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

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(-)

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