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| author | Mariusz Bialonczyk <manio@skyboo.net> | 2017-02-23 09:38:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-17 09:10:49 +0300 |
| commit | a9ee205883a36e3d51dff5b8f3a7c2c1c4fbab57 (patch) | |
| tree | 83c135ec5bdee2a36f008e90dc6403274db31849 /Documentation | |
| parent | c2a49fe8eeef301b40d0c8065d817c5425d31b11 (diff) | |
| download | linux-a9ee205883a36e3d51dff5b8f3a7c2c1c4fbab57.tar.xz | |
w1: add missing DS2413 documentation
Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/w1/slaves/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_ds2413 | 50 |
2 files changed, 52 insertions, 0 deletions
diff --git a/Documentation/w1/slaves/00-INDEX b/Documentation/w1/slaves/00-INDEX index 6e18c70c3474..cbcca1d3a680 100644 --- a/Documentation/w1/slaves/00-INDEX +++ b/Documentation/w1/slaves/00-INDEX @@ -2,6 +2,8 @@ - This file w1_therm - The Maxim/Dallas Semiconductor ds18*20 temperature sensor. +w1_ds2413 + - The Maxim/Dallas Semiconductor ds2413 dual channel addressable switch. w1_ds2423 - The Maxim/Dallas Semiconductor ds2423 counter device. w1_ds28e04 diff --git a/Documentation/w1/slaves/w1_ds2413 b/Documentation/w1/slaves/w1_ds2413 new file mode 100644 index 000000000000..936263a8ccb4 --- /dev/null +++ b/Documentation/w1/slaves/w1_ds2413 @@ -0,0 +1,50 @@ +Kernel driver w1_ds2413 +======================= + +Supported chips: + * Maxim DS2413 1-Wire Dual Channel Addressable Switch + +supported family codes: + W1_FAMILY_DS2413 0x3A + +Author: Mariusz Bialonczyk <manio@skyboo.net> + +Description +----------- + +The DS2413 chip has two open-drain outputs (PIO A and PIO B). +Support is provided through the sysfs files "output" and "state". + +Reading state +------------- +The "state" file provides one-byte value which is in the same format as for +the chip PIO_ACCESS_READ command (refer the datasheet for details): + +Bit 0: PIOA Pin State +Bit 1: PIOA Output Latch State +Bit 2: PIOB Pin State +Bit 3: PIOB Output Latch State +Bit 4-7: Complement of Bit 3 to Bit 0 (verified by the kernel module) + +This file is readonly. + +Writing output +-------------- +You can set the PIO pins using the "output" file. +It is writable, you can write one-byte value to this sysfs file. +Similarly the byte format is the same as for the PIO_ACCESS_WRITE command: + +Bit 0: PIOA +Bit 1: PIOB +Bit 2-7: No matter (driver will set it to "1"s) + + +The chip has some kind of basic protection against transmission errors. +When reading the state, there is a four complement bits. +The driver is checking this complement, and when it is wrong then it is +returning I/O error. + +When writing output, the master must repeat the PIO Output Data byte in +its inverted form and it is waiting for a confirmation. +If the write is unsuccessful for three times, the write also returns +I/O error. |