Re: [PATCH v6 4/6] clk: qcom: common: Add interconnect clocks support

[Varadarajan Narayanan <quic_varada@quicinc.com>]

On Tue, Apr 02, 2024 at 01:48:14PM +0300, Dmitry Baryshkov wrote:
> On Tue, 2 Apr 2024 at 13:34, Varadarajan Narayanan
> <quic_varada@quicinc.com> wrote:
> >
> > Unlike MSM platforms that manage NoC related clocks and scaling
> > from RPM, IPQ SoCs dont involve RPM in managing NoC related
> > clocks and there is no NoC scaling.
> >
> > However, there is a requirement to enable some NoC interface
> > clocks for accessing the peripheral controllers present on
> > these NoCs. Though exposing these as normal clocks would work,
> > having a minimalistic interconnect driver to handle these clocks
> > would make it consistent with other Qualcomm platforms resulting
> > in common code paths. This is similar to msm8996-cbf's usage of
> > icc-clk framework.
> >
> > Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
> > ---
> > v6: first_id -> icc_first_node_id
> >     Remove clock get so that the peripheral that uses the clock
> >     can do the clock get
> > v5: Split changes in common.c to separate patch
> >     Fix error handling
> >     Use devm_icc_clk_register instead of icc_clk_register
> > v4: Use clk_hw instead of indices
> >     Do icc register in qcom_cc_probe() call stream
> >     Add icc clock info to qcom_cc_desc structure
> > v3: Use indexed identifiers here to avoid confusion
> >     Fix error messages and move to common.c
> > v2: Move DTS to separate patch
> >     Update commit log
> >     Auto select CONFIG_INTERCONNECT & CONFIG_INTERCONNECT_CLK to fix build error
> > ---
> >  drivers/clk/qcom/common.c | 38 +++++++++++++++++++++++++++++++++++++-
> >  drivers/clk/qcom/common.h |  3 +++
> >  2 files changed, 40 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
> > index 75f09e6e057e..d5c008048994 100644
> > --- a/drivers/clk/qcom/common.c
> > +++ b/drivers/clk/qcom/common.c
> > @@ -8,6 +8,7 @@
> >  #include <linux/regmap.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/clk-provider.h>
> > +#include <linux/interconnect-clk.h>
> >  #include <linux/reset-controller.h>
> >  #include <linux/of.h>
> >
> > @@ -234,6 +235,41 @@ static struct clk_hw *qcom_cc_clk_hw_get(struct of_phandle_args *clkspec,
> >         return cc->rclks[idx] ? &cc->rclks[idx]->hw : NULL;
> >  }
> >
> > +static int qcom_cc_icc_register(struct device *dev,
> > +                               const struct qcom_cc_desc *desc)
> > +{
> > +       struct icc_clk_data *icd;
> > +       int i;
> > +
> > +       if (!IS_ENABLED(CONFIG_INTERCONNECT_CLK))
> > +               return 0;
> > +
> > +       if (!desc->icc_hws)
> > +               return 0;
> > +
> > +       icd = devm_kcalloc(dev, desc->num_icc_hws, sizeof(*icd), GFP_KERNEL);
> > +       if (!icd)
> > +               return -ENOMEM;
> > +
> > +       for (i = 0; i < desc->num_icc_hws; i++) {
> > +               /*
> > +                * get_clk will be done by the peripheral device using this
> > +                * clock with devm_clk_hw_get_clk() so that we can associate
> > +                * the clk handle with the consumer device. It would also help
> > +                * us make it so that drivers defer probe until their
> > +                * clk isn't an orphan.
>
> How the clock instance returned to the peripheral driver is supposed
> to correspond to the clock instance used by the icc-clk?
> > +                */
> > +               icd[i].clk = desc->icc_hws[i]->clk;
>
> You again are abusing clk_hw->clk. Please don't do that.

Ok, will clk_get in both the places.

Thanks
Varada

> > +               if (!icd[i].clk)
> > +                       return dev_err_probe(dev, -ENOENT,
> > +                                            "(%d) clock entry is null\n", i);
> > +               icd[i].name = clk_hw_get_name(desc->icc_hws[i]);
> > +       }
> > +
> > +       return PTR_ERR_OR_ZERO(devm_icc_clk_register(dev, desc->icc_first_node_id,
> > +                                                    desc->num_icc_hws, icd));
> > +}
> > +
> >  int qcom_cc_really_probe(struct platform_device *pdev,
> >                          const struct qcom_cc_desc *desc, struct regmap *regmap)
> >  {
> > @@ -303,7 +339,7 @@ int qcom_cc_really_probe(struct platform_device *pdev,
> >         if (ret)
> >                 return ret;
> >
> > -       return 0;
> > +       return qcom_cc_icc_register(dev, desc);
> >  }
> >  EXPORT_SYMBOL_GPL(qcom_cc_really_probe);
> >
> > diff --git a/drivers/clk/qcom/common.h b/drivers/clk/qcom/common.h
> > index 9c8f7b798d9f..9058ffd46260 100644
> > --- a/drivers/clk/qcom/common.h
> > +++ b/drivers/clk/qcom/common.h
> > @@ -29,6 +29,9 @@ struct qcom_cc_desc {
> >         size_t num_gdscs;
> >         struct clk_hw **clk_hws;
> >         size_t num_clk_hws;
> > +       struct clk_hw **icc_hws;
> > +       size_t num_icc_hws;
> > +       unsigned int icc_first_node_id;
> >  };
> >
> >  /**
> > --
> > 2.34.1
> >
>
>
> --
> With best wishes
>
> Dmitry