[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Seb James]

Hi,

I'm working on getting a ds1307 realtime clock working with a tqm823l as
a new user to u-boot (I've never compiled u-boot or ppcboot before).

I'd like to make some improvements to the README which is already
excellent but seems to have a couple of omissions, particularly
regarding the configuration of u-boot to work with i2c.


Firstly, the ds1307 code compiles fine, but of course it needs the i2c
code to be compiled alongside it. Although this is obvious, the newcomer
to u-boot doesn't (i.e. I didn't) know that calling for ds1307.c to be
compiled doesn't in itself cause the i2c code to be compiled, so a note
to this effect in the realtime clock section of the README would be a
helpful addition.



Now, in trying to get I2C properly compiled, I find quite a lot of
information about I2C setup in the README.


Here's a line from the README (starting at line 907):

"If this is selected, either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must
be defined	to include the appropriate I2C driver."


No mention is made of what values the 'appropriate driver' might have or
where to look for them. I assume you might define something like this:

#define CONFIG_HARD_I2C mpc8xx

But I can't see what you'd write for CONFIG_SOFT_I2C. A bit more
clarification here would be useful.

There are a number of extra defines related to CONFIG_SOFT_I2C, such as
I2C_INIT, I2C_PORT, etc. It's not too clear what these should be set to.
The diff between my TQM823L.h and the original TQM823L.h is (also
attached as changes.diff):

Some investigation has shown that I need to set I2C_SDA and I2C_SCL to
the name of the correct functions.  What are the possibilities for
these? The same seems to be true of I2C_READ.

What are the units for I2C_DELAY? I'm assuming seconds. Why is there
both I2C_DELAY and CFG_I2C_SPEED to configure? These seem to configure
the same thing  - the speed of the I2C clock line.

Ok, I think that should be enough for now,

best regards,

Seb James.

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Seb James]

Just a couple of edits to my posting.

Seb James wrote:

> Hi,
>
> I'm working on getting a ds1307 realtime clock working with a tqm823l as
> a new user to u-boot (I've never compiled u-boot or ppcboot before).
>
> I'd like to make some improvements to the README which is already
> excellent but seems to have a couple of omissions, particularly
> regarding the configuration of u-boot to work with i2c.
>
>
> Firstly, the ds1307 code compiles fine, but of course it needs the i2c
> code to be compiled alongside it... 

...in order to be able to link it into the u-boot image.

> Although this is obvious, the newcomer
> to u-boot doesn't (i.e. I didn't) know that calling for ds1307.c to be
> compiled doesn't in itself cause the i2c code to be compiled, so a note
> to this effect in the realtime clock section of the README would be a
> helpful addition.
>
>
>
> Now, in trying to get I2C properly compiled, I find quite a lot of
> information about I2C setup in the README.
>
>
> Here's a line from the README (starting at line 907):
>
> "If this is selected, either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must
> be defined    to include the appropriate I2C driver."
>
>
> No mention is made of what values the 'appropriate driver' might have or
> where to look for them. I assume you might define something like this:
>
> #define CONFIG_HARD_I2C mpc8xx
>
> But I can't see what you'd write for CONFIG_SOFT_I2C. A bit more
> clarification here would be useful.
>
> There are a number of extra defines related to CONFIG_SOFT_I2C, such as
> I2C_INIT, I2C_PORT, etc. It's not too clear what these should be set to.


Regarding this line:

> The diff between my TQM823L.h and the original TQM823L.h is (also
> attached as changes.diff): 

sorry - the diff wasn't attached, this line shouldn't have been in the 
posting. I was going to do this and then decided it wasn't necessary.

