Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1395247

Re: [RFC v2 10/13] usb: hub: Power sequence the ports on activation

Show all headers | View raw

On Thu, May 05, 2016 at 10:09:47AM -0400, Alan Stern wrote:
> On Thu, 5 May 2016, Krzysztof Kozlowski wrote:
> 
> > The autodetection of attached USB device might not work on certain
> > boards where the power is delivered externally. These devices also might
> > require a hard reset. Use pwrseq for that in USB hub.
> > 
> > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> > ---
> >  drivers/usb/core/hub.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index 1c82fcc448f5..0fddaacc62bf 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -26,6 +26,7 @@
> >  #include <linux/mutex.h>
> >  #include <linux/random.h>
> >  #include <linux/pm_qos.h>
> > +#include <linux/pwrseq.h>
> >  
> >  #include <asm/uaccess.h>
> >  #include <asm/byteorder.h>
> > @@ -1661,7 +1662,17 @@ static int hub_configure(struct usb_hub *hub,
> >  
> >  	usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
> >  
> > +	/* FIXME: When do the pre-power-on? */
> 
> It's hard to answer this without knowing what pre-power-on involves.

In my particular case, I want to achieve a full reset through regulator (off
and on) because the bootloader left it in initialized state. I assume
that if bootloader did not configure the device, the reset won't be
harmful.

In a MMC case, this pre-power-on on is setting the 'reset' GPIO (thus
triggering the reset) and post-power-on is clearing the 'reset'.

> Why not create a pwrseq_power_on() routine that does pre_power_on 
> followed by post_power_on?

For my purpose it seems sensible.

> 
> > +	/*
> > +	for (i = 0; i < maxchild; i++)
> > +		pwrseq_pre_power_on(hub->ports[i]->pwrseq);
> > +	*/
> > +
> > +	for (i = 0; i < maxchild; i++)
> > +		pwrseq_post_power_on(hub->ports[i]->pwrseq);
> 
> This is patch 10/13.  hub->ports[i]->pwrseq doesn't get added until 
> 11/13.  Obviously you never tried compiling each patch in the series.

Ahh yes, I forgot to reorder them. Thanks for spotting this.

> 
> > +
> >  	hub_activate(hub, HUB_INIT);
> > +
> 
> Unnecessary blank line added.

Thanks for feedback,
Krzysztof

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
  [RFC v2 03/13] MAINTAINERS: Retain Ulf Hansson as the same maintainer  of pwrseq Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 03/13] MAINTAINERS: Retain Ulf Hansson as the same  maintainer of pwrseq Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 20:50 +0200
  [RFC v2 08/13] usb: hub: Handle deferred probe Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
  [RFC v2 09/13] power: pwrseq: Add support for USB hubs with external  power Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 09/13] power: pwrseq: Add support for USB hubs with  external power Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 22:00 +0200
      Re: [RFC v2 09/13] power: pwrseq: Add support for USB hubs with  external power Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:30 +0200
  [RFC v2 10/13] usb: hub: Power sequence the ports on activation Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 10/13] usb: hub: Power sequence the ports on activation Alan Stern <stern@rowland.harvard.edu> - 2016-05-05 16:20 +0200
      Re: [RFC v2 10/13] usb: hub: Power sequence the ports on activation Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 19:40 +0200
    Re: [RFC v2 10/13] usb: hub: Power sequence the ports on activation Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 22:00 +0200
  [RFC v2 04/13] power: pwrseq: Enable COMPILE_TEST for drivers Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 04/13] power: pwrseq: Enable COMPILE_TEST for drivers Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 21:00 +0200
  [RFC v2 06/13] power: pwrseq: Generalize mmc_pwrseq operations by  removing mmc prefix Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 06/13] power: pwrseq: Generalize mmc_pwrseq operations by  removing mmc prefix Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 21:20 +0200
  [RFC v2 12/13] ARM: dts: exynos: Switch the buck8 to GPIO mode on  Odroid U3 Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
  [RFC v2 11/13] usb: port: Parse pwrseq phandle from Device Tree Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 11/13] usb: port: Parse pwrseq phandle from Device Tree Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 22:20 +0200
      Re: [RFC v2 11/13] usb: port: Parse pwrseq phandle from Device Tree Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:30 +0200
  [RFC v2 13/13] ARM: dts: exynos: Fix LAN and HUB after bootloader  initialization on Odroid U3 Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 13/13] ARM: dts: exynos: Fix LAN and HUB after bootloader  initialization on Odroid U3 Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 22:20 +0200
      Re: [RFC v2 13/13] ARM: dts: exynos: Fix LAN and HUB after bootloader  initialization on Odroid U3 Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:30 +0200
  [RFC v2 05/13] power: pwrseq: Remove mmc prefix from mmc_pwrseq Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 05/13] power: pwrseq: Remove mmc prefix from mmc_pwrseq Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 21:20 +0200
      Re: [RFC v2 05/13] power: pwrseq: Remove mmc prefix from mmc_pwrseq Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:30 +0200
  [RFC v2 07/13] power: pwrseq: simple: Add support for toggling  regulator Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:40 +0200
    Re: [RFC v2 07/13] power: pwrseq: simple: Add support for toggling  regulator Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 21:40 +0200
      Re: [RFC v2 07/13] power: pwrseq: simple: Add support for toggling  regulator Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:30 +0200
  [RFC v2 02/13] power/mmc: Move pwrseq drivers to power/pwrseq Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-05 14:50 +0200
    Re: [RFC v2 02/13] power/mmc: Move pwrseq drivers to power/pwrseq Javier Martinez Canillas <javier@osg.samsung.com> - 2016-05-05 20:50 +0200
      Re: [RFC v2 02/13] power/mmc: Move pwrseq drivers to power/pwrseq Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:20 +0200
  Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Rob Herring <robh@kernel.org> - 2016-05-06 00:50 +0200
    Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Peter Chen <hzpeterchen@gmail.com> - 2016-05-06 08:00 +0200
      Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:20 +0200
        Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Peter Chen <hzpeterchen@gmail.com> - 2016-05-06 09:30 +0200
    Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2016-05-06 08:20 +0200
      Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Rob Herring <robh@kernel.org> - 2016-05-06 15:10 +0200
    Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Ulf Hansson <ulf.hansson@linaro.org> - 2016-05-09 09:50 +0200
      Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Rob Herring <robh@kernel.org> - 2016-05-09 20:20 +0200
        Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Ulf Hansson <ulf.hansson@linaro.org> - 2016-05-10 13:10 +0200

csiph-web