Re: [PATCH 1/2] opp: ti-opp-supply: Dynamically update u_volt_min

From: Dave Gerlach
Date: Mon Nov 12 2018 - 17:05:55 EST


On 11/11/2018 09:15 PM, J, KEERTHY wrote:
>
>
> On 11/8/2018 11:24 AM, Viresh Kumar wrote:
>> On 07-11-18, 10:04, Keerthy wrote:
>>> The voltage range (min, max) provided in the device tree is from
>>> the data manual and is pretty big, catering to a wide range of devices.
>>> On a i2c read/write failure the regulator_set_voltage_triplet function
>>> falls back to set voltage between min and max. The min value from Device
>>> Tree can be lesser than the optimal value and in that case that can lead
>>> to a hang or crash. Hence set the u_volt_min dynamically to the optimal
>>> voltage value.
>>
>> And why shouldn't we fix the DT for this ?
>
> The DT voltages do not cater to the broad range of devices. In some
> particular cases the DT min voltage is slightly lower the voltage at
> which the device cannot sustain a particular frequency in which case the
> device just silently hangs. So best thing to do is to actually read the
> device specific voltages dynamically which will guarantee a particular
> device sustaining a particular frequency at the optimal voltage.
>

Acked-by: Dave Gerlach <d-gerlach@xxxxxx>

>>