[PATCH v4 0/4] Use devm helpers for regulator get and enable

[PATCH v4 0/4] Use devm helpers for regulator get and enable

[Matti Vaittinen]

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Simplify couple of drivers by using the new devm_regulator_*get_enable*()

These patches were previously part of the series:
https://lore.kernel.org/lkml/cover.1660934107.git.mazziesaccount@gmail.com/
"Devm helpers for regulator get and enable". I did keep the patch series
versioning even though I changed the series name (subject of this mail)
to "Use devm helpers for regulator get and enable". Name was changed
because the devm helpers are already in 6.1-rc1.

Also, most of the patches in the series are already merged to subsystem
trees so this series now contains only the patches that have not yet
been merged. I hope they can be now directly taken sirectly into
respective subsystem trees as the dependencies should be in v6.1-rc1.

Please note that these changes are only compile-tested as I don't have
the HW to do proper testing. Thus, reviewing / testing is highly
appreciated.

Revision history:

v3 => v4:
	- Drop applied patches
	- rewrite cover-letter
	- rebase on v6.1-rc1
	- split meson and sii902x into own patches as requested.
	- slightly modify dev_err_probe() return in sii902x.

---

Matti Vaittinen (4):
  gpu: drm: meson: Use devm_regulator_*get_enable*()
  gpu: drm: sii902x: Use devm_regulator_bulk_get_enable()
  hwmon: lm90: simplify using devm_regulator_get_enable()
  hwmon: adm1177: simplify using devm_regulator_get_enable()

 drivers/gpu/drm/bridge/sii902x.c      | 26 ++++----------------------
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
 drivers/hwmon/adm1177.c               | 27 +++------------------------
 drivers/hwmon/lm90.c                  | 20 ++------------------
 4 files changed, 12 insertions(+), 84 deletions(-)


base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780
-- 
2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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[PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[Matti Vaittinen]

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Simplify using the devm_regulator_get_enable_optional(). Also drop the
seemingly unused struct member 'hdmi_supply'.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>

---
v3 => v4:
- split meson part to own patch

RFCv1 => v2:
- Change also sii902x to use devm_regulator_bulk_get_enable()

Please note - this is only compile-tested due to the lack of HW. Careful
review and testing is _highly_ appreciated.
---
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 5cd2b2ebbbd3..7642f740272b 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -140,7 +140,6 @@ struct meson_dw_hdmi {
 	struct reset_control *hdmitx_apb;
 	struct reset_control *hdmitx_ctrl;
 	struct reset_control *hdmitx_phy;
-	struct regulator *hdmi_supply;
 	u32 irq_stat;
 	struct dw_hdmi *hdmi;
 	struct drm_bridge *bridge;
@@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
 
 }
 
-static void meson_disable_regulator(void *data)
-{
-	regulator_disable(data);
-}
-
 static void meson_disable_clk(void *data)
 {
 	clk_disable_unprepare(data);
@@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 	meson_dw_hdmi->data = match;
 	dw_plat_data = &meson_dw_hdmi->dw_plat_data;
 
-	meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, "hdmi");
-	if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
-		if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
-		meson_dw_hdmi->hdmi_supply = NULL;
-	} else {
-		ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
-		if (ret)
-			return ret;
-		ret = devm_add_action_or_reset(dev, meson_disable_regulator,
-					       meson_dw_hdmi->hdmi_supply);
-		if (ret)
-			return ret;
-	}
+	ret = devm_regulator_get_enable_optional(dev, "hdmi");
+	if (ret != -ENODEV)
+		return ret;
 
 	meson_dw_hdmi->hdmitx_apb = devm_reset_control_get_exclusive(dev,
 						"hdmitx_apb");
-- 
2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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Re: [PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[Neil Armstrong]

