backlight: pwm_bl: Use 64-bit division function

Started by Guru Das Srinagesh on Mar 20, 2020 · 8 messages from 4 authors · Last reply Apr 15, 2020

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Linus Torvalds

STALE2405d SUPERSEDED · 1 review, 1 by a maintainer

Status: Superseded by v16 (posted 2020-06-02). [go to v16]

Revision v11 (9 revisions archived); 1 review trailer.

Revisions (9)

2020-03-11 v8
2020-03-17 v9 [diff against previous]
2020-03-19 v10 [diff against previous]
2020-03-20 v11 current [diff against previous]
2020-04-09 v12 [diff against previous]
2020-04-22 v13 [diff against previous]
2020-04-30 v14 [diff against previous] re-posted 2020-05-04 go to this post re-posted 2020-05-13 go to this post
2020-05-26 v15 [diff against previous]
2020-06-02 v16 [diff against previous]

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Guru Das Srinagesh Mar 20, 01:41 #

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Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index efb4efc..3e5dbcf 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c

@@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 		pb->scale = data->max_brightness;
 	}
 
-	pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
+	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
+				pb->scale));
 
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = data->max_brightness;

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Lee Jones replied to Guru Das Srinagesh Mar 20, 13:30 #

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On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

quoted hunk

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index efb4efc..3e5dbcf 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c

@@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 		pb->scale = data->max_brightness;
 	}
 
-	pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
+	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
+				pb->scale));
 
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = data->max_brightness;

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Lee Jones replied to Lee Jones Mar 24, 11:06 #

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On Fri, 20 Mar 2020, Lee Jones wrote:

On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

quoted

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

Hellooooo ...

quoted

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index efb4efc..3e5dbcf 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c

@@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 		pb->scale = data->max_brightness;
 	}
 
-	pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
+	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
+				pb->scale));
 
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = data->max_brightness;

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Uwe Kleine-König replied to Lee Jones Mar 24, 12:57 #

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Hello Lee,

On Tue, Mar 24, 2020 at 11:07:10AM +0000, Lee Jones wrote:

On Fri, 20 Mar 2020, Lee Jones wrote:

quoted

On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

quoted

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

Hellooooo ...

Conceptually it can. As the last patch depends on this one (and the
others) some coordination might be beneficial. But that's up to Thierry
to decide how (and if) he want this series to be applied.

Best regards
Uwe

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

Daniel Thompson replied to Uwe Kleine-König Mar 24, 13:04 #

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On Tue, Mar 24, 2020 at 01:57:35PM +0100, Uwe Kleine-König wrote:

Hello Lee,

On Tue, Mar 24, 2020 at 11:07:10AM +0000, Lee Jones wrote:

quoted

On Fri, 20 Mar 2020, Lee Jones wrote:

quoted

On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

quoted

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

Hellooooo ...

Conceptually it can. As the last patch depends on this one (and the
others) some coordination might be beneficial. But that's up to Thierry
to decide how (and if) he want this series to be applied.

... and on the backlight side we definitely need to know about the "if"
otherwise there's no point in taking it.


Daniel.

Lee Jones replied to Daniel Thompson Mar 24, 14:23 #

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On Tue, 24 Mar 2020, Daniel Thompson wrote:

On Tue, Mar 24, 2020 at 01:57:35PM +0100, Uwe Kleine-König wrote:

quoted

Hello Lee,

On Tue, Mar 24, 2020 at 11:07:10AM +0000, Lee Jones wrote:

quoted

On Fri, 20 Mar 2020, Lee Jones wrote:

quoted

On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

quoted

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

Hellooooo ...

Conceptually it can. As the last patch depends on this one (and the
others) some coordination might be beneficial. But that's up to Thierry
to decide how (and if) he want this series to be applied.

... and on the backlight side we definitely need to know about the "if"
otherwise there's no point in taking it.

Right.

I'm happy to wait for Thierry.  Although this isn't the only set he's
currently blocking.  Is he okay?  On holiday perhaps?

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Uwe Kleine-König replied to Lee Jones Mar 24, 14:43 #

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On Tue, Mar 24, 2020 at 02:24:41PM +0000, Lee Jones wrote:

On Tue, 24 Mar 2020, Daniel Thompson wrote:

quoted

On Tue, Mar 24, 2020 at 01:57:35PM +0100, Uwe Kleine-König wrote:

quoted

Hello Lee,

On Tue, Mar 24, 2020 at 11:07:10AM +0000, Lee Jones wrote:

quoted

On Fri, 20 Mar 2020, Lee Jones wrote:

quoted

On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

quoted

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

Hellooooo ...

Conceptually it can. As the last patch depends on this one (and the
others) some coordination might be beneficial. But that's up to Thierry
to decide how (and if) he want this series to be applied.

... and on the backlight side we definitely need to know about the "if"
otherwise there's no point in taking it.

Right.

3 more quoted lines

The newest commit by him in next is from last week. My guess is he
just didn't come around yet to care for the PWM duties.

Best regards
Uwe

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

Lee Jones replied to Uwe Kleine-König Apr 15, 09:25 #

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On Tue, 24 Mar 2020, Uwe Kleine-König wrote:

On Tue, Mar 24, 2020 at 02:24:41PM +0000, Lee Jones wrote:

quoted

On Tue, 24 Mar 2020, Daniel Thompson wrote:

quoted

On Tue, Mar 24, 2020 at 01:57:35PM +0100, Uwe Kleine-König wrote:

quoted

Hello Lee,

On Tue, Mar 24, 2020 at 11:07:10AM +0000, Lee Jones wrote:

quoted

On Fri, 20 Mar 2020, Lee Jones wrote:

quoted

On Thu, 19 Mar 2020, Guru Das Srinagesh wrote:

quoted

Since the PWM framework is switching struct pwm_state.period's datatype
to u64, prepare for this transition by using div_u64 to handle a 64-bit
dividend instead of a straight division operation.

Cc: Lee Jones <redacted>
Cc: Daniel Thompson <redacted>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <redacted>
Cc: <redacted>
Cc: <redacted>
Cc: <redacted>

Signed-off-by: Guru Das Srinagesh <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Can this patch be taken on its own?

Hellooooo ...

Conceptually it can. As the last patch depends on this one (and the
others) some coordination might be beneficial. But that's up to Thierry
to decide how (and if) he want this series to be applied.

... and on the backlight side we definitely need to know about the "if"
otherwise there's no point in taking it.

7 more quoted lines

Looks like we missed the last release.

Let's hope we don't miss the next one also.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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