[v3,PATCH 0/3] Convert the mtk_disp driver to aotmic API

[v3,PATCH 0/3] Convert the mtk_disp driver to aotmic API

[Rex-BC Chen]

Changes since v3:
 - Modify commit message for PATCH 1/3 pwm: mtk_disp: clear the clock operations

Changes since v1:
 - Seperate clock operation as single patch.
 - Seperate apply() as single patch.
 - Seperate get_state() operation as single patch.

Rex-BC Chen (3):
  pwm: mtk_disp: clear the clock operations
  pwm: mtk_disp: convert the driver to atomic API
  pwm: mtk_disp: implement .get_state()

 drivers/pwm/pwm-mtk-disp.c | 179 +++++++++++++++++++++----------------
 1 file changed, 104 insertions(+), 75 deletions(-)

-- 
2.18.0
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[v3,PATCH 1/3] pwm: mtk_disp: clear the clock operations

[Rex-BC Chen]

Remove the clk_prepare from mtk_disp_pwm_probe.
Remove the clk_unprepare from mtk_disp_pwm_remove.

After using atomic API and get_state() function which are implemented in PATCH [2/3], [3/3],
clk_prepare/clk_unprepare are useless in probe/remove function.
So we remove clk_prepare/clk_unprepare in probe/remove fuinction.

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 87c6b4bc5d43..21416a8b6b47 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -192,14 +192,6 @@ 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.base = -1;
@@ -208,7 +200,7 @@ 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);
@@ -227,24 +219,13 @@ 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 = {
-- 
2.18.0
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Re: [v3,PATCH 1/3] pwm: mtk_disp: clear the clock operations

[Uwe Kleine-König]

[-- Attachment #1.1: Type: text/plain, Size: 859 bytes --]

Hello,

On Tue, Apr 06, 2021 at 05:57:40PM +0800, Rex-BC Chen wrote:
> Remove the clk_prepare from mtk_disp_pwm_probe.
> Remove the clk_unprepare from mtk_disp_pwm_remove.
> 
> After using atomic API and get_state() function which are implemented
> in PATCH [2/3], [3/3],

Refering to the following patches as 2/3 and 3/3 doesn't make sense once
these patches are applied to a tree.

> clk_prepare/clk_unprepare are useless in probe/remove function.
> So we remove clk_prepare/clk_unprepare in probe/remove fuinction.

Does the driver still work with only this patch applied? If not, please
rearrange and order this patch after the conversion to the atomic API.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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[v3,PATCH 2/3] pwm: mtk_disp: convert the driver to atomic API

[Rex-BC Chen]

Switch the driver to atomic API apply().

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 114 +++++++++++++++++++------------------
 1 file changed, 58 insertions(+), 56 deletions(-)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 21416a8b6b47..502228adf718 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -20,6 +20,7 @@
 #define PWM_CLKDIV_SHIFT	16
 #define PWM_CLKDIV_MAX		0x3ff
 #define PWM_CLKDIV_MASK		(PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
+#define PWM_POLARITY	BIT(2)
 
 #define PWM_PERIOD_BIT_WIDTH	12
 #define PWM_PERIOD_MASK		((1 << PWM_PERIOD_BIT_WIDTH) - 1)
@@ -47,6 +48,7 @@ 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)
@@ -66,11 +68,11 @@ static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
 	writel(value, address);
 }
 
-static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			       int duty_ns, int period_ns)
+static int mtk_disp_pwm_enable(struct pwm_chip *chip,
+			       const struct pwm_state *state)
 {
 	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
-	u32 clk_div, period, high_width, value;
+	u32 clk_div, period, high_width, value, polarity;
 	u64 div, rate;
 	int err;
 
@@ -84,33 +86,47 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
 	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
 	 */
+	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;
+		}
+	}
 	rate = clk_get_rate(mdp->clk_main);
-	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
+	clk_div = div_u64(rate * state->period, 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);
+		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);
+	period = div64_u64(rate * state->period, div);
 	if (period > 0)
 		period--;
 
-	high_width = div64_u64(rate * duty_ns, div);
+	high_width = div64_u64(rate * state->duty_cycle, 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;
-	}
+	polarity = 0;
+	if (state->polarity == PWM_POLARITY_INVERSED)
+		polarity = PWM_POLARITY;
 
 	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
 				 PWM_CLKDIV_MASK,
 				 clk_div << PWM_CLKDIV_SHIFT);
+	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
+				 PWM_POLARITY, polarity);
 	mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
 				 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
 				 value);
@@ -122,50 +138,49 @@ 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);
-
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
+				 mdp->data->enable_mask);
+	mdp->enabled = true;
 	return 0;
 }
 
