ads7846: fix gpio free without requesting

PATCH New Sourav Poddar 3 participants 4 messages Feb 3, 2011

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Sourav Poddar

author

2011-02-03 15:21 UTC #0 lore raw

PATCH v3 1/2 ads7846: fix gpio free without requesting

gpio_pendown in ads7846_probe is not getting initalized (defaulted to 0) resulting in gpio_free being called without a gpio_request. This results in the following backtrace in bootup (at least on an OMAP3430 SDP).

------------[ cut here ]------------
WARNING: at drivers/gpio/gpiolib.c:1258 gpio_free+0x100/0x12c()
Modules linked in:
[<c0061208>] (unwind_backtrace+0x0/0xe4) from [<c0091f58>](warn_slowpath_common+0x4c/0x64)
[<c0091f58>] (warn_slowpath_common+0x4c/0x64) from [<c0091f88>](warn_slowpath_null+0x18/0x1c)
[<c0091f88>] (warn_slowpath_null+0x18/0x1c) from [<c024e610>](gpio_free+0x100/0x12c)
[<c024e610>] (gpio_free+0x100/0x12c) from [<c03e9fbc>](ads7846_probe+0xa38/0xc5c)
[<c03e9fbc>] (ads7846_probe+0xa38/0xc5c) from [<c02cff14>](spi_drv_probe+0x18/0x1c)
[<c02cff14>] (spi_drv_probe+0x18/0x1c) from [<c028bca4>](driver_probe_device+0xc8/0x184)
[<c028bca4>] (driver_probe_device+0xc8/0x184) from [<c028bdc8>](__driver_attach+0x68/0x8c)
[<c028bdc8>] (__driver_attach+0x68/0x8c) from [<c028b4c8>](bus_for_each_dev+0x48/0x74)
[<c028b4c8>] (bus_for_each_dev+0x48/0x74) from [<c028ae08>](bus_add_driver+0xa0/0x220)
[<c028ae08>] (bus_add_driver+0xa0/0x220) from [<c028c0c0>](driver_register+0xa8/0x134)
[<c028c0c0>] (driver_register+0xa8/0x134) from [<c0050550>](do_one_initcall+0xcc/0x1a4)
[<c0050550>] (do_one_initcall+0xcc/0x1a4) from [<c00084e4>](kernel_init+0x14c/0x214)
[<c00084e4>] (kernel_init+0x14c/0x214) from [<c005b494>](kernel_thread_exit+0x0/0x8)
---[ end trace 4053287f8a5ec18f ]---

Initialize gpio_pendown in ads7846_probe to -EINVAL before ads7846_setup_pendown function and using gpio_is_valid function in conditional check removes the above backtrace warning.

Signed-off-by Sourav Poddar <[email protected]>

Signed-off-by Kishon Vijay Abraham I <[email protected]>

Cc Dmitry Torokhov <[email protected]>

---
Links related to the previous discussions:
http://www.spinics.net/lists/linux-omap/msg45093.html
http://www.mail-archive.com/linux-omap at vger.kernel.org/msg43506.html

 drivers/input/touchscreen/ads7846.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

drivers/input/touchscreen/ads7846.c +2 -1

index 14ea54b..ce5baee 100644
@@ -952,6 +952,7 @@ static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784
 
 	if (pdata->get_pendown_state) {
 		ts->get_pendown_state = pdata->get_pendown_state;
+		ts->gpio_pendown = -EINVAL;
 		return 0;
 	}

@@ -1353,7 +1354,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
  err_put_regulator:
 	regulator_put(ts->reg);
  err_free_gpio:
-	if (ts->gpio_pendown != -1)
+	if (gpio_is_valid(ts->gpio_pendown))
 		gpio_free(ts->gpio_pendown);
  err_cleanup_filter:
 	if (ts->filter_cleanup)

Signature · 1 line

1.7.0.4

Wolfram Sang

2011-02-03 15:47 UTC #1 lore raw

PATCH v3 1/2 ads7846: fix gpio free without requesting

Quoted 3 lines · Sourav Poddar

gpio_pendown in ads7846_probe is not getting initalized (defaulted to 0) resulting in gpio_free being called without a gpio_request. This results in the following backtrace in bootup (at least on an OMAP3430 SDP).

