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SubjectRe: [PATCH 4/4] usb: phy: omap-usb2: enable 960Mhz clock for omap5
Hi,

On Wed, Sep 26, 2012 at 11:10:48AM +0530, ABRAHAM, KISHON VIJAY wrote:
> Hi,
>
> On Wed, Sep 19, 2012 at 5:26 PM, Felipe Balbi <balbi@ti.com> wrote:
> > On Wed, Sep 19, 2012 at 05:00:29PM +0530, Kishon Vijay Abraham I wrote:
> >> "usb_otg_ss_refclk960m" is needed by usb2 phy present in omap5. For
> >> omap4, the clk_get of this clock will fail since it does not have this
> >> clock.
> >>
> >> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
> >> ---
> >> Documentation/devicetree/bindings/usb/usb-phy.txt | 3 +++
> >> drivers/usb/phy/omap-usb2.c | 28 ++++++++++++++++++++-
> >> 2 files changed, 30 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/usb-phy.txt b/Documentation/devicetree/bindings/usb/usb-phy.txt
> >> index 7c5fd89..d5626de 100644
> >> --- a/Documentation/devicetree/bindings/usb/usb-phy.txt
> >> +++ b/Documentation/devicetree/bindings/usb/usb-phy.txt
> >> @@ -24,6 +24,9 @@ Required properties:
> >> add the address of control module phy power register until a driver for
> >> control module is added
> >>
> >> +Optional properties:
> >> + - has960mhzclk: should be added if the phy needs 960mhz clock
> >> +
> >> This is usually a subnode of ocp2scp to which it is connected.
> >>
> >> usb3phy@4a084400 {
> >> diff --git a/drivers/usb/phy/omap-usb2.c b/drivers/usb/phy/omap-usb2.c
> >> index d36c282..d6612ba 100644
> >> --- a/drivers/usb/phy/omap-usb2.c
> >> +++ b/drivers/usb/phy/omap-usb2.c
> >> @@ -146,6 +146,7 @@ static int __devinit omap_usb2_probe(struct platform_device *pdev)
> >> struct omap_usb *phy;
> >> struct usb_otg *otg;
> >> struct resource *res;
> >> + struct device_node *np = pdev->dev.of_node;
> >>
> >> phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
> >> if (!phy) {
> >> @@ -190,6 +191,15 @@ static int __devinit omap_usb2_probe(struct platform_device *pdev)
> >> }
> >> clk_prepare(phy->wkupclk);
> >>
> >> + if (of_property_read_bool(np, "has960mhzclk")) {
> >> + phy->optclk = devm_clk_get(phy->dev, "usb_otg_ss_refclk960m");
> >> + if (IS_ERR(phy->optclk)) {
> >> + dev_err(&pdev->dev, "unable to get refclk960m\n");
> >> + return PTR_ERR(phy->optclk);
> >> + }
> >> + clk_prepare(phy->optclk);
> >> + }
> >
> > instead, can't you just always try to get the clock but ignore the error
> > if it fails ?
>
> This clock is needed for usb2 to work in dwc3 (omap5). So we have to
> report the error in case we dont get the clock no?

sure, but you don't need to bail out. Print a warning message such as:

dev_dbg(&pdev->dev, "couldn't get refclk960m, trying without\n");

or something similar. Then you don't need to add this has960mhzclk flag
to dts files.

--
balbi
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