[v3,1/2] spi: pxa2xx: Prepare for edge-triggered interrupts

Commit Message

Jan Kiszka Jan. 21, 2017, 9:06 a.m. UTC

When using the a device with edge-triggered interrupts, such as MSIs,
the interrupt handler has to ensure that there is a point in time during
its execution where all interrupts sources are silent so that a new
event can trigger a new interrupt again.

This is achieved here by disabling all interrupt sources for a moment
before processing them according to the status register. If a new
interrupt should have arrived after we read the status, it will now
re-trigger the interrupt, even in edge mode.

Signed-off-by: Jan Kiszka <[e-mail]>
Acked-by: Robert Jarzmik <[e-mail]>
---
 drivers/spi/spi-pxa2xx.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index bd843df..47b65d7 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -785,6 +785,9 @@  static irqreturn_t ssp_int(int irq, void *dev_id)
 	if (!(status & mask))
 		return IRQ_NONE;
 
+	pxa2xx_spi_write(drv_data, SSCR1, sccr1_reg & ~drv_data->int_cr1);
+	pxa2xx_spi_write(drv_data, SSCR1, sccr1_reg);
+
 	if (!drv_data->master->cur_msg) {
 		handle_bad_msg(drv_data);
 		/* Never fail */