Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 379A9C43383
From:   Can Guo <cang@codeaurora.org>
To:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, rnayak@codeaurora.org,
        linux-scsi@vger.kernel.org, kernel-team@android.com,
        saravanak@google.com, salyzyn@google.com, cang@codeaurora.org
Cc:     Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        linux-kernel@vger.kernel.org (open list),
        linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC
        support),
        linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC
        support)
Subject: [PATCH v10 2/7] scsi: ufs: set load before setting voltage in regulators
Date:   Mon, 10 Feb 2020 19:40:45 -0800
Message-Id: <1581392451-28743-3-git-send-email-cang@codeaurora.org>
In-Reply-To: <1581392451-28743-1-git-send-email-cang@codeaurora.org>
References: <1581392451-28743-1-git-send-email-cang@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Asutosh Das <asutoshd@codeaurora.org>

This sequence change is required to avoid dips in voltage
during boot-up.

Apparently, this dip is caused because in the original
sequence, the regulators are initialized in lpm mode.
And then when the load is set to high, and more current
is drawn, than is allowed in lpm, the dip is seen.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Hongwu Su <hongwus@codeaurora.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 10dbc0c..83ae093 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7248,6 +7248,11 @@ static int ufshcd_config_vreg(struct device *dev,
 	name = vreg->name;
 
 	if (regulator_count_voltages(reg) > 0) {
+		uA_load = on ? vreg->max_uA : 0;
+		ret = ufshcd_config_vreg_load(dev, vreg, uA_load);
+		if (ret)
+			goto out;
+
 		if (vreg->min_uV && vreg->max_uV) {
 			min_uV = on ? vreg->min_uV : 0;
 			ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);
@@ -7258,11 +7263,6 @@ static int ufshcd_config_vreg(struct device *dev,
 				goto out;
 			}
 		}
-
-		uA_load = on ? vreg->max_uA : 0;
-		ret = ufshcd_config_vreg_load(dev, vreg, uA_load);
-		if (ret)
-			goto out;
 	}
 out:
 	return ret;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project