-static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int mtk_disp_pwm_disable(struct pwm_chip *chip,
+				const struct pwm_state *state)
 {
 	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,
+				 0x0);
+	if (mdp->enabled) {
+		clk_disable_unprepare(mdp->clk_mm);
+		clk_disable_unprepare(mdp->clk_main);
 	}
 
-	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
-				 mdp->data->enable_mask);
+	mdp->enabled = false;
 
 	return 0;
 }
 
-static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			      const struct pwm_state *state)
 {
-	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	if (!state->enabled)
+		return mtk_disp_pwm_disable(chip, state);
 
-	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
-				 0x0);
-
-	clk_disable(mdp->clk_mm);
-	clk_disable(mdp->clk_main);
+	return mtk_disp_pwm_enable(chip, state);
 }
 
 static const struct pwm_ops mtk_disp_pwm_ops = {
-	.config = mtk_disp_pwm_config,
-	.enable = mtk_disp_pwm_enable,
-	.disable = mtk_disp_pwm_disable,
+	.apply = mtk_disp_pwm_apply,
 	.owner = THIS_MODULE,
 };
 
@@ -205,19 +220,6 @@ static int mtk_disp_pwm_probe(struct platform_device *pdev)
 
 	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;
 }
 
-- 
2.18.0
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Re: [v3,PATCH 2/3] pwm: mtk_disp: convert the driver to atomic API

[Uwe Kleine-König]

[-- Attachment #1.1: Type: text/plain, Size: 2969 bytes --]

Hello,

On Tue, Apr 06, 2021 at 05:57:41PM +0800, Rex-BC Chen wrote:
> @@ -84,33 +86,47 @@ static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
>  	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
>  	 */
> +	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);

Please use %pe, as this yields better readable error messages.

Also it might be sensible to first use the fact that (without patch 1
from this series) the clocks are always on and then rework the clk usage
in a separate patch.

> +			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;
> +		}
> +	}
>  	rate = clk_get_rate(mdp->clk_main);
> -	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
> +	clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >>
>  			  PWM_PERIOD_BIT_WIDTH;

rate * state->period might overflow, it would be great if this could be
catched. (But I don't consider this a stopper for this series.)

> -	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);

rate is an u64, %d isn't the right format for it. Doesn't this result in
a compiler warning?

> +		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);
> +	period = div64_u64(rate * state->period, div);
>  	if (period > 0)
>  		period--;
>  
> -	high_width = div64_u64(rate * duty_ns, div);
> +	high_width = div64_u64(rate * state->duty_cycle, 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;
> -	}
> +	polarity = 0;
> +	if (state->polarity == PWM_POLARITY_INVERSED)
> +		polarity = PWM_POLARITY;

I'm unsure if support for polarity should be added en passant in this
patch. Maybe it would be clearer to add is separately.

>  	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
>  				 PWM_CLKDIV_MASK,
>  				 clk_div << PWM_CLKDIV_SHIFT);
> +	mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
> +				 PWM_POLARITY, polarity);
>  	mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
>  				 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
>  				 value);

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [v3,PATCH 2/3] pwm: mtk_disp: convert the driver to atomic API

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 11583 bytes --]

