On 9/4/24 08:24, Patryk wrote:
[ ... ]
>>> We'll need to add some code to detect that condition and
>>> refrain from clearing the status register if the chip doesn't support
>>> writes (or maybe ignore errors from the clear operation). Ignoring the
>>> error might be the easiest fix.
>>
>> I will apply this fix to our codebase then, unless I come up with a better idea.
>>
>
> If yyou don't mind and have the time, it would be great if you can send a
> patch to be applied to the upstream kernel. If not, please let me know and
> I'll write one myself.
>
> Thanks,
> Guenter
>
Sure, I'll send a patch.
Thanks. Additional background: The ability to clear status registers was
added with PMBus version 1.2, so it is not surprising that older chips
don't support it. The best fix would probably be to read the revision
register and use its content to decide if the individual status register
should be cleared or if the clear_faults command should be executed.
Something like
struct pmbus_data {
...
u8 revision;
...
};
In pmbus.h:
#define PMBUS_REV_10 0x00
#define PMBUS_REV_11 0x11
#define PMBUS_REV_12 0x22
#definw PMBUS_REV_13 0x33
In pmbus_init_common():
ret = i2c_smbus_read_byte_data(client, PMBUS_REVISION);
if (!ret)
data->revision = ret;
In pmbus_show_boolean():
if (regval) {
if (data->revision >= PMBUS_REV_12)
ret = _pmbus_write_byte_data(client, page, reg, regval);
else
ret = pmbus_clear_fault_page(client, page);
if (ret)
goto unlock;
}
Thanks,
Guenter