On 21/10/2022 15:18, Matti Vaittinen wrote:
> Simplify using the devm_regulator_get_enable_optional(). Also drop the
> seemingly unused struct member 'hdmi_supply'.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> 
> ---
> v3 => v4:
> - split meson part to own patch
> 
> RFCv1 => v2:
> - Change also sii902x to use devm_regulator_bulk_get_enable()
> 
> Please note - this is only compile-tested due to the lack of HW. Careful
> review and testing is _highly_ appreciated.
> ---
>   drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>   1 file changed, 3 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 5cd2b2ebbbd3..7642f740272b 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>   	struct reset_control *hdmitx_apb;
>   	struct reset_control *hdmitx_ctrl;
>   	struct reset_control *hdmitx_phy;
> -	struct regulator *hdmi_supply;
>   	u32 irq_stat;
>   	struct dw_hdmi *hdmi;
>   	struct drm_bridge *bridge;
> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
>   
>   }
>   
> -static void meson_disable_regulator(void *data)
> -{
> -	regulator_disable(data);
> -}
> -
>   static void meson_disable_clk(void *data)
>   {
>   	clk_disable_unprepare(data);
> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>   	meson_dw_hdmi->data = match;
>   	dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>   
> -	meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, "hdmi");
> -	if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
> -		if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
> -			return -EPROBE_DEFER;
> -		meson_dw_hdmi->hdmi_supply = NULL;
> -	} else {
> -		ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
> -		if (ret)
> -			return ret;
> -		ret = devm_add_action_or_reset(dev, meson_disable_regulator,
> -					       meson_dw_hdmi->hdmi_supply);
> -		if (ret)
> -			return ret;
> -	}
> +	ret = devm_regulator_get_enable_optional(dev, "hdmi");
> +	if (ret != -ENODEV)
> +		return ret;
>   
>   	meson_dw_hdmi->hdmitx_apb = devm_reset_control_get_exclusive(dev,
>   						"hdmitx_apb");

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>


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Re: [PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[Laurent Pinchart]

Hi Matti,

On Fri, Oct 21, 2022 at 04:18:01PM +0300, Matti Vaittinen wrote:
> Simplify using the devm_regulator_get_enable_optional(). Also drop the
> seemingly unused struct member 'hdmi_supply'.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> 
> ---
> v3 => v4:
> - split meson part to own patch
> 
> RFCv1 => v2:
> - Change also sii902x to use devm_regulator_bulk_get_enable()
> 
> Please note - this is only compile-tested due to the lack of HW. Careful
> review and testing is _highly_ appreciated.
> ---
>  drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>  1 file changed, 3 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 5cd2b2ebbbd3..7642f740272b 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>  	struct reset_control *hdmitx_apb;
>  	struct reset_control *hdmitx_ctrl;
>  	struct reset_control *hdmitx_phy;
> -	struct regulator *hdmi_supply;
>  	u32 irq_stat;
>  	struct dw_hdmi *hdmi;
>  	struct drm_bridge *bridge;
> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
>  
>  }
>  
> -static void meson_disable_regulator(void *data)
> -{
> -	regulator_disable(data);
> -}
> -
>  static void meson_disable_clk(void *data)
>  {
>  	clk_disable_unprepare(data);
> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>  	meson_dw_hdmi->data = match;
>  	dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>  
> -	meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, "hdmi");
> -	if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
> -		if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
> -			return -EPROBE_DEFER;
> -		meson_dw_hdmi->hdmi_supply = NULL;
> -	} else {
> -		ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
> -		if (ret)
> -			return ret;
> -		ret = devm_add_action_or_reset(dev, meson_disable_regulator,
> -					       meson_dw_hdmi->hdmi_supply);
> -		if (ret)
> -			return ret;
> -	}
> +	ret = devm_regulator_get_enable_optional(dev, "hdmi");
> +	if (ret != -ENODEV)
> +		return ret;

As noted in the review of the series that introduced
devm_regulator_get_enable_optional(), the right thing to do is to
implement runtime PM in this driver to avoid wasting power.

>  
>  	meson_dw_hdmi->hdmitx_apb = devm_reset_control_get_exclusive(dev,
>  						"hdmitx_apb");

-- 
Regards,

Laurent Pinchart

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Re: [PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[Neil Armstrong]

