Hi Laxman,
On 21/11/16 09:36, Laxman Dewangan wrote:
>
> Hi Jon,
> I will update the patch per your comment.
Thanks.
> Here is answer for some of the query.
>
> Thanks,
> Laxman
>
>
> On Tuesday 15 November 2016 08:37 PM, Jon Hunter wrote:
>> On 09/11/16 13:06, Laxman Dewangan wrote:
>>> +/**
>>> + * Macro for 1.8V, keep 200mV as tolerance for deciding that
>>> + * IO pads should be set for 3.3V (high voltage) or 1.8V.
>>> + */
>>> +#define TEGRA_IO_PAD_1800000UV_UPPER_LIMIT 2000000
>> Is there a reference we could add for the source of this information?
>
> I had a discussion with the ASIC on this and as per them
> 1.8 V nominal is (1.62V, 1.98V)
> 3.3 V nominal is (2.97V,3.63V)
>
> I am working with them to update the TRM document but we can assume that
> this information will be there in TRM.
My feeling is that if all use-cases today are using either 1.8V or 3.3V,
then may be we should not worry about this and only support either 1.8V
or 3.3V. I would be more in favour of supporting other voltages if there
is a real need.
>>> + const struct pinctrl_pin_desc *pins_desc;
>>> + int num_pins_desc;
>>> +};
>>> +
>>> +struct tegra_io_pads_regulator_info {
>>> + struct device *dev;
>>> + const struct tegra_io_pads_cfg_info *pads_cfg;
>>> + struct regulator *regulator;
>>> + struct notifier_block regulator_nb;
>>> +};
>> Is this struct necessary? Seems to be a lot of duplicated information
>> from the other structs. Why not add the regulator and regulator_nb to
>> the main struct? OK, not all io_pads have a regulator but you are only
>> saving one pointer.
> Yes, some of IO pads support multi-voltage.
Yes, but I am saying why not put this information in the main struct and
not bother having yet another struct where half of the information is
duplicated.
>>
>> + if ((vdata->old_uV > TEGRA_IO_PAD_1800000UV_UPPER_LIMIT) &&
>> + (vdata->min_uV <= TEGRA_IO_PAD_1800000UV_UPPER_LIMIT))
>> + break;
>> The data-sheet for Tegra210 only lists 1.8V or 3.3V as supported
>> options. Do we need to support a range? Or does the h/w support a range
>> of voltages? I am just wondering why we cannot check explicitly for 1.8V
>> or 3.3V and treat anything else as an error.
>
> Two voltage level, not range.
Ok, then I think it would be much simpler if we just support the
voltages we are using today.
Cheers
Jon
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