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    SubjectRe: [PATCH v6 3/5] usb: dwc3: add phyif_utmi_quirk
    Date
    Hi William,

    Am Donnerstag, 7. Juli 2016, 10:54:24 schrieb William Wu:
    > Add a quirk to configure the core to support the
    > UTMI+ PHY with an 8- or 16-bit interface. UTMI+ PHY
    > interface is hardware property, and it's platform
    > dependent. Normall, the PHYIf can be configured
    > during coreconsultant. But for some specific usb
    > cores(e.g. rk3399 soc dwc3), the default PHYIf
    > configuration value is fault, so we need to
    > reconfigure it by software.
    >
    > And refer to the dwc3 databook, the GUSB2PHYCFG.USBTRDTIM
    > must be set to the corresponding value according to
    > the UTMI+ PHY interface.
    >
    > Signed-off-by: William Wu <william.wu@rock-chips.com>
    > ---
    [...]
    > diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt
    > b/Documentation/devicetree/bindings/usb/dwc3.txt index 020b0e9..8d7317d
    > 100644
    > --- a/Documentation/devicetree/bindings/usb/dwc3.txt
    > +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
    > @@ -42,6 +42,10 @@ Optional properties:
    > - snps,dis-u2-freeclk-exists-quirk: when set, clear the
    > u2_freeclk_exists in GUSB2PHYCFG, specify that USB2 PHY doesn't provide
    > a free-running PHY clock.
    > + - snps,phyif-utmi-quirk: when set core will set phyif UTMI+ interface.
    > + - snps,phyif-utmi: the value to configure the core to support a UTMI+
    > PHY + with an 8- or 16-bit interface. Value 0 select 8-bit
    > + interface, value 1 select 16-bit interface.

    maybe
    snps,phyif-utmi-width = <8> or <16>;

    devicetree is about describing the hardware, not the things that get written
    to registers :-) . The conversion from the described width to the register
    value can easily be done in the driver.


    Also I don't think you need two properties for this. If the snps,phyif-utmi
    property is specified it indicates that you want to manually set the width
    and if it is absent you want to use the IC default. All functions reading
    property-values indicate if the property is missing.

    But it looks like there is already a precendence in
    snps,tx_de_emphasis(_quirk), so maybe Felipe has a different opinion here?



    > - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
    > utmi_l1_suspend_n, false when asserts utmi_sleep_n
    > - snps,hird-threshold: HIRD threshold
    > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
    > index 0b7bfd2..94036b1 100644
    > --- a/drivers/usb/dwc3/core.c
    > +++ b/drivers/usb/dwc3/core.c
    > @@ -408,6 +408,7 @@ static void dwc3_cache_hwparams(struct dwc3 *dwc)
    > static int dwc3_phy_setup(struct dwc3 *dwc)
    > {
    > u32 reg;
    > + u32 usbtrdtim;
    > int ret;
    >
    > reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
    > @@ -503,6 +504,15 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
    > if (dwc->dis_u2_freeclk_exists_quirk)
    > reg &= ~DWC3_GUSB2PHYCFG_U2_FREECLK_EXISTS;
    >
    > + if (dwc->phyif_utmi_quirk) {
    > + reg &= ~(DWC3_GUSB2PHYCFG_PHYIF_MASK |
    > + DWC3_GUSB2PHYCFG_USBTRDTIM_MASK);
    > + usbtrdtim = dwc->phyif_utmi ? USBTRDTIM_UTMI_16_BIT :
    > + USBTRDTIM_UTMI_8_BIT;
    > + reg |= DWC3_GUSB2PHYCFG_PHYIF(dwc->phyif_utmi) |
    > + DWC3_GUSB2PHYCFG_USBTRDTIM(usbtrdtim);
    > + }
    > +
    > dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
    >
    > return 0;
    > @@ -834,6 +844,7 @@ static int dwc3_probe(struct platform_device *pdev)
    > struct resource *res;
    > struct dwc3 *dwc;
    > u8 lpm_nyet_threshold;
    > + u8 phyif_utmi;
    > u8 tx_de_emphasis;
    > u8 hird_threshold;
    >
    > @@ -880,6 +891,9 @@ static int dwc3_probe(struct platform_device *pdev)
    > /* default to highest possible threshold */
    > lpm_nyet_threshold = 0xff;
    >
    > + /* default to UTMI+ 8-bit interface */
    > + phyif_utmi = 0;
    > +
    > /* default to -3.5dB de-emphasis */
    > tx_de_emphasis = 1;
    >
    > @@ -929,6 +943,10 @@ static int dwc3_probe(struct platform_device *pdev)
    > "snps,dis_rxdet_inp3_quirk");
    > dwc->dis_u2_freeclk_exists_quirk = device_property_read_bool(dev,
    > "snps,dis-u2-freeclk-exists-quirk");
    > + dwc->phyif_utmi_quirk = device_property_read_bool(dev,
    > + "snps,phyif-utmi-quirk");
    > + device_property_read_u8(dev, "snps,phyif-utmi",
    > + &phyif_utmi);


    As described above device_property_read_u8 will return an error if the
    property is not present, so you could fill your dwc->phyif_utmi_quirk from
    that:

    ret = device_property_read_u8(dev, "snps,phyif-utmi",
    &phyif_utmi);
    dwc->phyif_utmi_quirk = (ret == 0) ? true : false;


    Heiko

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