From: khilman@baylibre•com (Kevin Hilman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 4/7] phy: meson: add USB2 PHY support for Meson8b and GXBB
Date: Tue, 13 Sep 2016 17:59:11 -0700 [thread overview]
Message-ID: <7hzinbmh40.fsf@baylibre.com> (raw)
In-Reply-To: <CAFBinCC+izGS72TZuiiBu=DjtSmoZXRZ6r76M6rC8W7UTpSD6g@mail.gmail.com> (Martin Blumenstingl's message of "Tue, 13 Sep 2016 20:38:06 +0200")
Martin Blumenstingl <martin.blumenstingl@googlemail•com> writes:
> On Tue, Sep 13, 2016 at 5:28 PM, Philipp Zabel <p.zabel@pengutronix•de> wrote:
[...]
>>> I added Philipp and Hans to this thread - maybe they can comment on this.
>>> To sum it up, our problem is:
>>> - there are two separate USB PHYs on Meson GXBB
>>> - both are sharing the same reset line (provided by the reset-meson driver)
>>> - during initialization of the PHYs we must only call
>>> reset_control_reset(rstc) once (if we do it for the first *and* second
>>> PHY then the first PHY gets confused once the second PHY uses the
>>> reset because the first PHY's state is reset as well)
>>
>> If you have an initially asserted reset line and you can enable the
>> first module by deasserting the reset via reset_control_deassert (and
>> reset_control_assert to signal when the module may be disabled again
>> after use), shared resets are for you.
>>
>> If you need a reset pulse or have no direct control over the reset line,
>> (device_reset), the reset framework currently has no solution for this.
>> The ugly thing about reset_control_once would be that it can't re-reset
>> modules when unloading and reloading driver modules.
>
> The corresponding reset driver in question is reset-meson, which only
> implements reset (assert/deassert are not implemented). However, I
> don't know if this is due to hardware design.
> I think the hardware implements the latter, but maybe Neil can give
> more information here (I currently don't have access to my board so I
> cannot test how the hardware actually behaves).
It's implemented that way because the hardware only supports a reset
pulse.
Kevin
next prev parent reply other threads:[~2016-09-14 0:59 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-04 21:31 [PATCH 0/7] usb/phy: Add Amlogic Meson8b and GXBB USB support Martin Blumenstingl
2016-09-04 21:31 ` [PATCH 1/7] clk: gxbb: expose USB clocks Martin Blumenstingl
2016-09-07 0:33 ` Stephen Boyd
2016-09-07 21:32 ` Martin Blumenstingl
2016-09-07 22:14 ` Stephen Boyd
2016-09-08 2:24 ` Kevin Hilman
2016-09-07 21:28 ` Stephen Boyd
2016-09-08 19:24 ` Kevin Hilman
2016-09-04 21:31 ` [PATCH 2/7] usb: dwc2: add support for Meson8b and GXBB SoCs Martin Blumenstingl
2016-09-07 21:04 ` John Youn
2016-09-04 21:31 ` [PATCH 3/7] Documentation: dt-bindings: Add documentation for the Meson USB2 PHYs Martin Blumenstingl
2016-09-04 21:31 ` [PATCH 4/7] phy: meson: add USB2 PHY support for Meson8b and GXBB Martin Blumenstingl
2016-09-08 19:35 ` Kevin Hilman
2016-09-08 19:40 ` Ben Dooks
2016-09-08 19:52 ` Martin Blumenstingl
2016-09-08 20:20 ` Ben Dooks
2016-09-08 20:42 ` Kevin Hilman
2016-09-08 20:53 ` Ben Dooks