Hi Rex-BC,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on v5.12-rc6]
[also build test WARNING on next-20210406]
[cannot apply to pwm/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rex-BC-Chen/Convert-the-mtk_disp-driver-to-aotmic-API/20210406-180018
base:    e49d033bddf5b565044e2abe4241353959bc9120
config: powerpc64-randconfig-r023-20210406 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project a46f59a747a7273cc439efaf3b4f98d8b63d2f20)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc64 cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # https://github.com/0day-ci/linux/commit/0a2486ac437e3b8d36a0bf8ce9648c22e42ffda4
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rex-BC-Chen/Convert-the-mtk_disp-driver-to-aotmic-API/20210406-180018
        git checkout 0a2486ac437e3b8d36a0bf8ce9648c22e42ffda4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:155:1: note: expanded from here
   __do_outl
   ^
   arch/powerpc/include/asm/io.h:537:62: note: expanded from macro '__do_outl'
   #define __do_outl(val, port)    writel(val,(PCI_IO_ADDR)_IO_BASE+port);
                                              ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/pwm/pwm-mtk-disp.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:43:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insb, (unsigned long p, void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:169:1: note: expanded from here
   __do_insb
   ^
   arch/powerpc/include/asm/io.h:556:56: note: expanded from macro '__do_insb'
   #define __do_insb(p, b, n)      readsb((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/pwm/pwm-mtk-disp.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:45:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insw, (unsigned long p, void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:171:1: note: expanded from here
   __do_insw
   ^
   arch/powerpc/include/asm/io.h:557:56: note: expanded from macro '__do_insw'
   #define __do_insw(p, b, n)      readsw((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/pwm/pwm-mtk-disp.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:47:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insl, (unsigned long p, void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:173:1: note: expanded from here
   __do_insl
   ^
   arch/powerpc/include/asm/io.h:558:56: note: expanded from macro '__do_insl'
   #define __do_insl(p, b, n)      readsl((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/pwm/pwm-mtk-disp.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:49:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsb, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:175:1: note: expanded from here
   __do_outsb
   ^
   arch/powerpc/include/asm/io.h:559:58: note: expanded from macro '__do_outsb'
   #define __do_outsb(p, b, n)     writesb((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/pwm/pwm-mtk-disp.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:51:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsw, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:177:1: note: expanded from here
   __do_outsw
   ^
   arch/powerpc/include/asm/io.h:560:58: note: expanded from macro '__do_outsw'
   #define __do_outsw(p, b, n)     writesw((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/pwm/pwm-mtk-disp.c:10:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:53:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsl, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:179:1: note: expanded from here
   __do_outsl
   ^
   arch/powerpc/include/asm/io.h:561:58: note: expanded from macro '__do_outsl'
   #define __do_outsl(p, b, n)     writesl((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
>> drivers/pwm/pwm-mtk-disp.c:109:4: warning: format specifies type 'int' but the argument has type 'u64' (aka 'unsigned long long') [-Wformat]
                           rate);
                           ^~~~
   include/linux/dev_printk.h:112:32: note: expanded from macro 'dev_err'
           _dev_err(dev, dev_fmt(fmt), ##__VA_ARGS__)
                                 ~~~     ^~~~~~~~~~~
   13 warnings generated.


vim +109 drivers/pwm/pwm-mtk-disp.c

    70	
    71	static int mtk_disp_pwm_enable(struct pwm_chip *chip,
    72				       const struct pwm_state *state)
    73	{
    74		struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
    75		u32 clk_div, period, high_width, value, polarity;
    76		u64 div, rate;
    77		int err;
    78	
    79		/*
    80		 * Find period, high_width and clk_div to suit duty_ns and period_ns.
    81		 * Calculate proper div value to keep period value in the bound.
    82		 *
    83		 * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
    84		 * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
    85		 *
    86		 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
    87		 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
    88		 */
    89		if (!mdp->enabled) {
    90			err = clk_prepare_enable(mdp->clk_main);
    91			if (err < 0) {
    92				dev_err(chip->dev, "Can't enable mdp->clk_main: %d\n",
    93					err);
    94				return err;
    95			}
    96			err = clk_prepare_enable(mdp->clk_mm);
    97			if (err < 0) {
    98				dev_err(chip->dev, "Can't enable mdp->clk_mm: %d\n",
    99					err);
   100				clk_disable_unprepare(mdp->clk_main);
   101				return err;
   102			}
   103		}
   104		rate = clk_get_rate(mdp->clk_main);
   105		clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >>
   106				  PWM_PERIOD_BIT_WIDTH;
   107		if (clk_div > PWM_CLKDIV_MAX) {
   108			dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
 > 109				rate);
   110			clk_disable_unprepare(mdp->clk_mm);
   111			clk_disable_unprepare(mdp->clk_main);
   112			return -EINVAL;
   113		}
   114		div = NSEC_PER_SEC * (clk_div + 1);
   115		period = div64_u64(rate * state->period, div);
   116		if (period > 0)
   117			period--;
   118	
   119		high_width = div64_u64(rate * state->duty_cycle, div);
   120		value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
   121		polarity = 0;
   122		if (state->polarity == PWM_POLARITY_INVERSED)
   123			polarity = PWM_POLARITY;
   124	
   125		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
   126					 PWM_CLKDIV_MASK,
   127					 clk_div << PWM_CLKDIV_SHIFT);
   128		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
   129					 PWM_POLARITY, polarity);
   130		mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
   131					 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
   132					 value);
   133	
   134		if (mdp->data->has_commit) {
   135			mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
   136						 mdp->data->commit_mask,
   137						 mdp->data->commit_mask);
   138			mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
   139						 mdp->data->commit_mask,
   140						 0x0);
   141		} else {
   142			mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
   143						 mdp->data->bls_debug_mask,
   144						 mdp->data->bls_debug_mask);
   145			mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
   146						 mdp->data->con0_sel,
   147						 mdp->data->con0_sel);
   148		}
   149	
   150		mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
   151					 mdp->data->enable_mask);
   152		mdp->enabled = true;
   153		return 0;
   154	}
   155	

