Re: [PATCH 1/4] reset: Add reset_reset() and reset_reset_bulk() API

[Michal Simek <michal.simek@amd.com>]

On 5/4/26 14:17, Simon Glass wrote:
> Hi Michal,
> 
> On 2026-04-30T12:20:00, Michal Simek <michal.simek@amd.com> wrote:
>> reset: Add reset_reset() and reset_reset_bulk() API
>>
>> Add reset_reset() and reset_reset_bulk() functions to the reset
>> controller API. These functions assert and then deassert reset signals
>> in a single call, providing a convenient way to pulse/toggle a reset
>> line.
>>
>> This mirrors the Linux kernel's reset_control_reset() and
>> reset_control_bulk_reset() APIs. The new functions are useful for
>> drivers that need to cycle a reset line during initialization or
>> error recovery.
>>
>> Signed-off-by: Michal Simek <michal.simek@amd.com>
>>
>> drivers/reset/reset-uclass.c | 30 ++++++++++++++++++++++++++++++
>>   include/reset-uclass.h       | 11 +++++++++++
>>   include/reset.h              | 35 +++++++++++++++++++++++++++++++++++
>>   3 files changed, 76 insertions(+)
> 
>> diff --git a/drivers/reset/reset-uclass.c b/drivers/reset/reset-uclass.c
>> @@ -225,6 +225,36 @@ int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
>> +int reset_reset(struct reset_ctl *reset_ctl)
>> +{
>> +     struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
>> +     int ret;
>> +
>> +     debug('%s(reset_ctl=%p)\n', __func__, reset_ctl);
>> +
>> +     if (ops->rst_reset)
>> +             return ops->rst_reset(reset_ctl);
>> +
>> +     ret = reset_assert(reset_ctl);
>> +     if (ret < 0)
>> +             return ret;
>> +
>> +     return reset_deassert(reset_ctl);
>> +}
> 
> Will this provide a long-enough pulse on real hardware?

In our case delays are handled by firmware itself because we are asking firmware 
to do it. It means no issue on our platform.

GPIO based reset can be also handled via gpio delay driver.
But I can add there one more parameter to also pass waiting delay. What do you 
think?


> 
>> diff --git a/include/reset.h b/include/reset.h
>> @@ -443,6 +468,16 @@ static inline int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
>> +static inline int reset_reset(struct reset_ctl *reset_ctl)
>> +{
>> +     return 0;
>> +}
> 
> Just to check - this matches the existing assert/deassert stubs,
> silently succeeding with !CONFIG_DM_RESET: is that intended? Should we
> return -NOSYS here?

Will look at this one.

M