[PATCH] regulator: Fix return type of of_map_mode()

[PATCH] regulator: Fix return type of of_map_mode()

[Douglas Anderson]

In of_get_regulation_constraints() it can clearly be seen that the
return value of of_map_mode() is assigned to a signed integer.  This
is important because the first thing the regulator core does with this
value is to compare it to -EINVAL.

Let's fix the return type of all of the current of_map_mode()
functions.  While we're at it, we'll remove one pointless "inline".

Fixes: 5e5e3a42c653 ("regulator: of: Add support for parsing initial and suspend modes")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

 drivers/regulator/cpcap-regulator.c     | 2 +-
 drivers/regulator/max77802-regulator.c  | 2 +-
 drivers/regulator/qcom_spmi-regulator.c | 2 +-
 drivers/regulator/twl-regulator.c       | 2 +-
 include/linux/regulator/driver.h        | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/regulator/cpcap-regulator.c b/drivers/regulator/cpcap-regulator.c
index f541b80f1b54..46eba038f8e9 100644
--- a/drivers/regulator/cpcap-regulator.c
+++ b/drivers/regulator/cpcap-regulator.c
@@ -214,7 +214,7 @@ static int cpcap_regulator_disable(struct regulator_dev *rdev)
 	return error;
 }
 
-static unsigned int cpcap_map_mode(unsigned int mode)
+static int cpcap_map_mode(unsigned int mode)
 {
 	switch (mode) {
 	case CPCAP_BIT_AUDIO_NORMAL_MODE:
diff --git a/drivers/regulator/max77802-regulator.c b/drivers/regulator/max77802-regulator.c
index b6261903818c..8c6b5d2aec86 100644
--- a/drivers/regulator/max77802-regulator.c
+++ b/drivers/regulator/max77802-regulator.c
@@ -75,7 +75,7 @@ struct max77802_regulator_prv {
 	unsigned int opmode[MAX77802_REG_MAX];
 };
 
-static inline unsigned int max77802_map_mode(unsigned int mode)
+static inline int max77802_map_mode(unsigned int mode)
 {
 	return mode == MAX77802_OPMODE_NORMAL ?
 		REGULATOR_MODE_NORMAL : REGULATOR_MODE_STANDBY;
diff --git a/drivers/regulator/qcom_spmi-regulator.c b/drivers/regulator/qcom_spmi-regulator.c
index 63c7a0c17777..c83124061632 100644
--- a/drivers/regulator/qcom_spmi-regulator.c
+++ b/drivers/regulator/qcom_spmi-regulator.c
@@ -1432,7 +1432,7 @@ static void spmi_regulator_get_dt_config(struct spmi_regulator *vreg,
 		&data->vs_soft_start_strength);
 }
 
-static unsigned int spmi_regulator_of_map_mode(unsigned int mode)
+static int spmi_regulator_of_map_mode(unsigned int mode)
 {
 	if (mode == 1)
 		return REGULATOR_MODE_NORMAL;
diff --git a/drivers/regulator/twl-regulator.c b/drivers/regulator/twl-regulator.c
index a4456db5849d..496917bfad05 100644
--- a/drivers/regulator/twl-regulator.c
+++ b/drivers/regulator/twl-regulator.c
@@ -266,7 +266,7 @@ static int twl4030reg_set_mode(struct regulator_dev *rdev, unsigned mode)
 	return twl4030_send_pb_msg(message);
 }
 
-static inline unsigned int twl4030reg_map_mode(unsigned int mode)
+static int twl4030reg_map_mode(unsigned int mode)
 {
 	switch (mode) {
 	case RES_STATE_ACTIVE:
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 4fc96cb8e5d7..c98da2500c9f 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -367,7 +367,7 @@ struct regulator_desc {
 
 	unsigned int off_on_delay;
 
-	unsigned int (*of_map_mode)(unsigned int mode);
+	int (*of_map_mode)(unsigned int mode);
 };
 
 /**
-- 
2.17.0.484.g0c8726318c-goog

Re: [PATCH] regulator: Fix return type of of_map_mode()

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 378 bytes --]

On Tue, Apr 17, 2018 at 10:12:04AM -0700, Douglas Anderson wrote:
> In of_get_regulation_constraints() it can clearly be seen that the
> return value of of_map_mode() is assigned to a signed integer.  This
> is important because the first thing the regulator core does with this
> value is to compare it to -EINVAL.

