spi: pxa2xx-pci: Balance reference count for PCI DMA device

The pci_get_slot() increases its reference count, the caller
must decrement the reference count by calling pci_dev_put().

Fixes: 743485ea ("spi: pxa2xx-pci: Do a specific setup in a separate function")
Fixes: 25014521 ("spi: pxa2xx-pci: Enable DMA for Intel Merrifield")
Reported-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220223191637.31147-1-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-pxa2xx-pci.c

@@ -76,14 +76,23 @@ static bool lpss_dma_filter(struct dma_chan *chan, void *param)
 	return true;
 }
 
+static void lpss_dma_put_device(void *dma_dev)
+{
+	pci_dev_put(dma_dev);
+}
+
 static int lpss_spi_setup(struct pci_dev *dev, struct pxa_spi_info *c)
 {
 	struct pci_dev *dma_dev;
+	int ret;
 
 	c->num_chipselect = 1;
 	c->max_clk_rate = 50000000;
 
 	dma_dev = pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
+	ret = devm_add_action_or_reset(&dev->dev, lpss_dma_put_device, dma_dev);
+	if (ret)
+		return ret;
 
 	if (c->tx_param) {
 		struct dw_dma_slave *slave = c->tx_param;
@@ -107,8 +116,9 @@ static int lpss_spi_setup(struct pci_dev *dev, struct pxa_spi_info *c)
 
 static int mrfld_spi_setup(struct pci_dev *dev, struct pxa_spi_info *c)
 {
-	struct pci_dev *dma_dev = pci_get_slot(dev->bus, PCI_DEVFN(21, 0));
 	struct dw_dma_slave *tx, *rx;
+	struct pci_dev *dma_dev;
+	int ret;
 
 	switch (PCI_FUNC(dev->devfn)) {
 	case 0:
@@ -133,6 +143,11 @@ static int mrfld_spi_setup(struct pci_dev *dev, struct pxa_spi_info *c)
 		return -ENODEV;
 	}
 
+	dma_dev = pci_get_slot(dev->bus, PCI_DEVFN(21, 0));
+	ret = devm_add_action_or_reset(&dev->dev, lpss_dma_put_device, dma_dev);
+	if (ret)
+		return ret;
+
 	tx = c->tx_param;
 	tx->dma_dev = &dma_dev->dev;