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authorJean Delvare <khali@linux-fr.org>2007-05-01 17:26:35 -0400
committerJean Delvare <khali@hyperion.delvare>2007-05-01 17:26:35 -0400
commiteefcd75e72f382270f8f64e030550b10e3882b2b (patch)
treeccd55fa7068067ddd6299fe62dc15b22cc3ca46a /Documentation/i2c/porting-clients
parent35532d20035d04b0ec28508583a56c7a65c5fa47 (diff)
i2c: Documentation update
Make the documentation on how to write and port i2c drivers more in line with the current state of things: * i2c-isa is deprecated and soon gone, so stop advertising it. * Drop many sensors-specific references. Most of them were outdated anyway. * Update the example code to reflect the recent and not-so-recent API and coding style preference changes. * Simplify the example init and cleanup functions. This should make things less complex to understand for newcomers. Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'Documentation/i2c/porting-clients')
-rw-r--r--Documentation/i2c/porting-clients18
1 files changed, 8 insertions, 10 deletions
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