spi: uniphier: Add handle_err callback function

This adds master->handle_err() callback function to stop transfer due to
error. The function also resets FIFOs and disables interrupt.
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/1577149107-30670-4-git-send-email-hayashi.kunihiko@socionext.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-uniphier.c

@@ -425,6 +425,22 @@ static int uniphier_spi_unprepare_transfer_hardware(struct spi_master *master)
 	return 0;
 }
 
+static void uniphier_spi_handle_err(struct spi_master *master,
+				    struct spi_message *msg)
+{
+	struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
+	u32 val;
+
+	/* stop running spi transfer */
+	writel(0, priv->base + SSI_CTL);
+
+	/* reset FIFOs */
+	val = SSI_FC_TXFFL | SSI_FC_RXFFL;
+	writel(val, priv->base + SSI_FC);
+
+	uniphier_spi_irq_disable(priv, SSI_IE_RCIE | SSI_IE_RORIE);
+}
+
 static irqreturn_t uniphier_spi_handler(int irq, void *dev_id)
 {
 	struct uniphier_spi_priv *priv = dev_id;
@@ -531,6 +547,7 @@ static int uniphier_spi_probe(struct platform_device *pdev)
 				= uniphier_spi_prepare_transfer_hardware;
 	master->unprepare_transfer_hardware
 				= uniphier_spi_unprepare_transfer_hardware;
+	master->handle_err = uniphier_spi_handle_err;
 	master->num_chipselect = 1;
 
 	ret = devm_spi_register_master(&pdev->dev, master);