[Trac #511] Machine LED's need a driver.

[Zarro Boogs per Child]

#511: Machine LED's need a driver.
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 Reporter:  jg       |        Owner:  dilinger
     Type:  task     |       Status:  new     
 Priority:  high     |    Milestone:  BTest-2 
Component:  kernel   |   Resolution:          
 Keywords:  relnote  |  
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Old description:

> There are LED's for illuminating the keyboard (or for general lighting
> use).
>
> We need a driver for them.
>
> Info provided by Mitch Bradley on #olpc:
>
> <Mitch_Bradley> reynaldo: Please add this information to the ticket:
>          The LED Light is controlled by GPIO08 in the EC chip...
> <Mitch_Bradley> GPIO08 is controlled by...
> <Mitch_Bradley> EC I/O addresses 0xfc10  (output enable), <Mitch_Bradley>
> no that is wrong, it is 0xfc11 ...
> <Mitch_Bradley> 0xfc01 (function select - 0 bit means GPIO)...
> <Mitch_Bradley> 0xfc21 (data value) ...
> <Mitch_Bradley> The least-significant bits of those
> registers are for the GPIO08 line (the next bit is for GPIO09, etc.)
> <Mitch_Bradley> to access an EC I/O port, you write the MSB of the
> "address" to PC I/O Port 0x381, the LSB of the "address" to I/O Port
> 0x382, and the data to port 0x383
> <Mitch_Bradley> to write the port, you write data to i/o
>          port 0x383, to read it, you read from 0x383.

New description:

 There are LED's for illuminating the keyboard (or for general lighting
 use).

 We need a driver for them.

 Info provided by Mitch Bradley on #olpc:

 <Mitch_Bradley> reynaldo: Please add this information to the ticket:
          The LED Light is controlled by GPIO08 in the EC chip...

 <Mitch_Bradley> GPIO08 is controlled by...

 <Mitch_Bradley> EC I/O addresses 0xfc10  (output enable),

 <Mitch_Bradley> no that is wrong, it is 0xfc11 ...

 <Mitch_Bradley> 0xfc01 (function select - 0 bit means GPIO)...

 <Mitch_Bradley> 0xfc21 (data value) ...

 <Mitch_Bradley> The least-significant bits of those
 registers are for the GPIO08 line (the next bit is for GPIO09, etc.)

 <Mitch_Bradley> to access an EC I/O port, you write the MSB of the
 "address" to PC I/O Port 0x381, the LSB of the "address" to I/O Port
 0x382, and the data to port 0x383

 <Mitch_Bradley> to write the port, you write data to i/o
 port 0x383, to read it, you read from 0x383.

-- 
Ticket URL: <http://dev.laptop.org/ticket/511#comment:2>
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