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Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards

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[view original message]
From: Constantin Baranov
Subject: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Tuesday, August 19, 2008 - 10:23 am

From: Constantin Baranov <const@tltsu.ru>

Driver for LEDs on PCEngines ALIX.2 and ALIX.3 system boards.

Signed-off-by: Constantin Baranov <const@tltsu.ru>
---
 drivers/leds/Kconfig     |    6 +
 drivers/leds/Makefile    |    1 
 drivers/leds/leds-alix.c |  146 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 153 insertions(+)

diff -uprN linux-2.6.27-rc3/drivers/leds/Kconfig linux-2.6.27-rc3-alix/drivers/leds/Kconfig
--- linux-2.6.27-rc3/drivers/leds/Kconfig	2008-08-19 20:14:06.355647765 +0500
+++ linux-2.6.27-rc3-alix/drivers/leds/Kconfig	2008-08-19 20:20:08.023147125 +0500
@@ -77,6 +77,12 @@ config LEDS_WRAP
 	help
 	  This option enables support for the PCEngines WRAP programmable LEDs.
 
+config LEDS_ALIX
+	tristate "LED support for ALIX series"
+	depends on LEDS_CLASS && X86
+	help
+	  This option enables support for the PCEngines ALIX.2 and ALIX.3 LEDs.
+
 config LEDS_H1940
 	tristate "LED Support for iPAQ H1940 device"
 	depends on LEDS_CLASS && ARCH_H1940
diff -uprN linux-2.6.27-rc3/drivers/leds/leds-alix.c linux-2.6.27-rc3-alix/drivers/leds/leds-alix.c
--- linux-2.6.27-rc3/drivers/leds/leds-alix.c	1970-01-01 04:00:00.000000000 +0400
+++ linux-2.6.27-rc3-alix/drivers/leds/leds-alix.c	2008-08-19 21:59:05.207153570 +0500
@@ -0,0 +1,146 @@
+/*
+ * LEDs driver for PCEngines ALIX.2 and ALIX.3
+ *
+ * Copyright (C) 2008 Constantin Baranov <const@tltsu.ru>
+ */
+
+#include <asm/io.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/platform_device.h>
+
+struct alix_led {
+	struct led_classdev cdev;
+	unsigned short port;
+	unsigned int on_value;
+	unsigned int off_value;
+};
+
+static void alix_led_set(struct led_classdev *led_cdev,
+			 enum led_brightness brightness)
+{
+	struct alix_led *led_dev =
+		container_of(led_cdev, struct alix_led, cdev);
+	if (brightness)
+		outl(led_dev->on_value, led_dev->port);
+	else
+		outl(led_dev->off_value, led_dev->port);
+}
+
+static struct ...
[ message continues ]
[view original message]
From: Andrew Morton
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Friday, August 22, 2008 - 11:51 am

On Tue, 19 Aug 2008 22:23:41 +0500


this is off-by-one, surely.




How's this look?

From: Andrew Morton <akpm@linux-foundation.org>

- cleanups

- fix off-by-one on error path

Cc: Constantin Baranov <const@tltsu.ru>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/leds/leds-alix.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff -puN drivers/leds/leds-alix.c~led-driver-for-leds-on-pcengines-alix2-and-alix3-boards-fix drivers/leds/leds-alix.c
--- a/drivers/leds/leds-alix.c~led-driver-for-leds-on-pcengines-alix2-and-alix3-boards-fix
+++ a/drivers/leds/leds-alix.c
@@ -4,7 +4,7 @@
  * Copyright (C) 2008 Constantin Baranov <const@tltsu.ru>
  */
 
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/leds.h>
@@ -22,6 +22,7 @@ static void alix_led_set(struct led_clas
 {
 	struct alix_led *led_dev =
 		container_of(led_cdev, struct alix_led, cdev);
+
 	if (brightness)
 		outl(led_dev->on_value, led_dev->port);
 	else
@@ -63,6 +64,7 @@ static struct alix_led alix_leds[] = {
 static int alix_led_suspend(struct platform_device *dev, pm_message_t state)
 {
 	int i;
+
 	for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
 		led_classdev_suspend(&alix_leds[i].cdev);
 	return 0;
@@ -71,6 +73,7 @@ static int alix_led_suspend(struct platf
 static int alix_led_resume(struct platform_device *dev)
 {
 	int i;
+
 	for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
 		led_classdev_resume(&alix_leds[i].cdev);
 	return 0;
@@ -92,7 +95,7 @@ static int __init alix_led_probe(struct 
 		ret = led_classdev_register(&pdev->dev, &alix_leds[i].cdev);
 
 	if (ret < 0) {
-		for (i = i - 2; i >= 0; i--)
+		while (--i >= 0)
 			led_classdev_unregister(&alix_leds[i].cdev);
 	}
 