Hi,

On 21/10/2022 17:02, Laurent Pinchart wrote:
> Hi Matti,
> 
> On Fri, Oct 21, 2022 at 04:18:01PM +0300, Matti Vaittinen wrote:
>> Simplify using the devm_regulator_get_enable_optional(). Also drop the
>> seemingly unused struct member 'hdmi_supply'.
>>
>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>>
>> ---
>> v3 => v4:
>> - split meson part to own patch
>>
>> RFCv1 => v2:
>> - Change also sii902x to use devm_regulator_bulk_get_enable()
>>
>> Please note - this is only compile-tested due to the lack of HW. Careful
>> review and testing is _highly_ appreciated.
>> ---
>>   drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>>   1 file changed, 3 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> index 5cd2b2ebbbd3..7642f740272b 100644
>> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>>   	struct reset_control *hdmitx_apb;
>>   	struct reset_control *hdmitx_ctrl;
>>   	struct reset_control *hdmitx_phy;
>> -	struct regulator *hdmi_supply;
>>   	u32 irq_stat;
>>   	struct dw_hdmi *hdmi;
>>   	struct drm_bridge *bridge;
>> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct meson_dw_hdmi *meson_dw_hdmi)
>>   
>>   }
>>   
>> -static void meson_disable_regulator(void *data)
>> -{
>> -	regulator_disable(data);
>> -}
>> -
>>   static void meson_disable_clk(void *data)
>>   {
>>   	clk_disable_unprepare(data);
>> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>>   	meson_dw_hdmi->data = match;
>>   	dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>>   
>> -	meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, "hdmi");
>> -	if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
>> -		if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
>> -			return -EPROBE_DEFER;
>> -		meson_dw_hdmi->hdmi_supply = NULL;
>> -	} else {
>> -		ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
>> -		if (ret)
>> -			return ret;
>> -		ret = devm_add_action_or_reset(dev, meson_disable_regulator,
>> -					       meson_dw_hdmi->hdmi_supply);
>> -		if (ret)
>> -			return ret;
>> -	}
>> +	ret = devm_regulator_get_enable_optional(dev, "hdmi");
>> +	if (ret != -ENODEV)
>> +		return ret;
> 
> As noted in the review of the series that introduced
> devm_regulator_get_enable_optional(), the right thing to do is to
> implement runtime PM in this driver to avoid wasting power.

While I agree, it's not really the same level of effort as this patch
should be functionally equivalent.

> 
>>   
>>   	meson_dw_hdmi->hdmitx_apb = devm_reset_control_get_exclusive(dev,
>>   						"hdmitx_apb");
> 

Neil

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Re: [PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[Vaittinen, Matti]

On 10/21/22 18:29, Neil Armstrong wrote:
> Hi,
> 
> On 21/10/2022 17:02, Laurent Pinchart wrote:
>> Hi Matti,
>>
>> On Fri, Oct 21, 2022 at 04:18:01PM +0300, Matti Vaittinen wrote:
>>> Simplify using the devm_regulator_get_enable_optional(). Also drop the
>>> seemingly unused struct member 'hdmi_supply'.
>>>
>>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>>>
>>> ---
>>> v3 => v4:
>>> - split meson part to own patch
>>>
>>> RFCv1 => v2:
>>> - Change also sii902x to use devm_regulator_bulk_get_enable()
>>>
>>> Please note - this is only compile-tested due to the lack of HW. Careful
>>> review and testing is _highly_ appreciated.
>>> ---

//Snip

>>
>> As noted in the review of the series that introduced
>> devm_regulator_get_enable_optional(), the right thing to do is to
>> implement runtime PM in this driver to avoid wasting power.
> 
> While I agree, it's not really the same level of effort as this patch
> should be functionally equivalent.
> 

Exactly. As I wrote, I do not have the HW to test this change. This 
intends to bring no functional changes. It is just a minor 
simplification while also making it harder to create a bug with the 
regulator control. (Registering the devm_action and leaving the handle 
to the regulator is more fragile than using this new API which does not 
give user the handle).

I am in no way against someone further improving the functionality here 
(by adding runtime PM) but this someone is not me. Yet, I don't see how 
this patch prevents runtime PM being implemented? The first thing that 
needs to be done is removing the devm-action assuming someone did 
implement power-saving by disabling the regulator(s) at runtime. After 
this patch is applied, the action removal is automatically a necessity 
in order to get the handle for regulator control.

I know this helper is not preferred by all but it is still safer than 
the current code which registers the action while allowing the regulator 
control.

