scsi: ufs-qcom: Fix ufs RST_n spec violation

According to the spec (JESD220E chapter 7.2), while powering off/on the ufs
device, RST_n signal should be between VSS(Ground) and VCCQ/VCCQ2.

Link: https://lore.kernel.org/r/1610103385-45755-3-git-send-email-ziqichen@codeaurora.orgAcked-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Ziqi Chen <ziqichen@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-qcom.c

@@ -568,6 +568,17 @@ static int ufs_qcom_link_startup_notify(struct ufs_hba *hba,
 	return err;
 }
 
+static void ufs_qcom_device_reset_ctrl(struct ufs_hba *hba, bool asserted)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+
+	/* reset gpio is optional */
+	if (!host->device_reset)
+		return;
+
+	gpiod_set_value_cansleep(host->device_reset, asserted);
+}
+
 static int ufs_qcom_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
@@ -582,6 +593,9 @@ static int ufs_qcom_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 		ufs_qcom_disable_lane_clks(host);
 		phy_power_off(phy);
 
+		/* reset the connected UFS device during power down */
+		ufs_qcom_device_reset_ctrl(hba, true);
+
 	} else if (!ufs_qcom_is_link_active(hba)) {
 		ufs_qcom_disable_lane_clks(host);
 	}
@@ -1421,10 +1435,10 @@ static int ufs_qcom_device_reset(struct ufs_hba *hba)
 	 * The UFS device shall detect reset pulses of 1us, sleep for 10us to
 	 * be on the safe side.
 	 */
-	gpiod_set_value_cansleep(host->device_reset, 1);
+	ufs_qcom_device_reset_ctrl(hba, true);
 	usleep_range(10, 15);
 
-	gpiod_set_value_cansleep(host->device_reset, 0);
+	ufs_qcom_device_reset_ctrl(hba, false);
 	usleep_range(10, 15);
 
 	return 0;