[v3,3/7] pwm: sun4i: Add an optional probe for bus clock
diff mbox series

Message ID 20191105131456.32400-4-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 bus clock to be enabled in order to work.

Add an optional probe for it and a fallback for previous
bindings without name on module clock.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
---
 drivers/pwm/pwm-sun4i.c | 45 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

Comments

Uwe Kleine-König Nov. 5, 2019, 1:57 p.m. UTC | #1
On Tue, Nov 05, 2019 at 02:14:52PM +0100, Clément Péron wrote:
> From: Jernej Skrabec <jernej.skrabec@siol.net>
> 
> H6 PWM core needs bus clock to be enabled in order to work.
> 
> Add an optional probe for it and a fallback for previous
> bindings without name on module clock.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> Signed-off-by: Clément Péron <peron.clem@gmail.com>
> ---
>  drivers/pwm/pwm-sun4i.c | 45 +++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 43 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> index 9ba83769a478..54e19fa56a4e 100644
> --- a/drivers/pwm/pwm-sun4i.c
> +++ b/drivers/pwm/pwm-sun4i.c
> @@ -78,6 +78,7 @@ struct sun4i_pwm_data {
>  
>  struct sun4i_pwm_chip {
>  	struct pwm_chip chip;
> +	struct clk *bus_clk;
>  	struct clk *clk;
>  	struct reset_control *rst;
>  	void __iomem *base;
> @@ -363,9 +364,35 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
>  	if (IS_ERR(pwm->base))
>  		return PTR_ERR(pwm->base);
>  
> -	pwm->clk = devm_clk_get(&pdev->dev, NULL);
> -	if (IS_ERR(pwm->clk))
> +	/* Get all clocks and reset line */
> +	pwm->clk = devm_clk_get_optional(&pdev->dev, "mod");
> +	if (IS_ERR(pwm->clk)) {
> +		dev_err(&pdev->dev, "get clock failed %ld\n",
> +			PTR_ERR(pwm->clk));

Please only print this message if PTR_ERR(pwm->clk) != -EPROBE_DEFER.
You might also want to make use of commit 57f5677e535b ("printf: add
support for printing symbolic error names") and use

	dev_err(&pdev->dev, "get clock failed: %pe\n", pwm->clk);

Other than that the patch is fine for me.

Best regards
Uwe
Clément Péron Nov. 5, 2019, 2:06 p.m. UTC | #2
Hi Uwe,

On Tue, 5 Nov 2019 at 14:57, Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
>
> On Tue, Nov 05, 2019 at 02:14:52PM +0100, Clément Péron wrote:
> > From: Jernej Skrabec <jernej.skrabec@siol.net>
> >
> > H6 PWM core needs bus clock to be enabled in order to work.
> >
> > Add an optional probe for it and a fallback for previous
> > bindings without name on module clock.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > Signed-off-by: Clément Péron <peron.clem@gmail.com>
> > ---
> >  drivers/pwm/pwm-sun4i.c | 45 +++++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 43 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
> > index 9ba83769a478..54e19fa56a4e 100644
> > --- a/drivers/pwm/pwm-sun4i.c
> > +++ b/drivers/pwm/pwm-sun4i.c
> > @@ -78,6 +78,7 @@ struct sun4i_pwm_data {
> >
> >  struct sun4i_pwm_chip {
> >       struct pwm_chip chip;
> > +     struct clk *bus_clk;
> >       struct clk *clk;
> >       struct reset_control *rst;
> >       void __iomem *base;
> > @@ -363,9 +364,35 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
> >       if (IS_ERR(pwm->base))
> >               return PTR_ERR(pwm->base);
> >
> > -     pwm->clk = devm_clk_get(&pdev->dev, NULL);
> > -     if (IS_ERR(pwm->clk))
> > +     /* Get all clocks and reset line */
> > +     pwm->clk = devm_clk_get_optional(&pdev->dev, "mod");
> > +     if (IS_ERR(pwm->clk)) {
> > +             dev_err(&pdev->dev, "get clock failed %ld\n",
> > +                     PTR_ERR(pwm->clk));
>
> Please only print this message if PTR_ERR(pwm->clk) != -EPROBE_DEFER.

I didn't do it because the sunxi clock can't be compiled as module but
indeed i can change it so it's more generic.

> You might also want to make use of commit 57f5677e535b ("printf: add
> support for printing symbolic error names") and use
>
>         dev_err(&pdev->dev, "get clock failed: %pe\n", pwm->clk);

Thanks I will change it,

Regards,
Clément

>
> Other than that the patch is fine for me.
>
> Best regards
> Uwe
>
> --
> Pengutronix e.K.                           | Uwe Kleine-König            |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Patch
diff mbox series

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 9ba83769a478..54e19fa56a4e 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -78,6 +78,7 @@  struct sun4i_pwm_data {
 
 struct sun4i_pwm_chip {
 	struct pwm_chip chip;
+	struct clk *bus_clk;
 	struct clk *clk;
 	struct reset_control *rst;
 	void __iomem *base;
@@ -363,9 +364,35 @@  static int sun4i_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->base))
 		return PTR_ERR(pwm->base);
 
-	pwm->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(pwm->clk))
+	/* Get all clocks and reset line */
+	pwm->clk = devm_clk_get_optional(&pdev->dev, "mod");
+	if (IS_ERR(pwm->clk)) {
+		dev_err(&pdev->dev, "get clock failed %ld\n",
+			PTR_ERR(pwm->clk));
 		return PTR_ERR(pwm->clk);
+	}
+
+	/*
+	 * Fallback for old dtbs with a single clock and no name.
+	 * If a parent has a clock-name called "mod" whereas the
+	 * current node is unnamed the clock reference will be
+	 * incorrectly obtained and will not go into this fallback.
+	 */
+	if (!pwm->clk) {
+		pwm->clk = devm_clk_get(&pdev->dev, NULL);
+		if (IS_ERR(pwm->clk)) {
+			dev_err(&pdev->dev, "get clock failed %ld\n",
+				PTR_ERR(pwm->clk));
+			return PTR_ERR(pwm->clk);
+		}
+	}
+
+	pwm->bus_clk = devm_clk_get_optional(&pdev->dev, "bus");
+	if (IS_ERR(pwm->bus_clk)) {
+		dev_err(&pdev->dev, "get bus_clock failed %ld\n",
+			PTR_ERR(pwm->bus_clk));
+		return PTR_ERR(pwm->bus_clk);
+	}
 
 	pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
 	if (IS_ERR(pwm->rst)) {
@@ -382,6 +409,17 @@  static int sun4i_pwm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/*
+	 * We're keeping the bus clock on for the sake of simplicity.
+	 * Actually it only needs to be on for hardware register
+	 * accesses.
+	 */
+	ret = clk_prepare_enable(pwm->bus_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot prepare and enable bus_clk\n");
+		goto err_bus;
+	}
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
@@ -402,6 +440,8 @@  static int sun4i_pwm_probe(struct platform_device *pdev)
 	return 0;
 
 err_pwm_add:
+	clk_disable_unprepare(pwm->bus_clk);
+err_bus:
 	reset_control_assert(pwm->rst);
 
 	return ret;
@@ -416,6 +456,7 @@  static int sun4i_pwm_remove(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	clk_disable_unprepare(pwm->bus_clk);
 	reset_control_assert(pwm->rst);
 
 	return 0;