On Thu, 12 May 2016, Wenyou Yang wrote: > In order to get lower consumption, as a workaround, suspend > the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt > Configuration Register while OHCI USB suspending.
What does this mean? What does suspending a port do? Is it the same as a normal USB port suspend? If it is the same, why doesn't the USB_PORT_FEAT_SUSPEND subcase of the SetPortFeature case in ohci_hub_control() already take care of this? > This suspend operation must be done before stopping the USB clock, > resume after the USB clock enabled. > > Signed-off-by: Wenyou Yang <wenyou.y...@atmel.com> > --- > @@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device *pdev) > > /*-------------------------------------------------------------------------*/ > > +struct regmap *at91_dt_syscon_sfr(void) > +{ > + struct regmap *regmap; > + > + regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr"); > + if (IS_ERR(regmap)) > + return NULL; If you get an error, the regmap pointer is set to NULL... > @@ -197,6 +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver > *driver, > goto err; > } > > + ohci_at91->sfr_regmap = at91_dt_syscon_sfr(); With no other error checking... > + > board = hcd->self.controller->platform_data; > ohci = hcd_to_ohci(hcd); > ohci->num_ports = board->ports; > +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable) > +{ > + u32 regval; > + int ret; > + > + if (IS_ERR(regmap)) > + return PTR_ERR(regmap); > + > + ret = regmap_read(regmap, SFR_OHCIICR, ®val); And now what happens if regmap is NULL? Hint: It won't be pretty... Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html