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,

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(-)

[PATCH v3 0/5] 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(-)

-- 
2.18.0

Re: [PATCH v3 0/5] scsi: ufs: Fix regulator operations and remove "<name>-fixed-regulator" device tree property

[Stanley Chu]

Hi Avri, Alim, Pedrom,

Gentle ping for this series.

On Mon, 2019-03-18 at 10:14 +0800, Stanley Chu wrote:
> 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(-)
> 

Thanks,
Stanley

[PATCH v3 1/5] 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

Re: [PATCH v3 1/5] scsi: ufs: Remove unused min_uA field in struct ufs_vreg

[Alim Akhtar]

Hi Stanley

On Mon, Mar 18, 2019 at 7:46 AM Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
>
> 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>
> ---
Looks good.
Acked-by: Alim Akhtar <alim.akhtar-Sze3O3UU22JBDgjK7y7TUQ@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
>


-- 
Regards,
Alim

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

[Stanley Chu]

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

[PATCH v3 3/5] scsi: ufs: Fix regulator 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 4e41fdfd0e53..9ae3256a705b 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 v3 4/5] scsi: ufs: Change "<name>-max-microamp" to non-mandatory property

[Stanley Chu]

In dt-bindings for ufs, "<name>-max-microamp" property indicates
current limit and is mandatory if "<name>-fixed-regulator" is not
defined on a specified regulator.

However, in some platforms, regulators without "<name>-fixed-regulator"
deifned may not need to define their current limit. They may only
want to define voltage range for proper voltage switching in
different power modes, especially for vcc, vccq or vccq2.

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

After resolving this, these regulators without "<name>-max-microamp"
will have undefined "max current" value, i.e., zero value in "max_uA"
field in struct ufs_vreg. Because we do bypass current switching
operation (by regulator_set_load) in case of undefined current limit,
this patch 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 v3 5/5] 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,

1. "<name>-max-microamp" becomes optional property: Undefined
   "<name>-max-microamp" will not cause initialization fail if
   "<name>-fixed-regulator" is not defined.

2. Current switching operation (by regulator_set_load) now has rules:
   Regulators will have undefined current limit if
   "<name>-fixed-regulator" is not defined. But this is safe because
   only regulator which has configured current limit from
   "<name>-max-microamp" property is allowed to change its load.

Although "<name>-fixed-regulator" is not used in any dt-bindings
in tree, this patch is still safe for regulators already defined
"<name>-fixed-regulator", the reason is described as below.

If a regulator defined "<name>-fixed-regulator" before, the behavior
after this patch is described as below,

1. "<name>-max-microamp":
   If a regulator defined "<name>-fixed-regulator", it is not necessary
   to define "<name>-max-microamp" property in device tree and it is
   expected to have an undefined current limit, i.e., "max_uA" field
   is zero in struct ufs_vreg. This is exactly the same as patched.

2. "vcc-supply-1p8" or volatge range settings:
   * For vcc, vccq or vccq2, these three regulators shall not define
     "<name>-fixed-regulator" because defining it will lead to
     undefined voltage range and thus voltage switching will be
     unexpected.
   * For other regulators with undefined voltage range, voltage range
     will be still undefined after patched.

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

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