Yours
	-- Matti

-- 
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Linux kernel developer at ROHM Semiconductors
Oulu Finland

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Re: [PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[Vaittinen, Matti]

Hi dee Ho Laurent & All,

On 10/21/22 18:29, Neil Armstrong wrote:
> Hi,
> 
> On 21/10/2022 17:02, Laurent Pinchart wrote:
>> Hi Matti,
>>
>> On Fri, Oct 21, 2022 at 04:18:01PM +0300, Matti Vaittinen wrote:
>>> Simplify using the devm_regulator_get_enable_optional(). Also drop the
>>> seemingly unused struct member 'hdmi_supply'.
>>>
>>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>>>
>>> ---
>>> v3 => v4:
>>> - split meson part to own patch
>>>
>>> RFCv1 => v2:
>>> - Change also sii902x to use devm_regulator_bulk_get_enable()
>>>
>>> Please note - this is only compile-tested due to the lack of HW. Careful
>>> review and testing is _highly_ appreciated.
>>> ---
>>>   drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>>>   1 file changed, 3 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c 
>>> b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> index 5cd2b2ebbbd3..7642f740272b 100644
>>> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>>>       struct reset_control *hdmitx_apb;
>>>       struct reset_control *hdmitx_ctrl;
>>>       struct reset_control *hdmitx_phy;
>>> -    struct regulator *hdmi_supply;
>>>       u32 irq_stat;
>>>       struct dw_hdmi *hdmi;
>>>       struct drm_bridge *bridge;
>>> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct 
>>> meson_dw_hdmi *meson_dw_hdmi)
>>>   }
>>> -static void meson_disable_regulator(void *data)
>>> -{
>>> -    regulator_disable(data);
>>> -}
>>> -
>>>   static void meson_disable_clk(void *data)
>>>   {
>>>       clk_disable_unprepare(data);
>>> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device 
>>> *dev, struct device *master,
>>>       meson_dw_hdmi->data = match;
>>>       dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>>> -    meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev, 
>>> "hdmi");
>>> -    if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
>>> -        if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
>>> -            return -EPROBE_DEFER;
>>> -        meson_dw_hdmi->hdmi_supply = NULL;
>>> -    } else {
>>> -        ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
>>> -        if (ret)
>>> -            return ret;
>>> -        ret = devm_add_action_or_reset(dev, meson_disable_regulator,
>>> -                           meson_dw_hdmi->hdmi_supply);
>>> -        if (ret)
>>> -            return ret;
>>> -    }
>>> +    ret = devm_regulator_get_enable_optional(dev, "hdmi");
>>> +    if (ret != -ENODEV)
>>> +        return ret;
>>
>> As noted in the review of the series that introduced
>> devm_regulator_get_enable_optional(), the right thing to do is to
>> implement runtime PM in this driver to avoid wasting power.
> 
> While I agree, it's not really the same level of effort as this patch
> should be functionally equivalent.

While we all agree that power savings gained by runtime PM would be 
great - I don't think we should stop minor improvements while waiting 
for that to magically happen ;)

I like the saying I first heard from Jonathan Cameron - "Don't let the 
perfect be an enemy of good".

After that being said, should I re-spin this or just drop it? (I am 
cleaning up my local git from old stuff, and these are about to vanish 
from my books).

Yours,
	-- Matti

-- 
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Linux kernel developer at ROHM Semiconductors
Oulu Finland

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Re: [PATCH v4 1/4] gpu: drm: meson: Use devm_regulator_*get_enable*()

[neil.armstrong]

