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How to test the return of a command in U-Boot CLI

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0

I would like to use the return of the command 'gpio input' in an if statement in U-Boot but it doesn't seem to work.

So I've tried something like :

if test gpio status 50 -eq 1; then echo 1; else echo 0; fi;

But it always return 1 whether the GPIO is high or low.

I also tried to store the result of the gpio status command into a variable by using the setenv command but it doesn't work either.

PS: I've modified the gpio.c file in the U-boot source code so the command returns just '0' or '1' instead of 'gpio: pin 50 (gpio 50) value is 1' but I think it doesn't matter. Just precising since otherwise the '-eq 1' makes no sense.

Do you have any idea of how I could proceed to do this ?

Thanks in advance !

command csh u-boot setenv

share|improve this question

asked Mar 27 at 16:01

p-lafondp-lafond

1

add a comment | 

0

I would like to use the return of the command 'gpio input' in an if statement in U-Boot but it doesn't seem to work.

So I've tried something like :

if test gpio status 50 -eq 1; then echo 1; else echo 0; fi;

But it always return 1 whether the GPIO is high or low.

I also tried to store the result of the gpio status command into a variable by using the setenv command but it doesn't work either.

PS: I've modified the gpio.c file in the U-boot source code so the command returns just '0' or '1' instead of 'gpio: pin 50 (gpio 50) value is 1' but I think it doesn't matter. Just precising since otherwise the '-eq 1' makes no sense.

Do you have any idea of how I could proceed to do this ?

Thanks in advance !

command csh u-boot setenv

share|improve this question

asked Mar 27 at 16:01

p-lafondp-lafond

1

add a comment | 

I would like to use the return of the command 'gpio input' in an if statement in U-Boot but it doesn't seem to work.

So I've tried something like :

if test gpio status 50 -eq 1; then echo 1; else echo 0; fi;

But it always return 1 whether the GPIO is high or low.

I also tried to store the result of the gpio status command into a variable by using the setenv command but it doesn't work either.

PS: I've modified the gpio.c file in the U-boot source code so the command returns just '0' or '1' instead of 'gpio: pin 50 (gpio 50) value is 1' but I think it doesn't matter. Just precising since otherwise the '-eq 1' makes no sense.

Do you have any idea of how I could proceed to do this ?

Thanks in advance !

command csh u-boot setenv

share|improve this question

asked Mar 27 at 16:01

p-lafondp-lafond

1

share|improve this question

asked Mar 27 at 16:01

p-lafondp-lafond

1

share|improve this question

asked Mar 27 at 16:01

p-lafondp-lafond

1

asked Mar 27 at 16:01

p-lafondp-lafond

1

asked Mar 27 at 16:01

p-lafondp-lafond

1

1 Answer
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oldest

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1

The return value of a command can be found in environment variable $?, e.g.

gpio input 50; echo $?

If an if statement exists depends on the configuration when compiling U-Boot. Use CONFIG_HUSH_PARSER=y to enable it. When enabled you can write

if gpio input 102; then setenv board_name revA ; else setenv board_name revB;fi

share|improve this answer

edited Mar 29 at 3:07

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks to @trini to pointing me to HUSH_PARSER.
  
  – Xypron
  Mar 29 at 3:09
  

  
  
  
  

add a comment | 

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1

The return value of a command can be found in environment variable $?, e.g.

gpio input 50; echo $?

If an if statement exists depends on the configuration when compiling U-Boot. Use CONFIG_HUSH_PARSER=y to enable it. When enabled you can write

if gpio input 102; then setenv board_name revA ; else setenv board_name revB;fi

share|improve this answer

edited Mar 29 at 3:07

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks to @trini to pointing me to HUSH_PARSER.
  
  – Xypron
  Mar 29 at 3:09
  

  
  
  
  

add a comment | 

1

The return value of a command can be found in environment variable $?, e.g.

gpio input 50; echo $?

If an if statement exists depends on the configuration when compiling U-Boot. Use CONFIG_HUSH_PARSER=y to enable it. When enabled you can write

if gpio input 102; then setenv board_name revA ; else setenv board_name revB;fi

share|improve this answer

edited Mar 29 at 3:07

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks to @trini to pointing me to HUSH_PARSER.
  
  – Xypron
  Mar 29 at 3:09
  

  
  
  
  

add a comment | 

The return value of a command can be found in environment variable $?, e.g.

gpio input 50; echo $?

If an if statement exists depends on the configuration when compiling U-Boot. Use CONFIG_HUSH_PARSER=y to enable it. When enabled you can write

if gpio input 102; then setenv board_name revA ; else setenv board_name revB;fi

share|improve this answer

edited Mar 29 at 3:07

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges

gpio input 50; echo $?

if gpio input 102; then setenv board_name revA ; else setenv board_name revB;fi

share|improve this answer

edited Mar 29 at 3:07

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges

answered Mar 28 at 21:35

XypronXypron

95211 gold badge55 silver badges1111 bronze badges