diff mbox series

[v4,1/3] pwm: mtk-disp: adjust the clocks to avoid them mismatch

Message ID 20210603100531.161901-2-jitao.shi@mediatek.com
State Changes Requested
Headers show
Series fix the clock on/off mismatch and switch pwm api to atomic API | expand

Commit Message

Jitao Shi June 3, 2021, 10:05 a.m. UTC 
The clk_main and clk_mm clocks are still on when system enter
suspend. That will casue the power consumption.

The clocks call the clk_prepare() in probe(), but the clk_unprepare()
is called in remove(), it isn't called when system suspend.

Remove the clcok opterations from probe() and remove.
Add the clk_prepare_enable() in config().
Add the clk_disable_unprepare() in disable().

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 81 ++++++++++++++++----------------------
 1 file changed, 33 insertions(+), 48 deletions(-)

Comments

Uwe Kleine-König June 6, 2021, 9:11 p.m. UTC | #1 
Hello,

you missed to address Lee and me for your patch series. I just happend
to stumble over this series by a fluke.

On Thu, Jun 03, 2021 at 06:05:29PM +0800, Jitao Shi wrote:
> The clk_main and clk_mm clocks are still on when system enter
> suspend. That will casue the power consumption.
> 
> The clocks call the clk_prepare() in probe(), but the clk_unprepare()
> is called in remove(), it isn't called when system suspend.

The English could be improved here. Something like:

	The clks "main" and "mm" are prepared in .probe() (and
	unprepared in .remove()). This results in the clocks being on
	during suspend which results in unnecessarily increased power
	consumption.

> Remove the clcok opterations from probe() and remove.

s/clcok/clock/, s/e\./e()/

> Add the clk_prepare_enable() in config().
> Add the clk_disable_unprepare() in disable().
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/pwm/pwm-mtk-disp.c | 81 ++++++++++++++++----------------------
>  1 file changed, 33 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> index 9b3ba401a3db..b5771e2c54b8 100644
> --- a/drivers/pwm/pwm-mtk-disp.c
> +++ b/drivers/pwm/pwm-mtk-disp.c
> @@ -47,6 +47,7 @@ struct mtk_disp_pwm {
>  	struct clk *clk_main;
>  	struct clk *clk_mm;
>  	void __iomem *base;
> +	bool enabled;
>  };
>  
>  static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
> @@ -74,6 +75,22 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	u64 div, rate;
>  	int err;
>  
> +	if (!mdp->enabled) {
> +		err = clk_prepare_enable(mdp->clk_main);
> +		if (err < 0) {
> +			dev_err(chip->dev, "Can't enable mdp->clk_main: %d\n",
> +				err);
> +			return err;

Please use %pe to get symbolic error names which are better
understandable.

> +		}
> +		err = clk_prepare_enable(mdp->clk_mm);
> +		if (err < 0) {
> +			dev_err(chip->dev, "Can't enable mdp->clk_mm: %d\n",
> +				err);
> +			clk_disable_unprepare(mdp->clk_main);
> +			return err;
> +		}
> +	}
> +
>  	/*
>  	 * Find period, high_width and clk_div to suit duty_ns and period_ns.
>  	 * Calculate proper div value to keep period value in the bound.
> @@ -87,9 +104,15 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	rate = clk_get_rate(mdp->clk_main);
>  	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
>  			  PWM_PERIOD_BIT_WIDTH;
> -	if (clk_div > PWM_CLKDIV_MAX)
> +	if (clk_div > PWM_CLKDIV_MAX) {
> +		dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
> +			rate);

Adding an error message here is orthogonal to this patch. Either drop it
or mention it in the commit log please.

> +		if (!mdp->enabled) {
> +			clk_disable_unprepare(mdp->clk_mm);
> +			clk_disable_unprepare(mdp->clk_main);
> +		}
>  		return -EINVAL;
> -
> +	}
>  	div = NSEC_PER_SEC * (clk_div + 1);
>  	period = div64_u64(rate * period_ns, div);
>  	if (period > 0)
> [...]
> @@ -135,18 +145,9 @@ static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>  	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
>  	int err;
>  
> -	err = clk_enable(mdp->clk_main);
> -	if (err < 0)
> -		return err;
> -
> -	err = clk_enable(mdp->clk_mm);
> -	if (err < 0) {
> -		clk_disable(mdp->clk_main);
> -		return err;
> -	}
> -
>  	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
>  				 mdp->data->enable_mask);
> +	mdp->enabled = true;

The modification to .enable() looks wrong. After the PWM was disabled
the clocks are off, so .enable() must reenable them, doesn't it?