I wonder if it makes sense to merge both patches under the name of "fix gpio-handling" or similar. Not sure, though...

drivers/input/touchscreen/ads7846.c static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784 · line 957

Quoted 11 lines

drivers/input/touchscreen/ads7846.c +1 -0

index 14ea54b..ce5baee 100644
@@ -952,6 +952,7 @@ static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784
 
 	if (pdata->get_pendown_state) {
 		ts->get_pendown_state = pdata->get_pendown_state;
+		ts->gpio_pendown = -EINVAL;
 		return 0;
 	}

Will probably work, but maybe it is better to reorganize the code to just have one success-exit-point. That would be mean adding an else branch to this if-block.

drivers/input/touchscreen/ads7846.c static int __devinit ads7846_probe(struct spi_device *spi) · line 1357

Quoted 7 lines

drivers/input/touchscreen/ads7846.c +1 -1

@@ -1353,7 +1354,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
  err_put_regulator:
 	regulator_put(ts->reg);
  err_free_gpio:
-	if (ts->gpio_pendown != -1)
+	if (gpio_is_valid(ts->gpio_pendown))

You could do the same in the remove-path.

Regards,

Wolfram

Signature · 9 lines

Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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Igor Grinberg

2011-02-03 16:29 UTC #2 lore raw

PATCH v3 1/2 ads7846: fix gpio free without requesting

Hi,

Quoted 6 lines · Wolfram Sang

Quoted 3 lines · Sourav Poddar
gpio_pendown in ads7846_probe is not getting initalized (defaulted to 0) resulting in gpio_free being called without a gpio_request. This results in the following backtrace in bootup (at least on an OMAP3430 SDP).
I wonder if it makes sense to merge both patches under the name of "fix gpio-handling" or similar. Not sure, though...

I'd rather not do that, because this patch fixes the request/free problem and the second is changing the functionality (e.g. configures the gpio as input)

Quoted 6 lines

drivers/input/touchscreen/ads7846.c +0 -0

index 14ea54b..ce5baee 100644
@@ -952,6 +952,7 @@ static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784

Quoted 8 lines

drivers/input/touchscreen/ads7846.c static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784 · line 957
Quoted 5 lines
drivers/input/touchscreen/ads7846.c +1 -0
 	if (pdata->get_pendown_state) {
 		ts->get_pendown_state = pdata->get_pendown_state;
+		ts->gpio_pendown = -EINVAL;
 		return 0;
 	}
Will probably work, but maybe it is better to reorganize the code to just have one success-exit-point. That would be mean adding an else branch to this if-block.

This is something that can be done, though I fear the code readability will suffer. Is it worth?

Quoted 8 lines

drivers/input/touchscreen/ads7846.c static int __devinit ads7846_probe(struct spi_device *spi) · line 1357
Quoted 7 lines
drivers/input/touchscreen/ads7846.c +1 -1
@@ -1353,7 +1354,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
  err_put_regulator:
 	regulator_put(ts->reg);
  err_free_gpio:
-	if (ts->gpio_pendown != -1)
+	if (gpio_is_valid(ts->gpio_pendown))
You could do the same in the remove-path.

You mean, _should_... ;)
Otherwise, the patch is not complete.

Signature · 2 lines

Regards,
Igor.

Wolfram Sang

2011-02-03 16:48 UTC #3 lore raw

PATCH v3 1/2 ads7846: fix gpio free without requesting

Quoted 5 lines

Quoted 2 lines
I wonder if it makes sense to merge both patches under the name of "fix gpio-handling" or similar. Not sure, though...
I'd rather not do that, because this patch fixes the request/free problem and the second is changing the functionality (e.g. configures the gpio as input)

Ack.

Quoted 16 lines

Quoted 7 lines
Quoted 7 lines
drivers/input/touchscreen/ads7846.c +0 -0
index 14ea54b..ce5baee 100644
@@ -952,6 +952,7 @@ static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784
 
Quoted 8 lines
drivers/input/touchscreen/ads7846.c static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads784 · line 957
Quoted 5 lines
drivers/input/touchscreen/ads7846.c +1 -0
 	if (pdata->get_pendown_state) {
 		ts->get_pendown_state = pdata->get_pendown_state;
+		ts->gpio_pendown = -EINVAL;
 		return 0;
 	}
Will probably work, but maybe it is better to reorganize the code to just have one success-exit-point. That would be mean adding an else branch to this if-block.

Quoted 2 lines

This is something that can be done, though I fear the code readability will suffer. Is it worth?

I thought it to be more readable to have one-entry-one-OK-exit. But actually I don't mind that much.

Quoted 11 lines

Quoted 9 lines
drivers/input/touchscreen/ads7846.c static int __devinit ads7846_probe(struct spi_device *spi) · line 1357
Quoted 8 lines
drivers/input/touchscreen/ads7846.c +1 -1
@@ -1353,7 +1354,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
  err_put_regulator:
 	regulator_put(ts->reg);
  err_free_gpio:
-	if (ts->gpio_pendown != -1)
+	if (gpio_is_valid(ts->gpio_pendown))
You could do the same in the remove-path.
You mean, _should_... ;)

Yes, I meant that :)

Signature · 9 lines

Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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