[RFC 1/3] misc: pch_phub: Read prefetch value from device tree if passed

[Zubair Lutfullah Kakakhel]

The default prefetch value for the eg20t device is hard coded to
0x000affaa.

Add support for an alternative to be read from DT if available

Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@xxxxxxxxxx>
---
 drivers/misc/pch_phub.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/pch_phub.c b/drivers/misc/pch_phub.c
index 4810e03..9b010a7 100644
--- a/drivers/misc/pch_phub.c
+++ b/drivers/misc/pch_phub.c
@@ -711,6 +711,12 @@ static int pch_phub_probe(struct pci_dev *pdev,
 
 	if (id->driver_data == 1) { /* EG20T PCH */
 		const char *board_name;
+		unsigned int prefetch = 0x000affaa;
+
+		if (pdev->dev.of_node)
+			of_property_read_u32(pdev->dev.of_node,
+						  "intel,eg20t-prefetch",
+						  &prefetch);
 
 		ret = sysfs_create_file(&pdev->dev.kobj,
 					&dev_attr_pch_mac.attr);
@@ -736,7 +742,7 @@ static int pch_phub_probe(struct pci_dev *pdev,
 						CLKCFG_UART_MASK);
 
 		/* set the prefech value */
-		iowrite32(0x000affaa, chip->pch_phub_base_address + 0x14);
+		iowrite32(prefetch, chip->pch_phub_base_address + 0x14);
 		/* set the interrupt delay value */
 		iowrite32(0x25, chip->pch_phub_base_address + 0x44);
 		chip->pch_opt_rom_start_address = PCH_PHUB_ROM_START_ADDR_EG20T;
-- 
1.9.1