Fixes a probe failure that occurs when dual SPI controllers are
enabled and INTx interrupts are used. Reduces the minimum required
number of interrupt vectors to 1 and registers a shared ISR when
the allocated vectors are fewer than the number of controllers.
This change ensures that the probe succeeds even with limited
vectors, restoring INTx functionality when multiple SPI
controllers are present.

Signed-off-by: Thangaraj Samynathan <thangaraj.s@microchip.com>
---
 drivers/spi/spi-pci1xxxx.c | 48 +++++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 14 deletions(-)

diff --git a/drivers/spi/spi-pci1xxxx.c b/drivers/spi/spi-pci1xxxx.c
index e9153570e9e9..9a7b86a5ec75 100644
--- a/drivers/spi/spi-pci1xxxx.c
+++ b/drivers/spi/spi-pci1xxxx.c
@@ -688,6 +688,17 @@ static irqreturn_t pci1xxxx_spi_isr(int irq, void *dev)
 		return pci1xxxx_spi_isr_io(irq, dev);
 }
 
+static irqreturn_t pci1xxxx_spi_shared_isr(int irq, void *dev)
+{
+	struct pci1xxxx_spi *par = dev;
+	u8 i = 0;
+
+	for (i = 0; i < par->total_hw_instances; i++)
+		pci1xxxx_spi_isr(irq, par->spi_int[i]);
+
+	return IRQ_HANDLED;
+}
+
 static bool pci1xxxx_spi_can_dma(struct spi_controller *host,
 				 struct spi_device *spi,
 				 struct spi_transfer *xfer)
@@ -705,6 +716,7 @@ static int pci1xxxx_spi_probe(struct pci_dev *pdev, const struct pci_device_id *
 	struct device *dev = &pdev->dev;
 	struct pci1xxxx_spi *spi_bus;
 	struct spi_controller *spi_host;
+	int num_vector = 0;
 	u32 regval;
 	int ret;
 
@@ -752,9 +764,9 @@ static int pci1xxxx_spi_probe(struct pci_dev *pdev, const struct pci_device_id *
 			if (!spi_bus->reg_base)
 				return -EINVAL;
 
-			ret = pci_alloc_irq_vectors(pdev, hw_inst_cnt, hw_inst_cnt,
-						    PCI_IRQ_ALL_TYPES);
-			if (ret < 0) {
+			num_vector = pci_alloc_irq_vectors(pdev, 1, hw_inst_cnt,
+							   PCI_IRQ_ALL_TYPES);
+			if (num_vector < 0) {
 				dev_err(&pdev->dev, "Error allocating MSI vectors\n");
 				return ret;
 			}
@@ -768,9 +780,15 @@ static int pci1xxxx_spi_probe(struct pci_dev *pdev, const struct pci_device_id *
 			       SPI_MST_EVENT_MASK_REG_OFFSET(spi_sub_ptr->hw_inst));
 			spi_sub_ptr->irq = pci_irq_vector(pdev, 0);
 
-			ret = devm_request_irq(&pdev->dev, spi_sub_ptr->irq,
-					       pci1xxxx_spi_isr, PCI1XXXX_IRQ_FLAGS,
-					       pci_name(pdev), spi_sub_ptr);
+			if (num_vector >= hw_inst_cnt)
+				ret = devm_request_irq(&pdev->dev, spi_sub_ptr->irq,
+						       pci1xxxx_spi_isr, PCI1XXXX_IRQ_FLAGS,
+						       pci_name(pdev), spi_sub_ptr);
+			else
+				ret = devm_request_irq(&pdev->dev, spi_sub_ptr->irq,
+						       pci1xxxx_spi_shared_isr,
+						       PCI1XXXX_IRQ_FLAGS | IRQF_SHARED,
+						       pci_name(pdev), spi_bus);
 			if (ret < 0) {
 				dev_err(&pdev->dev, "Unable to request irq : %d",
 					spi_sub_ptr->irq);
@@ -801,14 +819,16 @@ static int pci1xxxx_spi_probe(struct pci_dev *pdev, const struct pci_device_id *
 			regval &= ~SPI_INTR;
 			writel(regval, spi_bus->reg_base +
 			       SPI_MST_EVENT_MASK_REG_OFFSET(spi_sub_ptr->hw_inst));
-			spi_sub_ptr->irq = pci_irq_vector(pdev, iter);
-			ret = devm_request_irq(&pdev->dev, spi_sub_ptr->irq,
-					       pci1xxxx_spi_isr, PCI1XXXX_IRQ_FLAGS,
-					       pci_name(pdev), spi_sub_ptr);
-			if (ret < 0) {
-				dev_err(&pdev->dev, "Unable to request irq : %d",
-					spi_sub_ptr->irq);
-				return -ENODEV;
+			if (num_vector >= hw_inst_cnt) {
+				spi_sub_ptr->irq = pci_irq_vector(pdev, iter);
+				ret = devm_request_irq(&pdev->dev, spi_sub_ptr->irq,
+						       pci1xxxx_spi_isr, PCI1XXXX_IRQ_FLAGS,
+						       pci_name(pdev), spi_sub_ptr);
+				if (ret < 0) {
+					dev_err(&pdev->dev, "Unable to request irq : %d",
+						spi_sub_ptr->irq);
+					return -ENODEV;
+				}
 			}
 		}
 
-- 
2.25.1

On Tue, 27 May 2025 16:02:44 +0530, Thangaraj Samynathan wrote:
> Fixes a probe failure that occurs when dual SPI controllers are
> enabled and INTx interrupts are used. Reduces the minimum required
> number of interrupt vectors to 1 and registers a shared ISR when
> the allocated vectors are fewer than the number of controllers.
> This change ensures that the probe succeeds even with limited
> vectors, restoring INTx functionality when multiple SPI
> controllers are present.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: spi-pci1xxxx: Fix Probe failure with Dual SPI instance with INTx interrupts
      commit: b4608e944177531334a79f3df2cd14275b47808c

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark