From: Archit Taneja <a0393947@ti.com>
To: Benoit Cousson <b-cousson@ti.com>, "paul@pwsan.com" <paul@pwsan.com>
Cc: "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Subject: query about _setup() in omap_hwmod.c
Date: Wed, 11 Apr 2012 15:07:10 +0530 [thread overview]
Message-ID: <4F8550C6.9050402@ti.com> (raw)
Hi,
I had a query about the _setup() function in
arch/arm/mach-omap2/omap_hwmod.c:
The function enables slave clocks right in the beginning, and based on
the value of postsetup_state, it either calls _idle(), _shutdown() or
does nothing.
Now, for the case of _idle() or _shutdown(), I guess it's the job of
_disable_clocks() to disable the slave clocks before we exit _setup().
If we compare how the slave clocks are enabled and disabled in _setup()
and _disable_clocks() respectively:
static int _setup(struct omap_hwmod *oh, void *data)
{
...
...
if (os->flags & OCPIF_SWSUP_IDLE) {
/* XXX omap_iclk_deny_idle(c); */
} else {
/* XXX omap_iclk_allow_idle(c); */
clk_enable(c);
}
}
...
...
}
static int _disable_clocks(struct omap_hwmod *oh)
{
...
...
if (c && (os->flags & OCPIF_SWSUP_IDLE))
clk_disable(c);
...
...
}
Both these functions are taking different decisions based on whether
os->flags has OCPIF_SWSUP_IDLE or not.
Would this lead to some sort of clk_enable() and clk_disable() mismatch?
If I boot a 3.4-rc1 kernel on beagle with omap2plus_defconfig, I get:
cat /sys/kernel/debug/clock/summary | grep dss
name parent freq use_count
dss_ick l4_ick 83000000 4
dss2_alwon_fck sys_ck 13000000 0
dss_96m_fck omap_96m_fck 96000000 0
dss_tv_fck omap_54m_fck 54000000 0
dss1_alwon_fck dpll4_m4x2_ck 144000000 0
dss_ick is the slave clock of all the dss hwmods on omap3. This doesn't
seem to be right, does it?
Thanks,
Archit
next reply other threads:[~2012-04-11 9:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-11 9:37 Archit Taneja [this message]
2012-04-13 8:09 ` query about _setup() in omap_hwmod.c Paul Walmsley
2012-04-13 8:21 ` Archit Taneja
2012-04-13 8:35 ` Cousson, Benoit
2012-04-13 8:39 ` Paul Walmsley
2012-04-13 8:52 ` Archit Taneja
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