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Date:   Fri, 24 Apr 2020 10:30:52 -0700
From:   Matthias Kaehlcke <mka@chromium.org>
To:     Georgi Djakov <georgi.djakov@linaro.org>
Cc:     vireshk@kernel.org, nm@ti.com, sboyd@kernel.org,
        robh+dt@kernel.org, rjw@rjwysocki.net, saravanak@google.com,
        sibis@codeaurora.org, rnayak@codeaurora.org,
        bjorn.andersson@linaro.org, vincent.guittot@linaro.org,
        jcrouse@codeaurora.org, evgreen@chromium.org,
        linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 2/7] OPP: Add helpers for reading the binding
 properties
Message-ID: <20200424173052.GM199755@google.com>
References: <20200424155404.10746-1-georgi.djakov@linaro.org>
 <20200424155404.10746-3-georgi.djakov@linaro.org>
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Hi Georgi,

On Fri, Apr 24, 2020 at 06:53:59PM +0300, Georgi Djakov wrote:
> From: Saravana Kannan <saravanak@google.com>
> 
> The opp-hz DT property is not mandatory and we may use another property
> as a key in the OPP table. Add helper functions to simplify the reading
> and comparing the keys.
> 
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
> v7:
> * Extracted just the helpers from patch v6, as Viresh advised to split it.
> 
> v6: https://lore.kernel.org/r/20191207002424.201796-3-saravanak@google.com
> 
>  drivers/opp/core.c | 15 +++++++++++++--
>  drivers/opp/of.c   | 42 ++++++++++++++++++++++++++----------------
>  drivers/opp/opp.h  |  1 +
>  3 files changed, 40 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index ba43e6a3dc0a..c9c1bbe6ae27 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -1272,11 +1272,21 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
>  	return true;
>  }
>  
> +int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2)
> +{
> +	if (opp1->rate != opp2->rate)
> +		return opp1->rate < opp2->rate ? -1 : 1;
> +	if (opp1->level != opp2->level)
> +		return opp1->level < opp2->level ? -1 : 1;
> +	return 0;
> +}
> +
>  static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
>  			     struct opp_table *opp_table,
>  			     struct list_head **head)
>  {
>  	struct dev_pm_opp *opp;
> +	int opp_cmp;
>  
>  	/*
>  	 * Insert new OPP in order of increasing frequency and discard if
> @@ -1287,12 +1297,13 @@ static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
>  	 * loop.
>  	 */
>  	list_for_each_entry(opp, &opp_table->opp_list, node) {
> -		if (new_opp->rate > opp->rate) {
> +		opp_cmp = _opp_compare_key(new_opp, opp);
> +		if (opp_cmp > 0) {
>  			*head = &opp->node;
>  			continue;
>  		}
>  
> -		if (new_opp->rate < opp->rate)
> +		if (opp_cmp < 0)
>  			return 0;
>  
>  		/* Duplicate OPPs */
> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> index 9cd8f0adacae..e33169c7e045 100644
> --- a/drivers/opp/of.c
> +++ b/drivers/opp/of.c
> @@ -521,6 +521,28 @@ void dev_pm_opp_of_remove_table(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
>  
> +static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
> +			 bool *rate_not_available)
> +{
> +	u64 rate;
> +	int ret;
> +
> +	ret = of_property_read_u64(np, "opp-hz", &rate);
> +	if (!ret) {
> +		/*
> +		 * Rate is defined as an unsigned long in clk API, and so
> +		 * casting explicitly to its type. Must be fixed once rate is 64
> +		 * bit guaranteed in clk API.
> +		 */
> +		new_opp->rate = (unsigned long)rate;
> +	}

nit: curly braces are not needed

> +	*rate_not_available = !!ret;
> +
> +	of_property_read_u32(np, "opp-level", &new_opp->level);
> +
> +	return ret;
> +}
> +
>  /**
>   * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
>   * @opp_table:	OPP table
> @@ -558,26 +580,14 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
>  	if (!new_opp)
>  		return ERR_PTR(-ENOMEM);
>  
> -	ret = of_property_read_u64(np, "opp-hz", &rate);
> +	ret = _read_opp_key(new_opp, np, &rate_not_available);
>  	if (ret < 0) {
> -		/* "opp-hz" is optional for devices like power domains. */
> -		if (!opp_table->is_genpd) {
> -			dev_err(dev, "%s: opp-hz not found\n", __func__);
> -			goto free_opp;
> -		}
> +		if (!opp_table->is_genpd)
> +			dev_err(dev, "%s: opp key field not found\n", __func__);
>  
> -		rate_not_available = true;
> -	} else {
> -		/*
> -		 * Rate is defined as an unsigned long in clk API, and so
> -		 * casting explicitly to its type. Must be fixed once rate is 64
> -		 * bit guaranteed in clk API.
> -		 */
> -		new_opp->rate = (unsigned long)rate;
> +		goto free_opp;
>  	}
>  
> -	of_property_read_u32(np, "opp-level", &new_opp->level);
> -
>  	/* Check if the OPP supports hardware's hierarchy of versions or not */
>  	if (!_opp_is_supported(dev, opp_table, np)) {
>  		dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
> diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
> index d14e27102730..bcadb1e328a4 100644
> --- a/drivers/opp/opp.h
> +++ b/drivers/opp/opp.h
> @@ -211,6 +211,7 @@ struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_
>  void _dev_pm_opp_find_and_remove_table(struct device *dev);
>  struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);
>  void _opp_free(struct dev_pm_opp *opp);
> +int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2);
>  int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table, bool rate_not_available);
>  int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic);
>  void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, int last_cpu);

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>