On Thu, 2017-01-19 at 13:22 +0100, Matthias Brugger wrote: > > On 18/01/17 07:08, Chunfeng Yun wrote: > > usually, the reference clock comes from 26M oscillator directly, > > but some SoCs are not, add it for compatibility. > > > > Signed-off-by: Chunfeng Yun <[email protected]> > > --- > > drivers/usb/mtu3/mtu3.h | 1 + > > drivers/usb/mtu3/mtu3_plat.c | 21 +++++++++++++++++++-- > > 2 files changed, 20 insertions(+), 2 deletions(-) [...] > > @@ -154,6 +162,7 @@ static int ssusb_rscs_init(struct ssusb_mtk *ssusb) > > static void ssusb_rscs_exit(struct ssusb_mtk *ssusb) > > { > > clk_disable_unprepare(ssusb->sys_clk); > > + clk_disable_unprepare(ssusb->ref_clk); > > regulator_disable(ssusb->vusb33); > > ssusb_phy_power_off(ssusb); > > ssusb_phy_exit(ssusb); > > @@ -216,6 +225,12 @@ static int get_ssusb_rscs(struct platform_device > > *pdev, struct ssusb_mtk *ssusb) > > return PTR_ERR(ssusb->sys_clk); > > } > > > > + ssusb->ref_clk = devm_clk_get(dev, "ref_ck"); > > + if (IS_ERR(ssusb->ref_clk)) { > > + dev_err(dev, "failed to get ref clock\n"); > > + return PTR_ERR(ssusb->ref_clk); > > + } > > + > > That would break older dts bindings, right? Yes, So I send a new patch for the related dts. Maybe it's not a problem, only one dts file need be updated currently.
> ref_ck must be optional for the code. I tend to make it be optional for the dts, but not for the code. There are some "fixed-clock" which can be treated as dummy ones, and if a clock is really optional, we can use one fixed-clock in dts, and keep the code simple. In fact, the reference clock is essential for usb controller. > > Regards, > Matthias