@@ -102,6 +105,7 @@ static int __init alix_led_probe(struct 
 static int alix_led_remove(struct platform_device *pdev)
 {
 	int i;
+
 	for (i = 0; i < ...
[ message continues ]
[view original message]
From: Willy Tarreau
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Friday, August 22, 2008 - 12:44 pm

Hi Andrew,


No we will not because i is signed. We'll simply not enter the loop.
However, the code looks suspicious and the reasoning behind i-2 isn't
quite clear.

Willy

--


[ message continues ]
[view original message]
From: Constantin Baranov
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Friday, August 22, 2008 - 2:08 pm

At the first iteration this while-loop will attempt to unregister
device that has failed and thus is not registered.
My for-loop starts from device immediately before failed one.

I have fixed header and whitespaces.

From: Constantin Baranov <const@tltsu.ru>

Driver for LEDs on PCEngines ALIX.2 and ALIX.3 system boards.

Signed-off-by: Constantin Baranov <const@tltsu.ru>
---
 drivers/leds/Kconfig     |    6 +
 drivers/leds/Makefile    |    1 
 drivers/leds/leds-alix.c |  151 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 158 insertions(+)

diff -uprN linux-2.6.27-rc3/drivers/leds/Kconfig linux-2.6.27-rc3-alix/drivers/leds/Kconfig
--- linux-2.6.27-rc3/drivers/leds/Kconfig	2008-08-19 20:14:06.355647765 +0500
+++ linux-2.6.27-rc3-alix/drivers/leds/Kconfig	2008-08-19 20:20:08.023147125 +0500
@@ -77,6 +77,12 @@ config LEDS_WRAP
 	help
 	  This option enables support for the PCEngines WRAP programmable LEDs.
 
+config LEDS_ALIX
+	tristate "LED support for ALIX series"
+	depends on LEDS_CLASS && X86
+	help
+	  This option enables support for the PCEngines ALIX.2 and ALIX.3 LEDs.
+
 config LEDS_H1940
 	tristate "LED Support for iPAQ H1940 device"
 	depends on LEDS_CLASS && ARCH_H1940
diff -uprN linux-2.6.27-rc3/drivers/leds/leds-alix.c linux-2.6.27-rc3-alix/drivers/leds/leds-alix.c
--- linux-2.6.27-rc3/drivers/leds/leds-alix.c	1970-01-01 04:00:00.000000000 +0400
+++ linux-2.6.27-rc3-alix/drivers/leds/leds-alix.c	2008-08-19 21:59:05.207153570 +0500
@@ -0,0 +1,151 @@
+/*
+ * LEDs driver for PCEngines ALIX.2 and ALIX.3
+ *
+ * Copyright (C) 2008 Constantin Baranov <const@tltsu.ru>
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/platform_device.h>
+
+struct alix_led {
+	struct led_classdev cdev;
+	unsigned short port;
+	unsigned int on_value;
+	unsigned int off_value;
+};
+
+static void alix_led_set(struct led_classdev *led_cdev,
+			 enum led_brightness ...
[ message continues ]
[view original message]
From: Andrew Morton
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Friday, August 22, 2008 - 2:31 pm

On Sat, 23 Aug 2008 02:08:15 +0500

ug, OK, the complex expression in that for-loop is to blame.

For maintinability we should aim for code which is as simple and as
straightfroward as possible and which adheres to oft-used and
well-understood kernel idioms.

