drivers/iio/adc/at91_adc.c: use devm_ functions

The various devm_ functions allocate memory that is released when a driver
detaches. This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.

The call to platform_get_resource(pdev, IORESOURCE_MEM, 0) is moved coser
to the call to devm_request_and_ioremap, which is th first use of the
result of platform_get_resource.

This does not use devm_request_irq to ensure that free_irq is executed
before its idev argument is freed.

Signed-off-by: Julia Lawall <[e-mail]>
Reviewed-by: Lars-Peter Clausen <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/at91_adc.c

···
 		goto error_free_device;
 	}
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "No resource defined\n");
-		ret = -ENXIO;
-		goto error_ret;
-	}
-
 	platform_set_drvdata(pdev, idev);
 
 	idev->dev.parent = &pdev->dev;
···
 		goto error_free_device;
 	}
 
-	if (!request_mem_region(res->start, resource_size(res),
-				"AT91 adc registers")) {
-		dev_err(&pdev->dev, "Resources are unavailable.\n");
-		ret = -EBUSY;
-		goto error_free_device;
-	}
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 
-	st->reg_base = ioremap(res->start, resource_size(res));
+	st->reg_base = devm_request_and_ioremap(&pdev->dev, res);
 	if (!st->reg_base) {
-		dev_err(&pdev->dev, "Failed to map registers.\n");
 		ret = -ENOMEM;
-		goto error_release_mem;
+		goto error_free_device;
 	}
 
 	/*
···
 			  idev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
-		goto error_unmap_reg;
+		goto error_free_device;
 	}
 
-	st->clk = clk_get(&pdev->dev, "adc_clk");
+	st->clk = devm_clk_get(&pdev->dev, "adc_clk");
 	if (IS_ERR(st->clk)) {
 		dev_err(&pdev->dev, "Failed to get the clock.\n");
 		ret = PTR_ERR(st->clk);
···
 	ret = clk_prepare(st->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not prepare the clock.\n");
-		goto error_free_clk;
+		goto error_free_irq;
 	}
 
 	ret = clk_enable(st->clk);
···
 		goto error_unprepare_clk;
 	}
 
-	st->adc_clk = clk_get(&pdev->dev, "adc_op_clk");
+	st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
 	if (IS_ERR(st->adc_clk)) {
 		dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
 		ret = PTR_ERR(st->clk);
···
 	ret = clk_prepare(st->adc_clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not prepare the ADC clock.\n");
-		goto error_free_adc_clk;
+		goto error_disable_clk;
 	}
 
 	ret = clk_enable(st->adc_clk);
···
 	clk_disable(st->adc_clk);
 error_unprepare_adc_clk:
 	clk_unprepare(st->adc_clk);
-error_free_adc_clk:
-	clk_put(st->adc_clk);
 error_disable_clk:
 	clk_disable(st->clk);
 error_unprepare_clk:
 	clk_unprepare(st->clk);
-error_free_clk:
-	clk_put(st->clk);
 error_free_irq:
 	free_irq(st->irq, idev);
-error_unmap_reg:
-	iounmap(st->reg_base);
-error_release_mem:
-	release_mem_region(res->start, resource_size(res));
 error_free_device:
 	iio_device_free(idev);
 error_ret:
···
 static int __devexit at91_adc_remove(struct platform_device *pdev)
 {
 	struct iio_dev *idev = platform_get_drvdata(pdev);
-	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	struct at91_adc_state *st = iio_priv(idev);
 
 	iio_device_unregister(idev);
 	at91_adc_trigger_remove(idev);
 	at91_adc_buffer_remove(idev);
 	clk_disable_unprepare(st->adc_clk);
-	clk_put(st->adc_clk);
 	clk_disable(st->clk);
 	clk_unprepare(st->clk);
-	clk_put(st->clk);
 	free_irq(st->irq, idev);
-	iounmap(st->reg_base);
-	release_mem_region(res->start, resource_size(res));
 	iio_device_free(idev);
 
 	return 0;