Re: [PATCH v2 06/26] interconnect: icc-clk: add support for scaling using OPP

[Konrad Dybcio <konrad.dybcio@linaro.org>]

On 26.06.2023 15:44, Dmitry Baryshkov wrote:
> On 26/06/2023 14:28, Konrad Dybcio wrote:
>> On 25.06.2023 22:25, Dmitry Baryshkov wrote:
>>> Sometimes it might be required to scale the clock using the OPP
>>> framework (e.g. to scale regulators following the required clock rate).
>>> Extend the interconnec
>> 't'
>>
>>> -clk framework to handle OPP case in addition to
>>> scaling the clock.
>>>
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>> ---
>> I think we should check for OPP at the icc-clk registration time,
>> instead of passing it as a parameter, e.g.:
>>
>> qn.opp = IS_ERR(dev_pm_opp_get_opp_count)
>>
>> Not sure if there's a more idiomatic way.
> 
> No. icc-clk is not limited to a single clock->icc conversion. So it is possible to create several interconnect links, only one of which should be the OPP-based one.
Ugh. Right.

Konrad
> 
>>
>> Konrad
>>>   drivers/interconnect/icc-clk.c   | 13 +++++++++++--
>>>   include/linux/interconnect-clk.h |  1 +
>>>   2 files changed, 12 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/interconnect/icc-clk.c b/drivers/interconnect/icc-clk.c
>>> index 4d43ebff4257..c7962acdcee7 100644
>>> --- a/drivers/interconnect/icc-clk.c
>>> +++ b/drivers/interconnect/icc-clk.c
>>> @@ -7,10 +7,13 @@
>>>   #include <linux/device.h>
>>>   #include <linux/interconnect-clk.h>
>>>   #include <linux/interconnect-provider.h>
>>> +#include <linux/pm_opp.h>
>>>     struct icc_clk_node {
>>> +    struct device *dev;
>>>       struct clk *clk;
>>>       bool enabled;
>>> +    bool opp;
>>>   };
>>>     struct icc_clk_provider {
>>> @@ -25,12 +28,16 @@ struct icc_clk_provider {
>>>   static int icc_clk_set(struct icc_node *src, struct icc_node *dst)
>>>   {
>>>       struct icc_clk_node *qn = src->data;
>>> +    unsigned long rate = icc_units_to_bps(src->peak_bw);
>>>       int ret;
>>>         if (!qn || !qn->clk)
>>>           return 0;
>>>   -    if (!src->peak_bw) {
>>> +    if (qn->opp)
>>> +        return dev_pm_opp_set_rate(qn->dev, rate);
>>> +
>>> +    if (!rate) {
>>>           if (qn->enabled)
>>>               clk_disable_unprepare(qn->clk);
>>>           qn->enabled = false;
>>> @@ -45,7 +52,7 @@ static int icc_clk_set(struct icc_node *src, struct icc_node *dst)
>>>           qn->enabled = true;
>>>       }
>>>   -    return clk_set_rate(qn->clk, icc_units_to_bps(src->peak_bw));
>>> +    return clk_set_rate(qn->clk, rate);
>>>   }
>>>     static int icc_clk_get_bw(struct icc_node *node, u32 *avg, u32 *peak)
>>> @@ -106,7 +113,9 @@ struct icc_provider *icc_clk_register(struct device *dev,
>>>       icc_provider_init(provider);
>>>         for (i = 0, j = 0; i < num_clocks; i++) {
>>> +        qp->clocks[i].dev = dev;
>>>           qp->clocks[i].clk = data[i].clk;
>>> +        qp->clocks[i].opp = data[i].opp;
>>>             node = icc_node_create(first_id + j);
>>>           if (IS_ERR(node)) {
>>> diff --git a/include/linux/interconnect-clk.h b/include/linux/interconnect-clk.h
>>> index 0cd80112bea5..c695e5099901 100644
>>> --- a/include/linux/interconnect-clk.h
>>> +++ b/include/linux/interconnect-clk.h
>>> @@ -11,6 +11,7 @@ struct device;
>>>   struct icc_clk_data {
>>>       struct clk *clk;
>>>       const char *name;
>>> +    bool opp;
>>>   };
>>>     struct icc_provider *icc_clk_register(struct device *dev,
>