From: Suresh Gupta <b42...@freescale.com>

PHY_CLK_VALID bit for UTMI PHY in USBDR does not set even
if PHY is providing valid clock. Workaround for this
involves resetting of PHY and check PHY_CLK_VALID bit
multiple times. If PHY_CLK_VALID bit is still not set even
after 5 retries, it would be safe to deaclare that PHY
clock is not available.
This erratum is applicable for USBDR less then ver 2.4.

Signed-off-by: Suresh Gupta <b42...@freescale.com>
Signed-off-by: Yinbo Zhu <yinbo....@nxp.com>
---
Change in v2:
                replace Yinbo.Zhu with Yinbo Zhu.
Change in v3:
                replace in_be32 with ioread32be.
Change in v4:
                Incorrect indentation of the continuation line.
                replace pr_err with dev_err.
Change in v5:
                remove dev_err function unnecessary parameters.

 drivers/usb/host/ehci-fsl.c | 37 ++++++++++++++++++++++++++-----------
 drivers/usb/host/ehci-fsl.h |  3 +++
 2 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index 38674b7aa51e..8f3bf3efb038 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/drivers/usb/host/ehci-fsl.c
@@ -183,6 +183,17 @@ static int fsl_ehci_drv_probe(struct platform_device *pdev)
        return retval;
 }
 
+static bool usb_phy_clk_valid(struct usb_hcd *hcd)
+{
+       void __iomem *non_ehci = hcd->regs;
+       bool ret = true;
+
+       if (!(ioread32be(non_ehci + FSL_SOC_USB_CTRL) & PHY_CLK_VALID))
+               ret = false;
+
+       return ret;
+}
+
 static int ehci_fsl_setup_phy(struct usb_hcd *hcd,
                               enum fsl_usb2_phy_modes phy_mode,
                               unsigned int port_offset)
@@ -226,6 +237,16 @@ static int ehci_fsl_setup_phy(struct usb_hcd *hcd,
                /* fall through */
        case FSL_USB2_PHY_UTMI:
        case FSL_USB2_PHY_UTMI_DUAL:
+               /* PHY_CLK_VALID bit is de-featured from all controller
+                * versions below 2.4 and is to be checked only for
+                * internal UTMI phy
+                */
+               if (pdata->controller_ver > FSL_USB_VER_2_4 &&
+                   pdata->have_sysif_regs && !usb_phy_clk_valid(hcd)) {
+                       dev_err(dev, "USB PHY clock invalid\n");
+                       return -EINVAL;
+               }
+
                if (pdata->have_sysif_regs && pdata->controller_ver) {
                        /* controller version 1.6 or above */
                        tmp = ioread32be(non_ehci + FSL_SOC_USB_CTRL);
@@ -249,17 +270,11 @@ static int ehci_fsl_setup_phy(struct usb_hcd *hcd,
                break;
        }
 
-       /*
-        * check PHY_CLK_VALID to determine phy clock presence before writing
-        * to portsc
-        */
-       if (pdata->check_phy_clk_valid) {
-               if (!(ioread32be(non_ehci + FSL_SOC_USB_CTRL) &
-                   PHY_CLK_VALID)) {
-                       dev_warn(hcd->self.controller,
-                                "USB PHY clock invalid\n");
-                       return -EINVAL;
-               }
+       if (pdata->have_sysif_regs &&
+           pdata->controller_ver > FSL_USB_VER_1_6 &&
+           !usb_phy_clk_valid(hcd)) {
+               dev_warn(hcd->self.controller, "USB PHY clock invalid\n");
+               return -EINVAL;
        }
 
        ehci_writel(ehci, portsc, &ehci->regs->port_status[port_offset]);
diff --git a/drivers/usb/host/ehci-fsl.h b/drivers/usb/host/ehci-fsl.h
index cbc422032e50..9d18c6e6ab27 100644
--- a/drivers/usb/host/ehci-fsl.h
+++ b/drivers/usb/host/ehci-fsl.h
@@ -50,4 +50,7 @@
 #define UTMI_PHY_EN             (1<<9)
 #define ULPI_PHY_CLK_SEL        (1<<10)
 #define PHY_CLK_VALID          (1<<17)
+
+/* Retry count for checking UTMI PHY CLK validity */
+#define UTMI_PHY_CLK_VALID_CHK_RETRY 5
 #endif                         /* _EHCI_FSL_H */
-- 
2.17.1

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