On 16/11/2022 13:02, Vaittinen, Matti wrote:
> Hi dee Ho Laurent & All,
> 
> On 10/21/22 18:29, Neil Armstrong wrote:
>> Hi,
>>
>> On 21/10/2022 17:02, Laurent Pinchart wrote:
>>> Hi Matti,
>>>
>>> On Fri, Oct 21, 2022 at 04:18:01PM +0300, Matti Vaittinen wrote:
>>>> Simplify using the devm_regulator_get_enable_optional(). Also drop the
>>>> seemingly unused struct member 'hdmi_supply'.
>>>>
>>>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>>>>
>>>> ---
>>>> v3 => v4:
>>>> - split meson part to own patch
>>>>
>>>> RFCv1 => v2:
>>>> - Change also sii902x to use devm_regulator_bulk_get_enable()
>>>>
>>>> Please note - this is only compile-tested due to the lack of HW. Careful
>>>> review and testing is _highly_ appreciated.
>>>> ---
>>>>    drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +++--------------------
>>>>    1 file changed, 3 insertions(+), 20 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>>> b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>>> index 5cd2b2ebbbd3..7642f740272b 100644
>>>> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>>> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>>>> @@ -140,7 +140,6 @@ struct meson_dw_hdmi {
>>>>        struct reset_control *hdmitx_apb;
>>>>        struct reset_control *hdmitx_ctrl;
>>>>        struct reset_control *hdmitx_phy;
>>>> -    struct regulator *hdmi_supply;
>>>>        u32 irq_stat;
>>>>        struct dw_hdmi *hdmi;
>>>>        struct drm_bridge *bridge;
>>>> @@ -665,11 +664,6 @@ static void meson_dw_hdmi_init(struct
>>>> meson_dw_hdmi *meson_dw_hdmi)
>>>>    }
>>>> -static void meson_disable_regulator(void *data)
>>>> -{
>>>> -    regulator_disable(data);
>>>> -}
>>>> -
>>>>    static void meson_disable_clk(void *data)
>>>>    {
>>>>        clk_disable_unprepare(data);
>>>> @@ -723,20 +717,9 @@ static int meson_dw_hdmi_bind(struct device
>>>> *dev, struct device *master,
>>>>        meson_dw_hdmi->data = match;
>>>>        dw_plat_data = &meson_dw_hdmi->dw_plat_data;
>>>> -    meson_dw_hdmi->hdmi_supply = devm_regulator_get_optional(dev,
>>>> "hdmi");
>>>> -    if (IS_ERR(meson_dw_hdmi->hdmi_supply)) {
>>>> -        if (PTR_ERR(meson_dw_hdmi->hdmi_supply) == -EPROBE_DEFER)
>>>> -            return -EPROBE_DEFER;
>>>> -        meson_dw_hdmi->hdmi_supply = NULL;
>>>> -    } else {
>>>> -        ret = regulator_enable(meson_dw_hdmi->hdmi_supply);
>>>> -        if (ret)
>>>> -            return ret;
>>>> -        ret = devm_add_action_or_reset(dev, meson_disable_regulator,
>>>> -                           meson_dw_hdmi->hdmi_supply);
>>>> -        if (ret)
>>>> -            return ret;
>>>> -    }
>>>> +    ret = devm_regulator_get_enable_optional(dev, "hdmi");
>>>> +    if (ret != -ENODEV)
>>>> +        return ret;
>>>
>>> As noted in the review of the series that introduced
>>> devm_regulator_get_enable_optional(), the right thing to do is to
>>> implement runtime PM in this driver to avoid wasting power.
>>
>> While I agree, it's not really the same level of effort as this patch
>> should be functionally equivalent.
> 
> While we all agree that power savings gained by runtime PM would be
> great - I don't think we should stop minor improvements while waiting
> for that to magically happen ;)
> 
> I like the saying I first heard from Jonathan Cameron - "Don't let the
> perfect be an enemy of good".
> 
> After that being said, should I re-spin this or just drop it? (I am
> cleaning up my local git from old stuff, and these are about to vanish
> from my books).

I'm ok with you, please re-spin it.

Neil

> 
> Yours,
> 	-- Matti
> 


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[PATCH v4 2/4] gpu: drm: sii902x: Use devm_regulator_bulk_get_enable()

[Matti Vaittinen]

[-- Attachment #1.1: Type: text/plain, Size: 2886 bytes --]

Simplify using devm_regulator_bulk_get_enable()

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>

---
v3 => v4:
- split to own patch.
- return directly the value returned by the dev_err_probe()

Please note - this is only compile-tested due to the lack of HW. Careful
review and testing is _highly_ appreciated
---
 drivers/gpu/drm/bridge/sii902x.c | 26 ++++----------------------
 1 file changed, 4 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
index 878fb7d3732b..f6e8b401069b 100644
--- a/drivers/gpu/drm/bridge/sii902x.c
+++ b/drivers/gpu/drm/bridge/sii902x.c
@@ -171,7 +171,6 @@ struct sii902x {
 	struct drm_connector connector;
 	struct gpio_desc *reset_gpio;
 	struct i2c_mux_core *i2cmux;
-	struct regulator_bulk_data supplies[2];
 	bool sink_is_hdmi;
 	/*
 	 * Mutex protects audio and video functions from interfering
@@ -1072,6 +1071,7 @@ static int sii902x_probe(struct i2c_client *client,
 	struct device *dev = &client->dev;
 	struct device_node *endpoint;
 	struct sii902x *sii902x;
+	static const char * const supplies[] = {"iovcc", "cvcc12"};
 	int ret;
 
 	ret = i2c_check_functionality(client->adapter,
@@ -1122,27 +1122,11 @@ static int sii902x_probe(struct i2c_client *client,
 
 	mutex_init(&sii902x->mutex);
 
