As per specs, e.g, JESD220E chapter 7.2, while powering
off/on the ufs device, RST_N signal and REF_CLK signal
should be between VSS(Ground) and VCCQ/VCCQ2.

To flexibly control device reset line, refactor the function
ufschd_vops_device_reset(sturct ufs_hba *hba) to ufshcd_
vops_device_reset(sturct ufs_hba *hba, bool asserted). The
new parameter "bool asserted" is used to separate device reset
line pulling down from pulling up.

Cc: Kiwoong Kim <kwmad....@samsung.com>
Cc: Stanley Chu <stanley....@mediatek.com>
Signed-off-by: Ziqi Chen <ziqic...@codeaurora.org>
---
 drivers/scsi/ufs/ufs-mediatek.c | 32 ++++++++++++++++----------------
 drivers/scsi/ufs/ufs-qcom.c     | 24 +++++++++++++++---------
 drivers/scsi/ufs/ufshcd.c       | 36 +++++++++++++++++++++++++-----------
 drivers/scsi/ufs/ufshcd.h       |  8 ++++----
 4 files changed, 60 insertions(+), 40 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 80618af..072f4db 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -841,27 +841,27 @@ static int ufs_mtk_link_startup_notify(struct ufs_hba 
*hba,
        return ret;
 }
 
-static int ufs_mtk_device_reset(struct ufs_hba *hba)
+static int ufs_mtk_device_reset(struct ufs_hba *hba, bool asserted)
 {
        struct arm_smccc_res res;
 
-       ufs_mtk_device_reset_ctrl(0, res);
+       if (asserted) {
+               ufs_mtk_device_reset_ctrl(0, res);
 
-       /*
-        * The reset signal is active low. UFS devices shall detect
-        * more than or equal to 1us of positive or negative RST_n
-        * pulse width.
-        *
-        * To be on safe side, keep the reset low for at least 10us.
-        */
-       usleep_range(10, 15);
-
-       ufs_mtk_device_reset_ctrl(1, res);
-
-       /* Some devices may need time to respond to rst_n */
-       usleep_range(10000, 15000);
+               /*
+                * The reset signal is active low. UFS devices shall detect
+                * more than or equal to 1us of positive or negative RST_n
+                * pulse width.
+                *
+                * To be on safe side, keep the reset low for at least 10us.
+                */
+               usleep_range(10, 15);
+       } else {
+               ufs_mtk_device_reset_ctrl(1, res);
 
-       dev_info(hba->dev, "device reset done\n");
+               /* Some devices may need time to respond to rst_n */
+               usleep_range(10000, 15000);
+       }
 
        return 0;
 }
diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 2206b1e..fed10e5 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -1406,10 +1406,11 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba)
 /**
  * ufs_qcom_device_reset() - toggle the (optional) device reset line
  * @hba: per-adapter instance
+ * @asserted: assert or deassert device reset line
  *
  * Toggles the (optional) reset line to reset the attached device.
  */
-static int ufs_qcom_device_reset(struct ufs_hba *hba)
+static int ufs_qcom_device_reset(struct ufs_hba *hba, bool asserted)
 {
        struct ufs_qcom_host *host = ufshcd_get_variant(hba);
 
@@ -1417,15 +1418,20 @@ static int ufs_qcom_device_reset(struct ufs_hba *hba)
        if (!host->device_reset)
                return -EOPNOTSUPP;
 
-       /*
-        * 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);
-       usleep_range(10, 15);
+       if (asserted) {
+               gpiod_set_value_cansleep(host->device_reset, 1);
 
-       gpiod_set_value_cansleep(host->device_reset, 0);
-       usleep_range(10, 15);
+               /*
+                * The UFS device shall detect reset pulses of 1us, sleep for 
10us to
+                * be on the safe side.
+                */
+               usleep_range(10, 15);
+       } else {
+               gpiod_set_value_cansleep(host->device_reset, 0);
+
+                /* Some devices may need time to respond to rst_n */
+               usleep_range(10, 15);
+       }
 
        return 0;
 }
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e221add..f2daac2 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -585,7 +585,13 @@ static void ufshcd_device_reset(struct ufs_hba *hba)
 {
        int err;
 
-       err = ufshcd_vops_device_reset(hba);
+       err = ufshcd_vops_device_reset(hba, true);
+       if (err) {
+               dev_err(hba->dev, "asserting device reset failed: %d\n", err);
+               return;
+       }
+
+       err = ufshcd_vops_device_reset(hba, false);
 
        if (!err) {
                ufshcd_set_ufs_dev_active(hba);
@@ -593,7 +599,11 @@ static void ufshcd_device_reset(struct ufs_hba *hba)
                        hba->wb_enabled = false;
                        hba->wb_buf_flush_enabled = false;
                }
+               dev_dbg(hba->dev, "device reset done\n");
+       } else {
+               dev_err(hba->dev, "deasserting device reset failed: %d\n", err);
        }
+
        if (err != -EOPNOTSUPP)
                ufshcd_update_evt_hist(hba, UFS_EVT_DEV_RESET, err);
 }
@@ -8686,8 +8696,6 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
        if (ret)
                goto set_dev_active;
 
