[PATCH 1/2] devicetree: i2c-hid: Add regulator support

[PATCH 1/2] devicetree: i2c-hid: Add regulator support

[Brian Norris]

From: Caesar Wang <wxt@rock-chips.com>

Document a "vdd-supply" and an initialization delay. Can be used for
powering on/off a HID.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: linux-input@vger.kernel.org
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
v2:
 * add compatible property for wacom, per Rob's request
 * name the regulator property specifically (VDD)

v3:
 * remove wacom property, per Benjamin's request
 * add delay property

v4: no change
---
 Documentation/devicetree/bindings/input/hid-over-i2c.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.txt b/Documentation/devicetree/bindings/input/hid-over-i2c.txt
index 488edcb264c4..1ea290167652 100644
--- a/Documentation/devicetree/bindings/input/hid-over-i2c.txt
+++ b/Documentation/devicetree/bindings/input/hid-over-i2c.txt
@@ -17,6 +17,11 @@ Required properties:
 - interrupt-parent: the phandle for the interrupt controller
 - interrupts: interrupt line
 
+Optional properties:
+- vdd-supply: phandle of the regulator that provides the supply voltage.
+- init-delay-ms: time required by the device after power-on before it is ready
+  for communication.
+
 Example:
 
 	i2c-hid-dev@2c {
-- 
2.8.0.rc3.226.g39d4020

[PATCH 2/2] HID: i2c-hid: support regulator power on/off

[Brian Norris]

On some boards, we need to enable a regulator before using the HID, and
it's also nice to save power in suspend by disabling it. Support an
optional "vdd-supply" and a companion initialization delay.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: linux-input@vger.kernel.org
---
v2:
 * support compatible property for wacom, with specific "vdd-supply"
 * name
 * support the 100ms delay needed for this digitizer
 * target regulator support only at specific device

v3:
 * drop Wacom specifics and allow this to be used generically
 * add "init-delay-ms" property support

v4:
 * use devm_regulator_get() (with a 'dummy' regulator for most cases)
   instead of _optional() version, to make code less conditional (Dmitry)
 * fix but where 'init_delay_ms' wasn't getting assigned properly
 * disable regulator in probe() failure path
---
 drivers/hid/i2c-hid/i2c-hid.c | 44 +++++++++++++++++++++++++++++++++++++++++--
 include/linux/i2c/i2c-hid.h   |  6 ++++++
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index b3ec4f2de875..5c6e037613d7 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -38,6 +38,7 @@
 #include <linux/acpi.h>
 #include <linux/of.h>
 #include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
 
 #include <linux/i2c/i2c-hid.h>
 
@@ -937,6 +938,10 @@ static int i2c_hid_of_probe(struct i2c_client *client,
 	}
 	pdata->hid_descriptor_address = val;
 
+	ret = of_property_read_u32(dev->of_node, "init-delay-ms", &val);
+	if (!ret)
+		pdata->init_delay_ms = val;
+
 	return 0;
 }
 
@@ -983,6 +988,15 @@ static int i2c_hid_probe(struct i2c_client *client,
 		ihid->pdata = *platform_data;
 	}
 
+	ihid->pdata.supply = devm_regulator_get(&client->dev, "vdd");
+	if (IS_ERR(ihid->pdata.supply)) {
+		ret = PTR_ERR(ihid->pdata.supply);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&client->dev, "Failed to get regulator: %d\n",
+				ret);
+		return ret;
+	}
+
 	if (client->irq > 0) {
 		ihid->irq = client->irq;
 	} else if (ACPI_COMPANION(&client->dev)) {
@@ -1000,6 +1014,15 @@ static int i2c_hid_probe(struct i2c_client *client,
 		}
 	}
 
