spi: atmel-quadspi: Free resources even if runtime resume failed in .remove()

An early error exit in atmel_qspi_remove() doesn't prevent the device
unbind. So this results in an spi controller with an unbound parent
and unmapped register space (because devm_ioremap_resource() is undone).
So using the remaining spi controller probably results in an oops.

Instead unregister the controller unconditionally and only skip hardware
access and clk disable.

Also add a warning about resume failing and return zero unconditionally.
The latter has the only effect to suppress a less helpful error message by
the spi core.

Fixes: 4a2f83b7 ("spi: atmel-quadspi: add runtime pm support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20230317084232.142257-3-u.kleine-koenig@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/atmel-quadspi.c

@@ -706,18 +706,28 @@ static int atmel_qspi_remove(struct platform_device *pdev)
 	struct atmel_qspi *aq = spi_controller_get_devdata(ctrl);
 	int ret;
 
-	ret = pm_runtime_resume_and_get(&pdev->dev);
-	if (ret < 0)
-		return ret;
-
 	spi_unregister_controller(ctrl);
-	atmel_qspi_write(QSPI_CR_QSPIDIS, aq, QSPI_CR);
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret >= 0) {
+		atmel_qspi_write(QSPI_CR_QSPIDIS, aq, QSPI_CR);
+		clk_disable(aq->qspick);
+		clk_disable(aq->pclk);
+	} else {
+		/*
+		 * atmel_qspi_runtime_{suspend,resume} just disable and enable
+		 * the two clks respectively. So after resume failed these are
+		 * off, and we skip hardware access and disabling these clks again.
+		 */
+		dev_warn(&pdev->dev, "Failed to resume device on remove\n");
+	}
+
+	clk_unprepare(aq->qspick);
+	clk_unprepare(aq->pclk);
 
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 
-	clk_disable_unprepare(aq->qspick);
-	clk_disable_unprepare(aq->pclk);
 	return 0;
 }