2016-09-08 21:48 ` Martin Blumenstingl
2016-09-09 15:33 ` Kevin Hilman
2016-09-09 16:14 ` Martin Blumenstingl
2016-09-09 17:04 ` Kevin Hilman
2016-09-09 17:21 ` Ben Dooks
2016-09-09 20:37 ` Martin Blumenstingl
2016-09-16 8:19 ` Kishon Vijay Abraham I
2016-09-16 13:47 ` Arnd Bergmann
2016-09-18 19:56 ` Martin Blumenstingl
2016-09-19 4:59 ` Kishon Vijay Abraham I
2016-09-19 7:37 ` Arnd Bergmann
2016-09-09 20:36 ` Martin Blumenstingl
2016-09-11 13:44 ` Martin Blumenstingl
2016-09-12 17:32 ` Kevin Hilman
2016-09-13 15:28 ` Philipp Zabel
2016-09-13 18:38 ` Martin Blumenstingl
2016-09-14 0:59 ` Kevin Hilman [this message]
2016-09-14 8:36 ` Philipp Zabel
2016-09-14 8:37 ` Philipp Zabel
2016-09-14 21:09 ` Martin Blumenstingl
2016-09-14 8:37 ` Philipp Zabel
2016-09-14 21:23 ` Martin Blumenstingl
2016-09-15 10:30 ` Philipp Zabel
2016-09-04 21:31 ` [PATCH 5/7] ARM64: meson-gxbb: add USB Nodes Martin Blumenstingl
2016-09-05 0:23 ` Andreas Färber
2016-09-04 21:31 ` [PATCH 6/7] ARM64: meson-gxbb-p20x: Enable " Martin Blumenstingl
2016-09-04 21:31 ` [PATCH 7/7] ARM64: meson-gxbb-vega-s95: " Martin Blumenstingl
2016-09-11 13:41 ` [PATCH v2 0/6] usb/phy: Add Amlogic Meson8b and GXBB USB support Martin Blumenstingl
2016-09-11 13:41 ` [PATCH v2 1/6] usb: dwc2: add support for Meson8b and GXBB SoCs Martin Blumenstingl
2016-09-14 16:11 ` Kevin Hilman
2016-09-14 18:12 ` John Youn
2016-09-14 18:17 ` Kevin Hilman
2016-09-14 18:26 ` John Youn
2016-09-14 18:36 ` Kevin Hilman
2016-09-20 14:27 ` Rob Herring
2016-09-11 13:41 ` [PATCH v2 2/6] Documentation: dt-bindings: Add documentation for the Meson USB2 PHYs Martin Blumenstingl
2016-09-20 14:29 ` Rob Herring
2016-09-21 18:38 ` Kevin Hilman
2016-09-11 13:41 ` [PATCH v2 3/6] phy: meson: add USB2 PHY support for Meson8b and GXBB Martin Blumenstingl
2016-09-14 16:06 ` Kevin Hilman
2016-09-17 4:17 ` Kishon Vijay Abraham I
2016-09-19 16:42 ` Kevin Hilman
2016-09-20 5:01 ` Kishon Vijay Abraham I
2016-09-14 21:30 ` Martin Blumenstingl
2016-09-11 13:41 ` [PATCH v2 4/6] ARM64: meson-gxbb: add USB Nodes Martin Blumenstingl
2016-09-15 22:10 ` Kevin Hilman
2016-09-11 13:41 ` [PATCH v2 5/6] ARM64: meson-gxbb-p20x: Enable " Martin Blumenstingl
2016-09-14 18:05 ` Kevin Hilman
2016-09-15 22:09 ` Kevin Hilman
2016-09-11 13:41 ` [PATCH v2 6/6] ARM64: meson-gxbb-vega-s95: " Martin Blumenstingl
2016-09-15 22:10 ` Kevin Hilman
2016-10-01 12:18 ` [PATCH v3 0/3] usb/phy: Add Amlogic Meson8b and GXBB USB support Martin Blumenstingl
2016-10-01 12:18 ` [PATCH v3 1/3] Documentation: dt-bindings: update the meson-usb2-phy example Martin Blumenstingl
2016-10-09 1:28 ` Rob Herring
2016-10-01 12:18 ` [PATCH v3 2/3] Documentation: dt-bindings: rename meson-usb2-phy to meson8b-usb2-phy Martin Blumenstingl
2016-10-09 1:28 ` Rob Herring
2016-10-01 12:19 ` [PATCH v3 3/3] phy: meson: add USB2 PHY support for Meson8b and GXBB Martin Blumenstingl
2016-10-13 20:27 ` [PATCH v3 0/3] usb/phy: Add Amlogic Meson8b and GXBB USB support Martin Blumenstingl
2016-10-19 10:52 ` Kishon Vijay Abraham I
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