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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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