On Mon, Sep 19, 2016 at 01:44:36PM +0200, Sascha Hauer wrote: > When switching from gadget to host the driver waits for VBUS
It should be switching from host to gadget > to disappear before doing the actual switch. This waiting is > done by letting hw_wait_reg() poll the OTGSC register. This is > buggy. hw_wait_reg() directly reads the register, but for > reading the OTGSC register hw_read_otgsc() must be used since > this function eventually patches the VBUS status read from extcon > into the raw register value. > To fix this inline the hw_wait_reg() code into its only user and > use the correct function to read the OTGSC register. Since > hw_wait_reg() is unused now remove it. > Stephen Boyd has already posted a similar fix at below: http://www.spinics.net/lists/linux-usb/msg146304.html For patch 1, if there is a separate API to wait vbus to be low, it seems not so necessary. Peter > Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de> > --- > drivers/usb/chipidea/ci.h | 3 --- > drivers/usb/chipidea/core.c | 32 -------------------------------- > drivers/usb/chipidea/otg.c | 16 ++++++++++++---- > 3 files changed, 12 insertions(+), 39 deletions(-) > > diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h > index cd41455..05bc4d6 100644 > --- a/drivers/usb/chipidea/ci.h > +++ b/drivers/usb/chipidea/ci.h > @@ -428,9 +428,6 @@ int hw_port_test_set(struct ci_hdrc *ci, u8 mode); > > u8 hw_port_test_get(struct ci_hdrc *ci); > > -int hw_wait_reg(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask, > - u32 value, unsigned int timeout_ms); > - > void ci_platform_configure(struct ci_hdrc *ci); > > int dbg_create_files(struct ci_hdrc *ci); > diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c > index 69426e6..01390e0 100644 > --- a/drivers/usb/chipidea/core.c > +++ b/drivers/usb/chipidea/core.c > @@ -516,38 +516,6 @@ int hw_device_reset(struct ci_hdrc *ci) > return 0; > } > > -/** > - * hw_wait_reg: wait the register value > - * > - * Sometimes, it needs to wait register value before going on. > - * Eg, when switch to device mode, the vbus value should be lower > - * than OTGSC_BSV before connects to host. > - * > - * @ci: the controller > - * @reg: register index > - * @mask: mast bit > - * @value: the bit value to wait > - * @timeout_ms: timeout in millisecond > - * > - * This function returns an error code if timeout > - */ > -int hw_wait_reg(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask, > - u32 value, unsigned int timeout_ms) > -{ > - unsigned long elapse = jiffies + msecs_to_jiffies(timeout_ms); > - > - while (hw_read(ci, reg, mask) != value) { > - if (time_after(jiffies, elapse)) { > - dev_err(ci->dev, "timeout waiting for %08x in %d\n", > - mask, reg); > - return -ETIMEDOUT; > - } > - msleep(20); > - } > - > - return 0; > -} > - > static irqreturn_t ci_irq(int irq, void *data) > { > struct ci_hdrc *ci = data; > diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c > index 91989be..d1c4cdf 100644 > --- a/drivers/usb/chipidea/otg.c > +++ b/drivers/usb/chipidea/otg.c > @@ -104,7 +104,6 @@ void ci_handle_vbus_change(struct ci_hdrc *ci) > usb_gadget_vbus_disconnect(&ci->gadget); > } > > -#define CI_VBUS_STABLE_TIMEOUT_MS 5000 > static void ci_handle_id_switch(struct ci_hdrc *ci) > { > enum ci_role role = ci_otg_role(ci); > @@ -117,10 +116,19 @@ static void ci_handle_id_switch(struct ci_hdrc *ci) > > ci_role_stop(ci); > > - if (role == CI_ROLE_GADGET) > + if (role == CI_ROLE_GADGET) { > + unsigned long elapse = jiffies + msecs_to_jiffies(5000); > + > /* wait vbus lower than OTGSC_BSV */ > - hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0, > - CI_VBUS_STABLE_TIMEOUT_MS); > + while (hw_read_otgsc(ci, OTGSC_BSV)) { > + if (time_after(jiffies, elapse)) { > + dev_err(ci->dev, > + "timeout waiting for VBUS disappear\n"); > + break; > + } > + msleep(20); > + } > + } > > ci_role_start(ci, role); > } > -- > 2.8.1 > > -- > 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 -- Best Regards, Peter Chen -- 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
