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

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

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.

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,