usb: ehci-spear: fix call balance of sehci clk handling routines

If the clock sehci->clk was not enabled in spear_ehci_hcd_drv_probe,
it should not be disabled in any path.

Conversely, if it was enabled in spear_ehci_hcd_drv_probe, it must be disabled
in all error paths to ensure proper cleanup.

Found by Linux Verification Center (linuxtesting.org) with Klever.

Fixes: 7675d6b ("USB: EHCI: make ehci-spear a separate driver")
Cc: [email protected]
Signed-off-by: Vitalii Mordan <[email protected]>
Acked-by: Alan Stern <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: vmordan

drivers/usb/host/ehci-spear.c

@@ -105,7 +105,9 @@ static int spear_ehci_hcd_drv_probe(struct platform_device *pdev)
 	/* registers start at offset 0x0 */
 	hcd_to_ehci(hcd)->caps = hcd->regs;
 
-	clk_prepare_enable(sehci->clk);
+	retval = clk_prepare_enable(sehci->clk);
+	if (retval)
+		goto err_put_hcd;
 	retval = usb_add_hcd(hcd, irq, IRQF_SHARED);
 	if (retval)
 		goto err_stop_ehci;
@@ -130,8 +132,7 @@ static void spear_ehci_hcd_drv_remove(struct platform_device *pdev)
 
 	usb_remove_hcd(hcd);
 
-	if (sehci->clk)
-		clk_disable_unprepare(sehci->clk);
+	clk_disable_unprepare(sehci->clk);
 	usb_put_hcd(hcd);
 }