pwm: atmel-hlcdc: Fix default PWM polarity

PATCH New Boris Brezillon 2 participants 8 messages May 17, 2016 – Jun 14, 2016

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Arm/Microchip (AT91) SoC support PWM

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Boris Brezillon

author

2016-05-17 09:12 UTC #0 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.

Signed-off-by Boris Brezillon <[email protected]>

Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")

---
 drivers/pwm/pwm-atmel-hlcdc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/pwm/pwm-atmel-hlcdc.c +1 -1

index f994c7e..14fc011 100644
@@ -272,7 +272,7 @@ static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
 	chip->chip.of_pwm_n_cells = 3;
 	chip->chip.can_sleep = 1;
 
-	ret = pwmchip_add(&chip->chip);
+	ret = pwmchip_add_with_polarity(&chip->chip, PWM_POLARITY_INVERSED);
 	if (ret) {
 		clk_disable_unprepare(hlcdc->periph_clk);
 		return ret;

Signature · 1 line

2.7.4

Thierry Reding

2016-05-17 11:00 UTC #1 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

Quoted 9 lines · Boris Brezillon

The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")

That's not technically correct, because it's the driver that has the bug. The core change merely exposes it. How about if I sort this into the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.

Then again, given the breakage caused by the pwm_args patch I suppose it doesn't matter much because that's part of a stable branch that I can't rebase.

Thierry
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Boris Brezillon

author

2016-05-17 11:04 UTC #2 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

Quoted 8 lines · On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding <[email protected]>…

Quoted 7 lines · Boris Brezillon
The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.

Quoted 5 lines

Quoted 2 lines
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")
That's not technically correct, because it's the driver that has the bug. The core change merely exposes it.

Agree.

Quoted 3 lines

How about if I sort this into
the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.

As you wish.

Quoted 4 lines

Then again, given the breakage caused by the pwm_args patch I suppose it doesn't matter much because that's part of a stable branch that I can't rebase.

Yep, I know :-(.

Signature · 3 lines

Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Boris Brezillon

author

2016-05-17 12:08 UTC #3 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

In reply to Thierry Reding

Hi Thierry,

Quoted 11 lines · On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding <[email protected]>…

Quoted 9 lines · Boris Brezillon
The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")

Quoted 8 lines

That's not technically correct, because it's the driver that has the bug. The core change merely exposes it. How about if I sort this into the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.
Then again, given the breakage caused by the pwm_args patch I suppose it doesn't matter much because that's part of a stable branch that I can't rebase.

If I understood correctly, you plan to rebase your pwm-atomic branch to insert this commit before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates").

Could you consider taking the following commit (or something similar if you already have a fix) as the first commit of your pwm-atomic branch?

Sorry for the mess around the introduction of pwm_args and pwm_state (that's not an excuse, but I've reworked this series so many time that I forgot to check bisectibility on the last versions :-().

---

Quoted 1 line

From ad73fa3a56c7320979425d64ab54c09b9d83d4cf Mon Sep 17 00:00:00 2001

From: Boris Brezillon <[email protected]>
Date: Tue, 17 May 2016 13:55:02 +0200
Subject: [PATCH] pwm: Fix pwm_apply_args() call sites

pwm_apply_args() is supposed to initialize a PWM device according to the arguments provided by the DT or the PWM lookup, but this function was called inside pwm_device_request(), which in turn was called before the core had a chance to initialize the pwm->args fields.

Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get() after initializing pwm->args field.

This commit also fixes an invalid pointer dereference introduced by commit e39c0df1be5a ("pwm: Introduce the pwm_args concept").

Signed-off-by Boris Brezillon <[email protected]>

Fixes e39c0df1be5a ("pwm: Introduce the pwm_args concept")

---
 drivers/pwm/core.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

drivers/pwm/core.c +17 ~~-10~~

index 680fbc7..22cf395 100644
@@ -128,13 +128,6 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
 	set_bit(PWMF_REQUESTED, &pwm->flags);
 	pwm->label = label;
 
-	/*
-	 * FIXME: This should be removed once all PWM users properly make use
-	 * of struct pwm_args to initialize the PWM device. As long as this is
-	 * here, the PWM state and hardware state can get out of sync.
-	 */
-	pwm_apply_args(pwm);
-
 	return 0;
 }

@@ -627,6 +620,13 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 
 	pwm->label = con_id;
 
+	/*
+	 * FIXME: This should be removed once all PWM users properly make use
+	 * of struct pwm_args to initialize the PWM device. As long as this is
+	 * here, the PWM state and hardware state can get out of sync.
+	 */
+	pwm_apply_args(pwm);
+
 put:
 	of_node_put(args.np);

@@ -754,13 +754,20 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 	if (!chip)
 		goto out;
 
