iio: adc: exynos_adc: fix OF populate on driver rebind

Since commit c6e126d ("of: Keep track of populated platform
devices") child devices will not be created by of_platform_populate()
if the devices had previously been deregistered individually so that the
OF_POPULATED flag is still set in the corresponding OF nodes.

Switch to using of_platform_depopulate() instead of open coding so that
the child devices are created if the driver is rebound.

Fixes: c6e126d ("of: Keep track of populated platform devices")
Cc: stable@vger.kernel.org	# 3.16
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: jhovold

drivers/iio/adc/exynos_adc.c

@@ -540,15 +540,6 @@ static const struct iio_chan_spec exynos_adc_iio_channels[] = {
 	ADC_CHANNEL(9, "adc9"),
 };
 
-static int exynos_adc_remove_devices(struct device *dev, void *c)
-{
-	struct platform_device *pdev = to_platform_device(dev);
-
-	platform_device_unregister(pdev);
-
-	return 0;
-}
-
 static int exynos_adc_probe(struct platform_device *pdev)
 {
 	struct exynos_adc *info = NULL;
@@ -660,8 +651,7 @@ static int exynos_adc_probe(struct platform_device *pdev)
 	return 0;
 
 err_of_populate:
-	device_for_each_child(&indio_dev->dev, NULL,
-				exynos_adc_remove_devices);
+	of_platform_depopulate(&indio_dev->dev);
 	iio_device_unregister(indio_dev);
 err_irq:
 	free_irq(info->irq, info);
@@ -681,8 +671,7 @@ static void exynos_adc_remove(struct platform_device *pdev)
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct exynos_adc *info = iio_priv(indio_dev);
 
-	device_for_each_child(&indio_dev->dev, NULL,
-				exynos_adc_remove_devices);
+	of_platform_depopulate(&indio_dev->dev);
 	iio_device_unregister(indio_dev);
 	free_irq(info->irq, info);
 	if (info->data->exit_hw)