linux-kernel - Re: [PATCH] OPP: Fix handling of multiple power domains

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Message-ID: <20190308043712.3aca6lygz2oya3lc@vireshk-i7>
Date:   Fri, 8 Mar 2019 10:07:12 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rajendra Nayak <rnayak@...eaurora.org>, rjw@...ysocki.net
Cc:     nm@...com, sboyd@...nel.org, linux-pm@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] OPP: Fix handling of multiple power domains

On 06-03-19, 09:37, Rajendra Nayak wrote:
> We seem to rely on the number of phandles specified in the
> 'required-opps' property to identify cases where a device is
> associated with multiple power domains and hence would have
> multiple virtual devices that have to be dealt with.
> 
> In cases where we do have devices with multiple power domains
> but with only one of them being scalable, this logic seems to
> fail.
> 
> Instead read the number of power domains from DT to identify
> such cases.
> 
> Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
> ---
>  drivers/opp/of.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> index 06f0f632ec47..443c305ae100 100644
> --- a/drivers/opp/of.c
> +++ b/drivers/opp/of.c
> @@ -172,7 +172,7 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
>  	struct opp_table **required_opp_tables;
>  	struct device **genpd_virt_devs = NULL;
>  	struct device_node *required_np, *np;
> -	int count, i;
> +	int count, count_pd, i;
>  
>  	/* Traversing the first OPP node is all we need */
>  	np = of_get_next_available_child(opp_np, NULL);
> @@ -185,7 +185,19 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
>  	if (!count)
>  		goto put_np;
>  
> -	if (count > 1) {
> +	/*
> +	 * Check the number of power-domains to know if we need to deal
> +	 * with virtual devices. In some cases we have devices with multiple
> +	 * power domains but with only one of them being scalable, hence
> +	 * 'count' could be 1, but we still have to deal with multiple genpds
> +	 * and virtual devices.
> +	 */
> +	count_pd = of_count_phandle_with_args(dev->of_node, "power-domains",
> +					      "#power-domain-cells");
> +	if (!count_pd)
> +		goto put_np;
> +
> +	if (count_pd > 1) {
>  		genpd_virt_devs = kcalloc(count, sizeof(*genpd_virt_devs),
>  					GFP_KERNEL);
>  		if (!genpd_virt_devs)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

@Rafael, please pick this up for 5.1-rc2 directly. Thanks.

-- 
viresh