[#4246] simple gpio doesn't work for bf533 stamp board on 08r1 branch

Submitted By: Mingquan Pan

Open Date

2008-07-16 00:09:16 Close Date

2008-07-25 04:33:26

Priority:

Low Assignee:

Mike Frysinger

Michael Hennerich

Status:

Closed Fixed In Release:

N/A

Found In Release:

N/A Release:

Category:

N/A Board:

N/A

Processor:

N/A Silicon Revision:

Is this bug repeatable?:

Yes Resolution:

Fixed

Uboot version or rev.:

Toolchain version or rev.:

08r1.5-14

App binary format:

N/A

Summary: simple gpio doesn't work for bf533 stamp board on 08r1 branch

Details:

simple gpio doesn't work for bf533 stamp board on 08r1 branch.

Run:

root:/bin> ./simple-gpio-test

Usage: simple-gpio-test <gpio device>

This will open the specified gpio device, set it to input

mode, and then wait for it to go high.

You should specify a gpio device that represents a button.

Quick cheat sheet:

BF533-STAMP:

LED1 => GPIO2 PB1 => GPIO5

LED2 => GPIO3 PB2 => GPIO6

LED3 => GPIO4 PB3 => GPIO8

root:/bin> ./simple-gpio-test /dev/gpio5

Going to sleep until the gpio goes high.

(if this is a button, you should push it :p)

The gpio went high! Time to bail!

root:/bin>

It directly finishs, and don't wait for PB1 to be pushed and go to high.

config file for kernel is attached.

Follow-ups

--- Mike Frysinger 2008-07-16 06:27:45

should be fixed now ... the test assumed that all buttons were active low and

that the PB changed it to active high. this assumption holds true on the

BF537-STAMP, but not the BF533-STAMP.

--- Mingquan Pan 2008-07-17 00:23:24

It is working except the first time you push the button. For the first time you

run: ./simple-gpio-test /dev/gpio5, it just doesn't exit and no reponse on

bf533.

--- Mike Frysinger 2008-07-17 03:40:16

Michael: is there something that needs to be backported here ? the first time i

boot up and attempt to read gpio5 (push button 1), the level never changes from

1. but if i close and re-open, then it works.

perhaps something occurs in gpio_free() that changes the state to something

usable which gpio_request() should be doing ? if i change the open() function

to do:

gpio_request(); gpio_free(); gpio_request();

then it works just fine

to reproduce on the 2008R1 branch, boot up and load the simple gpio module.

then do:

cat /dev/gpio5

then in a different terminal, do:

echo I > /dev/gpio5

this should show a constant stream of 1's ... the only thing the driver has

done is gpio_request(), gpio_direction_output(), and gpio_get_value(). pushing

the button does not change the level to 0. if you kill the cat and repeat the

cat/echo, then pushing the button results in value changes as expected.

running things on trunk seems to work fine

--- Michael Hennerich 2008-07-21 03:35:55

Mike,

- just saw your comment. I'll have a look.

-Michael

--- Sonic Zhang 2008-07-23 22:20:39

Mike will add a walkaround in the uboot 2008R1.5 branch. But, Michael still need

to fix it in kernel someday. The walkaround only hide the bug in kernel.

--- Mike Frysinger 2008-07-24 00:01:45

ive committed the cleanup to the branch that was in trunk for the swap_to()

function. as discovered by Michael, extraneous registers related to interrupts

(mask/polarity/etc...) were being programmed that didnt actually need to be.

this cause the weird behavior seen once the kernel was booted.

ive started [#4274] to track the long term resolution.

--- Mingquan Pan 2008-07-25 05:33:24

The checkin in u-boot works. So close.

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[#4246] simple gpio doesn't work for bf533 stamp board on 08r1 branch