>
>
> Some investigation has shown that I need to set I2C_SDA and I2C_SCL to
> the name of the correct functions.  What are the possibilities for
> these? The same seems to be true of I2C_READ.
>
> What are the units for I2C_DELAY? I'm assuming seconds. Why is there
> both I2C_DELAY and CFG_I2C_SPEED to configure? These seem to configure
> the same thing  - the speed of the I2C clock line.
>
> Ok, I think that should be enough for now,
>
> best regards,
>
> Seb James.
>
>
>
>
>
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[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Wolfgang Denk]

Dear Seb,

in message <3F002BCA.9070609@peak.uklinux.net> you wrote:
> 
> I'm working on getting a ds1307 realtime clock working with a tqm823l as
> a new user to u-boot (I've never compiled u-boot or ppcboot before).

This is not correct.  You  compiled  and  installed  PPCBoot  in  our
training a year and a couple of days ago :-)

> Firstly, the ds1307 code compiles fine, but of course it needs the i2c
> code to be compiled alongside it. Although this is obvious, the newcomer
> to u-boot doesn't (i.e. I didn't) know that calling for ds1307.c to be
> compiled doesn't in itself cause the i2c code to be compiled, so a note
> to this effect in the realtime clock section of the README would be a
> helpful addition.

Please feel free to submit a patch...

> Here's a line from the README (starting at line 907):
> 
> "If this is selected, either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must
> be defined	to include the appropriate I2C driver."
> 
> 
> No mention is made of what values the 'appropriate driver' might have or
> where to look for them. I assume you might define something like this:
> 
> #define CONFIG_HARD_I2C mpc8xx

No. Just "#define CONFIG_HARD_I2C" is OK, as for each  CPU  there  is
always exactly one hard-i2c and one soft-i2c driver.

> But I can't see what you'd write for CONFIG_SOFT_I2C. A bit more
> clarification here would be useful.

Just:
	#define	CONFIG_SOFT_I2C

It must be defined - that's all :-)

> There are a number of extra defines related to CONFIG_SOFT_I2C, such as
> I2C_INIT, I2C_PORT, etc. It's not too clear what these should be set to.
> The diff between my TQM823L.h and the original TQM823L.h is (also
> attached as changes.diff):

No diff attached.


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
There are two ways of constructing a software design. One way  is  to
make  it  so  simple that there are obviously no deficiencies and the
other is to make it so complicated that there are  no  obvious  defi-
ciencies.                             - Charles Anthony Richard Hoare

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Wolfgang Denk]

In message <3F002ED5.4050803@peak.uklinux.net> you wrote:
>
> > Some investigation has shown that I need to set I2C_SDA and I2C_SCL to
> > the name of the correct functions.  What are the possibilities for
> > these? The same seems to be true of I2C_READ.

These are macros that define code (think of inline functions) to  set
the  SDA  resp. SCL port pin to high (bit=1) or low (bit-0). I2C_READ
will read the state of the SDA port pin.

Isn't this obvious from the sources?

> > What are the units for I2C_DELAY? I'm assuming seconds. Why is there

Again, see  the  source  code.  A  definition  like  this  should  be
self-explainatory:

	#define I2C_DELAY      udelay(5)       /* 1/4 I2C clock duration */

> > both I2C_DELAY and CFG_I2C_SPEED to configure? These seem to configure
> > the same thing  - the speed of the I2C clock line.

Hysterical reasons. I2C_DELAY => soft_i2c, CFG_I2C_SPEED => hard-i2c


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
A dog always bit deepest on the veterinary hand.
                                    - Terry Pratchett, _Wyrd Sisters_

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Seb James]

Thanks for the help Wolfgang,

Wolfgang Denk wrote:

>Dear Seb,
>
>in message <3F002BCA.9070609@peak.uklinux.net> you wrote:
>  
>
>>I'm working on getting a ds1307 realtime clock working with a tqm823l as
>>a new user to u-boot (I've never compiled u-boot or ppcboot before).
>>    
>>
>
>This is not correct.  You  compiled  and  installed  PPCBoot  in  our
>training a year and a couple of days ago :-)
>  
>
That's true. Ok, not for a while though...

