Re: [PATCH V3 4/4] soc/tegra: pmc: Use the new reset APIs to manage reset controllers

[Philipp Zabel <p.zabel@pengutronix.de>]

On Tue, 2017-04-18 at 16:51 +0530, Vivek Gautam wrote:
> Make use of reset_control_array_*() set of APIs to manage
> an array of reset controllers available with the device.
> 
> Cc: Thierry Reding <treding@nvidia.com>
> Cc: Philipp Zabel <p.zabel@pengutronix.de>
> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> ---
>  drivers/soc/tegra/pmc.c | 99 ++++++++++++++++++-------------------------------
>  1 file changed, 36 insertions(+), 63 deletions(-)
> 
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index e233dd5dcab3..4d039fa3db1b 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_array *resets;
>  };
>  
>  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_array_assert(pg->resets);
>  }
>  
> -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_array_deassert(pg->resets);
>  }
>  
>  static int tegra_powergate_power_up(struct tegra_powergate *pg,
> @@ -558,6 +539,7 @@ int tegra_powergate_sequence_power_up(unsigned int id, struct clk *clk,
>  				      struct reset_control *rst)
>  {
>  	struct tegra_powergate pg;
> +	struct reset_control_array *resets;
>  	int err;
>  
>  	if (!tegra_powergate_is_available(id))
> @@ -566,12 +548,25 @@ 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;

Oh, I didn't notice that the resets array is often used for a single
reset. I think in this case instead of wrapping a reset_control_array
around the passed reset, you could store it as an additional pointer in
tegra_powergate->reset and add
	if (pg->reset)
		return reset_control_(de)assert(pg->resets);
to the tegra_powergate_reset_(de)assert functions ...

> +
> +	resets = kzalloc(sizeof(*resets) + sizeof(resets->rstc[0]) * 1,
> +			 GFP_KERNEL);
> +	if (!resets)
> +		return -ENOMEM;
> +
> +	resets->rstc[0] = rst;
> +	pg.resets = resets;
>  
>  	err = tegra_powergate_power_up(&pg, false);
> -	if (err)
> +	if (err) {
>  		pr_err("failed to turn on partition %d: %d\n", id, err);
> +		goto free_reset;
> +	}
> +
> +	return 0;
> +
> +free_reset:
> +	kfree(resets);
>  

... as having to open code this handling of struct reset_control_array
internals completely negates its convenience.

>  	return err;
>  }
> @@ -755,45 +750,26 @@ 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->resets = of_reset_control_array_get_exclusive(np);
> +	if (IS_ERR(pg->resets)) {
> +		pr_err("failed to get device resets\n");
> +		return PTR_ERR(pg->resets);
>  	}
>  
> -	pg->num_resets = count;
> +	if (off)
> +		err = reset_control_array_assert(pg->resets);
> +	else
> +		err = reset_control_array_deassert(pg->resets);
>  
> -	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_array_put(pg->resets);
>  
>  	return err;
>  }
> @@ -885,10 +861,7 @@ 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_array_put(pg->resets);
>  
>  remove_clks:
>  	while (pg->num_clks--)

regards
Philipp