init_data'. Hose functions and structures can be removed after 475by `__initdata'. These functions and structures can be removed after
506kernel booting (or module loading) is completed. 476kernel booting (or module loading) is completed.
507 477
508 478
@@ -632,110 +602,7 @@ General purpose routines
632Below all general purpose routines are listed, that were not mentioned 602Below all general purpose routines are listed, that were not mentioned
633before. 603before.
634 604
635 /* This call returns a unique low identifier for each registered adapter, 605 /* This call returns a unique low identifier for each registered adapter.
636 * or -1 if the adapter was not registered.
637 */ 606 */
638 extern int i2c_adapter_id(struct i2c_adapter *adap); 607 extern int i2c_adapter_id(struct i2c_adapter *adap);
639 608
640
641The sensors sysctl/proc interface
642=================================
643
644This section only applies if you write `sensors' drivers.
645
646Each sensors driver creates a directory in /proc/sys/dev/sensors for each
647registered client. The directory is called something like foo-i2c-4-65.
648The sensors module helps you to do this as easily as possible.
649
650The template
651------------
652
653You will need to define a ctl_table template. This template will automatically
654be copied to a newly allocated structure and filled in where necessary when
655you call sensors_register_entry.
656
657First, I will give an example definition.
658 static ctl_table foo_dir_table_template[] = {
659 { FOO_SYSCTL_FUNC1, "func1", NULL, 0, 0644, NULL, &i2c_proc_real,
660 &i2c_sysctl_real,NULL,&foo_func },
661 { FOO_SYSCTL_FUNC2, "func2", NULL, 0, 0644, NULL, &i2c_proc_real,
662 &i2c_sysctl_real,NULL,&foo_func },
663 { FOO_SYSCTL_DATA, "data", NULL, 0, 0644, NULL, &i2c_proc_real,
664 &i2c_sysctl_real,NULL,&foo_data },
665 { 0 }
666 };
667
668In the above example, three entries are defined. They can either be
669accessed through the /proc interface, in the /proc/sys/dev/sensors/*
670directories, as files named func1, func2 and data, or alternatively
671through the sysctl interface, in the appropriate table, with identifiers
672FOO_SYSCTL_FUNC1, FOO_SYSCTL_FUNC2 and FOO_SYSCTL_DATA.
673
674The third, sixth and ninth parameters should always be NULL, and the
675fourth should always be 0. The fifth is the mode of the /proc file;
6760644 is safe, as the file will be owned by root:root.
677
678The seventh and eighth parameters should be &i2c_proc_real and
679&i2c_sysctl_real if you want to export lists of reals (scaled
680integers). You can also use your own function for them, as usual.
681Finally, the last parameter is the call-back to gather the data
682(see below) if you use the *_proc_real functions.
683
684
685Gathering the data
686------------------
687
688The call back functions (foo_func and foo_data in the above example)
689can be called in several ways; the operation parameter determines
690what should be done:
691
692 * If operation == SENSORS_PROC_REAL_INFO, you must return the
693 magnitude (scaling) in nrels_mag;
694 * If operation == SENSORS_PROC_REAL_READ, you must read information
695 from the chip and return it in results. The number of integers
696 to display should be put in nrels_mag;
697 * If operation == SENSORS_PROC_REAL_WRITE, you must write the
698 supplied information to the chip. nrels_mag will contain the number
699 of integers, results the integers themselves.
700
701The *_proc_real functions will display the elements as reals for the
702/proc interface. If you set the magnitude to 2, and supply 345 for
703SENSORS_PROC_REAL_READ, it would display 3.45; and if the user would
704write 45.6 to the /proc file, it would be returned as 4560 for
705SENSORS_PROC_REAL_WRITE. A magnitude may even be negative!
706
707An example function:
708
709 /* FOO_FROM_REG and FOO_TO_REG translate between scaled values and
710 register values. Note the use of the read cache. */
711 void foo_in(struct i2c_client *client, int operation, int ctl_name,
712 int *nrels_mag, long *results)
713 {
714 struct foo_data *data = client->data;
715 int nr = ctl_name - FOO_SYSCTL_FUNC1; /* reduce to 0 upwards */
716
717 if (operation == SENSORS_PROC_REAL_INFO)
718 *nrels_mag = 2;
719 else if (operation == SENSORS_PROC_REAL_READ) {
720 /* Update the readings cache (if necessary) */
721 foo_update_client(client);
722 /* Get the readings from the cache */
723 results[0] = FOO_FROM_REG(data->foo_func_base[nr]);
724 results[1] = FOO_FROM_REG(data->foo_func_more[nr]);
725 results[2] = FOO_FROM_REG(data->foo_func_readonly[nr]);
726 *nrels_mag = 2;
727 } else if (operation == SENSORS_PROC_REAL_WRITE) {
728 if (*nrels_mag >= 1) {
729 /* Update the cache */
730 data->foo_base[nr] = FOO_TO_REG(results[0]);
731 /* Update the chip */
732 foo_write_value(client,FOO_REG_FUNC_BASE(nr),data->foo_base[nr]);
733 }
734 if (*nrels_mag >= 2) {
735 /* Update the cache */
736 data->foo_more[nr] = FOO_TO_REG(results[1]);
737 /* Update the chip */
738 foo_write_value(client,FOO_REG_FUNC_MORE(nr),data->foo_more[nr]);
739 }
740 }
741 }