[PATCH v3 2/5] scsi: ufs: Avoid configuring undefined voltage range on a regulator

From: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
To: linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	martin.petersen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org,
	avri.altman-Sjgp3cTcYWE@public.gmane.org,
	alim.akhtar-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org,
	pedrom.sousa-HKixBCOQz3hWk0Htik3J/w@public.gmane.org
Cc: marc.w.gonzalez-GANU6spQydw@public.gmane.org,
	chun-hung.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	kuohong.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	peter.wang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
	matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
Subject: [PATCH v3 2/5] scsi: ufs: Avoid configuring undefined voltage range on a regulator
Date: Mon, 18 Mar 2019 10:14:37 +0800	[thread overview]
Message-ID: <1552875280-16196-4-git-send-email-stanley.chu@mediatek.com> (raw)
In-Reply-To: <1552875280-16196-1-git-send-email-stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>

For regulators used by UFS, vcc, vccq and vccq2 will have voltage range
initialized by ufshcd_populate_vreg(), however other regulators may
not have voltage range settings if undefined in dt-bindings.

In this case, both "min_uV" and "max_uV" fields in ufs_vreg struct
will be zero values and used as new voltage range for voltage
configuration in different power modes.

Currently this may have no harm because if both "min_uV" and "max_uV"
always keep "zero value", regulator_set_voltage() will always bypass
such invalid values and return "good" results.

However improper values shall be fixed to avoid future potential
bug. Simply bypass voltage configuration if voltage range is not
defined.

Signed-off-by: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 drivers/scsi/ufs/ufshcd.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8b9a01073d62..4e41fdfd0e53 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7024,12 +7024,15 @@ static int ufshcd_config_vreg(struct device *dev,
 	name = vreg->name;
 
 	if (regulator_count_voltages(reg) > 0) {
-		min_uV = on ? vreg->min_uV : 0;
-		ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);
-		if (ret) {
-			dev_err(dev, "%s: %s set voltage failed, err=%d\n",
+		if (vreg->min_uV && vreg->max_uV) {
+			min_uV = on ? vreg->min_uV : 0;
+			ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);
+			if (ret) {
+				dev_err(dev,
+					"%s: %s set voltage failed, err=%d\n",
 					__func__, name, ret);
-			goto out;
+				goto out;
+			}
 		}
 
 		uA_load = on ? vreg->max_uA : 0;
-- 
2.18.0