>  
>
>>Firstly, the ds1307 code compiles fine, but of course it needs the i2c
>>code to be compiled alongside it. Although this is obvious, the newcomer
>>to u-boot doesn't (i.e. I didn't) know that calling for ds1307.c to be
>>compiled doesn't in itself cause the i2c code to be compiled, so a note
>>to this effect in the realtime clock section of the README would be a
>>helpful addition.
>>    
>>
>
>Please feel free to submit a patch...
>  
>
Yes, I'll do that when I'm sure I think there needs to be one and what 
it should be :)

>  
>
>>Here's a line from the README (starting at line 907):
>>
>>"If this is selected, either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must
>>be defined	to include the appropriate I2C driver."
>>
>>
>>No mention is made of what values the 'appropriate driver' might have or
>>where to look for them. I assume you might define something like this:
>>
>>#define CONFIG_HARD_I2C mpc8xx
>>    
>>
>
>No. Just "#define CONFIG_HARD_I2C" is OK, as for each  CPU  there  is
>always exactly one hard-i2c and one soft-i2c driver.
>
>  
>
>>But I can't see what you'd write for CONFIG_SOFT_I2C. A bit more
>>clarification here would be useful.
>>    
>>
>
>Just:
>	#define	CONFIG_SOFT_I2C
>
>It must be defined - that's all :-)
>
>  
>
Ok, well I've successfully compiled with CONFIG_HARD_I2C and have 
communicated with my clock, so that is good. Next up is transferring the 
date in u-boot to linux, but I'm sure that will be documented somewhere.

As for CONFIG_SOFT_I2C; Attached (really this time) is a diff between 
the original u-boot-0.4.0/include/configs/TQM823L.h and the one that I 
have altered. The compile of soft_i2c.c fails with the following error 
messages:

ppc_8xx-gcc -g  -Os   -mrelocatable -ffixed-r14 -meabi -D__KERNEL__ 
-DTEXT_BASE=0x40000000 -I/eldk/ppc_8xx/usr/src/u-boot-0.4.0/include 
-fno-builtin -nostdinc -isystem 
/eldk/usr/lib/gcc-lib/ppc-linux/2.95.4/include -pipe  -DCONFIG_PPC 
-D__powerpc__ -DCONFIG_8xx -ffixed-r2 -ffixed-r29 -mstring -mcpu=860 
-msoft-float -Wall -Wstrict-prototypes -c -o soft_i2c.o soft_i2c.c
soft_i2c.c: In function `send_reset':
soft_i2c.c:86: warning: implicit declaration of function `I2C_SCL'
soft_i2c.c:87: warning: implicit declaration of function `I2C_SDA'
soft_i2c.c:91: `I2C_TRISTATE' undeclared (first use in this function)
soft_i2c.c:91: (Each undeclared identifier is reported only once
soft_i2c.c:91: for each function it appears in.)
soft_i2c.c:94: `I2C_DELAY' undeclared (first use in this function)
soft_i2c.c:82: warning: unused variable `immr'
soft_i2c.c: In function `send_start':
soft_i2c.c:116: `I2C_DELAY' undeclared (first use in this function)
soft_i2c.c:118: `I2C_ACTIVE' undeclared (first use in this function)
soft_i2c.c:113: warning: unused variable `immr'
soft_i2c.c: In function `send_stop':
soft_i2c.c:139: `I2C_DELAY' undeclared (first use in this function)
soft_i2c.c:141: `I2C_ACTIVE' undeclared (first use in this function)
soft_i2c.c:147: `I2C_TRISTATE' undeclared (first use in this function)
soft_i2c.c:135: warning: unused variable `immr'
soft_i2c.c: In function `send_ack':
soft_i2c.c:163: `I2C_ACTIVE' undeclared (first use in this function)
soft_i2c.c:165: `I2C_DELAY' undeclared (first use in this function)
soft_i2c.c:160: warning: unused variable `immr'
soft_i2c.c: In function `write_byte':
soft_i2c.c:193: `I2C_ACTIVE' undeclared (first use in this function)
soft_i2c.c:196: `I2C_DELAY' undeclared (first use in this function)
soft_i2c.c:212: `I2C_TRISTATE' undeclared (first use in this function)
soft_i2c.c:217: `I2C_READ' undeclared (first use in this function)
soft_i2c.c:188: warning: unused variable `immr'
soft_i2c.c:191: warning: `nack' might be used uninitialized in this function
soft_i2c.c: In function `read_byte':
soft_i2c.c:244: `I2C_TRISTATE' undeclared (first use in this function)
soft_i2c.c:248: `I2C_DELAY' undeclared (first use in this function)
soft_i2c.c:252: `I2C_READ' undeclared (first use in this function)
soft_i2c.c:236: warning: unused variable `immr'
make[1]: *** [soft_i2c.o] Error 1
make[1]: Leaving directory `/eldk/ppc_8xx/usr/src/u-boot-0.4.0/common'
make: *** [subdirs] Error 1
[seb at mst26 u-boot-0.4.0]$

