From: Stanley Chu <stanley.chu@mediatek.com>
To: Rob Herring <robh+dt@kernel.org>
Cc: Marc Gonzalez <marc.w.gonzalez@free.fr>,
Avri Altman <avri.altman@wdc.com>,
Alim Akhtar <alim.akhtar@samsung.com>,
"Bjorn Andersson <bjorn.andersson@linaro.org>,
Jeffrey Hugo <jhugo@codeaurora.org>,
DT" <devicetree@vger.kernel.org>,
SCSI <linux-scsi@vger.kernel.org>,
kuohong.wang@mediatek.com, peter.wang@mediatek.com,
chun-hung.wu@mediatek.com, stanley.chu@mediatek.com
Subject: Re: [PATCH v3 5/7] dt-bindings: scsi: ufs: Add document for ufs-mediatek
Date: Fri, 15 Mar 2019 12:04:27 +0800 [thread overview]
Message-ID: <1552622667.30977.70.camel@mtkswgap22> (raw)
In-Reply-To: <CAL_Jsq+O5O6JL2tafojn5xEC95dw7dMNzrcoDm7N4No6HfonxQ@mail.gmail.com>
Hi Rob and all,
On Fri, 2019-03-15 at 00:44 +0800, Rob Herring wrote:
> On Thu, Mar 14, 2019 at 3:46 AM Marc Gonzalez <marc.w.gonzalez@free.fr> wrote:
> >
> > On 13/03/2019 20:48, Rob Herring wrote:
> >
> > Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt mentions:
> > - <name>-fixed-regulator : boolean property specifying that <name>-supply is a fixed regulator.
> >
> > > There are no users of that property in tree and doesn't look like
> > > adding it was ever reviewed. We have standard ways to handle this and
> > > don't need a custom property.
> >
> > FWIW, it seems to come from downstream:
>
> The question would be is downstream compliant with the upstream
> binding. If so, then we shouldn't really break things as that's just
> out of tree which is fine.
>
> Or we just need a better explanation of why it is needed. MMC has some
> properties related to card voltages for example. Maybe the need is
> similar.
>
For short-term, could this patch series be merged without "vcc" related
property defined in dt-bindings (like PATCH V5 does)? Or using
"vcc-supply" along with "vcc-fixed-regulator" with a detailed
explanation can be accepted?
ufs-mediatek can work fine without "vcc" related property but with a
limitation that driver cannot control "vcc" power which is enabled
by-default on MediaTek chipsets.
For long-term, it seems to me that "<name>-fixed-regulator" can be
removed from both dt-bindings and UFS driver without impact, even for
downstream usage found by Marc.
If "<name>-fixed-regulator" property is defined in device tree, such
regulator will skip "current limit" assignment from
"<name>-max-microamp" property, and voltage range assignment from
"vcc-supply-lp8" property (for vcc, vccq, and vccq2 only). If driver can
handle above both cases correctly, "<name>-fixed-regulator" can be
removed.
In MediaTek chipsets, "vcc-supply" can ignore above two properties.
However if "vcc-fixed-regulator" is not added, driver will get fail
during device tree probing due to undefined "vcc-max-microamp".
If our target is removing "<name>-fixed-regulator", we could try to fix
and resolve above all. And if we do not merge "vcc" related property
this time, after that we can add "vcc-supply" back to dt-bindings to
provide vcc control capability in ufs-mediatek driver.
Would you please provide any suggestions?
> Rob
next prev parent reply other threads:[~2019-03-15 4:04 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 7:23 scsi: ufs-mediatek: Add UFS support for Mediatek SoC chips Stanley Chu
[not found] ` <1551252192-535-1-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-02-27 7:23 ` [PATCH v3 0/7] " Stanley Chu
[not found] ` <1551252192-535-2-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-06 1:32 ` Stanley Chu
2019-02-27 7:23 ` [PATCH v3 1/7] scsi: ufs: Introduce ufshcd_get_pwr_dev_param Stanley Chu
2019-02-27 7:23 ` [PATCH v3 2/7] scsi: ufs-qcom: Re-factor ufshcd_get_pwr_dev_param Stanley Chu
2019-02-27 7:23 ` [PATCH v3 3/7] scsi: ufs-hisi: " Stanley Chu
2019-02-27 7:23 ` [PATCH v3 4/7] dt-bindings: phy: Add document for phy-mtk-ufs Stanley Chu
[not found] ` <1551252192-535-6-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-12 13:25 ` Rob Herring
2019-03-13 2:42 ` Stanley Chu
2019-03-13 10:27 ` Stanley Chu
2019-03-13 10:21 ` [SPAM][PATCH " Yingjoe Chen
2019-03-13 14:05 ` Stanley Chu
2019-03-13 19:52 ` Rob Herring
[not found] ` <CAL_JsqKohcSXw5BcqpQ2eVHf36kVoPdVe+rxJ+6XvdqM4nQ0Wg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-14 3:42 ` [PATCH " Stanley Chu
2019-02-27 7:23 ` [PATCH v3 5/7] dt-bindings: scsi: ufs: Add document for ufs-mediatek Stanley Chu
[not found] ` <1551252192-535-7-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-12 13:31 ` Rob Herring
2019-03-13 2:41 ` Stanley Chu
2019-03-13 19:48 ` Rob Herring
[not found] ` <CAL_JsqJ8EkM5EsQCCsyY0M1SuDar2qQi6QjA=91+Svv79-8rAg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-03-14 3:45 ` Stanley Chu
2019-03-14 8:46 ` Marc Gonzalez
2019-03-14 16:44 ` Rob Herring
2019-03-15 4:04 ` Stanley Chu [this message]
2019-03-14 8:54 ` Marc Gonzalez
2019-02-27 7:23 ` [PATCH v3 6/7] phy: mediatek: Add UFS M-PHY driver Stanley Chu
[not found] ` <1551252192-535-8-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2019-03-01 7:13 ` Chunfeng Yun
2019-03-13 9:37 ` Yingjoe Chen
2019-03-13 10:17 ` Stanley Chu
2019-02-27 7:23 ` [PATCH v3 7/7] scsi: ufs-mediatek: Add UFS support for Mediatek SoC chips Stanley Chu
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