spi: rspi: Fix invalid SPI use during system suspend

If the SPI queue is running during system suspend, the system may lock
up.

Fix this by stopping/restarting the queue during system suspend/resume,
by calling spi_master_suspend()/spi_master_resume() from the PM
callbacks.  In-kernel users will receive an -ESHUTDOWN error while
system suspend/resume is in progress.

Based on a patch for sh-msiof by Gaku Inami.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

drivers/spi/spi-rspi.c

@@ -1350,12 +1350,36 @@ static const struct platform_device_id spi_driver_ids[] = {
 
 MODULE_DEVICE_TABLE(platform, spi_driver_ids);
 
+#ifdef CONFIG_PM_SLEEP
+static int rspi_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rspi_data *rspi = platform_get_drvdata(pdev);
+
+	return spi_master_suspend(rspi->master);
+}
+
+static int rspi_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rspi_data *rspi = platform_get_drvdata(pdev);
+
+	return spi_master_resume(rspi->master);
+}
+
+static SIMPLE_DEV_PM_OPS(rspi_pm_ops, rspi_suspend, rspi_resume);
+#define DEV_PM_OPS	&rspi_pm_ops
+#else
+#define DEV_PM_OPS	NULL
+#endif /* CONFIG_PM_SLEEP */
+
 static struct platform_driver rspi_driver = {
 	.probe =	rspi_probe,
 	.remove =	rspi_remove,
 	.id_table =	spi_driver_ids,
 	.driver		= {
 		.name = "renesas_spi",
+		.pm = DEV_PM_OPS,
 		.of_match_table = of_match_ptr(rspi_of_match),
 	},
 };