[PATCH] spi: spi-pxa2xx: Check status register to determine if SSSR_TINT is disabled

[Tan Jui Nee <jui.nee.tan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

From: "Tan, Jui Nee" <jui.nee.tan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

On Intel Baytrail, there is case when interrupt handler get called, no SPI
message is captured. The RX FIFO is indeed empty when RX timeout pending
interrupt (SSSR_TINT) happens.

Use the BIOS version where both HSUART and SPI are on the same IRQ. Both
drivers are using IRQF_SHARED when calling the request_irq function. When
running two separate and independent SPI and HSUART application that
generate data traffic on both components, user will see messages like
below on the console:

  pxa2xx-spi pxa2xx-spi.0: bad message state in interrupt handler

This commit will fix this by first checking Receiver Time-out Interrupt,
if it is disabled, ignore the request and return without servicing.

Signed-off-by: Tan, Jui Nee <jui.nee.tan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 drivers/spi/spi-pxa2xx.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index fdd79197..a8ef38e 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -654,6 +654,10 @@ static irqreturn_t ssp_int(int irq, void *dev_id)
 	if (!(sccr1_reg & SSCR1_TIE))
 		mask &= ~SSSR_TFS;
 
+	/* Ignore RX timeout interrupt if it is disabled */
+	if (!(sccr1_reg & SSCR1_TINTE))
+		mask &= ~SSSR_TINT;
+
 	if (!(status & mask))
 		return IRQ_NONE;
 
-- 
1.9.3

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