[PATCH v2 4/8] spi: lantiq: Add support to acknowledge interrupt

[Dilip Kota]

On newer chipsets interrupt need to be acknowledged as they use
different interrupt controller which does not acknowledge the
interrupts automatically.

Signed-off-by: Dilip Kota <eswara.k...@linux.intel.com>
---
 drivers/spi/spi-lantiq-ssc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/spi/spi-lantiq-ssc.c b/drivers/spi/spi-lantiq-ssc.c
index 98e1c5d807597..cbe019f995999 100644
--- a/drivers/spi/spi-lantiq-ssc.c
+++ b/drivers/spi/spi-lantiq-ssc.c
@@ -161,6 +161,7 @@ struct lantiq_ssc_hwcfg {
        unsigned int    irnen_t;
        unsigned int    irncr;
        unsigned int    irnicr;
+       bool            irq_ack;
 };
 
 struct lantiq_ssc_spi {
@@ -623,9 +624,14 @@ static void rx_request(struct lantiq_ssc_spi *spi)
 static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, void *data)
 {
        struct lantiq_ssc_spi *spi = data;
+       const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
+       u32 val = lantiq_ssc_readl(spi, hwcfg->irncr);
        unsigned long flags;
 
        spin_lock_irqsave(&spi->lock, flags);
+       if (hwcfg->irq_ack)
+               lantiq_ssc_writel(spi, val, hwcfg->irncr);
+
        if (spi->tx) {
                if (spi->rx && spi->rx_todo)
                        rx_fifo_read_full_duplex(spi);
@@ -660,13 +666,18 @@ static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, 
void *data)
 static irqreturn_t lantiq_ssc_err_interrupt(int irq, void *data)
 {
        struct lantiq_ssc_spi *spi = data;
+       const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
        u32 stat = lantiq_ssc_readl(spi, LTQ_SPI_STAT);
+       u32 val = lantiq_ssc_readl(spi, hwcfg->irncr);
        unsigned long flags;
 
        if (!(stat & LTQ_SPI_STAT_ERRORS))
                return IRQ_NONE;
 
        spin_lock_irqsave(&spi->lock, flags);
+       if (hwcfg->irq_ack)
+               lantiq_ssc_writel(spi, val, hwcfg->irncr);
+
        if (stat & LTQ_SPI_STAT_RUE)
                dev_err(spi->dev, "receive underflow error\n");
        if (stat & LTQ_SPI_STAT_TUE)
@@ -797,6 +808,7 @@ static const struct lantiq_ssc_hwcfg lantiq_ssc_xway = {
        .irnen_t        = LTQ_SPI_IRNEN_T_XWAY,
        .irnicr         = 0xF8,
        .irncr          = 0xFC,
+       .irq_ack        = false,
 };
 
 static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = {
@@ -804,6 +816,7 @@ static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = {
        .irnen_t        = LTQ_SPI_IRNEN_T_XRX,
        .irnicr         = 0xF8,
        .irncr          = 0xFC,
+       .irq_ack        = false,
 };
 
 static const struct of_device_id lantiq_ssc_match[] = {
-- 
2.11.0