[PATCH v5 phy-next 10/27] scsi: ufs: qcom: keep parallel track of PHY power state

[Vladimir Oltean]

As explained in the similar ufs-exynos.c change, PHY consumer drivers
should not look at the phy->power_count, because in the general case
there might also be other consumers who have called phy_power_on() too,
so the fact that the power_count is non-zero does not mean that we did.

Moreover, struct phy will become opaque soon, so the qcom UFS driver
will not be able to apply this pattern. Keep parallel track of the PHY
power state, instead of looking at a field which will become unavailable
(phy->power_count).

About treating the phy_power_off() return code: from an API perspective,
this should have probably returned void, otherwise consumers would be
stuck in a state they can't escape. The provider, phy-qcom-qmp-ufs.c,
does return 0 in its power_off() implementation. I consider it safe to
discard potential errors from phy_power_off() instead of complicating
the phy_powered_on logic.

Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
---
Cc: "James E.J. Bottomley" <James.Bottomley at HansenPartnership.com>
Cc: Manivannan Sadhasivam <mani at kernel.org>
Cc: "Martin K. Petersen" <martin.petersen at oracle.com>
Cc: Nitin Rawat <quic_nitirawa at quicinc.com>

v4->v5: patch is new
---
 drivers/ufs/host/ufs-qcom.c | 9 +++++++--
 drivers/ufs/host/ufs-qcom.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 375fd24ba458..3b8bd9968235 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -508,9 +508,10 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
 	if (ret)
 		return ret;
 
-	if (phy->power_count)
+	if (host->phy_powered_on) {
 		phy_power_off(phy);
-
+		host->phy_powered_on = false;
+	}
 
 	/* phy initialization - calibrate the phy */
 	ret = phy_init(phy);
@@ -531,6 +532,7 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
 			__func__, ret);
 		goto out_disable_phy;
 	}
+	host->phy_powered_on = true;
 
 	ret = phy_calibrate(phy);
 	if (ret) {
@@ -1268,6 +1270,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 				dev_err(hba->dev, "phy power off failed, ret=%d\n", err);
 				return err;
 			}
+			host->phy_powered_on = false;
 		}
 		break;
 	case POST_CHANGE:
@@ -1277,6 +1280,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 				dev_err(hba->dev, "phy power on failed, ret = %d\n", err);
 				return err;
 			}
+			host->phy_powered_on = true;
 
 			/* enable the device ref clock for HS mode*/
 			if (ufshcd_is_hs_mode(&hba->pwr_info))
@@ -1467,6 +1471,7 @@ static void ufs_qcom_exit(struct ufs_hba *hba)
 
 	ufs_qcom_disable_lane_clks(host);
 	phy_power_off(host->generic_phy);
+	host->phy_powered_on = false;
 	phy_exit(host->generic_phy);
 }
 
diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
index 1111ab34da01..72ce0687fa42 100644
--- a/drivers/ufs/host/ufs-qcom.h
+++ b/drivers/ufs/host/ufs-qcom.h
@@ -282,6 +282,7 @@ struct ufs_qcom_host {
 	struct clk_bulk_data *clks;
 	u32 num_clks;
 	bool is_lane_clks_enabled;
+	bool phy_powered_on;
 
 	struct icc_path *icc_ddr;
 	struct icc_path *icc_cpu;
-- 
2.43.0