[PATCH] Add lvgl_hello: Sample Hello world app using littleVGL and libbsd

[Christian Mauderer]

On 17/09/2019 08:46, Vijay Kumar Banerjee wrote:
> 
> 
> On Thu, Sep 12, 2019 at 2:37 PM Christian Mauderer
> <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>> wrote:
> 
> 
> 
>     On 12/09/2019 10:28, Vijay Kumar Banerjee wrote:
>     >
>     >
>     >
>     > On Wed, Sep 11, 2019 at 4:38 PM Christian Mauderer
>     > <christian.mauderer at embedded-brains.de
>     <mailto:christian.mauderer at embedded-brains.de>
>     > <mailto:christian.mauderer at embedded-brains.de
>     <mailto:christian.mauderer at embedded-brains.de>>> wrote:
>     >
>     >     On 11/09/2019 10:48, Vijay Kumar Banerjee wrote:
>     >     >
>     >     >  Hi,
>     >     >
>     >     > Since adding I2C in BBB initialization seems like the right
>     solution,
>     >     > should we ask
>     >     > in devel and user lists in a separate thread, to know if
>     anyone is
>     >     > opposed to this change?
>     >
>     >     Hello Vijay,
>     >
>     >     just send a patch. That will start the discussion if someone
>     objects
>     >     to it.
>     >
>     >     >
>     >     > Where should I be looking for to add i2c in BBB initialization?
>     >
>     >     Please take a look at the dependencies. If there are any (like
>     clocks or
>     >     similar) you have to add it afterwards.
>     >
>     >     Take a look at some other BSPs where similar hardware (like
>     I2C, SPI,
>     >     some external chips, ...) is initialized. For example the
>     mvme3100 uses
>     >     a RTEMS_SYSINIT_ITEM to pick a random sample. But I think most
>     BSPs use
>     >     a special init function similar to the one in BBB.
>     >
>     > Hi,
>     >
>     > I tried a very similar approach and added RTEMS_SYSINIT_ITEM
>     > :
>     > ```
>     > diff --git a/bsps/arm/beagle/start/bspstart.c
>     > b/bsps/arm/beagle/start/bspstart.c
>     > index 224f9ecf3b..35839e774b 100644
>     > --- a/bsps/arm/beagle/start/bspstart.c
>     > +++ b/bsps/arm/beagle/start/bspstart.c
>     > @@ -17,6 +17,8 @@
>     >  #include <bsp/irq-generic.h>
>     >  #include <bsp/fdt.h>
>     >  #include <bsp/linker-symbols.h>
>     > +#include <bsp/i2c.h>
>     > +#include <rtems/sysinit.h>
>     >  
>     >  #include "bspdebug.h"
>     >  
>     > @@ -41,3 +43,15 @@ uint32_t bsp_fdt_map_intr(const uint32_t *intr,
>     > size_t icells)
>     >  {
>     >    return intr[0];
>     >  }
>     > +
>     > +static void bbb_i2c_0_initialize(void)
>     > +{
>     > +  bbb_register_i2c_0();
>     > +}
>     > +
>     > +RTEMS_SYSINIT_ITEM(
>     > +  bbb_i2c_0_initialize,
>     > +  RTEMS_SYSINIT_BSP_PRE_DRIVERS,
>     > +  RTEMS_SYSINIT_ORDER_MIDDLE
>     > +);
>     > ``` 
>     > This is successfully calling the `am335x_i2c_bus_register` but
>     > the issue with this approach is that it's returning the following
>     > internal error after `am335x_i2c_reset` call.
>     > ```
>     > _Terminate (the_source=the_source at entry=INTERNAL_ERROR_CORE,
>     > the_error=the_error at entry=30)
>     > ```
>     >
>     > Any hint on what might be the cause of the error?
> 
>     Just a guess: Are you sure that "BSP_PRE_DRIVERS" is the right order?
>     It's a driver so maybe somewhen during the drivers?
> 
> I tried RTEMS_SYSINIT_DEVICE_DRIVERS, and eve RTEMS_SYSINIT_LAST,
> but it doesn't seem to work. Maybe it needs to be called in a further
> later stage.

I think you have a debugger? Could you set a breakpoint to _Terminate
and take a look at the back trace what caused the error?

> 
>     Does bbb_i2c_0_initialize has a type that is compatible with the sysinit
>     items?
> 
> yes, I checked this. the function is called and it's reaching
> am335x_i2c_* calls
> but it's getting stuck somewhere between i2c_reset and pinmux. Am I possibly
> missing some other drivers that it depends on? 
> Can you please point me to the doc/note where the init sequence is properly 
> described. Also, if there's some other bsp that has initialized a driver
> at init, please
> point me to that for reference.  
> 
>     >
>     >     Best regards
>     >
>     >     Christian
>     >
> 
>     -- 
>     --------------------------------------------
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>     Herr Christian Mauderer
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>     email: christian.mauderer at embedded-brains.de
>     <mailto:christian.mauderer at embedded-brains.de>
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>     Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
> 
> 
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