FAILED: patch "[PATCH] spi: spi-fsl-dspi: Fix lockup if device is removed during SPI" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7684580d45bd3d84ed9b453a4cadf7a9a5605a3f Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <[email protected]>
Date: Mon, 22 Jun 2020 13:05:40 +0200
Subject: [PATCH] spi: spi-fsl-dspi: Fix lockup if device is removed during SPI
transfer

During device removal, the driver should unregister the SPI controller and stop the hardware. Otherwise the dspi_transfer_one_message() could wait on completion infinitely.

Additionally, calling spi_unregister_controller() first in device removal reverse-matches the probe function, where SPI controller is registered at the end.

index 58190c94561f..ec0fd0d366eb 100644
@@ -1434,9 +1434,18 @@ static int dspi_remove(struct platform_device *pdev)
 	struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr);
 
 	/* Disconnect from the SPI framework */
+	spi_unregister_controller(dspi->ctlr);
+
+	/* Disable RX and TX */
+	regmap_update_bits(dspi->regmap, SPI_MCR,
+			   SPI_MCR_DIS_TXF | SPI_MCR_DIS_RXF,
+			   SPI_MCR_DIS_TXF | SPI_MCR_DIS_RXF);
+
+	/* Stop Running */
+	regmap_update_bits(dspi->regmap, SPI_MCR, SPI_MCR_HALT, SPI_MCR_HALT);
+
 	dspi_release_dma(dspi);
 	clk_disable_unprepare(dspi->clk);
-	spi_unregister_controller(dspi->ctlr);
 
 	return 0;
 }