Re: [PATCH 2/2] iio: ti_am335x_adc: Add continuous sampling support

On Wed, Aug 28, 2013 at 06:43:08PM +0200, Sebastian Andrzej Siewior wrote:

* Zubair Lutfullah | 2013-08-25 23:45:24 [+0100]:

quoted

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index a952538..ae2202b 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c

@@ -231,28 +406,56 @@ static int tiadc_probe(struct platform_device *pdev)

…

quoted

+err_free_device:
+	iio_device_free(indio_dev);

I am not sure about this one.

If I understand correctly, if devm_iio_device_alloc 
is successful earlier in the code and subsequent stuff fails. 

Then the code jumps to err_free_device and this is needed.

quoted

+err_ret:
	return err;
}

@@ -262,11 +465,14 @@ static int tiadc_remove(struct platform_device *pdev)

	struct tiadc_device *adc_dev = iio_priv(indio_dev);
	u32 step_en;

+	free_irq(adc_dev->irq, indio_dev);
	iio_device_unregister(indio_dev);
+	iio_buffer_unregister(indio_dev);
	tiadc_channels_remove(indio_dev);

	step_en = get_adc_step_mask(adc_dev);
	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
+	iio_device_free(indio_dev);

But this one is wrong. The will be removed via dev_res() and if you do
it here as well then dev_res() will decrement the reference of an unused
object.

I was unaware of this aspect.

*but*

iio_simple_dummy.c has it in its remove function.
And I just checked and found it in several drivers as well.

I'll leave this to the more experienced folks on the list..

quoted

	return 0;
}

Sebastian