MUSB: Workarounds for TUSB PLL

Add workarounds for various chip issues relating to the TUSB chip PLL
getting properly initialized after resume.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

diff --git a/drivers/usb/musb/tusb6010.c b/drivers/usb/musb/tusb6010.c
index 3a1dad2cdeaec969248f402865055273d0cf3a41..2176bcb3bddbcd2fa73aa4776699c0f617726d63 100644 (file)
--- a/drivers/usb/musb/tusb6010.c
+++ b/drivers/usb/musb/tusb6010.c
@@ -162,6 +162,24 @@ static inline void tusb_enable_vbus_charge(struct musb *musb)
        musb_writel(base, TUSB_PRCM_MNGMT, reg);
 }
 
+/* workaround for issue 13:  change clock during chip idle
+ * (to be fixed in rev3 silicon) ... symptoms include disconnect
+ * or looping suspend/resume cycles
+ */
+void tusb_set_clock_source(struct musb *musb, int mode)
+{
+       void __iomem    *base = musb->ctrl_base;
+       u32             reg;
+
+       reg = musb_readl(base, TUSB_PRCM_CONF);
+       reg &= ~TUSB_PRCM_CONF_SYS_CLKSEL(0x3);
+
+       if (mode > 0)
+               reg |= TUSB_PRCM_CONF_SYS_CLKSEL(mode & 0x3);
+
+       musb_writel(base, TUSB_PRCM_CONF, reg);
+}
+
 /*
  * Idle TUSB6010 until next wake-up event; NOR access always wakes.
  * Other code ensures that we idle unless we're connected _and_ the
@@ -173,6 +191,8 @@ static inline void tusb_allow_idle(struct musb *musb, u32 wakeup_enables)
        void __iomem    *base = musb->ctrl_base;
        u32             reg;
 
+       tusb_set_clock_source(musb, 0);
+
        wakeup_enables |= TUSB_PRCM_WNORCS;
        musb_writel(base, TUSB_PRCM_WAKEUP_MASK, ~wakeup_enables);
 
@@ -351,8 +371,25 @@ irqreturn_t tusb_interrupt(int irq, void *__hci, struct pt_regs *r)
 
        /* Acknowledge wake-up source interrupts */
        if (int_src & TUSB_INT_SRC_DEV_WAKEUP) {
-               u32     reg = musb_readl(base, TUSB_PRCM_WAKEUP_SOURCE);
+               u32     reg;
+               u32     i;
+
+               /* there are issues re-locking the PLL on wakeup ... */
+
+               /* work around issue 8 */
+               for (i = 0xf7f7f7; i > 0xf7f7f7 - 1000; i--) {
+                       musb_writel(base, TUSB_SCRATCH_PAD, 0);
+                       musb_writel(base, TUSB_SCRATCH_PAD, i);
+                       reg = musb_readl(base, TUSB_SCRATCH_PAD);
+                       if (reg == i)
+                               break;
+                       DBG(1, "TUSB NOR not ready\n");
+               }
+
+               /* work around issue 13 (2nd half) */
+               tusb_set_clock_source(musb, 1);
 
+               reg = musb_readl(base, TUSB_PRCM_WAKEUP_SOURCE);
                musb_writel(base, TUSB_PRCM_WAKEUP_CLEAR, reg);
                if (reg & ~TUSB_PRCM_WNORCS) {
                        musb->is_active = 1;