usb: phy: ab8500-usb: fix eye diagram for ab8500 v2.0

AB8500 v2.0 has eye diagram issues when drawing more than 100mA from
VBUS.  Force charging current to 100mA in case of standard host.

Signed-off-by: Sakethram Bommisetti <sakethram.bommisetti@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/usb/phy/phy-ab8500-usb.c b/drivers/usb/phy/phy-ab8500-usb.c
index 5b92a59804eb..441b2954cffd 100644
--- a/drivers/usb/phy/phy-ab8500-usb.c
+++ b/drivers/usb/phy/phy-ab8500-usb.c
@@ -485,6 +485,19 @@ static void ab8500_usb_phy_disable_work(struct work_struct *work)
                 ab8500_usb_peri_phy_dis(ab);
 }
 
+static unsigned ab8500_eyediagram_workaroud(struct ab8500_usb *ab, unsigned mA)
+{
+        /*
+         * AB8500 V2 has eye diagram issues when drawing more than 100mA from
+         * VBUS.  Set charging current to 100mA in case of standard host
+         */
+        if (is_ab8500_2p0_or_earlier(ab->ab8500))
+                if (mA > 100)
+                        mA = 100;
+
+        return mA;
+}
+
 static int ab8500_usb_set_power(struct usb_phy *phy, unsigned mA)
 {
         struct ab8500_usb *ab;
@@ -494,6 +507,8 @@ static int ab8500_usb_set_power(struct usb_phy *phy, unsigned mA)
 
         ab = phy_to_ab(phy);
 
+        mA = ab8500_eyediagram_workaroud(ab, mA);
+
         ab->vbus_draw = mA;
 
         if (mA)