spi/bcm63xx: Ensure that memory is freed only after it is no longer used

The call to spi_unregister_master() in the device remove function frees device
memory, and with it any device local data. However, device local data is still
accessed after the call to spi_unregister_master().

Acquire a reference to the SPI device and release it after cleanup is complete
to solve the problem.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/spi/spi-bcm63xx.c

@@ -438,7 +438,7 @@ static int __devinit bcm63xx_spi_probe(struct platform_device *pdev)
 
 static int __devexit bcm63xx_spi_remove(struct platform_device *pdev)
 {
-	struct spi_master *master = platform_get_drvdata(pdev);
+	struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
 	struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 
 	spi_unregister_master(master);
@@ -452,6 +452,8 @@ static int __devexit bcm63xx_spi_remove(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, 0);
 
+	spi_master_put(master);
+
 	return 0;
 }