linux-kernel - Re: [PATCH 3/5 v12] arm: omap: usb: register hwmods of usbhs

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Message-ID: <CAP05o4L1iR++BhYmYYEc-uV6pGfjBeSPPcFqhRizdBeV7Ko26g@mail.gmail.com>
Date:	Fri, 30 Sep 2011 14:45:32 +0530
From:	"Munegowda, Keshava" <keshava_mgowda@...com>
To:	balbi@...com
Cc:	Paul Walmsley <paul@...an.com>, linux-usb@...r.kernel.org,
	linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org,
	khilman@...com, b-cousson@...com, gadiyar@...com,
	sameo@...ux.intel.com, parthab@...ia.ti.com, tony@...mide.com,
	johnstul@...ibm.com, vishwanath.bs@...com
Subject: Re: [PATCH 3/5 v12] arm: omap: usb: register hwmods of usbhs

On Fri, Sep 30, 2011 at 1:04 PM, Felipe Balbi <balbi@...com> wrote:
> Hi,
>
> On Fri, Sep 30, 2011 at 01:15:55AM -0600, Paul Walmsley wrote:
>> > The hwmod structure of usb_host_hs  and usb_tll are
>> > retrieved and registered with omap device
>> >
>> > Signed-off-by: Keshava Munegowda <keshava_mgowda@...com>
>> > Reviewed-by: Partha Basak <parthab@...ia.ti.com>
>> > ---
>> >  arch/arm/mach-omap2/usb-host.c |  100 ++++++++++++++--------------------------
>> >  1 files changed, 34 insertions(+), 66 deletions(-)
>> >
>> > diff --git a/arch/arm/mach-omap2/usb-host.c b/arch/arm/mach-omap2/usb-host.c
>> > index 89ae298..771dc78 100644
>> > --- a/arch/arm/mach-omap2/usb-host.c
>> > +++ b/arch/arm/mach-omap2/usb-host.c
>> > @@ -28,51 +28,28 @@
>>
>> > +   oh[0] = omap_hwmod_lookup(USBHS_UHH_HWMODNAME);
>> > +   if (!oh[0]) {
>> > +           pr_err("Could not look up %s\n", USBHS_UHH_HWMODNAME);
>> > +           return;
>> >     }
>> >
>> > -   if (platform_device_register(&usbhs_device) < 0)
>> > -           printk(KERN_ERR "USBHS platform_device_register failed\n");
>> > +   oh[1] = omap_hwmod_lookup(USBHS_TLL_HWMODNAME);
>> > +   if (!oh[1]) {
>> > +           pr_err("Could not look up %s\n", USBHS_TLL_HWMODNAME);
>> > +           return;
>> > +   }
>> >
>> > -init_end:
>> > -   return;
>> > +   od = omap_device_build_ss(OMAP_USBHS_DEVICE, bus_id, oh, 2,
>> > +                           (void *)&usbhs_data, sizeof(usbhs_data),
>> > +                           omap_uhhtll_latency,
>> > +                           ARRAY_SIZE(omap_uhhtll_latency), false);
>>
>> Usually there's something wrong with omap_devices that contain
>> multiple hwmods.  Is there some reason why there isn't a separate driver
>> for the TLL?  Judging by a brief look at drivers/mfd/omap_usb_host.c, the
>> TLL handling looks logically distinct?
>
> Yes, I have the same feeling. To my understanding, USB Host Subsystem on
> OMAP is composed of the Transceiver-less link (TLL) and USB Host (UHH).
> Aparently, they could be handled by separate drivers.
>
> --
> balbi

yes, it can be as two separate drivers for uhh and tll;  But i don't
think driver can be used effectively.
Now ehci and ohci gets the clocks , config reg and port settings
through usb host which is sufficient.
If you make them as two different drivers; then ehci and ohci has to
interact with both the drivers separately.
which will be an unnecessary complications. I feel not divided this
driver into two

regards
keshava
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