From: Adrian Hunter <adrian.hunter@intel.com>
To: Ziqi Chen <ziqichen@codeaurora.org>,
asutoshd@codeaurora.org, nguyenb@codeaurora.org,
cang@codeaurora.org, hongwus@codeaurora.org,
rnayak@codeaurora.org, vinholikatti@gmail.com,
jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
linux-scsi@vger.kernel.org, kernel-team@android.com,
saravanak@google.com, salyzyn@google.com, kwmad.kim@samsung.com,
stanley.chu@mediatek.com
Cc: Bart Van Assche <bvanassche@acm.org>,
"open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@vger.kernel.org>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
open list <linux-kernel@vger.kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Avri Altman <avri.altman@wdc.com>, Andy Gross <agross@kernel.org>,
"moderated list:UNIVERSAL FLASH STORAGE HOST CONTROLLER
DRIVER..." <linux-mediatek@lists.infradead.org>,
Alim Akhtar <alim.akhtar@samsung.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Satya Tangirala <satyat@google.com>,
"moderated list:ARM/Mediatek SoC support"
<linux-arm-kernel@lists.infradead.org>,
Bean Huo <beanhuo@micron.com>
Subject: Re: [PATCH RFC v4 1/1] scsi: ufs: Fix ufs power down/on specs violation
Date: Mon, 4 Jan 2021 11:15:23 +0200 [thread overview]
Message-ID: <e8980753-fa48-7862-e5ce-0d756d5d97a6@intel.com> (raw)
In-Reply-To: <1608644981-46267-1-git-send-email-ziqichen@codeaurora.org>
On 22/12/20 3:49 pm, Ziqi Chen wrote:
> As per specs, e.g, JESD220E chapter 7.2, while powering
> off/on the ufs device, RST_N signal and REF_CLK signal
> should be between VSS(Ground) and VCCQ/VCCQ2.
>
> To flexibly control device reset line, refactor the function
> ufschd_vops_device_reset(sturct ufs_hba *hba) to ufshcd_
> vops_device_reset(sturct ufs_hba *hba, bool asserted). The
> new parameter "bool asserted" is used to separate device reset
> line pulling down from pulling up.
This patch assumes the power is controlled by voltage regulators, but for us
it is controlled by firmware (ACPI), so it is not correct to change RST_n
for all host controllers as you are doing.
Also we might need to use a firmware interface for device reset, in which
case the 'asserted' value doe not make sense.
Can we leave the device reset callback alone, and instead introduce a new
variant operation for setting RST_n to match voltage regulator power changes?
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next prev parent reply other threads:[~2021-01-04 9:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 13:49 [PATCH RFC v4 1/1] scsi: ufs: Fix ufs power down/on specs violation Ziqi Chen
2020-12-23 9:33 ` Stanley Chu
2020-12-23 20:45 ` Avri Altman
2020-12-28 17:55 ` Bjorn Andersson
[not found] ` <4c3035c418d0a0c4344be84fb1919314@codeaurora.org>
2021-01-04 18:57 ` Bjorn Andersson
[not found] ` <182321abfc98e0cfca071d1ec1255f6d@codeaurora.org>
2021-01-04 18:59 ` Bjorn Andersson
2021-01-04 9:15 ` Adrian Hunter [this message]
2021-01-04 18:55 ` Bjorn Andersson
2021-01-05 7:16 ` Adrian Hunter
[not found] ` <ff2c3c4379cb8bc41580d5615b01f86a@codeaurora.org>
2021-01-05 7:33 ` Adrian Hunter
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