>  	return 0;
>  }

Best regards
Uwe
diff mbox series

Patch

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 9b3ba401a3db..b5771e2c54b8 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -47,6 +47,7 @@  struct mtk_disp_pwm {
 	struct clk *clk_main;
 	struct clk *clk_mm;
 	void __iomem *base;
+	bool enabled;
 };
 
 static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
@@ -74,6 +75,22 @@  static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	u64 div, rate;
 	int err;
 
+	if (!mdp->enabled) {
+		err = clk_prepare_enable(mdp->clk_main);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_main: %d\n",
+				err);
+			return err;
+		}
+		err = clk_prepare_enable(mdp->clk_mm);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_mm: %d\n",
+				err);
+			clk_disable_unprepare(mdp->clk_main);
+			return err;
+		}
+	}
+
 	/*
 	 * Find period, high_width and clk_div to suit duty_ns and period_ns.
 	 * Calculate proper div value to keep period value in the bound.
@@ -87,9 +104,15 @@  static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	rate = clk_get_rate(mdp->clk_main);
 	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
 			  PWM_PERIOD_BIT_WIDTH;
-	if (clk_div > PWM_CLKDIV_MAX)
+	if (clk_div > PWM_CLKDIV_MAX) {
+		dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
+			rate);
+		if (!mdp->enabled) {
+			clk_disable_unprepare(mdp->clk_mm);
+			clk_disable_unprepare(mdp->clk_main);
+		}
 		return -EINVAL;
-
+	}
 	div = NSEC_PER_SEC * (clk_div + 1);
 	period = div64_u64(rate * period_ns, div);
 	if (period > 0)
@@ -98,16 +121,6 @@  static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	high_width = div64_u64(rate * duty_ns, div);
 	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
 
-	err = clk_enable(mdp->clk_main);
-	if (err < 0)
-		return err;
-
-	err = clk_enable(mdp->clk_mm);
-	if (err < 0) {
-		clk_disable(mdp->clk_main);
-		return err;
-	}
-
 	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
 				 PWM_CLKDIV_MASK,
 				 clk_div << PWM_CLKDIV_SHIFT);
@@ -124,9 +137,6 @@  static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 					 0x0);
 	}
 
-	clk_disable(mdp->clk_mm);
-	clk_disable(mdp->clk_main);
-
 	return 0;
 }
 
@@ -135,18 +145,9 @@  static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
 	int err;
 
-	err = clk_enable(mdp->clk_main);
-	if (err < 0)
-		return err;
-
-	err = clk_enable(mdp->clk_mm);
-	if (err < 0) {
-		clk_disable(mdp->clk_main);
-		return err;
-	}
-
 	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
 				 mdp->data->enable_mask);
+	mdp->enabled = true;
 
 	return 0;
 }
@@ -158,8 +159,11 @@  static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
 				 0x0);
 
-	clk_disable(mdp->clk_mm);
-	clk_disable(mdp->clk_main);
+	if (mdp->enabled) {
+		clk_disable_unprepare(mdp->clk_mm);
+		clk_disable_unprepare(mdp->clk_main);
+	}
+	mdp->enabled = false;
 }
 
 static const struct pwm_ops mtk_disp_pwm_ops = {
@@ -192,14 +196,6 @@  static int mtk_disp_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(mdp->clk_mm))
 		return PTR_ERR(mdp->clk_mm);
 
-	ret = clk_prepare(mdp->clk_main);
-	if (ret < 0)
-		return ret;
-
-	ret = clk_prepare(mdp->clk_mm);
-	if (ret < 0)
-		goto disable_clk_main;
-
 	mdp->chip.dev = &pdev->dev;
 	mdp->chip.ops = &mtk_disp_pwm_ops;
 	mdp->chip.npwm = 1;
@@ -207,7 +203,7 @@  static int mtk_disp_pwm_probe(struct platform_device *pdev)
 	ret = pwmchip_add(&mdp->chip);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
-		goto disable_clk_mm;
+		return ret;
 	}
 
 	platform_set_drvdata(pdev, mdp);
@@ -226,24 +222,13 @@  static int mtk_disp_pwm_probe(struct platform_device *pdev)
 	}
 
 	return 0;
-
-disable_clk_mm:
-	clk_unprepare(mdp->clk_mm);
-disable_clk_main:
-	clk_unprepare(mdp->clk_main);
-	return ret;
 }
 
 static int mtk_disp_pwm_remove(struct platform_device *pdev)
 {
 	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
-	int ret;
-
-	ret = pwmchip_remove(&mdp->chip);
-	clk_unprepare(mdp->clk_mm);
-	clk_unprepare(mdp->clk_main);
 
-	return ret;
+	return pwmchip_remove(&mdp->chip);
 }
 
 static const struct mtk_pwm_data mt2701_pwm_data = {