scsi: ufs: fix regulator operations and remove "<name>-fixed-regulator" device tree property

scsi: ufs: fix regulator operations and remove "<name>-fixed-regulator" device tree property

[Stanley Chu]

Hi,

This patch series fixes UFS regulator operations and removes "<name>-fixed-regulator" device tree property.

Stanley Chu (4):
  scsi: ufs: remove unused min_uA field in struct ufs_vreg
  scsi: ufs: fix regulator set load and icc-level configuration
  scsi: ufs: change "<name>-max-microamp" to non-mandatory property
  scsi: ufs: remove "<name>-fixed-regulator" device tree property

 drivers/scsi/ufs/ufs.h           |  1 -
 drivers/scsi/ufs/ufshcd-pltfrm.c | 14 +++-----------
 drivers/scsi/ufs/ufshcd.c        | 15 ++++++++++++---
 3 files changed, 15 insertions(+), 15 deletions(-)

[PATCH v2 0/4] scsi: ufs: fix regulator operations and remove "<name>-fixed-regulator" device tree property

[Stanley Chu]

Hi,

This patch series fixes UFS regulator operations and removes "<name>-fixed-regulator" device tree property.

Stanley Chu (4):
  scsi: ufs: remove unused min_uA field in struct ufs_vreg
  scsi: ufs: fix regulator set load and icc-level configuration
  scsi: ufs: change "<name>-max-microamp" to non-mandatory property
  scsi: ufs: remove "<name>-fixed-regulator" device tree property

 drivers/scsi/ufs/ufs.h           |  1 -
 drivers/scsi/ufs/ufshcd-pltfrm.c | 14 +++-----------
 drivers/scsi/ufs/ufshcd.c        | 15 ++++++++++++---
 3 files changed, 15 insertions(+), 15 deletions(-)

-- 
2.18.0

[PATCH v2 1/4] scsi: ufs: remove unused min_uA field in struct ufs_vreg

[Stanley Chu]

There are two fields related to regulator current limit in struct
ufs_vreg: "min_uA" and "max_uA".

"max_uA" is probed by "<name>-max-microamp" property from device
tree and used for

- regulator_set_load operations, and
- icc_level configuration in device.

However "min_uA" field is not used anywhere, thus we can remove it.

Signed-off-by: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
Reviewed-by: Marc Gonzalez <marc.w.gonzalez-GANU6spQydw@public.gmane.org>
---
 drivers/scsi/ufs/ufs.h           | 1 -
 drivers/scsi/ufs/ufshcd-pltfrm.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 7da7318eb6a6..0f23ac80bacd 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -516,7 +516,6 @@ struct ufs_vreg {
 	bool enabled;
 	int min_uV;
 	int max_uV;
-	int min_uA;
 	int max_uA;
 };
 
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index 895a9b5ac989..588079286e8a 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -164,7 +164,6 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
 		goto out;
 	}
 
-	vreg->min_uA = 0;
 	if (!strcmp(name, "vcc")) {
 		if (of_property_read_bool(np, "vcc-supply-1p8")) {
 			vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
-- 
2.18.0

[PATCH v2 2/4] scsi: ufs: fix regulator set load and icc-level configuration

[Stanley Chu]

Currently if a regulator has "<name>-fixed-regulator"
property in device tree, it will skip current limit configuration.
This lead to a zero "max_uA" value in struct ufs_vreg.

However, "regulator_set_load" operation shall be required
on those regulators which specifically configured current
limit, otherwise a zero max_uA value may cause unexpected behavior
when this regulator is enabled or set as high power mode.

Similarly, in icc_level configuration flow, icc_level shall be
updated if specified regulator has also configured current limit,
otherwise a zero max_uA will lead to wrong icc_level which may
cause unexpected results after written to device.

Signed-off-by: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 drivers/scsi/ufs/ufshcd.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8b9a01073d62..61cdae74de62 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6279,19 +6279,19 @@ static u32 ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
 		goto out;
 	}
 
-	if (hba->vreg_info.vcc)
+	if (hba->vreg_info.vcc && hba->vreg_info.vcc->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vcc->max_uA,
 				POWER_DESC_MAX_ACTV_ICC_LVLS - 1,
 				&desc_buf[PWR_DESC_ACTIVE_LVLS_VCC_0]);
 
-	if (hba->vreg_info.vccq)
+	if (hba->vreg_info.vccq && hba->vreg_info.vccq->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vccq->max_uA,
 				icc_level,
 				&desc_buf[PWR_DESC_ACTIVE_LVLS_VCCQ_0]);
 
-	if (hba->vreg_info.vccq2)
+	if (hba->vreg_info.vccq2 && hba->vreg_info.vccq2->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vccq2->max_uA,
 				icc_level,
@@ -6989,6 +6989,15 @@ static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
 	if (!vreg)
 		return 0;
 
+	/*
+	 * "set_load" operation shall be required on those regulators
+	 * which specifically configured current limitation. Otherwise
+	 * zero max_uA may cause unexpected behavior when regulator is
+	 * enabled or set as high power mode.
+	 */
+	if (!vreg->max_uA)
+		return 0;
+
 	ret = regulator_set_load(vreg->reg, ua);
 	if (ret < 0) {
 		dev_err(dev, "%s: %s set load (ua=%d) failed, err=%d\n",
-- 
2.18.0

[PATCH v2 3/4] scsi: ufs: change "<name>-max-microamp" to non-mandatory property

[Stanley Chu]

In some platforms, vcc, vccq and vccq2 regulators may not need
to define their current limit but need to define their voltage
range for correct regulator_set_voltage behaviors.

