linux-kernel - Re: [PATCH v5 6/6] soc/tegra: pmc: Use the new reset APIs to manage reset controllers

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Date:   Mon, 19 Jun 2017 14:37:38 +0200
From:   Philipp Zabel <p.zabel@...gutronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     Vivek Gautam <vivek.gautam@...eaurora.org>,
        Jon Hunter <jonathanh@...dia.com>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thierry Reding <treding@...dia.com>,
        linux-tegra@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v5 6/6] soc/tegra: pmc: Use the new reset APIs to manage
 reset controllers

On Thu, 2017-06-01 at 18:52 +0200, Philipp Zabel wrote:
> From: Vivek Gautam <vivek.gautam@...eaurora.org>
> 
> Make use of reset_control_array_*() set of APIs to manage
> an array of reset controllers available with the device.
> 
> Cc: Jon Hunter <jonathanh@...dia.com>
> Cc: Thierry Reding <treding@...dia.com>
> Cc: Philipp Zabel <p.zabel@...gutronix.de>
> Signed-off-by: Vivek Gautam <vivek.gautam@...eaurora.org>
> ---
>  drivers/soc/tegra/pmc.c | 82 ++++++++++++-------------------------------------
>  1 file changed, 20 insertions(+), 62 deletions(-)
> 
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index e233dd5dcab3d..749b218147a19 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -124,8 +124,7 @@ struct tegra_powergate {
>  	unsigned int id;
>  	struct clk **clks;
>  	unsigned int num_clks;
> -	struct reset_control **resets;
> -	unsigned int num_resets;
> +	struct reset_control *reset;

Jon, do you think this changed API is a better fit for the tegra/pmc use
case? The reset control array is now handled behind the scenes. Except
for the initial of_reset_control_array_get_exclusive() call, there is no
difference to the user between single reset controls and reset control
arrays anymore.

regards
Philipp

>  };
>  
>  struct tegra_io_pad_soc {
> @@ -348,32 +347,14 @@ static int tegra_powergate_enable_clocks(struct tegra_powergate *pg)
>  	return err;
>  }
>  
> -static int tegra_powergate_reset_assert(struct tegra_powergate *pg)
> +static inline int tegra_powergate_reset_assert(struct tegra_powergate *pg)
>  {
> -	unsigned int i;
> -	int err;
> -
> -	for (i = 0; i < pg->num_resets; i++) {
> -		err = reset_control_assert(pg->resets[i]);
> -		if (err)
> -			return err;
> -	}
> -
> -	return 0;
> +	return reset_control_assert(pg->reset);
>  }
>  
> -static int tegra_powergate_reset_deassert(struct tegra_powergate *pg)
> +static inline int tegra_powergate_reset_deassert(struct tegra_powergate *pg)
>  {
> -	unsigned int i;
> -	int err;
> -
> -	for (i = 0; i < pg->num_resets; i++) {
> -		err = reset_control_deassert(pg->resets[i]);
> -		if (err)
> -			return err;
> -	}
> -
> -	return 0;
> +	return reset_control_deassert(pg->reset);
>  }
>  
>  static int tegra_powergate_power_up(struct tegra_powergate *pg,
> @@ -566,8 +547,7 @@ int tegra_powergate_sequence_power_up(unsigned int id, struct clk *clk,
>  	pg.id = id;
>  	pg.clks = &clk;
>  	pg.num_clks = 1;
> -	pg.resets = &rst;
> -	pg.num_resets = 1;
> +	pg.reset = IS_ERR(rst) ? NULL : rst;
>  
>  	err = tegra_powergate_power_up(&pg, false);
>  	if (err)
> @@ -755,45 +735,26 @@ static int tegra_powergate_of_get_clks(struct tegra_powergate *pg,
>  static int tegra_powergate_of_get_resets(struct tegra_powergate *pg,
>  					 struct device_node *np, bool off)
>  {
> -	struct reset_control *rst;
> -	unsigned int i, count;
>  	int err;
>  
> -	count = of_count_phandle_with_args(np, "resets", "#reset-cells");
> -	if (count == 0)
> -		return -ENODEV;
> -
> -	pg->resets = kcalloc(count, sizeof(rst), GFP_KERNEL);
> -	if (!pg->resets)
> -		return -ENOMEM;
> -
> -	for (i = 0; i < count; i++) {
> -		pg->resets[i] = of_reset_control_get_by_index(np, i);
> -		if (IS_ERR(pg->resets[i])) {
> -			err = PTR_ERR(pg->resets[i]);
> -			goto error;
> -		}
> -
> -		if (off)
> -			err = reset_control_assert(pg->resets[i]);
> -		else
> -			err = reset_control_deassert(pg->resets[i]);
> -
> -		if (err) {
> -			reset_control_put(pg->resets[i]);
> -			goto error;
> -		}
> +	pg->reset = of_reset_control_array_get_exclusive(np);
> +	if (IS_ERR(pg->reset)) {
> +		pr_err("failed to get device resets\n");
> +		return PTR_ERR(pg->reset);
>  	}
>  
> -	pg->num_resets = count;
> +	if (off)
> +		err = reset_control_assert(pg->reset);
> +	else
> +		err = reset_control_deassert(pg->reset);
>  
> -	return 0;
> +	if (err)
> +		goto put_reset;
>  
> -error:
> -	while (i--)
> -		reset_control_put(pg->resets[i]);
> +	return 0;
>  
> -	kfree(pg->resets);
> +put_reset:
> +	reset_control_put(pg->reset);
>  
>  	return err;
>  }
> @@ -885,10 +846,7 @@ static void tegra_powergate_add(struct tegra_pmc *pmc, struct device_node *np)
>  	pm_genpd_remove(&pg->genpd);
>  
>  remove_resets:
> -	while (pg->num_resets--)
> -		reset_control_put(pg->resets[pg->num_resets]);
> -
> -	kfree(pg->resets);
> +	reset_control_put(pg->reset);
>  
>  remove_clks:
>  	while (pg->num_clks--)