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[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Wolfgang Denk]

In message <3F0037AA.7060205@peak.uklinux.net> you wrote:
>
> >This is not correct.  You  compiled  and  installed  PPCBoot  in  our
> >training a year and a couple of days ago :-)
> >  
> >
> That's true. Ok, not for a while though...

:-)

> >Please feel free to submit a patch...
> >
> Yes, I'll do that when I'm sure I think there needs to be one and what 
> it should be :)

There shouldbe one. You asked these questions after all - prrof  that
such an explanation is needed.

> Ok, well I've successfully compiled with CONFIG_HARD_I2C and have 
> communicated with my clock, so that is good. Next up is transferring the 
> date in u-boot to linux, but I'm sure that will be documented somewhere.

You don't "transfer" the daye. Linux will pick it  up  itself  (which
requires an RTC driver and eventually some modifications).

> As for CONFIG_SOFT_I2C; Attached (really this time) is a diff between 
> the original u-boot-0.4.0/include/configs/TQM823L.h and the one that I 
> have altered. The compile of soft_i2c.c fails with the following error 
> messages:

That's because you did  not  define  the  required  macros  (see  for
example the configuration in lwmon.h).


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Life is a game. Money is how we keep score.              - Ted Turner

Re: [U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Seb James]

Wolfgang Denk wrote:
[ snip ]

>>Ok, well I've successfully compiled with CONFIG_HARD_I2C and have
>>communicated with my clock, so that is good. Next up is transferring the
>>date in u-boot to linux, but I'm sure that will be documented somewhere.
>>
>>
>
>You don't "transfer" the daye. Linux will pick it  up  itself  (which
>requires an RTC driver and eventually some modifications).
>

Let me check that I understand: As far as I can see the u-boot realtime
clock drivers just allow you to set and read the time from the u-boot
command line; a useful utility. If linux is to read the time from the
realtime clock it must have a realtime clock driver of its own; there's
no way that u-boot can pass the time to linux at boot time? (Of course,
this would be fraught with difficulties, because depending on how fast
your cpu boots linux, a different amount of time would elapse before
linux could actually do something with the passed date stamp).

So, next up for me is to write a linux driver for the ds1307. I was
actually in the middle of that before getting sidetracked by the u-boot
rtc code. However, the u-boot code has enabled me to hardware debug my
realtime clock circuit, so that was very useful.  Has anyone written a
linux driver for the ds1307 or similar? (I'm cross posting to the
linuxppc-embedded list to ask this question).