-	sii902x->supplies[0].supply = "iovcc";
-	sii902x->supplies[1].supply = "cvcc12";
-	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(sii902x->supplies),
-				      sii902x->supplies);
+	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(supplies), supplies);
 	if (ret < 0)
-		return ret;
-
-	ret = regulator_bulk_enable(ARRAY_SIZE(sii902x->supplies),
-				    sii902x->supplies);
-	if (ret < 0) {
-		dev_err_probe(dev, ret, "Failed to enable supplies");
-		return ret;
-	}
+		return dev_err_probe(dev, ret, "Failed to enable supplies");
 
-	ret = sii902x_init(sii902x);
-	if (ret < 0) {
-		regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),
-				       sii902x->supplies);
-	}
-
-	return ret;
+	return sii902x_init(sii902x);
 }
 
 static void sii902x_remove(struct i2c_client *client)
@@ -1152,8 +1136,6 @@ static void sii902x_remove(struct i2c_client *client)
 
 	i2c_mux_del_adapters(sii902x->i2cmux);
 	drm_bridge_remove(&sii902x->bridge);
-	regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),
-			       sii902x->supplies);
 }
 
 static const struct of_device_id sii902x_dt_ids[] = {
-- 
2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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Re: [PATCH v4 2/4] gpu: drm: sii902x: Use devm_regulator_bulk_get_enable()

[Matti Vaittinen]

On 10/21/22 16:18, Matti Vaittinen wrote:
> Simplify using devm_regulator_bulk_get_enable()
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> Reviewed-by: Robert Foss <robert.foss@linaro.org>

Robert, I did slightly modify the return from probe when using the 
dev_err_probe(). I still decided to keep your RBT - please let me know 
if you disagree.

Eg, this:
> -	if (ret < 0) {
> -		dev_err_probe(dev, ret, "Failed to enable supplies");
> -		return ret;
> -	}

was converted to:
 >   	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to enable supplies");

Yours
	-- Matti

-- 
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Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~


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Re: [PATCH v4 2/4] gpu: drm: sii902x: Use devm_regulator_bulk_get_enable()

[Robert Foss]

On Fri, 21 Oct 2022 at 15:24, Matti Vaittinen <mazziesaccount@gmail.com> wrote:
>
> On 10/21/22 16:18, Matti Vaittinen wrote:
> > Simplify using devm_regulator_bulk_get_enable()
> >
> > Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> > Reviewed-by: Robert Foss <robert.foss@linaro.org>
>
> Robert, I did slightly modify the return from probe when using the
> dev_err_probe(). I still decided to keep your RBT - please let me know
> if you disagree.

Not a problem. In fact, feel free to upgrade it to an acked-by, to
simplify merging this series.

Acked-by: Robert Foss <robert.foss@linaro.org>

>
> Eg, this:
> > -     if (ret < 0) {
> > -             dev_err_probe(dev, ret, "Failed to enable supplies");
> > -             return ret;
> > -     }
>
> was converted to:
>  >      if (ret < 0)
> > +             return dev_err_probe(dev, ret, "Failed to enable supplies");
>
> Yours
>         -- Matti
>
> --
> Matti Vaittinen
> Linux kernel developer at ROHM Semiconductors
> Oulu Finland
>
> ~~ When things go utterly wrong vim users can always type :help! ~~
>

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[PATCH v4 3/4] hwmon: lm90: simplify using devm_regulator_get_enable()

[Matti Vaittinen]

[-- Attachment #1.1: Type: text/plain, Size: 2114 bytes --]

Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
add_action_or_reset(regulator_disable)' and use the
devm_regulator_get_enable().

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>

---
RFCv1 => v2:
- No changes
---
 drivers/hwmon/lm90.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index db595f7d01f8..a3f95ba00dbf 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -2663,11 +2663,6 @@ static void lm90_remove_pec(void *dev)
 	device_remove_file(dev, &dev_attr_pec);
 }
 
-static void lm90_regulator_disable(void *regulator)
-{
-	regulator_disable(regulator);
-}
-
 static int lm90_probe_channel_from_dt(struct i2c_client *client,
 				      struct device_node *child,
 				      struct lm90_data *data)
@@ -2749,24 +2744,13 @@ static int lm90_probe(struct i2c_client *client)
 	struct device *dev = &client->dev;
 	struct i2c_adapter *adapter = client->adapter;
 	struct hwmon_channel_info *info;
-	struct regulator *regulator;
 	struct device *hwmon_dev;
 	struct lm90_data *data;
 	int err;
 
