Re: [PATCH 2/3] ARM: dts: use vmmc-supply of emmc/sd for exynos5422-odroidxu3

[Anand Moon <linux.amoon@gmail.com>]

Hi Krzysztof,

On 12 October 2015 at 17:43, Krzysztof Kozlowski
<k.kozlowski@samsung.com> wrote:
> W dniu 12.10.2015 o 20:08, Anand Moon pisze:
>> Hi Krzysztof,
>>
>> On 12 October 2015 at 11:19, Krzysztof Kozlowski
>> <k.kozlowski@samsung.com> wrote:
>>> On 12.10.2015 13:42, Krzysztof Kozlowski wrote:
>>>> On 12.10.2015 00:46, Anand Moon wrote:
>>>>> Added support for vmmc/vqmmc-supply for emmc/sd cards.
>>>>> Fixed the min values for regulator ldo13_reg (VDDQ_MMC2).
>>>>
>>>> I can't see the description of a problem which is fixed. If you fix
>>>> something, then please describe what is wrong.
>>>>
>>>>> Added ramp-delay for LDO9(VDD33_USB3_0).
>>>>> Added ramp-delay for LDO13(VDDQ_MMC2).
>>>>> Added ramp-delay for LDO15(ETH_P3V3).
>>>>>
>>>>> Signed-off-by: Anand Moon <linux.amoon@gmail.com>
>>>>>
>>>>> ---
>>>>> Changes based on git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung.git v4.4-next/dt-samsung branch
>>>>>
>>>>> Note:
>>>>> Changes need for support of UHS-I highspeed cards.
>>>>> changes for vqmmc-supply for emmc is not supported.
>>>>>
>>>>> [    1.831136] vdd_ldo9: ramp_delay not set
>>>>> [    1.843049] vdd_ldo13: ramp_delay not set
>>>>> [    1.850975] vdd_ldo15: ramp_delay not set
>>>>> [    1.862816] vdd_sd: ramp_delay not set
>>>>> ---
>>>>>  arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 8 +++++++-
>>>>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>>>> index 26decbd..58c06d3 100644
>>>>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>>>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>>>> @@ -157,6 +157,7 @@
>>>>>                              regulator-min-microvolt = <3000000>;
>>>>>                              regulator-max-microvolt = <3000000>;
>>>>>                              regulator-always-on;
>>>>> +                            regulator-ramp-delay = <12000>;
>>>>>                      };
>>>>>
>>>>>                      ldo10_reg: LDO10 {
>>>>> @@ -182,9 +183,10 @@
>>>>>
>>>>>                      ldo13_reg: LDO13 {
>>>>>                              regulator-name = "vdd_ldo13";
>>>>> -                            regulator-min-microvolt = <2800000>;
>>>>> +                            regulator-min-microvolt = <1800000>;
>>>>>                              regulator-max-microvolt = <2800000>;
>>>>>                              regulator-always-on;
>>>>> +                            regulator-ramp-delay = <12000>;
>>>>>                      };
>>>>>
>>>>>                      ldo15_reg: LDO15 {
>>>>> @@ -213,6 +215,7 @@
>>>>>                              regulator-min-microvolt = <2800000>;
>>>>>                              regulator-max-microvolt = <2800000>;
>>>>>                              regulator-always-on;
>>>>> +                            regulator-ramp-delay = <12000>;
>>>>
>>>> Where did you get this value from? It looks wrong... My datasheet does
>>>> not have 12000 uV/uS.
>>>
>>
>>> Anand,
>>>
>>> We have actually been here:
>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/351601.html
>>>
>>> That time you used 8000. I asked the same question - how did you figure
>>> out the exact value.
>>>
>>> Now we have the same question - why 12000?
>>>
>>> It is completely fine to make a mistake (I do a lot of them) but please
>>> try not to make the same mistake again.
>>>
>>> BR,
>>> Krzysztof
>>
>> I will focus more in the future to clamp down my mistakes to minimal.
>>
>>>
>>>>
>>>>>                      };
>>>>>
>>>>>                      ldo24_reg: LDO24 {
>>>>> @@ -338,6 +341,7 @@
>>>>>      samsung,dw-mshc-ddr-timing = <0 2>;
>>>>>      samsung,dw-mshc-hs400-timing = <0 2>;
>>>>>      samsung,read-strobe-delay = <90>;
>>>>> +    vmmc-supply = <&ldo3_reg>;
>>>>>      pinctrl-names = "default";
>>>>>      pinctrl-0 = <&sd0_clk &sd0_cmd &sd0_bus1 &sd0_bus4 &sd0_bus8 &sd0_cd &sd0_rclk>;
>>>>>      bus-width = <8>;
>>>>> @@ -352,6 +356,8 @@
>>>>>      samsung,dw-mshc-ciu-div = <3>;
>>>>>      samsung,dw-mshc-sdr-timing = <0 4>;
>>>>>      samsung,dw-mshc-ddr-timing = <0 2>;
>>>>> +    vmmc-supply = <&ldo19_reg>;
>>>>> +    vqmmc-supply = <&ldo13_reg>;
>>>>
>>>> It looks wrong. LDO13 is used in one place as VQMMC and in other as
>>>> VMMC. How did you figure out which regulator supplies which power domain?
>>>>
>>
>> I refer Schematics diagram to XU4_MAIN_REV0.1.pdf
>>
>> From the PWR_PMCI_S2MPS11_LDO_CTRL document it LDO13 point to VDDQ_MMC2.
>>
>
> Aaa right, by mistake I thought that you put LDO13 here and in the node
> before, but there is LDO3, not 13. You did this correctly.
>
> But I have two other questions:
> 1. Maybe these regulators now should not be always-enabled?

regulator-always-on         can be removed: I have tested this.

> 2. Why changing minimum voltage of LDO13 to 1.8V? The schematics says 2.8V.
>

In the schematics diagram to XU4_MAIN_REV0.1.pdf

>From the EXYNOS5422 MMC UFS diagram CH2 range is VDDQ_MMC2 (1.8V/2.8V).

-Anand Moon

> Best regards,
> Krzysztof
>
>