---
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Re: [v3,PATCH 2/3] pwm: mtk_disp: convert the driver to atomic API

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 6099 bytes --]

Hi Rex-BC,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on v5.12-rc6]
[also build test WARNING on next-20210401]
[cannot apply to pwm/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rex-BC-Chen/Convert-the-mtk_disp-driver-to-aotmic-API/20210406-180018
base:    e49d033bddf5b565044e2abe4241353959bc9120
config: xtensa-allyesconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/0a2486ac437e3b8d36a0bf8ce9648c22e42ffda4
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rex-BC-Chen/Convert-the-mtk_disp-driver-to-aotmic-API/20210406-180018
        git checkout 0a2486ac437e3b8d36a0bf8ce9648c22e42ffda4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/device.h:15,
                    from include/linux/node.h:18,
                    from include/linux/cpu.h:17,
                    from include/linux/of_device.h:5,
                    from drivers/pwm/pwm-mtk-disp.c:13:
   drivers/pwm/pwm-mtk-disp.c: In function 'mtk_disp_pwm_enable':
>> drivers/pwm/pwm-mtk-disp.c:108:22: warning: format '%d' expects argument of type 'int', but argument 3 has type 'u64' {aka 'long long unsigned int'} [-Wformat=]
     108 |   dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
         |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/dev_printk.h:19:22: note: in definition of macro 'dev_fmt'
      19 | #define dev_fmt(fmt) fmt
         |                      ^~~
   drivers/pwm/pwm-mtk-disp.c:108:3: note: in expansion of macro 'dev_err'
     108 |   dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
         |   ^~~~~~~
   drivers/pwm/pwm-mtk-disp.c:108:55: note: format string is defined here
     108 |   dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
         |                                                      ~^
         |                                                       |
         |                                                       int
         |                                                      %lld


vim +108 drivers/pwm/pwm-mtk-disp.c

    70	
    71	static int mtk_disp_pwm_enable(struct pwm_chip *chip,
    72				       const struct pwm_state *state)
    73	{
    74		struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
    75		u32 clk_div, period, high_width, value, polarity;
    76		u64 div, rate;
    77		int err;
    78	
    79		/*
    80		 * Find period, high_width and clk_div to suit duty_ns and period_ns.
    81		 * Calculate proper div value to keep period value in the bound.
    82		 *
    83		 * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
    84		 * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
    85		 *
    86		 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
    87		 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
    88		 */
    89		if (!mdp->enabled) {
    90			err = clk_prepare_enable(mdp->clk_main);
    91			if (err < 0) {
    92				dev_err(chip->dev, "Can't enable mdp->clk_main: %d\n",
    93					err);
    94				return err;
    95			}
    96			err = clk_prepare_enable(mdp->clk_mm);
    97			if (err < 0) {
    98				dev_err(chip->dev, "Can't enable mdp->clk_mm: %d\n",
    99					err);
   100				clk_disable_unprepare(mdp->clk_main);
   101				return err;
   102			}
   103		}
   104		rate = clk_get_rate(mdp->clk_main);
   105		clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >>
   106				  PWM_PERIOD_BIT_WIDTH;
   107		if (clk_div > PWM_CLKDIV_MAX) {
 > 108			dev_err(chip->dev, "clock rate is too high: rate = %d Hz\n",
   109				rate);
   110			clk_disable_unprepare(mdp->clk_mm);
   111			clk_disable_unprepare(mdp->clk_main);
   112			return -EINVAL;
   113		}
   114		div = NSEC_PER_SEC * (clk_div + 1);
   115		period = div64_u64(rate * state->period, div);
   116		if (period > 0)
   117			period--;
   118	
   119		high_width = div64_u64(rate * state->duty_cycle, div);
   120		value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
   121		polarity = 0;
   122		if (state->polarity == PWM_POLARITY_INVERSED)
   123			polarity = PWM_POLARITY;
   124	
   125		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
   126					 PWM_CLKDIV_MASK,
   127					 clk_div << PWM_CLKDIV_SHIFT);
   128		mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
   129					 PWM_POLARITY, polarity);
   130		mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
   131					 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
   132					 value);
   133	
   134		if (mdp->data->has_commit) {
   135			mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
   136						 mdp->data->commit_mask,
   137						 mdp->data->commit_mask);
   138			mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
   139						 mdp->data->commit_mask,
   140						 0x0);
   141		} else {
   142			mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
   143						 mdp->data->bls_debug_mask,
   144						 mdp->data->bls_debug_mask);
   145			mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
   146						 mdp->data->con0_sel,
   147						 mdp->data->con0_sel);
   148		}
   149	
   150		mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
   151					 mdp->data->enable_mask);
   152		mdp->enabled = true;
   153		return 0;
   154	}
   155	

