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

[Dmitry Baryshkov]

On Tue, 2 Apr 2024 at 13:34, Varadarajan Narayanan
<quic_varada@xxxxxxxxxxx> 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@xxxxxxxxxxx>
> ---
> 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.

> +               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