Hrm, so how does the compiler manage to not warn about this?

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH] regulator: Fix return type of of_map_mode()

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 839 bytes --]

On Tue, Apr 17, 2018 at 10:12:04AM -0700, Douglas Anderson wrote:
> In of_get_regulation_constraints() it can clearly be seen that the
> return value of of_map_mode() is assigned to a signed integer.  This
> is important because the first thing the regulator core does with this
> value is to compare it to -EINVAL.
> 
> Let's fix the return type of all of the current of_map_mode()
> functions.  While we're at it, we'll remove one pointless "inline".

Ah, I see...  the thing here is that the mode is always an unsigned int
since it's a bitmask - this goes out beying the use in of_map_mode() and
into all the other APIs.  We only actually use 4 bits currently so I
think there's no problem switching to int but it seems we should
probably do that consistently throughout the API so that things don't
get missed later on.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH] regulator: Fix return type of of_map_mode()

[Javier Martinez Canillas]

On Tue, Apr 17, 2018 at 7:22 PM, Mark Brown <broonie@kernel.org> wrote:
> On Tue, Apr 17, 2018 at 10:12:04AM -0700, Douglas Anderson wrote:
>> In of_get_regulation_constraints() it can clearly be seen that the
>> return value of of_map_mode() is assigned to a signed integer.  This
>> is important because the first thing the regulator core does with this
>> value is to compare it to -EINVAL.
>>

Sorry about that, as Mark mentioned both the regulator device specific
and standard modes are a bitmap, and that's why I used an unsigned int
as return type.

IIRC, at some point in the review someone mentioned error handling and
I just blindly added a check for -EINVAL assuming the drivers would
return that, but forgot about the return type :(

>> Let's fix the return type of all of the current of_map_mode()
>> functions.  While we're at it, we'll remove one pointless "inline".
>
> Ah, I see...  the thing here is that the mode is always an unsigned int
> since it's a bitmask - this goes out beying the use in of_map_mode() and
> into all the other APIs.  We only actually use 4 bits currently so I
> think there's no problem switching to int but it seems we should
> probably do that consistently throughout the API so that things don't
> get missed later on.

Maybe another option could be to add a REGULATOR_MODE_INVALID with
value 0x0, and fix the drivers that are returning -EINVAL to return
that instead?

In of_get_regulation_constraints() we could check for that and
propagate -EINVAL.

Best regards,
Javier

Re: [PATCH] regulator: Fix return type of of_map_mode()

[Doug Anderson]

Hi,

On Tue, Apr 17, 2018 at 10:48 AM, Javier Martinez Canillas
<javier@dowhile0.org> wrote:
>>> Let's fix the return type of all of the current of_map_mode()
>>> functions.  While we're at it, we'll remove one pointless "inline".
>>
>> Ah, I see...  the thing here is that the mode is always an unsigned int
>> since it's a bitmask - this goes out beying the use in of_map_mode() and
>> into all the other APIs.  We only actually use 4 bits currently so I
>> think there's no problem switching to int but it seems we should
>> probably do that consistently throughout the API so that things don't
>> get missed later on.
>
> Maybe another option could be to add a REGULATOR_MODE_INVALID with
> value 0x0, and fix the drivers that are returning -EINVAL to return
> that instead?
>
> In of_get_regulation_constraints() we could check for that and
> propagate -EINVAL.

I like this idea.  Posted at
<https://patchwork.kernel.org/patch/10347345/>.  Note that there's no
actual error to propagate since of_get_regulation_constraints() just
prints the error and continues on its merry way.

-Doug