From: Stanley Chu <stanley.chu@mediatek.com>
To: Can Guo <cang@codeaurora.org>
Cc: <linux-scsi@vger.kernel.org>, <martin.petersen@oracle.com>,
<avri.altman@wdc.com>, <alim.akhtar@samsung.com>,
<jejb@linux.ibm.com>, <beanhuo@micron.com>,
<asutoshd@codeaurora.org>, <matthias.bgg@gmail.com>,
<bvanassche@acm.org>, <linux-mediatek@lists.infradead.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <kuohong.wang@mediatek.com>,
<peter.wang@mediatek.com>, <chun-hung.wu@mediatek.com>,
<andy.teng@mediatek.com>
Subject: Re: [PATCH v1 1/2] scsi: ufs: add required delay after gating reference clock
Date: Wed, 19 Feb 2020 17:11:35 +0800 [thread overview]
Message-ID: <1582103495.26304.42.camel@mtksdccf07> (raw)
In-Reply-To: <a8cd5beee0a1e12a40da752c6cd9b5de@codeaurora.org>
Hi Can,
On Wed, 2020-02-19 at 10:35 +0800, Can Guo wrote:
> Since we all need this delay here, how about put the delay in the
> entrence of ufshcd_setup_clocks(), before vops_setup_clocks()?
> If so, we can remove all the delays we added in our vops since the
> delay anyways delays everything inside ufshcd_setup_clocks().
>
Always putting the delay in the entrance of ufshcd_setup_clocks() may
add unwanted delay for vendors, just like your current implementation,
or some other vendors who do not want to disable the reference clock.
I think current patch is more reasonable because the delay is applied to
clock only named as "ref_clk" specifically.
If you needs to keep "ref_clk" in DT, would you consider to remove the
delay in your ufs_qcom_dev_ref_clk_ctrl() and let the delay happens via
common ufshcd_setup_clocks() only? However you may still need delay if
call path comes from ufs_qcom_pwr_change_notify().
What do you think?
> Meanwhile, if you want to modify the delay
> (hba->dev_info.clk_gating_wait_us) for some reasons, say for specific
> UFS devices, you still can do it in vops_apply_dev_quirks().
>
> What do you say?
>
> Thanks,
> Can Guo.
Thanks,
Stanley Chu
next prev parent reply other threads:[~2020-02-19 9:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-17 9:35 [PATCH v1 0/2] scsi: ufs: fix waiting time for reference clock Stanley Chu
2020-02-17 9:35 ` [PATCH v1 1/2] scsi: ufs: add required delay after gating " Stanley Chu
2020-02-17 12:58 ` Can Guo
2020-02-17 13:12 ` Stanley Chu
2020-02-17 13:22 ` Can Guo
2020-02-17 13:34 ` Stanley Chu
2020-02-17 13:42 ` Can Guo
2020-02-19 2:35 ` Can Guo
2020-02-19 9:11 ` Stanley Chu [this message]
2020-02-19 10:33 ` Can Guo
2020-02-20 13:30 ` Stanley Chu
2020-02-17 16:17 ` Bart Van Assche
2020-02-18 0:50 ` Stanley Chu
2020-02-17 9:35 ` [PATCH v1 2/2] scsi: ufs: ufs-mediatek: add waiting time for " Stanley Chu
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