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[v3,PATCH 3/3] pwm: mtk_disp: implement .get_state()

[Rex-BC Chen]

implement get_state function for pwm-mtk-disp

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/pwm/pwm-mtk-disp.c | 46 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
index 502228adf718..166e0a8ca703 100644
--- a/drivers/pwm/pwm-mtk-disp.c
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -179,8 +179,54 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return mtk_disp_pwm_enable(chip, state);
 }
 
+static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   struct pwm_state *state)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u32 clk_div, period, high_width, con0, con1;
+	u64 rate;
+	int err;
+
+	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 = 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;
+	}
+
+	rate = clk_get_rate(mdp->clk_main);
+
+	con0 = readl(mdp->base + mdp->data->con0);
+	con1 = readl(mdp->base + mdp->data->con1);
+
+	state->polarity = con0 & PWM_POLARITY ?
+			  PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
+	state->enabled = !!(con0 & BIT(0));
+
+	clk_div = (con0 & PWM_CLKDIV_MASK) >> PWM_CLKDIV_SHIFT;
+	period = con1 & PWM_PERIOD_MASK;
+	state->period = div_u64(period * (clk_div + 1) * NSEC_PER_SEC, rate);
+	high_width = (con1 & PWM_HIGH_WIDTH_MASK) >> PWM_HIGH_WIDTH_SHIFT;
+	state->duty_cycle = div_u64(high_width * (clk_div + 1) * NSEC_PER_SEC,
+				    rate);
+
+	if (!state->enabled) {
+		clk_disable_unprepare(mdp->clk_mm);
+		clk_disable_unprepare(mdp->clk_main);
+	}
+
+	mdp->enabled = state->enabled;
+}
+
 static const struct pwm_ops mtk_disp_pwm_ops = {
 	.apply = mtk_disp_pwm_apply,
+	.get_state = mtk_disp_pwm_get_state,
 	.owner = THIS_MODULE,
 };
 
-- 
2.18.0
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Re: [v3,PATCH 3/3] pwm: mtk_disp: implement .get_state()

[Uwe Kleine-König]

[-- Attachment #1.1: Type: text/plain, Size: 2851 bytes --]

On Tue, Apr 06, 2021 at 05:57:42PM +0800, Rex-BC Chen wrote:
> implement get_state function for pwm-mtk-disp
> 
> Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>

Ideally you S-o-b line is the last one to show the order in which this
patch went from one person to another.

> ---
>  drivers/pwm/pwm-mtk-disp.c | 46 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
> 
> diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> index 502228adf718..166e0a8ca703 100644
> --- a/drivers/pwm/pwm-mtk-disp.c
> +++ b/drivers/pwm/pwm-mtk-disp.c
> @@ -179,8 +179,54 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  	return mtk_disp_pwm_enable(chip, state);
>  }
>  
> +static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
> +				   struct pwm_device *pwm,
> +				   struct pwm_state *state)
> +{
> +	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
> +	u32 clk_div, period, high_width, con0, con1;
> +	u64 rate;
> +	int err;
> +
> +	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 = 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);

As before: %pe please

> +		return;
> +	}
> +
> +	rate = clk_get_rate(mdp->clk_main);
> +
> +	con0 = readl(mdp->base + mdp->data->con0);
> +	con1 = readl(mdp->base + mdp->data->con1);
> +
> +	state->polarity = con0 & PWM_POLARITY ?
> +			  PWM_POLARITY_INVERSED : PWM_POLARITY_NORMAL;
> +	state->enabled = !!(con0 & BIT(0));
> +
> +	clk_div = (con0 & PWM_CLKDIV_MASK) >> PWM_CLKDIV_SHIFT;
> +	period = con1 & PWM_PERIOD_MASK;
> +	state->period = div_u64(period * (clk_div + 1) * NSEC_PER_SEC, rate);
> +	high_width = (con1 & PWM_HIGH_WIDTH_MASK) >> PWM_HIGH_WIDTH_SHIFT;
> +	state->duty_cycle = div_u64(high_width * (clk_div + 1) * NSEC_PER_SEC,
> +				    rate);

Please round up these divisions as in .apply() we're rounding down.
Otherwise .get_state isn't the inverse of .apply().

