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| author | Jean Delvare <khali@linux-fr.org> | 2008-07-16 19:30:06 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@mahadeva.delvare> | 2008-07-16 19:30:06 +0200 |
| commit | 833bedb813689807385ae73175389c73a3f855c1 (patch) | |
| tree | f9b33add52ca947fd9f8ae89753eb8d534efc70e /Documentation/i2c | |
| parent | 8b77e6ac4911a79993e583ece719736a9e035b1d (diff) | |
| download | op-kernel-dev-833bedb813689807385ae73175389c73a3f855c1.zip op-kernel-dev-833bedb813689807385ae73175389c73a3f855c1.tar.gz | |
i2c: Convert the pcf8574 driver to a new-style i2c driver
The new-style pcf8574 driver implements the optional detect() callback
to cover the use cases of the legacy driver.
Warning: users will now have to use the force module parameter to get
the driver to attach to their device. That's not a bad thing as these
devices can't be detected anyway.
Note that this doesn't change the fact that this driver is deprecated
in favor of gpio/pcf857x.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'Documentation/i2c')
| -rw-r--r-- | Documentation/i2c/chips/pcf8574 | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/Documentation/i2c/chips/pcf8574 b/Documentation/i2c/chips/pcf8574 index 5c1ad13..235815c 100644 --- a/Documentation/i2c/chips/pcf8574 +++ b/Documentation/i2c/chips/pcf8574 @@ -4,13 +4,13 @@ Kernel driver pcf8574 Supported chips: * Philips PCF8574 Prefix: 'pcf8574' - Addresses scanned: I2C 0x20 - 0x27 + Addresses scanned: none Datasheet: Publicly available at the Philips Semiconductors website http://www.semiconductors.philips.com/pip/PCF8574P.html * Philips PCF8574A Prefix: 'pcf8574a' - Addresses scanned: I2C 0x38 - 0x3f + Addresses scanned: none Datasheet: Publicly available at the Philips Semiconductors website http://www.semiconductors.philips.com/pip/PCF8574P.html @@ -38,12 +38,10 @@ For more informations see the datasheet. Accessing PCF8574(A) via /sys interface ------------------------------------- -! Be careful ! The PCF8574(A) is plainly impossible to detect ! Stupid chip. -So every chip with address in the interval [20..27] and [38..3f] are -detected as PCF8574(A). If you have other chips in this address -range, the workaround is to load this module after the one -for your others chips. +So, you have to pass the I2C bus and address of the installed PCF857A +and PCF8574A devices explicitly to the driver at load time via the +force=... parameter. On detection (i.e. insmod, modprobe et al.), directories are being created for each detected PCF8574(A): |
