From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/4] ARM: OMAP2+: omap_hwmod: Introduce ti,no-init dt property
Date: Thu, 5 Mar 2015 12:17:14 -0800 [thread overview]
Message-ID: <20150305201713.GH13520@atomide.com> (raw)
In-Reply-To: <54F8B2C7.7060202@ti.com>
* Dave Gerlach <d-gerlach@ti.com> [150305 11:53]:
> On 03/05/2015 12:49 PM, Tony Lindgren wrote:
> > * Paul Walmsley <paul@pwsan.com> [150305 10:16]:
> >> On Thu, 5 Mar 2015, Dave Gerlach wrote:
> >>
> >>> Introduce a dt property, ti,no-init, that prevents hwmod initialization.
> >>> Even if a dt node is marked as disabled, hwmod still at least enables
> >>> the hwmod and programs the sysconfig before attempting to idle it at
> >>> boot. If an IP has been disabled by the hardware configuration on a
> >>> platform, this will cause a hang due to writing to inactive registers.
> >>> This property prevents that from happening by marking the hwmod as
> >>> _HWMOD_STATE_DISABLED during init.
> >>
> >> I'm kind of wondering if hwmod should even touch a device if it's marked
> >> as disabled in the DT. Tony, what do you think?
> >
> > Well nothing happens if a device is status = "disabled". No dev entry
> > gets created for it at all and hwmod won't have any data for the device
> > populated. The only way hwmod code could see that device if the device
> > gets it's data from the legacy omap_hwmod_*_data.c instead of DT.
> >
>
> We still need this for the sysconfig programming, correct? hwmod programs that
> regardless of dt status and then idles the IP,
Well hwmod does not even know about the IP IO addresses if it's marked
with status = "disabled".. Which IP are you having problems with?
> which is why I needed the ti,no-init for the epos evm. It isn't just a
> matter of we shouldnt write to it because we don't want to use it; we
> can't write to it because the module is held off so it causes an
> external abort if we do.
Well hard to say not knowing which module this is.. Pretty much all
the modules have drivers and the driver just does pm_runtime_get()
on it?
Regards,
Tony
next prev parent reply other threads:[~2015-03-05 20:17 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-05 13:13 [PATCH 0/4] Add AM437x RTC Dave Gerlach
2015-03-05 13:13 ` [PATCH 1/4] ARM: OMAP2+: omap_hwmod: Introduce ti, no-init dt property Dave Gerlach
2015-03-05 18:16 ` [PATCH 1/4] ARM: OMAP2+: omap_hwmod: Introduce ti,no-init " Paul Walmsley
2015-03-05 18:49 ` Tony Lindgren
2015-03-05 19:47 ` Dave Gerlach
2015-03-05 20:17 ` Tony Lindgren [this message]
2015-03-06 0:41 ` Tony Lindgren
2015-03-06 17:28 ` Dave Gerlach
2015-03-06 17:45 ` Tony Lindgren
2015-03-10 16:12 ` Dave Gerlach
2015-03-10 17:36 ` Grygorii Strashko
2015-03-10 17:59 ` Dave Gerlach
2015-03-11 16:32 ` Grygorii Strashko
2015-03-12 20:05 ` Dave Gerlach
2015-03-05 13:13 ` [PATCH 2/4] ARM: OMAP2+: AM43xx hwmod: Add RTC hwmod for AM43xx Dave Gerlach
2015-03-06 4:26 ` Paul Walmsley
2015-03-06 17:30 ` Dave Gerlach
2015-03-06 17:44 ` Paul Walmsley
2015-03-06 17:50 ` Dave Gerlach
2015-03-07 0:37 ` Paul Walmsley
2015-03-05 13:13 ` [PATCH 3/4] ARM: dts: am43x-epos-evm: Add rtc node with ti, no-init property Dave Gerlach
2015-03-05 13:13 ` [PATCH 4/4] ARM: dts: am437x-gp-evm: Enable RTC Dave Gerlach
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