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From: Tero Kristo <t-kristo@ti.com>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Tony Lindgren <tony@atomide.com>, Archit Taneja <archit@ti.com>
Subject: Re: [PATCH 3/3] ARM: OMAP3: fix dpll4_m3_ck and dpll4_m4_ck dividers
Date: Wed, 9 Oct 2013 16:43:29 +0300	[thread overview]
Message-ID: <52555D81.7070100@ti.com> (raw)
In-Reply-To: <52555B37.80407@ti.com>

On 10/09/2013 04:33 PM, Tomi Valkeinen wrote:
> On 09/10/13 16:22, Tero Kristo wrote:
>> On 10/09/2013 04:12 PM, Tomi Valkeinen wrote:
>>> dpll4_m3_ck and dpll4_m4_ck have divider bit fields which are 6 bits
>>> wide. However, only values from 1 to 32 are allowed. This means we have
>>> to add a divider tables and list the dividers explicitly.
>>>
>>> I believe the same issue is there for other dpll4_mx_ck clocks, but as
>>> I'm not familiar with them, I didn't touch them.
>>
>> I think you can limit the max value with a mask only, no need to define
>> new tables.
>
> The bit field is 6 bits wide, so the mask is correct. It's just that the
> biggest allowed value is 32, which takes 6 bits, not 63.
>
> Changing the mask to 5 bits would limit the divider to 31, wouldn't it?

Oh true. Sucks with legacy clocks then.

For dt clocks, you should be able to declare max / min divider values 
for ti,divider-clock type which would take care of this case. Just 
change the ti,max-div = <63>; field to ... = <32>;

-Tero


WARNING: multiple messages have this Message-ID (diff)
From: t-kristo@ti.com (Tero Kristo)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] ARM: OMAP3: fix dpll4_m3_ck and dpll4_m4_ck dividers
Date: Wed, 9 Oct 2013 16:43:29 +0300	[thread overview]
Message-ID: <52555D81.7070100@ti.com> (raw)
In-Reply-To: <52555B37.80407@ti.com>

On 10/09/2013 04:33 PM, Tomi Valkeinen wrote:
> On 09/10/13 16:22, Tero Kristo wrote:
>> On 10/09/2013 04:12 PM, Tomi Valkeinen wrote:
>>> dpll4_m3_ck and dpll4_m4_ck have divider bit fields which are 6 bits
>>> wide. However, only values from 1 to 32 are allowed. This means we have
>>> to add a divider tables and list the dividers explicitly.
>>>
>>> I believe the same issue is there for other dpll4_mx_ck clocks, but as
>>> I'm not familiar with them, I didn't touch them.
>>
>> I think you can limit the max value with a mask only, no need to define
>> new tables.
>
> The bit field is 6 bits wide, so the mask is correct. It's just that the
> biggest allowed value is 32, which takes 6 bits, not 63.
>
> Changing the mask to 5 bits would limit the divider to 31, wouldn't it?

Oh true. Sucks with legacy clocks then.

For dt clocks, you should be able to declare max / min divider values 
for ti,divider-clock type which would take care of this case. Just 
change the ti,max-div = <63>; field to ... = <32>;

-Tero

  reply	other threads:[~2013-10-09 13:43 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-09 13:12 [PATCH 1/3] ARM: OMAP4: use CLK_SET_RATE_PARENT for dss_dss_clk Tomi Valkeinen
2013-10-09 13:12 ` Tomi Valkeinen
2013-10-09 13:12 ` [PATCH 2/3] ARM: OMAP3: use CLK_SET_RATE_PARENT for dss clocks Tomi Valkeinen
2013-10-09 13:12   ` Tomi Valkeinen
2013-10-24 15:13   ` Paul Walmsley
2013-10-24 15:13     ` Paul Walmsley
2013-10-09 13:12 ` [PATCH 3/3] ARM: OMAP3: fix dpll4_m3_ck and dpll4_m4_ck dividers Tomi Valkeinen
2013-10-09 13:12   ` Tomi Valkeinen
2013-10-09 13:22   ` Tero Kristo
2013-10-09 13:22     ` Tero Kristo
2013-10-09 13:33     ` Tomi Valkeinen
2013-10-09 13:33       ` Tomi Valkeinen
2013-10-09 13:43       ` Tero Kristo [this message]
2013-10-09 13:43         ` Tero Kristo
2013-10-24 15:14   ` Paul Walmsley
2013-10-24 15:14     ` Paul Walmsley
2013-10-09 13:22 ` [PATCH 1/3] ARM: OMAP4: use CLK_SET_RATE_PARENT for dss_dss_clk Tero Kristo
2013-10-09 13:22   ` Tero Kristo
2013-10-09 13:39   ` Tomi Valkeinen
2013-10-09 13:39     ` Tomi Valkeinen
2013-10-24  8:03 ` Tomi Valkeinen
2013-10-24  8:03   ` Tomi Valkeinen
2013-10-24 13:23   ` Tero Kristo
2013-10-24 13:23     ` Tero Kristo
2013-10-24 13:28     ` Tony Lindgren
2013-10-24 13:28       ` Tony Lindgren
2013-10-24 13:31       ` Tero Kristo
2013-10-24 13:31         ` Tero Kristo
2013-10-24 13:42         ` Tony Lindgren
2013-10-24 13:42           ` Tony Lindgren
2013-10-24 15:13 ` Paul Walmsley
2013-10-24 15:13   ` Paul Walmsley

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