On some Bay Trail (BYT) systems the firmware does not enable the ULPI Refclk.
This commit adds a helper which checks and if necessary enabled the Refclk and calls this helper for BYT machines. Signed-off-by: Hans de Goede <[email protected]> --- drivers/usb/dwc3/dwc3-pci.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c index 34b84d3bc7cf..65bc110388f3 100644 --- a/drivers/usb/dwc3/dwc3-pci.c +++ b/drivers/usb/dwc3/dwc3-pci.c @@ -42,6 +42,9 @@ #define PCI_INTEL_BXT_STATE_D0 0 #define PCI_INTEL_BXT_STATE_D3 3 +#define GP_RWREG1 0xa0 +#define GP_RWREG1_ULPI_REFCLK_DISABLE (1 << 17) + /** * struct dwc3_pci - Driver private structure * @dwc3: child dwc3 platform_device @@ -78,6 +81,34 @@ static struct gpiod_lookup_table platform_bytcr_gpios = { }, }; +static void dwc3_pci_enable_ulpi_refclock(struct pci_dev *pci) +{ + void __iomem *reg; + struct resource res; + struct device *dev = &pci->dev; + u32 value; + + res.start = pci_resource_start(pci, 1); + res.end = pci_resource_end(pci, 1); + res.name = "dwc_usb3_bar1"; + res.flags = IORESOURCE_MEM; + + reg = devm_ioremap_resource(dev, &res); + if (IS_ERR(reg)) { + dev_err(dev, "cannot check GP_RWREG1 to assert ulpi refclock\n"); + return; + } + + value = readl(reg + GP_RWREG1); + if (!(value & GP_RWREG1_ULPI_REFCLK_DISABLE)) + return; /* ULPI refclk already enabled */ + + dev_warn(dev, "ULPI refclock is disabled from the BIOS, enabling it\n"); + value &= ~GP_RWREG1_ULPI_REFCLK_DISABLE; + writel(value, reg + GP_RWREG1); + msleep(100); +} + static int dwc3_pci_quirks(struct dwc3_pci *dwc) { struct platform_device *dwc3 = dwc->dwc3; @@ -134,6 +165,9 @@ static int dwc3_pci_quirks(struct dwc3_pci *dwc) struct gpio_desc *gpio; const char *vendor; + /* On BYT the FW does not always enable the refclock */ + dwc3_pci_enable_ulpi_refclock(pdev); + ret = devm_acpi_dev_add_driver_gpios(&pdev->dev, acpi_dwc3_byt_gpios); if (ret) -- 2.17.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
