1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/ata/pata_pdc2027x.c b/drivers/ata/pata_pdc2027x.c
index 0d2cc49fde4b..69a5aa4949f5 100644
--- a/drivers/ata/pata_pdc2027x.c
+++ b/drivers/ata/pata_pdc2027x.c
@@ -689,10 +689,12 @@ static long pdc_detect_pll_input_clock(struct ata_host *host)
         void __iomem *mmio_base = host->iomap[PDC_MMIO_BAR];
         u32 scr;
         long start_count, end_count;
-        long pll_clock;
+        struct timeval start_time, end_time;
+        long pll_clock, usec_elapsed;
 
         /* Read current counter value */
         start_count = pdc_read_counter(host);
+        do_gettimeofday(&start_time);
 
         /* Start the test mode */
         scr = readl(mmio_base + PDC_SYS_CTL);
@@ -705,6 +707,7 @@ static long pdc_detect_pll_input_clock(struct ata_host *host)
 
         /* Read the counter values again */
         end_count = pdc_read_counter(host);
+        do_gettimeofday(&end_time);
 
         /* Stop the test mode */
         scr = readl(mmio_base + PDC_SYS_CTL);
@@ -713,7 +716,11 @@ static long pdc_detect_pll_input_clock(struct ata_host *host)
         readl(mmio_base + PDC_SYS_CTL); /* flush */
 
         /* calculate the input clock in Hz */
-        pll_clock = (start_count - end_count) * 10;
+        usec_elapsed = (end_time.tv_sec - start_time.tv_sec) * 1000000 +
+                (end_time.tv_usec - start_time.tv_usec);
+
+        pll_clock = (start_count - end_count) / 100 *
+                (100000000 / usec_elapsed);
 
         PDPRINTK("start[%ld] end[%ld] \n", start_count, end_count);
         PDPRINTK("PLL input clock[%ld]Hz\n", pll_clock);