-       ufshcd_vreg_set_lpm(hba);
-
 disable_clks:
        /*
         * Call vendor specific suspend callback. As these callbacks may access
@@ -8703,6 +8711,9 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
         */
        ufshcd_disable_irq(hba);
 
+       if (ufshcd_is_link_off(hba))
+               ufshcd_vops_device_reset(hba, true);
+
        ufshcd_setup_clocks(hba, false);
 
        if (ufshcd_is_clkgating_allowed(hba)) {
@@ -8711,6 +8722,8 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
                                        hba->clk_gating.state);
        }
 
+       ufshcd_vreg_set_lpm(hba);
+
        /* Put the host controller in low power mode if possible */
        ufshcd_hba_vreg_set_lpm(hba);
        goto out;
@@ -8778,18 +8791,19 @@ static int ufshcd_resume(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
        old_link_state = hba->uic_link_state;
 
        ufshcd_hba_vreg_set_hpm(hba);
+
+       ret = ufshcd_vreg_set_hpm(hba);
+       if (ret)
+               goto out;
+
        /* Make sure clocks are enabled before accessing controller */
        ret = ufshcd_setup_clocks(hba, true);
        if (ret)
-               goto out;
+               goto disable_vreg;
 
        /* enable the host irq as host controller would be active soon */
        ufshcd_enable_irq(hba);
 
-       ret = ufshcd_vreg_set_hpm(hba);
-       if (ret)
-               goto disable_irq_and_vops_clks;
-
        /*
         * Call vendor specific resume callback. As these callbacks may access
         * vendor specific host controller register space call them when the
@@ -8797,7 +8811,7 @@ static int ufshcd_resume(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
         */
        ret = ufshcd_vops_resume(hba, pm_op);
        if (ret)
-               goto disable_vreg;
+               goto disable_irq_and_vops_clks;
 
        /* For DeepSleep, the only supported option is to have the link off */
        WARN_ON(ufshcd_is_ufs_dev_deepsleep(hba) && !ufshcd_is_link_off(hba));
@@ -8864,8 +8878,6 @@ static int ufshcd_resume(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
        ufshcd_link_state_transition(hba, old_link_state, 0);
 vendor_suspend:
        ufshcd_vops_suspend(hba, pm_op);
-disable_vreg:
-       ufshcd_vreg_set_lpm(hba);
 disable_irq_and_vops_clks:
        ufshcd_disable_irq(hba);
        if (hba->clk_scaling.is_allowed)
@@ -8876,6 +8888,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum 
ufs_pm_op pm_op)
                trace_ufshcd_clk_gating(dev_name(hba->dev),
                                        hba->clk_gating.state);
        }
+disable_vreg:
+       ufshcd_vreg_set_lpm(hba);
 out:
        hba->pm_op_in_progress = 0;
        if (ret)
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 9bb5f0e..d5fbaba 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -319,7 +319,7 @@ struct ufs_pwr_mode_info {
  * @resume: called during host controller PM callback
  * @dbg_register_dump: used to dump controller debug information
  * @phy_initialization: used to initialize phys
- * @device_reset: called to issue a reset pulse on the UFS device
+ * @device_reset: called to assert or deassert device reset line
  * @program_key: program or evict an inline encryption key
  * @event_notify: called to notify important events
  */
@@ -350,7 +350,7 @@ struct ufs_hba_variant_ops {
        int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
        void    (*dbg_register_dump)(struct ufs_hba *hba);
        int     (*phy_initialization)(struct ufs_hba *);
-       int     (*device_reset)(struct ufs_hba *hba);
+       int     (*device_reset)(struct ufs_hba *hba, bool asserted);
        void    (*config_scaling_param)(struct ufs_hba *hba,
                                        struct devfreq_dev_profile *profile,
                                        void *data);
@@ -1216,10 +1216,10 @@ static inline void ufshcd_vops_dbg_register_dump(struct 
ufs_hba *hba)
                hba->vops->dbg_register_dump(hba);
 }
 
-static inline int ufshcd_vops_device_reset(struct ufs_hba *hba)
+static inline int ufshcd_vops_device_reset(struct ufs_hba *hba, bool asserted)
 {
        if (hba->vops && hba->vops->device_reset)
-               return hba->vops->device_reset(hba);
+               return hba->vops->device_reset(hba, asserted);
 
        return -EOPNOTSUPP;
 }
-- 
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