spi: spi-fsl-lpspi: Fix transmissions when using CONT

[ Upstream commit 782a7c7 ]

Commit 6a13044 ("spi: lpspi: Fix wrong transmission when don't use
CONT") breaks transmissions when CONT is used. The TDIE interrupt should
not be disabled in all cases. If CONT is used and the TX transfer is not
yet completed yet, but the interrupt handler is called because there are
characters to be received, TDIE is replaced with FCIE. When the transfer
is finally completed, SR_TDF is set but the interrupt handler isn't
called again.

Fixes: 6a13044 ("spi: lpspi: Fix wrong transmission when don't use CONT")
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20250828-james-nxp-lpspi-v2-1-6262b9aa9be4@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Larisa Grigore

drivers/spi/spi-fsl-lpspi.c

@@ -3,7 +3,7 @@
 // Freescale i.MX7ULP LPSPI driver
 //
 // Copyright 2016 Freescale Semiconductor, Inc.
-// Copyright 2018 NXP Semiconductors
+// Copyright 2018, 2023, 2025 NXP
 
 #include <linux/clk.h>
 #include <linux/completion.h>
@@ -786,7 +786,7 @@ static irqreturn_t fsl_lpspi_isr(int irq, void *dev_id)
 	if (temp_SR & SR_MBF ||
 	    readl(fsl_lpspi->base + IMX7ULP_FSR) & FSR_TXCOUNT) {
 		writel(SR_FCF, fsl_lpspi->base + IMX7ULP_SR);
-		fsl_lpspi_intctrl(fsl_lpspi, IER_FCIE);
+		fsl_lpspi_intctrl(fsl_lpspi, IER_FCIE | (temp_IER & IER_TDIE));
 		return IRQ_HANDLED;
 	}