linux-kernel - Re: [PATCH 3/4] opp: Reused enabled flag and remove regulator

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Message-ID: <e232d06c-f19f-a806-637b-8f0ffed19594@codeaurora.org>
Date:   Tue, 18 Aug 2020 12:40:10 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Rafael Wysocki <rjw@...ysocki.net>, mka@...omium.org,
        sibis@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] opp: Reused enabled flag and remove regulator_enabled


On 8/13/2020 9:59 AM, Viresh Kumar wrote:
> The common "enabled" flag can be used here instead of
> "regulator_enabled" now.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>   drivers/opp/core.c | 13 +++----------
>   drivers/opp/opp.h  |  2 --
>   2 files changed, 3 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index e8882e7fd8a5..5f5da257f58a 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -703,12 +703,10 @@ static int _generic_set_opp_regulator(struct opp_table *opp_table,
>   	 * Enable the regulator after setting its voltages, otherwise it breaks
>   	 * some boot-enabled regulators.
>   	 */
> -	if (unlikely(!opp_table->regulator_enabled)) {
> +	if (unlikely(!opp_table->enabled)) {
>   		ret = regulator_enable(reg);
>   		if (ret < 0)
>   			dev_warn(dev, "Failed to enable regulator: %d", ret);
> -		else
> -			opp_table->regulator_enabled = true;
>   	}
>   
>   	return 0;
> @@ -905,10 +903,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
>   		if (ret)
>   			goto put_opp_table;
>   
> -		if (opp_table->regulator_enabled) {
> -			regulator_disable(opp_table->regulators[0]);
> -			opp_table->regulator_enabled = false;
> -		}
> +		regulator_disable(opp_table->regulators[0]);

unconditionally calling regulator_disable() here based on the common
'enabled' flag results in a crash on platforms without regulators
associated with the opp table.

>   
>   		ret = _set_required_opps(dev, opp_table, NULL);
>   		if (!ret)
> @@ -1795,11 +1790,9 @@ void dev_pm_opp_put_regulators(struct opp_table *opp_table)
>   	/* Make sure there are no concurrent readers while updating opp_table */
>   	WARN_ON(!list_empty(&opp_table->opp_list));
>   
> -	if (opp_table->regulator_enabled) {
> +	if (opp_table->enabled) {
>   		for (i = opp_table->regulator_count - 1; i >= 0; i--)
>   			regulator_disable(opp_table->regulators[i]);
> -
> -		opp_table->regulator_enabled = false;
>   	}
>   
>   	for (i = opp_table->regulator_count - 1; i >= 0; i--)
> diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
> index bd35802acc6e..0c3de3f6db5c 100644
> --- a/drivers/opp/opp.h
> +++ b/drivers/opp/opp.h
> @@ -147,7 +147,6 @@ enum opp_table_access {
>    * @clk: Device's clock handle
>    * @regulators: Supply regulators
>    * @regulator_count: Number of power supply regulators. Its value can be -1
> - * @regulator_enabled: Set to true if regulators were previously enabled.
>    * (uninitialized), 0 (no opp-microvolt property) or > 0 (has opp-microvolt
>    * property).
>    * @paths: Interconnect path handles
> @@ -196,7 +195,6 @@ struct opp_table {
>   	struct clk *clk;
>   	struct regulator **regulators;
>   	int regulator_count;
> -	bool regulator_enabled;
>   	struct icc_path **paths;
>   	unsigned int path_count;
>   	bool enabled;
> 

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