[v3,2/7] pwm: sun4i: Add an optional probe for reset line
diff mbox series

Message ID 20191105131456.32400-3-peron.clem@gmail.com
State New
Headers show
Series
  • Add support for H6 PWM
Related show

Commit Message

Clément Péron Nov. 5, 2019, 1:14 p.m. UTC
From: Jernej Skrabec <jernej.skrabec@siol.net>

H6 PWM core needs deasserted reset line in order to work.

Add an optional probe for it.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
---
 drivers/pwm/pwm-sun4i.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

Comments

Philipp Zabel Nov. 5, 2019, 1:36 p.m. UTC | #1
On Tue, 2019-11-05 at 14:14 +0100, Clément Péron wrote:
> From: Jernej Skrabec <jernej.skrabec@siol.net>
> 
> H6 PWM core needs deasserted reset line in order to work.
> 
> Add an optional probe for it.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> Signed-off-by: Clément Péron <peron.clem@gmail.com>

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

> ---
>  drivers/pwm/pwm-sun4i.c | 33 +++++++++++++++++++++++++++++++--
>  1 file changed, 31 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> index 6f5840a1a82d..9ba83769a478 100644
> --- a/drivers/pwm/pwm-sun4i.c
> +++ b/drivers/pwm/pwm-sun4i.c
[...]
> @@ -365,6 +367,21 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
>  	if (IS_ERR(pwm->clk))
>  		return PTR_ERR(pwm->clk);
>  
> +	pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
> +	if (IS_ERR(pwm->rst)) {
> +		if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "get reset failed %ld\n",
> +				PTR_ERR(pwm->rst));
> +		return PTR_ERR(pwm->rst);
> +	}
> +
> +	/* Deassert reset */

Nitpick: isn't the API function name explanatory enough?

regards
Philipp
Uwe Kleine-König Nov. 5, 2019, 1:53 p.m. UTC | #2
On Tue, Nov 05, 2019 at 02:14:51PM +0100, Clément Péron wrote:
> From: Jernej Skrabec <jernej.skrabec@siol.net>
> 
> H6 PWM core needs deasserted reset line in order to work.
> 
> Add an optional probe for it.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> Signed-off-by: Clément Péron <peron.clem@gmail.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks
Uwe
Clément Péron Nov. 5, 2019, 2:01 p.m. UTC | #3
Hi Philipp,

On Tue, 5 Nov 2019 at 14:36, Philipp Zabel <p.zabel@pengutronix.de> wrote:
>
> On Tue, 2019-11-05 at 14:14 +0100, Clément Péron wrote:
> > From: Jernej Skrabec <jernej.skrabec@siol.net>
> >
> > H6 PWM core needs deasserted reset line in order to work.
> >
> > Add an optional probe for it.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > Signed-off-by: Clément Péron <peron.clem@gmail.com>
>
> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
>
> > ---
> >  drivers/pwm/pwm-sun4i.c | 33 +++++++++++++++++++++++++++++++--
> >  1 file changed, 31 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> > index 6f5840a1a82d..9ba83769a478 100644
> > --- a/drivers/pwm/pwm-sun4i.c
> > +++ b/drivers/pwm/pwm-sun4i.c
> [...]
> > @@ -365,6 +367,21 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
> >       if (IS_ERR(pwm->clk))
> >               return PTR_ERR(pwm->clk);
> >
> > +     pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
> > +     if (IS_ERR(pwm->rst)) {
> > +             if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
> > +                     dev_err(&pdev->dev, "get reset failed %ld\n",
> > +                             PTR_ERR(pwm->rst));
> > +             return PTR_ERR(pwm->rst);
> > +     }
> > +
> > +     /* Deassert reset */
>
> Nitpick: isn't the API function name explanatory enough?

Yes I can remove this comment,

Clément
>
> regards
> Philipp
>

Patch
diff mbox series

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 6f5840a1a82d..9ba83769a478 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -16,6 +16,7 @@ 
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/time.h>
@@ -78,6 +79,7 @@  struct sun4i_pwm_data {
 struct sun4i_pwm_chip {
 	struct pwm_chip chip;
 	struct clk *clk;
+	struct reset_control *rst;
 	void __iomem *base;
 	spinlock_t ctrl_lock;
 	const struct sun4i_pwm_data *data;
@@ -365,6 +367,21 @@  static int sun4i_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->clk))
 		return PTR_ERR(pwm->clk);
 
+	pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+	if (IS_ERR(pwm->rst)) {
+		if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "get reset failed %ld\n",
+				PTR_ERR(pwm->rst));
+		return PTR_ERR(pwm->rst);
+	}
+
+	/* Deassert reset */
+	ret = reset_control_deassert(pwm->rst);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot deassert reset control\n");
+		return ret;
+	}
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
@@ -377,19 +394,31 @@  static int sun4i_pwm_probe(struct platform_device *pdev)
 	ret = pwmchip_add(&pwm->chip);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
-		return ret;
+		goto err_pwm_add;
 	}
 
 	platform_set_drvdata(pdev, pwm);
 
 	return 0;
+
+err_pwm_add:
+	reset_control_assert(pwm->rst);
+
+	return ret;
 }
 
 static int sun4i_pwm_remove(struct platform_device *pdev)
 {
 	struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&pwm->chip);
+	if (ret)
+		return ret;
+
+	reset_control_assert(pwm->rst);
 
-	return pwmchip_remove(&pwm->chip);
+	return 0;
 }
 
 static struct platform_driver sun4i_pwm_driver = {