pata_cypress: fix PIO timings underclocking

Timing registers should be programmed with the desired number of clocks
minus one clock.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/ata/pata_cypress.c b/drivers/ata/pata_cypress.c
index 8fb040bf7361..ff6c37de5a12 100644
--- a/drivers/ata/pata_cypress.c
+++ b/drivers/ata/pata_cypress.c
@@ -62,14 +62,16 @@ static void cy82c693_set_piomode(struct ata_port *ap, struct ata_device *adev)
                 return;
         }
 
-        time_16 = clamp_val(t.recover, 0, 15) | (clamp_val(t.active, 0, 15) << 4);
-        time_8 = clamp_val(t.act8b, 0, 15) | (clamp_val(t.rec8b, 0, 15) << 4);
+        time_16 = clamp_val(t.recover - 1, 0, 15) |
+                  (clamp_val(t.active - 1, 0, 15) << 4);
+        time_8 = clamp_val(t.act8b - 1, 0, 15) |
+                 (clamp_val(t.rec8b - 1, 0, 15) << 4);
 
         if (adev->devno == 0) {
                 pci_read_config_dword(pdev, CY82_IDE_ADDRSETUP, &addr);
 
                 addr &= ~0x0F;  /* Mask bits */
-                addr |= clamp_val(t.setup, 0, 15);
+                addr |= clamp_val(t.setup - 1, 0, 15);
 
                 pci_write_config_dword(pdev, CY82_IDE_ADDRSETUP, addr);
                 pci_write_config_byte(pdev, CY82_IDE_MASTER_IOR, time_16);
@@ -79,7 +81,7 @@ static void cy82c693_set_piomode(struct ata_port *ap, struct ata_device *adev)
                 pci_read_config_dword(pdev, CY82_IDE_ADDRSETUP, &addr);
 
                 addr &= ~0xF0;  /* Mask bits */
-                addr |= (clamp_val(t.setup, 0, 15) << 4);
+                addr |= (clamp_val(t.setup - 1, 0, 15) << 4);
 
                 pci_write_config_dword(pdev, CY82_IDE_ADDRSETUP, addr);
                 pci_write_config_byte(pdev, CY82_IDE_SLAVE_IOR, time_16);