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From: Tomi Valkeinen <tomi.valkeinen@ti.com>
To: Tero Kristo <t-kristo@ti.com>, Stefan Roese <stefan.roese@gmail.com>
Cc: linux-omap <linux-omap@vger.kernel.org>,
	Paul Walmsley <paul@pwsan.com>,
	Mike Turquette <mturquette@linaro.org>
Subject: Re: Odd behavior with dpll4_m4x2_ck on omap3 + DT
Date: Wed, 11 Sep 2013 10:21:18 +0300	[thread overview]
Message-ID: <523019EE.5000508@ti.com> (raw)
In-Reply-To: <522F1BF9.5050006@ti.com>

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On 10/09/13 16:17, Tero Kristo wrote:

> In theory, DPLLs can also be used in their bypass mode to feed customer
> nodes clocks. I just think the check in the clkoutx2_recalc is wrong,
> and should be enhanced to actually check what is the target mode for the
> clock once it is enabled. Maybe something like this would work properly:
> 
> diff --git a/arch/arm/mach-omap2/dpll3xxx.c
> b/arch/arm/mach-omap2/dpll3xxx.c
> index 3a0296c..ba218fb 100644
> --- a/arch/arm/mach-omap2/dpll3xxx.c
> +++ b/arch/arm/mach-omap2/dpll3xxx.c
> @@ -658,14 +658,12 @@ unsigned long omap3_clkoutx2_recalc(struct clk_hw
> *hw,
> 
>         dd = pclk->dpll_data;
> 
> -       WARN_ON(!dd->enable_mask);
> -
> -       v = __raw_readl(dd->control_reg) & dd->enable_mask;
> -       v >>= __ffs(dd->enable_mask);
> -       if ((v != OMAP3XXX_EN_DPLL_LOCKED) || (dd->flags & DPLL_J_TYPE))
> +       if ((dd->flags & DPLL_J_TYPE) ||
> +           __clk_get_rate(dd->clk_bypass) == __clk_get_rate(pclk))
>                 rate = parent_rate;
>         else
>                 rate = parent_rate * 2;
> +
>         return rate;
>  }

Stefan, are you able to test the above?

I'd rather have a proper fix for this, than hack omapdss =).

>> How is the DPLL4's clock rate 432000000 anyway in bypass mode. Isn't
>> bypass mode usually plain sys-clock, or such?
> 
> This again reflects the rate that the clock has once it is enabled, the
> clkoutx2 does not.

Ok. Then it does sound like the clkoutx2 is calculated wrong, as you say.

 Tomi



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  parent reply	other threads:[~2013-09-11  7:21 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-28  9:22 Odd behavior with dpll4_m4x2_ck on omap3 + DT Tomi Valkeinen
2013-08-28  9:48 ` Tero Kristo
2013-08-28 10:14   ` Tomi Valkeinen
2013-08-28 11:40     ` Tero Kristo
2013-09-10 11:33       ` Stefan Roese
2013-09-10 12:12         ` Tero Kristo
2013-09-10 12:19           ` Tomi Valkeinen
2013-09-10 12:24             ` Tero Kristo
2013-09-10 12:40               ` Tomi Valkeinen
2013-09-10 13:17                 ` Tero Kristo
2013-09-10 21:17                   ` Mike Turquette
2013-09-10 21:57                     ` Mike Turquette
2013-09-11  7:21                   ` Tomi Valkeinen [this message]
2013-09-13  7:51                     ` Stefan Roese
2013-09-13 11:34                       ` Tero Kristo
2013-09-16 19:45                         ` Mike Turquette
2013-09-27  8:41                         ` Tomi Valkeinen
2013-09-27 11:24                           ` Tero Kristo
2013-09-30  7:56                             ` Tomi Valkeinen
2013-10-07  8:21                   ` Paul Walmsley
2013-10-08  1:35                     ` Mike Turquette
2013-10-13 20:17                       ` Paul Walmsley
2013-09-10 12:25           ` Stefan Roese

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