linux-kernel - Re: [PATCH] regulator: palmas: Fix SMPS enable/disable/is

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Date:	Mon, 23 Jun 2014 15:29:17 -0500
From:	Nishanth Menon <nm@...com>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	linux-omap <linux-omap@...r.kernel.org>, acourbot@...dia.com,
	gnurou@...il.com, Keerthy <j-keerthy@...com>,
	linux-tegra@...r.kernel.org
Subject: Re: [PATCH] regulator: palmas: Fix SMPS enable/disable/is_enabled

On Mon, Jun 23, 2014 at 3:20 PM, Stephen Warren <swarren@...dotorg.org> wrote:
> On 06/23/2014 02:11 PM, Nishanth Menon wrote:
>> On Mon, Jun 23, 2014 at 2:50 PM, Stephen Warren <swarren@...dotorg.org> wrote:
>>> On 06/20/2014 11:26 AM, Nishanth Menon wrote:
>>>> We use regmap regulator ops to enable/disable and check if regulator
>>>> is enabled for various SMPS. However, these depend on valid
>>>> enable_reg, enable_mask and enable_value in regulator descriptor.
>>>>
>>>> Currently we do not populate these for SMPS other than SMPS10, this
>>>> results in spurious results as regmap assumes that the values are
>>>> valid and ends up reading register 0x0 RTC:SECONDS_REG on Palmas
>>>> variants that do have RTC! To fix this, we update proper parameters
>>>> for the descriptor fields.
>>>>
>>>> Further, we want to ensure the behavior consistent with logic
>>>> prior to commit dbabd624d4eec50b6, where, once you do a set_mode,
>>>> enable/disable ensure the logic remains consistent and configures
>>>> Palmas to the configuration that we set with set_mode (since the
>>>> configuration register is common). To do this, we can rely on the
>>>> regulator core's regulator_register behavior where the regulator
>>>> descriptor pointer provided by the regulator driver is stored. (no
>>>> reallocation and copy is done). This lets us update the enable_value
>>>> post registration, to remain consistent with the mode we configure as
>>>> part of set_mode.
>>>>
>>>> Fixes: dbabd624d4eec50b6 ("regulator: palmas: Reemove open coded functions with helper functions")
>>>> Reported-by: Alexandre Courbot <acourbot@...dia.com>
>>>> Signed-off-by: Nishanth Menon <nm@...com>
>>>
>>> Unfortunately, there is still some lingering problem in the original
>>> commit. In next-20130623 (and indeed since at least next-20140611),
>>> neither the LCD panel or HDMI work on the NVIDIA Dalmore board.
>>> Reverting this commit (just for conflicts) and the original problematic
>>> commit "regulator: palmas: Reemove open coded functions with helper
>>> functions" solves this. I see the following on boot:
>>>
>>>> [    3.558776] tegra-dsi 54300000.dsi: cannot get VDD supply
>>>> [    3.564272] platform 54300000.dsi: Driver tegra-dsi requests probe deferral
>>>> [    3.571990] tegra-hdmi 54280000.hdmi: failed to get PLL regulator
>>>> [    3.578377] platform 54280000.hdmi: Driver tegra-hdmi requests probe deferral
>>>
>>> ... but probe deferral never completes, yet with your "remove open coded
>>> ..." patch reverted, it all works fine.
>>>
>>> Can you please take another look at the original patch?
>>
>> Will let keerthy (original patch author) comment on it.
>>
>> arch/arm/boot/dts/tegra114-dalmore.dts tps65090, avdd_lcd_reg I
>> suppose is the path in question?
>>
>> Seems to use drivers/mfd/tps65090.c and
>> drivers/regulator/tps65090-regulator.c and not palmas?
>>
>> Am I looking at the right dts?
>
> Yes, that's the right DTS.
>
> There's both a 65090 and a Palmas on the board. It's probably simpler to
> look at the HDMI PLL regulator, since the path to the Palmas is more
> obvious:
>
> / {
>         host1x@...00000 {
>                 hdmi@...80000 {
>                         pll-supply = <&palmas_smps3_reg>;
> ...
>         i2c@...0d000 {
>                 palmas: tps65913@58 {
>                         compatible = "ti,palmas";
>                         pmic {
>                                 compatible = "ti,tps65913-pmic",
>                                                 "ti,palmas-pmic";
>                                 regulators {
>                                         palmas_smps3_reg: smps3 {
>

based on "tegra-dsi 54300000.dsi: cannot get VDD supply" (from
drivers/gpu/drm/tegra/dsi.c), first fail of the log,  I suspect LDO
and not smps?

 avdd_1v2_reg: ldo3 {
         regulator-name = "avdd-dsi-csi";
         regulator-min-microvolt = <1200000>;
         regulator-max-microvolt = <1200000>;
 };

Do you have a complete boot log? there could be cascade fail that
results in LDO not being available. a post on hastebin/slexy.org would
be nice.

The trouble is that when 1 registration fails, the entire cascade of
regulators will not get registered :(.

---
Regards,
Nishanth Menon
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