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

From: Philipp Zabel
Date: Wed Apr 19 2017 - 06:40:51 EST


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@xxxxxxxxxx>
> Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
> ---
> 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