Re: [PATCH v9 6/9] MFD: TWL4030: workaround changes for TWL4030 Erratum 27

["Manuel, Lesly Arackal" <leslyam@ti.com>]

Hi Samuel,

On Tue, Apr 26, 2011 at 3:43 PM, Samuel Ortiz <sameo@linux.intel.com> wrote:
> Hi Lesly,
>
> On Thu, Apr 14, 2011 at 05:57:54PM +0530, Lesly A M wrote:
>> Workaround for TWL5030 Silicon Errata 27 & 28:
>>       27 - VDD1, VDD2, may have glitches when their output value is updated.
>>       28 - VDD1 and / or VDD2 DCDC clock may stop working when internal clock
>>               is switched from internal to external.
>>
>> Erratum 27:
>>       If the DCDC regulators is running on their internal oscillator,
>>       negative glitches may occur on VDD1, VDD2 output when voltage is changed.
>>       The OMAP device may reboot if the VDD1 or VDD2 go below the
>>       core minimum operating voltage.
>>
>>       WORKAROUND
>>       Set up the TWL5030 DC-DC power supplies to use the HFCLKIN instead of
>>       the internal oscillator.
>>
>> Erratum 28:
>>       VDD1/VDD2 clock system may hang during switching the clock source from
>>       internal oscillator to external. VDD1/VDD2 output voltages may collapse
>>       if clock stops.
>>
>>       WORKAROUND
>>       If HFCLK is disabled in OFFMODE, modify the sleep/wakeup sequence and
>>       setuptimes to make sure the switching will happen only when HFCLKIN is stable.
>>       Also use the TWL5030 watchdog to safeguard the first switching from
>>       internal oscillator to HFCLKIN during the TWL5030 init.
>>
>>       IMPACT
>>       power sequence is changed.
>>       sleep/wakeup time values will be changed.
>>
>> The workaround changes are called from twl4030_power_init(), since we have to
>> make some i2c_read calls to check the TWL4030 version & the i2c will not be
>> initialized in the early stage.
>>
>> This workaround is required for TWL5030 Silicon version less than ES1.2
>> The power script & setup time changes are recommended by TI HW team.
>>
>> http://omapedia.org/wiki/TWL4030_power_scripts
>>
>> Changes taken from TWL4030 Erratum 27 workaround patch by Nishanth Menon.
> This patch and the following one depend on patch#4. Please re-send it once you
> agreed with Tony about where it should go.
>

I will make the changes for Tony's comments and repost the patches.

Thanks & Regards,
Lesly A M
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