Re: [PATCH v1 4/6] pwm: tegra: Simplify using devm_reset_control_get_exclusive_deasserted()

Philipp Zabel <[email protected]>
Newsgroups org.kernel.vger.linux-tegra,org.kernel.vger.linux-pwm
Message-ID <[email protected]>
On Di, 2026-07-14 at 14:02 +0200, Uwe Kleine-König wrote:
> This function ensures the reset is already deasserted at probe time and
> asserted at unbind. So the remove function and the error paths in the
> probe function can be simplified accordingly.
> 
> Signed-off-by: Uwe Kleine-König <[email protected]>
> ---
>  drivers/pwm/pwm-tegra.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
> index e99e1c5b18c3..d7f4baa4cd9b 100644
> --- a/drivers/pwm/pwm-tegra.c
> +++ b/drivers/pwm/pwm-tegra.c
> @@ -108,7 +108,6 @@ struct tegra_pwm_soc {
>  
>  struct tegra_pwm_chip {
>  	struct clk *clk;
> -	struct reset_control*rst;
>  
>  	unsigned long clk_rate;
>  	unsigned long min_period_ns;
> @@ -319,6 +318,7 @@ static int tegra_pwm_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct pwm_chip *chip;
>  	struct tegra_pwm_chip *pc;
> +	struct reset_control*rst;

You could use this opportunity to add a space between reset_control and
*rst.

>  	const struct tegra_pwm_soc *soc;
>  	int ret;
>  
> @@ -391,20 +391,17 @@ static int tegra_pwm_probe(struct platform_device *pdev)
>  	pc->min_period_ns =
>  	    (NSEC_PER_SEC / (pc->clk_rate / TEGRA_PWM_DEPTH)) + 1;
>  
> -	pc->rst = devm_reset_control_get_exclusive(dev, "pwm");
> -	if (IS_ERR(pc->rst)) {
> -		ret = dev_err_probe(dev, PTR_ERR(pc->rst), "Failed to get reset control\n");
> +	rst = devm_reset_control_get_exclusive_deasserted(dev, "pwm");
> +	if (IS_ERR(rst)) {
> +		ret = dev_err_probe(dev, PTR_ERR(rst), "Failed to get reset control\n");
>  		goto put_pm;
>  	}
>  
> -	reset_control_deassert(pc->rst);
> -
>  	chip->ops = &tegra_pwm_ops;
>  
>  	ret = pwmchip_add(chip);
>  	if (ret < 0) {
>  		dev_err_probe(dev, ret, "Adding pwmchip failed\n");
> -		reset_control_assert(pc->rst);

With this change, pm_runtime_put_sync_suspend() and
pm_runtime_force_suspend() are called before the reset control is
asserted again in the error case. Is this safe?

regards
Philipp
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.