-	regulator = devm_regulator_get(dev, "vcc");
-	if (IS_ERR(regulator))
-		return PTR_ERR(regulator);
-
-	err = regulator_enable(regulator);
-	if (err < 0) {
-		dev_err(dev, "Failed to enable regulator: %d\n", err);
-		return err;
-	}
-
-	err = devm_add_action_or_reset(dev, lm90_regulator_disable, regulator);
+	err = devm_regulator_get_enable(dev, "vcc");
 	if (err)
-		return err;
+		return dev_err_probe(dev, err, "Failed to enable regulator\n");
 
 	data = devm_kzalloc(dev, sizeof(struct lm90_data), GFP_KERNEL);
 	if (!data)
-- 
2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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Re: [PATCH v4 3/4] hwmon: lm90: simplify using devm_regulator_get_enable()

[Guenter Roeck]

On Fri, Oct 21, 2022 at 04:18:43PM +0300, Matti Vaittinen wrote:
> Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
> add_action_or_reset(regulator_disable)' and use the
> devm_regulator_get_enable().
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> Acked-by: Guenter Roeck <linux@roeck-us.net>

Applied to hwmon-next.

Thanks,
Guenter

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[PATCH v4 4/4] hwmon: adm1177: simplify using devm_regulator_get_enable()

[Matti Vaittinen]

[-- Attachment #1.1: Type: text/plain, Size: 2619 bytes --]

Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
add_action_or_reset(regulator_disable)' and use the
devm_regulator_get_enable() and drop the pointer to the regulator.
This simplifies code and makes it less tempting to add manual control
for the regulator which is also controlled by devm.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>

---
v2 => v3:
New patch
---
 drivers/hwmon/adm1177.c | 27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

diff --git a/drivers/hwmon/adm1177.c b/drivers/hwmon/adm1177.c
index 0c5dbc5e33b4..be17a26a84f1 100644
--- a/drivers/hwmon/adm1177.c
+++ b/drivers/hwmon/adm1177.c
@@ -26,14 +26,12 @@
 /**
  * struct adm1177_state - driver instance specific data
  * @client:		pointer to i2c client
- * @reg:		regulator info for the power supply of the device
  * @r_sense_uohm:	current sense resistor value
  * @alert_threshold_ua:	current limit for shutdown
  * @vrange_high:	internal voltage divider
  */
 struct adm1177_state {
 	struct i2c_client	*client;
-	struct regulator	*reg;
 	u32			r_sense_uohm;
 	u32			alert_threshold_ua;
 	bool			vrange_high;
@@ -189,13 +187,6 @@ static const struct hwmon_chip_info adm1177_chip_info = {
 	.info = adm1177_info,
 };
 
-static void adm1177_remove(void *data)
-{
-	struct adm1177_state *st = data;
-
-	regulator_disable(st->reg);
-}
-
 static int adm1177_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
@@ -210,21 +201,9 @@ static int adm1177_probe(struct i2c_client *client)
 
 	st->client = client;
 
-	st->reg = devm_regulator_get_optional(&client->dev, "vref");
-	if (IS_ERR(st->reg)) {
-		if (PTR_ERR(st->reg) == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
-
-		st->reg = NULL;
-	} else {
-		ret = regulator_enable(st->reg);
-		if (ret)
-			return ret;
-		ret = devm_add_action_or_reset(&client->dev, adm1177_remove,
-					       st);
-		if (ret)
-			return ret;
-	}
+	ret = devm_regulator_get_enable_optional(&client->dev, "vref");
+	if (ret == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
 				     &st->r_sense_uohm))
-- 
2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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Re: [PATCH v4 4/4] hwmon: adm1177: simplify using devm_regulator_get_enable()

[Guenter Roeck]

On Fri, Oct 21, 2022 at 04:19:04PM +0300, Matti Vaittinen wrote:
> Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
> add_action_or_reset(regulator_disable)' and use the
> devm_regulator_get_enable() and drop the pointer to the regulator.
> This simplifies code and makes it less tempting to add manual control
> for the regulator which is also controlled by devm.
> 
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> Acked-by: Guenter Roeck <linux@roeck-us.net>

Applied to hwmon-next.

Thanks,
Guenter

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