> +
> +	if (!state->enabled) {
> +		clk_disable_unprepare(mdp->clk_mm);
> +		clk_disable_unprepare(mdp->clk_main);

That's wrong, you enabled unconditionally so you should also disable
unconditionally. If you want to prevent that clocks of a running PWM are
disabled by the unused clk initcall, this must be done in .probe() to be
sure it runs exactly once and early enough.

> +	}
> +
> +	mdp->enabled = state->enabled;
> +}
> +

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [v3,PATCH 3/3] pwm: mtk_disp: implement .get_state()

[Thierry Reding]

[-- Attachment #1.1: Type: text/plain, Size: 1987 bytes --]

On Tue, Apr 06, 2021 at 12:27:56PM +0200, Uwe Kleine-König wrote:
> On Tue, Apr 06, 2021 at 05:57:42PM +0800, Rex-BC Chen wrote:
> > implement get_state function for pwm-mtk-disp
> > 
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> 
> Ideally you S-o-b line is the last one to show the order in which this
> patch went from one person to another.
> 
> > ---
> >  drivers/pwm/pwm-mtk-disp.c | 46 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> > 
> > diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> > index 502228adf718..166e0a8ca703 100644
> > --- a/drivers/pwm/pwm-mtk-disp.c
> > +++ b/drivers/pwm/pwm-mtk-disp.c
> > @@ -179,8 +179,54 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> >  	return mtk_disp_pwm_enable(chip, state);
> >  }
> >  
> > +static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
> > +				   struct pwm_device *pwm,
> > +				   struct pwm_state *state)
> > +{
> > +	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
> > +	u32 clk_div, period, high_width, con0, con1;
> > +	u64 rate;
> > +	int err;
> > +
> > +	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 = 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);
> 
> As before: %pe please

According to the documentation %pe only works on pointers for which
IS_ERR() is true, so I'm not sure it can be used with plain integer
error codes.

Looks like there's a bunch of drivers that will do %pe and then use
ERR_PTR(err) to make this work, but to be honest, that seems like
jumping through hoops.

But I don't feel strongly either way, so choose whichever you want.

Thierry

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Re: [v3,PATCH 3/3] pwm: mtk_disp: implement .get_state()

[Uwe Kleine-König]

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On Fri, Apr 09, 2021 at 02:24:43PM +0200, Thierry Reding wrote:
> On Tue, Apr 06, 2021 at 12:27:56PM +0200, Uwe Kleine-König wrote:
> > On Tue, Apr 06, 2021 at 05:57:42PM +0800, Rex-BC Chen wrote:
> > > implement get_state function for pwm-mtk-disp
> > > 
> > > Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> > > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > 
> > Ideally you S-o-b line is the last one to show the order in which this
> > patch went from one person to another.
> > 
> > > ---
> > >  drivers/pwm/pwm-mtk-disp.c | 46 ++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 46 insertions(+)
> > > 
> > > diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> > > index 502228adf718..166e0a8ca703 100644
> > > --- a/drivers/pwm/pwm-mtk-disp.c
> > > +++ b/drivers/pwm/pwm-mtk-disp.c
> > > @@ -179,8 +179,54 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> > >  	return mtk_disp_pwm_enable(chip, state);
> > >  }
> > >  
> > > +static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
> > > +				   struct pwm_device *pwm,
> > > +				   struct pwm_state *state)
> > > +{
> > > +	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
> > > +	u32 clk_div, period, high_width, con0, con1;
> > > +	u64 rate;
> > > +	int err;
> > > +
> > > +	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 = 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);
> > 
> > As before: %pe please
> 
> According to the documentation %pe only works on pointers for which
> IS_ERR() is true, so I'm not sure it can be used with plain integer
> error codes.

It cannot.

> Looks like there's a bunch of drivers that will do %pe and then use
> ERR_PTR(err) to make this work, but to be honest, that seems like
> jumping through hoops.

When I suggested to implement %dE to print error codes this was shot
down by the printk guys who's position is that %pe has to be good enough
for everybody. And yes, you'd need to pass ERR_PTR(err) then.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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