However, missing "<name>-max-microamp" property in device tree
will lead to initialization fail. This limitation shall be
resolved to tolerate such kind of regulators.

Because we do bypass regulator_set_load operations in case
current limit is undefined, so this change shall be safe.

Signed-off-by: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 drivers/scsi/ufs/ufshcd-pltfrm.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index 588079286e8a..2f244d388ca8 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -157,11 +157,9 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
 		goto out;
 
 	snprintf(prop_name, MAX_PROP_SIZE, "%s-max-microamp", name);
-	ret = of_property_read_u32(np, prop_name, &vreg->max_uA);
-	if (ret) {
-		dev_err(dev, "%s: unable to find %s err %d\n",
-				__func__, prop_name, ret);
-		goto out;
+	if (of_property_read_u32(np, prop_name, &vreg->max_uA)) {
+		dev_info(dev, "%s: unable to find %s\n", __func__, prop_name);
+		vreg->max_uA = 0;
 	}
 
 	if (!strcmp(name, "vcc")) {
-- 
2.18.0

[PATCH v2 4/4] scsi: ufs: remove "<name>-fixed-regulator" device tree property

[Stanley Chu]

"<name>-fixed-regulator" device tree property can be
safely removed because below things are fixed or resolved,

- "<name>-max-microamp" becomes optional property: Undefined
  "<name>-max-microamp" will not cause initialization fail.

- regulator_set_load operation now has rules: Only those regulators
  which have configured current limit from "<name>-max-microamp"
  property is allowed to change its load.

The difference of regulators which define "<name>-fixed-regulator"
or not is listed as below,

- "<name>-max-microamp": If an existed regulator which defined
  "<name>-fixed-regulator", it shall be lack of "<name>-max-microamp"
  property in device tree thus regulator_set_load behaviors will be
  the same as before this patch.

- "vcc-supply-1p8": This only impacts "vcc-supply" regulator. However
  vcc shall not define "<name>-fixed-regulator" in device tree
  otherwise ufshcd_config_vreg() will use zero voltage values as
  request to regulator_set_voltage() and may lead to unexpected
  results.

Therefore this patch is safe for all existed regulators with
"<name>-fixed-regulator" property already used.

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

diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index 2f244d388ca8..a667e7ba1c8b 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -151,11 +151,6 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
 
 	vreg->name = kstrdup(name, GFP_KERNEL);
 
-	/* if fixed regulator no need further initialization */
-	snprintf(prop_name, MAX_PROP_SIZE, "%s-fixed-regulator", name);
-	if (of_property_read_bool(np, prop_name))
-		goto out;
-
 	snprintf(prop_name, MAX_PROP_SIZE, "%s-max-microamp", name);
 	if (of_property_read_u32(np, prop_name, &vreg->max_uA)) {
 		dev_info(dev, "%s: unable to find %s\n", __func__, prop_name);
-- 
2.18.0

scsi: ufs: Fix regulator operations and remove "<name>-fixed-regulator" device tree property

[Stanley Chu]

Hi,

Sorry please help review V3 instead of previous versions.
In this version I fix and add more details in commit messages, and add one patch to fix "undefined voltage range" issue as well.

This patch series fixes UFS regulator operations, including voltage and current (re-)configuration flow during initialization or different power modes.

Besides, remove "<name>-fixed-regulator" device tree property because it is not necessary anymore after fixes.

V3:
- Fix and add more details in commit messages.
- Add one patch "scsi: ufs: Avoid configuring undefined voltage range on a regulator".

V2:
- Add two patches to prepare to and remove "<name>-fixed-regulator" device tree property.
- Add more details on patch "scsi: ufs: remove unused min_uA field in struct ufs_vreg" (Marc Gonzalez).

Stanley Chu (5):
  scsi: ufs: Remove unused min_uA field in struct ufs_vreg
  scsi: ufs: Avoid configuring undefined voltage range on a regulator
  scsi: ufs: Fix regulator load and icc-level configuration
  scsi: ufs: Change "<name>-max-microamp" to non-mandatory property
  scsi: ufs: Remove "<name>-fixed-regulator" device tree property

 drivers/scsi/ufs/ufs.h           |  1 -
 drivers/scsi/ufs/ufshcd-pltfrm.c | 14 +++-----------
 drivers/scsi/ufs/ufshcd.c        | 28 ++++++++++++++++++++--------
 3 files changed, 23 insertions(+), 20 deletions(-)