linux-kernel - Re: [PATCH 4/5] soc/tegra: pmc: Implement acquire/release for resets

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Date:   Tue, 19 Mar 2019 17:45:08 +0100
From:   Philipp Zabel <p.zabel@...gutronix.de>
To:     Thierry Reding <thierry.reding@...il.com>
Cc:     Jonathan Hunter <jonathanh@...dia.com>,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] soc/tegra: pmc: Implement acquire/release for resets

On Thu, 2019-02-21 at 16:25 +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@...dia.com>
> 
> By implementing the acquire/release protocol, the resets can be shared
> with other drivers that also adhere to this protocol. This will be used
> for example by the SOR driver to put hardware into a known good state,
> irrespective of whether or not the power domain can be reset.
> 
> Signed-off-by: Thierry Reding <treding@...dia.com>
> ---
>  drivers/soc/tegra/pmc.c | 39 +++++++++++++++++++++++++++++++++------
>  1 file changed, 33 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index 0df258518693..0c5f79528e5f 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -656,10 +656,15 @@ static int tegra_genpd_power_on(struct generic_pm_domain *domain)
>  	int err;
>  
>  	err = tegra_powergate_power_up(pg, true);
> -	if (err)
> +	if (err) {
>  		dev_err(dev, "failed to turn on PM domain %s: %d\n",
>  			pg->genpd.name, err);
> +		goto out;
> +	}
>  
> +	reset_control_release(pg->reset);
> +
> +out:
>  	return err;
>  }
>  
> @@ -669,10 +674,18 @@ static int tegra_genpd_power_off(struct generic_pm_domain *domain)
>  	struct device *dev = pg->pmc->dev;
>  	int err;
>  
> +	err = reset_control_acquire(pg->reset);
> +	if (err < 0) {
> +		pr_err("failed to acquire resets: %d\n", err);
> +		return err;
> +	}
> +
>  	err = tegra_powergate_power_down(pg);
> -	if (err)
> +	if (err) {
>  		dev_err(dev, "failed to turn off PM domain %s: %d\n",
>  			pg->genpd.name, err);
> +		reset_control_release(pg->reset);
> +	}
>  
>  	return err;
>  }
> @@ -937,20 +950,34 @@ static int tegra_powergate_of_get_resets(struct tegra_powergate *pg,
>  	struct device *dev = pg->pmc->dev;
>  	int err;
>  
> -	pg->reset = of_reset_control_array_get_exclusive(np);
> +	pg->reset = of_reset_control_array_get_exclusive_released(np);
>  	if (IS_ERR(pg->reset)) {
>  		err = PTR_ERR(pg->reset);
>  		dev_err(dev, "failed to get device resets: %d\n", err);
>  		return err;
>  	}
>  
> -	if (off)
> +	err = reset_control_acquire(pg->reset);
> +	if (err < 0) {
> +		pr_err("failed to acquire resets: %d\n", err);
> +		goto out;
> +	}
> +
> +	if (off) {
>  		err = reset_control_assert(pg->reset);
> -	else
> +	} else {
>  		err = reset_control_deassert(pg->reset);
> +		if (err < 0)
> +			goto out;
>  
> -	if (err)
> +		reset_control_release(pg->reset);
> +	}
> +
> +out:
> +	if (err) {
> +		reset_control_release(pg->reset);
>  		reset_control_put(pg->reset);
> +	}
>  
>  	return err;
>  }

Reviewed-by: Philipp Zabel <p.zabel@...gutronix.de>

regards
Philipp