[SOLVED} Re: Activate a Real Time Clock chip on I2C in Raspberry Pi 4B with Debian (not Raspbian)

["Rick Thomas" <rick.thomas@pobox.com>]

Turns out that the PiHut has a tutorial webpage for just this problem!

    https://thepihut.com/blogs/raspberry-pi-tutorials/17209332-adding-a-real-time-clock-to-your-raspberry-pi

Thanks for all the help!
Rick

On Tue, Apr 18, 2023, at 11:06 PM, Rick Thomas wrote:
> Thanks very much, Pabs!  I will follow up on those links and hopefully 
> get a better understanding of what is going on and why.  Perhaps the 
> next time someone has a question like mine, I'll be able to be as 
> helpful to them as the folks here have been to me!
>
> Rick
>
> On Tue, Apr 18, 2023, at 4:57 PM, Paul Wise wrote:
>> On Mon, 2023-04-17 at 22:21 -0700, Rick Thomas wrote:
>>
>>> What would have been even greater is if the error messages include
>>> references to some documentation that explained the problem and gave
>>> some clues to the larger context in which the problem arose.
>>
>> The messages I sent that patch adding are for very simple issues;
>> "/proc not mounted", "/sys not mounted" and "i2c-dev not loaded" and
>> since they all have very simple solutions, I just added the commands
>> to fix them instead of pointers to documentation about each error.
>>
>> Probably the i2c manual pages should get some links to the Linux kernel
>> documentation and wiki for I2C. I'm unlikely to work on that though,
>> hopefully someone else is willing to do that.
>>
>>> For example, I'd like to know why it chose bus3 rather than one of
>>> the other busses (0,1,2,4)?
>>
>> I expect that depends on the bus driver code for your device,
>> those do not seem to document their ordering though and it
>> looks like your particular i2c bus driver has no documentation.
>>
>> https://www.kernel.org/doc/html/latest/i2c/busses/index.html
>>
>>> I'd also like to know what the various modules do and what kinds of
>>> parameters there are to influence the detailed behavior?
>>
>> Looks like the devices are defined by DeviceTree, ACPI, board files,
>> dynamically by drivers for other devices, hardware probing or sysfs:
>>
>> https://www.kernel.org/doc/html/latest/i2c/instantiating-devices.html
>>
>>> And where is the documentation for the magic writing into /sys ?
>>
>> Seems to be here:
>>
>> https://www.kernel.org/doc/html/latest/i2c/instantiating-devices.html#method-4-instantiate-from-user-space
>> https://www.kernel.org/doc/html/latest/i2c/i2c-sysfs.html
>>
>> These may also be useful:
>>
>> https://www.kernel.org/doc/html/latest/i2c/
>> https://archive.kernel.org/oldwiki/i2c.wiki.kernel.org/
>>
>> PS: I am subscribed, no need to CC me, please respect Reply-To.
>>
>> -- 
>> bye,
>> pabs
>>
>> https://wiki.debian.org/PaulWise
>>
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