[2/3] usb: dwc3: pci: Enable ULPI Refclk on platforms where the firmware doesnot

Hi,

On 07-06-18 18:43, Sergei Shtylyov wrote:

Hello!

On 06/07/2018 01:38 PM, Hans de Goede wrote:

quoted

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 <redacted>
---
  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

[...]

quoted

@@ -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");

    Eh?
    BTW, devm_ioremap_resource() prints the error cause already...

quoted

+		return;
+	}
+
+	value = readl(reg + GP_RWREG1);
+	if (!(value & GP_RWREG1_ULPI_REFCLK_DISABLE))

    I guess that dev_err() belongs here...

Nope the error is that GP_RWREG1 cannot be read because the remap
fails. I agree that this is a bit silly and I will fix for v2,
but returning here without printing anything is correct.

Regards,

Hans

quoted

+		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;

[...]

MBR, Sergei

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