For example, this?

static int __init alix_led_probe(struct platform_device *pdev)
{
	int i;
	int ret;

	for (i = 0; i < ARRAY_SIZE(alix_leds); i++) {
		ret = led_classdev_register(&pdev->dev, &alix_leds[i].cdev);
		if (ret < 0)
			goto fail;
	}
	return 0;

fail:
	while (--i >= 0)
		led_classdev_unregister(&alix_leds[i].cdev);
	return ret;
}


That's what you get for copying stuff :(
--


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[view original message]
From: Constantin Baranov
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Saturday, August 23, 2008 - 10:11 am

Well, this variant looks better and correct and still works.
Should I post again patch or fix-patch?
--


[ message continues ]
[view original message]
From: Andrew Morton
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Saturday, August 23, 2008 - 10:36 pm

I already queued that as an incremental:

--- a/drivers/leds/leds-alix.c~led-driver-for-leds-on-pcengines-alix2-and-alix3-boards-fix
+++ a/drivers/leds/leds-alix.c
@@ -4,7 +4,7 @@
  * Copyright (C) 2008 Constantin Baranov <const@tltsu.ru>
  */
 
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/leds.h>
@@ -22,6 +22,7 @@ static void alix_led_set(struct led_clas
 {
 	struct alix_led *led_dev =
 		container_of(led_cdev, struct alix_led, cdev);
+
 	if (brightness)
 		outl(led_dev->on_value, led_dev->port);
 	else
@@ -63,6 +64,7 @@ static struct alix_led alix_leds[] = {
 static int alix_led_suspend(struct platform_device *dev, pm_message_t state)
 {
 	int i;
+
 	for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
 		led_classdev_suspend(&alix_leds[i].cdev);
 	return 0;
@@ -71,6 +73,7 @@ static int alix_led_suspend(struct platf
 static int alix_led_resume(struct platform_device *dev)
 {
 	int i;
+
 	for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
 		led_classdev_resume(&alix_leds[i].cdev);
 	return 0;
@@ -86,22 +89,25 @@ static int alix_led_resume(struct platfo
 static int __init alix_led_probe(struct platform_device *pdev)
 {
 	int i;
-	int ret = 0;
+	int ret;
 
-	for (i = 0; i < ARRAY_SIZE(alix_leds) && ret >= 0; i++)
+	for (i = 0; i < ARRAY_SIZE(alix_leds); i++) {
 		ret = led_classdev_register(&pdev->dev, &alix_leds[i].cdev);
-
-	if (ret < 0) {
-		for (i = i - 2; i >= 0; i--)
-			led_classdev_unregister(&alix_leds[i].cdev);
+		if (ret < 0)
+			goto fail;
 	}
+	return 0;
 
+fail:
+	while (--i >= 0)
+		led_classdev_unregister(&alix_leds[i].cdev);
 	return ret;
 }
 
 static int alix_led_remove(struct platform_device *pdev)
 {
 	int i;
+
 	for (i = 0; i < ARRAY_SIZE(alix_leds); i++)
 		led_classdev_unregister(&alix_leds[i].cdev);
 	return 0;
@@ -122,6 +128,7 @@ static struct platform_device *pdev;
 static int __init alix_led_init(void)
 {
 	int ret;
+
 	pdev = ...
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[view original message]
From: Stefan Richter
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Sunday, August 24, 2008 - 3:08 am

Really?  Constantin's code looks correct to me.  He increments i once 
more after failure.

Perhaps write it easier to read; i.e. in the same way as most error 
return checks everywhere in the kernel:

	for (i = 0; i < ARRAY_SIZE(alix_leds); i++) {
		ret = led_classdev_register(...etc...);
		if (ret < 0)
			break;
	}

	if (ret < 0)
		while (i--)
			led_classdev_unregister(&alix_leds[i].cdev);


Or		while (--i >= 0)

or		for (i--; i >= 0; i--)
-- 
Stefan Richter
-=====-==--- =--- ==---
http://arcgraph.de/sr/
--


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[view original message]
From: Stefan Richter
Subject: Re: [PATCH 2.6.27-rc3] led: driver for LEDs on PCEngines ALIX.2 and ALIX.3 boards
Date: Sunday, August 24, 2008 - 3:33 am

Stefan Richter wrote:
[...something that has already been resolved.  Need to remember to check 
inbox.lkml before replying to an almost 2 days old post.]
-- 
Stefan Richter
-=====-==--- =--- ==---
http://arcgraph.de/sr/
--


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