-	pwm->args.period = chosen->period;
-	pwm->args.polarity = chosen->polarity;
-
 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
 	if (IS_ERR(pwm))
 		goto out;
 
+	pwm->args.period = chosen->period;
+	pwm->args.polarity = chosen->polarity;
+
+	/*
+	 * FIXME: This should be removed once all PWM users properly make use
+	 * of struct pwm_args to initialize the PWM device. As long as this is
+	 * here, the PWM state and hardware state can get out of sync.
+	 */
+	pwm_apply_args(pwm);
+
 out:
 	mutex_unlock(&pwm_lookup_lock);
 	return pwm;

Thierry Reding

2016-05-17 12:19 UTC #4 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

Quoted 50 lines · Boris Brezillon

Hi Thierry,
Quoted 11 lines · On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding <[email protected]>…
Quoted 9 lines · Boris Brezillon
The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")
Quoted 8 lines
That's not technically correct, because it's the driver that has the bug. The core change merely exposes it. How about if I sort this into the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.
Then again, given the breakage caused by the pwm_args patch I suppose it doesn't matter much because that's part of a stable branch that I can't rebase.
If I understood correctly, you plan to rebase your pwm-atomic branch to insert this commit before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates").
Could you consider taking the following commit (or something similar if you already have a fix) as the first commit of your pwm-atomic branch?
Sorry for the mess around the introduction of pwm_args and pwm_state (that's not an excuse, but I've reworked this series so many time that I forgot to check bisectibility on the last versions :-().
---
From ad73fa3a56c7320979425d64ab54c09b9d83d4cf Mon Sep 17 00:00:00 2001
From: Boris Brezillon <[email protected]>
Date: Tue, 17 May 2016 13:55:02 +0200
Subject: [PATCH] pwm: Fix pwm_apply_args() call sites
pwm_apply_args() is supposed to initialize a PWM device according to the arguments provided by the DT or the PWM lookup, but this function was called inside pwm_device_request(), which in turn was called before the core had a chance to initialize the pwm->args fields.
Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get() after initializing pwm->args field.

Quoted 8 lines

This commit also fixes an invalid pointer dereference introduced by commit e39c0df1be5a ("pwm: Introduce the pwm_args concept").
Signed-off-by Boris Brezillon <[email protected]>
Fixes e39c0df1be5a ("pwm: Introduce the pwm_args concept")
---
 drivers/pwm/core.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

This looks good to me. However I can't easily apply this because git gets confused by the existing headers. Also manually copying out the patch yields patch corruption that I don't exactly know how to fix.

I think you can inline patches by using a scissor mark (--- >8 ---) instead of the signature separator (---). Or you can attach the patch with "Content-Disposition: inline".

Rather than putting this into the pwm-atomic branch, I'll probably stick it into the pwm-args branch on top of the existing patch. Technically only the existing patch needs to be stable, so the branch can still evolve.

Boris Brezillon

author

2016-05-17 12:27 UTC #5 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

Quoted 60 lines · On Tue, 17 May 2016 14:19:17 +0200 Thierry Reding <[email protected]>…

Quoted 50 lines · Boris Brezillon
Hi Thierry,
Quoted 11 lines · On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding <[email protected]>…
Quoted 9 lines · Boris Brezillon
The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")
Quoted 8 lines
That's not technically correct, because it's the driver that has the bug. The core change merely exposes it. How about if I sort this into the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.
Then again, given the breakage caused by the pwm_args patch I suppose it doesn't matter much because that's part of a stable branch that I can't rebase.
If I understood correctly, you plan to rebase your pwm-atomic branch to insert this commit before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates").
Could you consider taking the following commit (or something similar if you already have a fix) as the first commit of your pwm-atomic branch?
Sorry for the mess around the introduction of pwm_args and pwm_state (that's not an excuse, but I've reworked this series so many time that I forgot to check bisectibility on the last versions :-().
---
From ad73fa3a56c7320979425d64ab54c09b9d83d4cf Mon Sep 17 00:00:00 2001
From: Boris Brezillon <[email protected]>
Date: Tue, 17 May 2016 13:55:02 +0200
Subject: [PATCH] pwm: Fix pwm_apply_args() call sites
pwm_apply_args() is supposed to initialize a PWM device according to the arguments provided by the DT or the PWM lookup, but this function was called inside pwm_device_request(), which in turn was called before the core had a chance to initialize the pwm->args fields.
Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get() after initializing pwm->args field.
Quoted 8 lines
This commit also fixes an invalid pointer dereference introduced by commit e39c0df1be5a ("pwm: Introduce the pwm_args concept").
Signed-off-by Boris Brezillon <[email protected]>
Fixes e39c0df1be5a ("pwm: Introduce the pwm_args concept")
---
 drivers/pwm/core.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)  

Quoted 7 lines

This looks good to me. However I can't easily apply this because git gets confused by the existing headers. Also manually copying out the patch yields patch corruption that I don't exactly know how to fix.
I think you can inline patches by using a scissor mark (--- >8 ---) instead of the signature separator (---). Or you can attach the patch with "Content-Disposition: inline".