>>As for CONFIG_SOFT_I2C; Attached (really this time) is a diff between
>>the original u-boot-0.4.0/include/configs/TQM823L.h and the one that I
>>have altered. The compile of soft_i2c.c fails with the following error
>>messages:
>>
>>
>
>That's because you did  not  define  the  required  macros  (see  for
>example the configuration in lwmon.h).
>
>
Right, so it's not the case that you just #define CONFIG_SOFT_I2C; you
have to correctly define the macros. I shall do some work on the readme
and post a diff later on. Thanks for the pointers.

best,

Seb


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Seb James]

Wolfgang Denk wrote:
[ snip ]

>>Ok, well I've successfully compiled with CONFIG_HARD_I2C and have 
>>communicated with my clock, so that is good. Next up is transferring the 
>>date in u-boot to linux, but I'm sure that will be documented somewhere.
>>    
>>
>
>You don't "transfer" the daye. Linux will pick it  up  itself  (which
>requires an RTC driver and eventually some modifications).
>

Let me check that I understand: As far as I can see the u-boot realtime 
clock drivers just allow you to set and read the time from the u-boot 
command line; a useful utility. If linux is to read the time from the 
realtime clock it must have a realtime clock driver of its own; there's 
no way that u-boot can pass the time to linux at boot time? (Of course, 
this would be fraught with difficulties, because depending on how fast 
your cpu boots linux, a different amount of time would elapse before 
linux could actually do something with the passed date stamp).

So, next up for me is to write a linux driver for the ds1307. I was 
actually in the middle of that before getting sidetracked by the u-boot 
rtc code. However, the u-boot code has enabled me to hardware debug my 
realtime clock circuit, so that was very useful.  Has anyone written a 
linux driver for the ds1307 or similar? (I'm cross posting to the 
linuxppc-embedded list to ask this question).

>>As for CONFIG_SOFT_I2C; Attached (really this time) is a diff between 
>>the original u-boot-0.4.0/include/configs/TQM823L.h and the one that I 
>>have altered. The compile of soft_i2c.c fails with the following error 
>>messages:
>>    
>>
>
>That's because you did  not  define  the  required  macros  (see  for
>example the configuration in lwmon.h).
>  
>
Right, so it's not the case that you just #define CONFIG_SOFT_I2C; you 
have to correctly define the macros. I shall do some work on the readme 
and post a diff later on. Thanks for the pointers.

best,

Seb

Re: [U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Wolfgang Denk]

Dear Seb,

in message <3F004440.6000301@peak.uklinux.net> you wrote:
>
> command line; a useful utility. If linux is to read the time from the
> realtime clock it must have a realtime clock driver of its own; there's
> no way that u-boot can pass the time to linux at boot time? (Of course,

Correct.


Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Old programmers never die, they just become managers.

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Wolfgang Denk]

Dear Seb,

in message <3F004440.6000301@peak.uklinux.net> you wrote:
> 
> command line; a useful utility. If linux is to read the time from the 
> realtime clock it must have a realtime clock driver of its own; there's 
> no way that u-boot can pass the time to linux at boot time? (Of course, 

Correct.


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Old programmers never die, they just become managers.

[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Seb James]

Wolfgang Denk wrote:

>Dear Seb,
>
>in message <3F004440.6000301@peak.uklinux.net> you wrote:
>  
>
>>command line; a useful utility. If linux is to read the time from the
>>realtime clock it must have a realtime clock driver of its own; there's
>>no way that u-boot can pass the time to linux at boot time? (Of course,
>>    
>>
>
>Correct.
>
>  
>
Ok. Here is a diff (created as specified in the README) of the README. 
The old file is the README file that came in the u-boot-0.4.0 tarball. 
The changes that I've made are some extra information to help someone to 
add i2c and realtime clock support to u-boot.

Seb.
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[U-Boot-Users] soft_i2c and ds1307 with tqm823l

[Wolfgang Denk]

In message <3F005003.7020202@peak.uklinux.net> you wrote:
>
> Ok. Here is a diff (created as specified in the README) of the README. 
> The old file is the README file that came in the u-boot-0.4.0 tarball. 

Thanks, added.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
While money can't buy happiness, it certainly lets  you  choose  your
own form of misery.