mrf24j40: async interrupt handling

This patch removes the threaded irq handling and do a hardirq instead.
We need to switch to spi_async for this step for getting the irq status
register.

Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/net/ieee802154/mrf24j40.c b/drivers/net/ieee802154/mrf24j40.c
index 0cb251e..940fc0a 100644 (file)
--- a/drivers/net/ieee802154/mrf24j40.c
+++ b/drivers/net/ieee802154/mrf24j40.c
@@ -181,8 +181,10 @@ struct mrf24j40 {
        u8 rx_fifo_buf[RX_FIFO_SIZE];
        struct spi_transfer rx_fifo_buf_trx;
 
-       struct mutex buffer_mutex; /* only used to protect buf */
-       u8 *buf; /* 3 bytes. Used for SPI single-register transfers. */
+       /* isr handling for reading intstat */
+       struct spi_message irq_msg;
+       u8 irq_buf[2];
+       struct spi_transfer irq_trx;
 };
 
 /* regmap information for short address register access */
@@ -486,34 +488,6 @@ static const struct regmap_bus mrf24j40_long_regmap_bus = {
        .val_format_endian_default = REGMAP_ENDIAN_BIG,
 };
 
-static int read_short_reg(struct mrf24j40 *devrec, u8 reg, u8 *val)
-{
-       int ret = -1;
-       struct spi_message msg;
-       struct spi_transfer xfer = {
-               .len = 2,
-               .tx_buf = devrec->buf,
-               .rx_buf = devrec->buf,
-       };
-
-       spi_message_init(&msg);
-       spi_message_add_tail(&xfer, &msg);
-
-       mutex_lock(&devrec->buffer_mutex);
-       devrec->buf[0] = MRF24J40_READSHORT(reg);
-       devrec->buf[1] = 0;
-
-       ret = spi_sync(devrec->spi, &msg);
-       if (ret)
-               dev_err(printdev(devrec),
-                       "SPI read Failed for short register 0x%hhx\n", reg);
-       else
-               *val = devrec->buf[1];
-
-       mutex_unlock(&devrec->buffer_mutex);
-       return ret;
-}
-
 static void write_tx_buf_complete(void *context)
 {
        struct mrf24j40 *devrec = context;
@@ -812,16 +786,12 @@ static const struct ieee802154_ops mrf24j40_ops = {
        .set_hw_addr_filt = mrf24j40_filter,
 };
 
-static irqreturn_t mrf24j40_isr(int irq, void *data)
+static void mrf24j40_intstat_complete(void *context)
 {
-       struct mrf24j40 *devrec = data;
-       u8 intstat;
-       int ret;
+       struct mrf24j40 *devrec = context;
+       u8 intstat = devrec->irq_buf[1];
 
-       /* Read the interrupt status */
-       ret = read_short_reg(devrec, REG_INTSTAT, &intstat);
-       if (ret)
-               goto out;
+       enable_irq(devrec->spi->irq);
 
        /* Check for TX complete */
        if (intstat & 0x1)
@@ -830,8 +800,23 @@ static irqreturn_t mrf24j40_isr(int irq, void *data)
        /* Check for Rx */
        if (intstat & 0x8)
                mrf24j40_handle_rx(devrec);
+}
+
+static irqreturn_t mrf24j40_isr(int irq, void *data)
+{
+       struct mrf24j40 *devrec = data;
+       int ret;
+
+       disable_irq_nosync(irq);
+
+       devrec->irq_buf[0] = MRF24J40_READSHORT(REG_INTSTAT);
+       /* Read the interrupt status */
+       ret = spi_async(devrec->spi, &devrec->irq_msg);
+       if (ret) {
+               enable_irq(irq);
+               return IRQ_NONE;
+       }
 
-out:
        return IRQ_HANDLED;
 }
 
@@ -978,6 +963,18 @@ mrf24j40_setup_rx_spi_messages(struct mrf24j40 *devrec)
        spi_message_add_tail(&devrec->rx_lqi_trx, &devrec->rx_buf_msg);
 }
 
+static void
+mrf24j40_setup_irq_spi_messages(struct mrf24j40 *devrec)
+{
+       spi_message_init(&devrec->irq_msg);
+       devrec->irq_msg.context = devrec;
+       devrec->irq_msg.complete = mrf24j40_intstat_complete;
+       devrec->irq_trx.len = 2;
+       devrec->irq_trx.tx_buf = devrec->irq_buf;
+       devrec->irq_trx.rx_buf = devrec->irq_buf;
+       spi_message_add_tail(&devrec->irq_trx, &devrec->irq_msg);
+}
+
 static void  mrf24j40_phy_setup(struct mrf24j40 *devrec)
 {
        ieee802154_random_extended_addr(&devrec->hw->phy->perm_extended_addr);
@@ -1008,6 +1005,7 @@ static int mrf24j40_probe(struct spi_device *spi)
 
        mrf24j40_setup_tx_spi_messages(devrec);
        mrf24j40_setup_rx_spi_messages(devrec);
+       mrf24j40_setup_irq_spi_messages(devrec);
 
        devrec->regmap_short = devm_regmap_init_spi(spi,
                                                    &mrf24j40_short_regmap);
@@ -1028,32 +1026,21 @@ static int mrf24j40_probe(struct spi_device *spi)
                goto err_register_device;
        }
 
-       devrec->buf = devm_kzalloc(&spi->dev, 3, GFP_KERNEL);
-       if (!devrec->buf)
-               goto err_register_device;
-
        if (spi->max_speed_hz > MAX_SPI_SPEED_HZ) {
                dev_warn(&spi->dev, "spi clock above possible maximum: %d",
                         MAX_SPI_SPEED_HZ);
                return -EINVAL;
        }
 
-       mutex_init(&devrec->buffer_mutex);
-
        ret = mrf24j40_hw_init(devrec);
        if (ret)
                goto err_register_device;
 
        mrf24j40_phy_setup(devrec);
 
-       ret = devm_request_threaded_irq(&spi->dev,
-                                       spi->irq,
-                                       NULL,
-                                       mrf24j40_isr,
-                                       IRQF_TRIGGER_LOW|IRQF_ONESHOT,
-                                       dev_name(&spi->dev),
-                                       devrec);
-
+       ret = devm_request_irq(&spi->dev, spi->irq, mrf24j40_isr,
+                              IRQF_TRIGGER_LOW, dev_name(&spi->dev),
+                              devrec);
        if (ret) {
                dev_err(printdev(devrec), "Unable to get IRQ");
                goto err_register_device;