Ok, it's my PEBKAC day. Here it is with the scissor mark. As mentioned on IRC, you'll also have to squash those changes [1] into 93c0d9b ("pwm: Keep PWM state in sync with hardware state").

Quoted 5 lines

Rather than putting this into the pwm-atomic branch, I'll probably stick it into the pwm-args branch on top of the existing patch. Technically only the existing patch needs to be stable, so the branch can still evolve.

Ok, great!

Thanks,

Boris

[1]http://code.bulix.org/egoo4y-98645

--->8---

Quoted 1 line

From ad73fa3a56c7320979425d64ab54c09b9d83d4cf Mon Sep 17 00:00:00 2001

From: Boris Brezillon <[email protected]>
Date: Tue, 17 May 2016 13:55:02 +0200
Subject: [PATCH] pwm: Fix pwm_apply_args() call sites

Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get() after initializing pwm->args field.

This commit also fixes an invalid pointer dereference introduced by commit e39c0df1be5a ("pwm: Introduce the pwm_args concept").

Signed-off-by Boris Brezillon <[email protected]>

Fixes e39c0df1be5a ("pwm: Introduce the pwm_args concept")

---
 drivers/pwm/core.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

drivers/pwm/core.c +17 ~~-10~~

index 680fbc7..22cf395 100644
@@ -128,13 +128,6 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
 	set_bit(PWMF_REQUESTED, &pwm->flags);
 	pwm->label = label;
 
-	/*
-	 * FIXME: This should be removed once all PWM users properly make use
-	 * of struct pwm_args to initialize the PWM device. As long as this is
-	 * here, the PWM state and hardware state can get out of sync.
-	 */
-	pwm_apply_args(pwm);
-
 	return 0;
 }

@@ -627,6 +620,13 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 
 	pwm->label = con_id;
 
+	/*
+	 * FIXME: This should be removed once all PWM users properly make use
+	 * of struct pwm_args to initialize the PWM device. As long as this is
+	 * here, the PWM state and hardware state can get out of sync.
+	 */
+	pwm_apply_args(pwm);
+
 put:
 	of_node_put(args.np);

@@ -754,13 +754,20 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 	if (!chip)
 		goto out;
 
-	pwm->args.period = chosen->period;
-	pwm->args.polarity = chosen->polarity;
-
 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
 	if (IS_ERR(pwm))
 		goto out;
 
+	pwm->args.period = chosen->period;
+	pwm->args.polarity = chosen->polarity;
+
+	/*
+	 * FIXME: This should be removed once all PWM users properly make use
+	 * of struct pwm_args to initialize the PWM device. As long as this is
+	 * here, the PWM state and hardware state can get out of sync.
+	 */
+	pwm_apply_args(pwm);
+
 out:
 	mutex_unlock(&pwm_lookup_lock);
 	return pwm;

Boris Brezillon

author

2016-06-14 07:58 UTC #6 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

In reply to Thierry Reding

Hi Thierry,

Quoted 8 lines · On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding <[email protected]>…

Quoted 7 lines · Boris Brezillon
The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.

Quoted 7 lines

Quoted 2 lines
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")
That's not technically correct, because it's the driver that has the bug. The core change merely exposes it. How about if I sort this into the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.

I don't see this change in your branch. Do you want me to resend this fix after reworking the commit message?

Regards,

Boris

Signature · 3 lines

Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Thierry Reding

2016-06-14 08:55 UTC #7 lore raw

PATCH 1/1 pwm: atmel-hlcdc: Fix default PWM polarity

Quoted 16 lines · Boris Brezillon

Hi Thierry,
Quoted 11 lines · On Tue, 17 May 2016 13:00:05 +0200 Thierry Reding <[email protected]>…
Quoted 9 lines · Boris Brezillon
The PWM device exposed by the HLCDC IP is configured with an inverted polarity by default. Registering the PWM chip with the normal polarity was not a problem before commit 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates") because the ->set_polarity() hook was called no matter the current polarity state, but this is no longer the case.
Signed-off-by Boris Brezillon <[email protected]>
Fixes 42e8992c58d4 ("pwm: Add core infrastructure to allow atomic updates")

Quoted 7 lines

Quoted 4 lines
That's not technically correct, because it's the driver that has the bug. The core change merely exposes it. How about if I sort this into the pwm-atomic branch and reword the commit message accordingly? That way things should all stay bisectible.
I don't see this change in your branch. Do you want me to resend this fix after reworking the commit message?

I must have forgotten about it. I've applied it to my fixes branch now, for which I plan on sending a pull request tomorrow.