diff mbox series

[v5,1/3] pwm: mtk-disp: adjust the clocks to avoid them mismatch

Message ID 20210616085224.157318-2-jitao.shi@mediatek.com (mailing list archive)
State New, archived
Headers show
Series fix the clks on/off mismatch issue and switch pwm-mtk-disp to atomic APIs | expand

Commit Message

Jitao Shi June 16, 2021, 8:52 a.m. UTC 
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 clock operations from .probe() and .remove().
Add the clk_prepare_enable() in .config().
Add the clk_disable_unprepare() in .disable().
Remove the MT2701 double buffer comment.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 116 ++++++++++++++++++-------------------
 1 file changed, 57 insertions(+), 59 deletions(-)

Comments

Uwe Kleine-König June 25, 2021, 5:47 p.m. UTC | #1 
On Wed, Jun 16, 2021 at 04:52:22PM +0800, Jitao Shi wrote:
> 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 clock operations from .probe() and .remove().
> Add the clk_prepare_enable() in .config().
> Add the clk_disable_unprepare() in .disable().
> Remove the MT2701 double buffer comment.
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/pwm/pwm-mtk-disp.c | 116 ++++++++++++++++++-------------------
>  1 file changed, 57 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> index 9b3ba401a3db..204d76beeb26 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: %pe\n",
> +				ERR_PTR(err));
> +			return err;
> +		}
> +		err = clk_prepare_enable(mdp->clk_mm);
> +		if (err < 0) {
> +			dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
> +				ERR_PTR(err));
> +			clk_disable_unprepare(mdp->clk_main);
> +			return err;
> +		}
> +	}
> +

The logic becomes a tad simpler if you prepare_enable unconditionally on
entry and disable_unprepare on exit. Given that in the mdp->enabled ==
true the clocks are already on they are a noop in this case and the
matching disable just decreases the usage count.

>  	/*
>  	 * 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 +104,13 @@ 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) {
> +		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 +119,6 @@ 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);
> @@ -122,10 +133,19 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  		mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
>  					 mdp->data->commit_mask,
>  					 0x0);
> +	} else {
> +		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
> +					 mdp->data->bls_debug_mask,
> +					 mdp->data->bls_debug_mask);
> +		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> +					 mdp->data->con0_sel,
> +					 mdp->data->con0_sel);

This is unrelated for this patch, isn't it?

>  	}
>  
> -	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);
> +	}
>  
>  	return 0;
>  }
> @@ -135,18 +155,25 @@ 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;
> +	if (!mdp->enabled) {
> +		err = clk_prepare_enable(mdp->clk_main);
> +		if (err < 0) {
> +			dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n",
> +				ERR_PTR(err));
> +			return err;
> +		}
> +		err = clk_prepare_enable(mdp->clk_mm);
> +		if (err < 0) {
> +			dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
> +				ERR_PTR(err));
> +			clk_disable_unprepare(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 +185,11 @@ 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 = {
> @@ -192,58 +222,26 @@ 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;
>  
>  	ret = pwmchip_add(&mdp->chip);
>  	if (ret < 0) {
> -		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
> -		goto disable_clk_mm;
> +		dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
> +		return ret;
>  	}
>  
>  	platform_set_drvdata(pdev, mdp);
>  
> -	/*
> -	 * For MT2701, disable double buffer before writing register
> -	 * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
> -	 */
> -	if (!mdp->data->has_commit) {
> -		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
> -					 mdp->data->bls_debug_mask,
> -					 mdp->data->bls_debug_mask);
> -		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> -					 mdp->data->con0_sel,
> -					 mdp->data->con0_sel);
> -	}
> -

Similar than above this is unrelated at least to what you described in
the commit log. Maybe this part is better split into a separate patch?


>  	return 0;
> -
> -disable_clk_mm:
> -	clk_unprepare(mdp->clk_mm);
> -disable_clk_main:
> -	clk_unprepare(mdp->clk_main);
> -	return ret;
>  }

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..204d76beeb26 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: %pe\n",
+				ERR_PTR(err));
+			return err;
+		}
+		err = clk_prepare_enable(mdp->clk_mm);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
+				ERR_PTR(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 +104,13 @@  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) {
+		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 +119,6 @@  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);
@@ -122,10 +133,19 @@  static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
 					 mdp->data->commit_mask,
 					 0x0);
+	} else {
+		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
+					 mdp->data->bls_debug_mask,
+					 mdp->data->bls_debug_mask);
+		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
+					 mdp->data->con0_sel,
+					 mdp->data->con0_sel);
 	}
 
-	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);
+	}
 
 	return 0;
 }
@@ -135,18 +155,25 @@  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;
+	if (!mdp->enabled) {
+		err = clk_prepare_enable(mdp->clk_main);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n",
+				ERR_PTR(err));
+			return err;
+		}
+		err = clk_prepare_enable(mdp->clk_mm);
+		if (err < 0) {
+			dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
+				ERR_PTR(err));
+			clk_disable_unprepare(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 +185,11 @@  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 = {
@@ -192,58 +222,26 @@  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;
 
 	ret = pwmchip_add(&mdp->chip);
 	if (ret < 0) {
-		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
-		goto disable_clk_mm;
+		dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
+		return ret;
 	}
 
 	platform_set_drvdata(pdev, mdp);
 
-	/*
-	 * For MT2701, disable double buffer before writing register
-	 * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
-	 */
-	if (!mdp->data->has_commit) {
-		mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
-					 mdp->data->bls_debug_mask,
-					 mdp->data->bls_debug_mask);
-		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
-					 mdp->data->con0_sel,
-					 mdp->data->con0_sel);
-	}
-
 	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 = {