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:

quoted

On 09/11/16 13:06, Laxman Dewangan wrote:

quoted

+/**
+ * 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.

quoted

quoted

+    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.

quoted

+        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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