Linux on ARM based TI OMAP SoCs
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From: Roger Quadros <rogerq@ti.com>
To: Tero Kristo <t-kristo@ti.com>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Cc: "Menon, Nishanth" <nm@ti.com>,
	"tony@atomide.com" <tony@atomide.com>,
	Michael Trimarchi <michael@amarulasolutions.com>,
	"Balbi, Felipe" <balbi@ti.com>,
	George Cherian <george.cherian@ti.com>
Subject: Re: omap USB_DPLL not configured as per manual
Date: Wed, 15 Oct 2014 11:22:04 +0300	[thread overview]
Message-ID: <543E2EAC.6010808@ti.com> (raw)
In-Reply-To: <543D7E3B.7010503@ti.com>

On 10/14/2014 10:49 PM, Tero Kristo wrote:
> On 10/14/2014 01:47 PM, Roger Quadros wrote:
>> Hi Tero,
>>
>> The USB_DPLL doesn't have recommended M/N settings as per the TRM [1]
>> Thus the omapconf audit fails.
>>
>> Any ideas of how we can fix this up? Should we add a new clock.ops structure for
>> USB_DPLL to make sure that we don't violate the TRM recommended settings?
>> or should we just add some flags in dpll_data? We would need a new compatible id for sure.
>>
>> [1] - OMAP4460_ES1.x_NDA_TRM_vP.pdf - 3.6.3.9.5 DPLL_USB Preferred Settings
> 
> The version of TRM I have doesn't have the recommended settings chapter, I need to download the doc.
> 
> I guess we probably should introduce new fields to the dpll_data for this, does the TRM list an expected minimum divider / multiplier or just a single pair of recommended values? Do the other DPLLs have similar values? Looking at the DM I have here I see a recommended internal reference clock values for the DPLLs (min/max) and is calculated based on the refclk + N value.
> 

At least for the USB_DPLL it is single M:N pair for each possible sysclk frequency.
For other DPLLs they seem to depend on OPP as well as sys_clk.

cheers,
-roger

>>
>> panda4460> omapconf audit dpll -d usb
>> |-------------------------------------------------------------------------------------|
>> | DPLL_USB AUDIT (@OPP OPP100, sysclk=38.4MHz) | Current Setting | Expected  | STATUS |
>> |-------------------------------------------------------------------------------------|
>> | Status                                       | Locked          | Locked    | Pass   |
>> | Mode                                         | Lock            | Lock      | Pass   |
>> | Autoidle Mode                                | Auto LPST       | Auto LPST | Pass   |
>> | Low-Power Mode                               | Disabled        | Disabled  | Pass   |
>> | REGM4XEN Mode                                | Disabled        | Disabled  | Pass   |
>> | DCC Mode                                     | Disabled        | Disabled  | Pass   |
>> | M Divider                                    | 25              | 400       | FAIL   |
>> | N Divider                                    | 0               | 15        | FAIL   |
>> | Lock Frequency                               | 960.0MHz        | 960.0MHz  | Pass   |
>> | M2 Divider                                   | 2               | 2         | Pass   |
>> | CLKOUT Output Rate                           | 480.0MHz        | 480.0MHz  | Pass   |
>> | CLKDCOLDO Output Rate                        | 960.0MHz        | 960.0MHz  | Pass   |
>> |-------------------------------------------------------------------------------------|
>>
>> cheers,
>> -roger
>>
> 


      reply	other threads:[~2014-10-15  8:22 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-14 10:47 omap USB_DPLL not configured as per manual Roger Quadros
2014-10-14 19:49 ` Tero Kristo
2014-10-15  8:22   ` Roger Quadros [this message]

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