diff --git a/drivers/ata/pata_hpt3x2n.c b/drivers/ata/pata_hpt3x2n.c
index 1f6afd8ee29b3..d1595e17dca26 100644
--- a/drivers/ata/pata_hpt3x2n.c
+++ b/drivers/ata/pata_hpt3x2n.c
@@ -24,7 +24,7 @@
 #include <linux/libata.h>
 
 #define DRV_NAME	"pata_hpt3x2n"
-#define DRV_VERSION	"0.3.18"
+#define DRV_VERSION	"0.3.19"
 
 enum {
 	PCI66		=	(1 << 1),
@@ -403,17 +403,20 @@ static int hpt3xn_calibrate_dpll(struct pci_dev *dev)
 	return 0;
 }
 
-static int hpt3x2n_pci_clock(struct pci_dev *pdev)
+static int hpt3x2n_pci_clock(struct pci_dev *pdev, unsigned int base)
 {
-	unsigned long freq;
+	unsigned int freq;
 	u32 fcnt;
-	unsigned long iobase = pci_resource_start(pdev, 4);
 
-	fcnt = inl(iobase + 0x90);	/* Not PCI readable for some chips */
+	/*
+	 * Some devices do not let this value be accessed via PCI space
+	 * according to the old driver.
+	 */
+	fcnt = inl(pci_resource_start(pdev, 4) + 0x90);
 	if ((fcnt >> 12) != 0xABCDE) {
+		u32 total = 0;
 		int i;
 		u16 sr;
-		u32 total = 0;
 
 		dev_warn(&pdev->dev, "BIOS clock data not set\n");
 
@@ -427,7 +430,7 @@ static int hpt3x2n_pci_clock(struct pci_dev *pdev)
 	}
 	fcnt &= 0x1FF;
 
-	freq = (fcnt * 77) / 192;
+	freq = (fcnt * base) / 192;	/* in MHz */
 
 	/* Clamp to bands */
 	if (freq < 40)
@@ -559,7 +562,7 @@ static int hpt3x2n_init_one(struct pci_dev *dev, const struct pci_device_id *id)
 	 * 50 for UDMA100. Right now we always use 66
 	 */
 
-	pci_mhz = hpt3x2n_pci_clock(dev);
+	pci_mhz = hpt3x2n_pci_clock(dev, 77);
 
 	f_low = (pci_mhz * 48) / 66;	/* PCI Mhz for 66Mhz DPLL */
 	f_high = f_low + 2;		/* Tolerance */