+	ret = regulator_enable(ihid->pdata.supply);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to enable regulator: %d\n",
+			ret);
+		goto err;
+	}
+	if (ihid->pdata.init_delay_ms)
+		msleep(ihid->pdata.init_delay_ms);
+
 	i2c_set_clientdata(client, ihid);
 
 	ihid->client = client;
@@ -1015,7 +1038,7 @@ static int i2c_hid_probe(struct i2c_client *client,
 	 * real computation later. */
 	ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
 	if (ret < 0)
-		goto err;
+		goto err_regulator;
 
 	pm_runtime_get_noresume(&client->dev);
 	pm_runtime_set_active(&client->dev);
@@ -1070,6 +1093,9 @@ static int i2c_hid_probe(struct i2c_client *client,
 	pm_runtime_put_noidle(&client->dev);
 	pm_runtime_disable(&client->dev);
 
+err_regulator:
+	regulator_disable(ihid->pdata.supply);
+
 err:
 	if (ihid->desc)
 		gpiod_put(ihid->desc);
@@ -1100,6 +1126,8 @@ static int i2c_hid_remove(struct i2c_client *client)
 	if (ihid->desc)
 		gpiod_put(ihid->desc);
 
+	regulator_disable(ihid->pdata.supply);
+
 	kfree(ihid);
 
 	acpi_dev_remove_driver_gpios(ACPI_COMPANION(&client->dev));
@@ -1152,6 +1180,11 @@ static int i2c_hid_suspend(struct device *dev)
 		else
 			hid_warn(hid, "Failed to enable irq wake: %d\n",
 				wake_status);
+	} else {
+		ret = regulator_disable(ihid->pdata.supply);
+		if (ret < 0)
+			hid_warn(hid, "Failed to disable supply: %d\n",
+				 ret);
 	}
 
 	return 0;
@@ -1165,7 +1198,14 @@ static int i2c_hid_resume(struct device *dev)
 	struct hid_device *hid = ihid->hid;
 	int wake_status;
 
-	if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
+	if (!device_may_wakeup(&client->dev)) {
+		ret = regulator_enable(ihid->pdata.supply);
+		if (ret < 0)
+			hid_warn(hid, "Failed to enable supply: %d\n",
+				 ret);
+		if (ihid->pdata.init_delay_ms)
+			msleep(ihid->pdata.init_delay_ms);
+	} else if (ihid->irq_wake_enabled) {
 		wake_status = disable_irq_wake(ihid->irq);
 		if (!wake_status)
 			ihid->irq_wake_enabled = false;
diff --git a/include/linux/i2c/i2c-hid.h b/include/linux/i2c/i2c-hid.h
index 7aa901d92058..97688cde4a91 100644
--- a/include/linux/i2c/i2c-hid.h
+++ b/include/linux/i2c/i2c-hid.h
@@ -14,9 +14,13 @@
 
 #include <linux/types.h>
 
+struct regulator;
+
 /**
  * struct i2chid_platform_data - used by hid over i2c implementation.
  * @hid_descriptor_address: i2c register where the HID descriptor is stored.
+ * @supply: regulator for powering on the device.
+ * @init_delay_ms: delay after powering on before device is usable.
  *
  * Note that it is the responsibility of the platform driver (or the acpi 5.0
  * driver, or the flattened device tree) to setup the irq related to the gpio in
@@ -31,6 +35,8 @@
  */
 struct i2c_hid_platform_data {
 	u16 hid_descriptor_address;
+	struct regulator *supply;
+	int init_delay_ms;
 };
 
 #endif /* __LINUX_I2C_HID_H */
-- 
2.8.0.rc3.226.g39d4020

Re: [PATCH 2/2] HID: i2c-hid: support regulator power on/off

[Dmitry Torokhov]

On Fri, Dec 02, 2016 at 02:19:00PM -0800, Brian Norris wrote:
> On some boards, we need to enable a regulator before using the HID, and
> it's also nice to save power in suspend by disabling it. Support an
> optional "vdd-supply" and a companion initialization delay.
> 
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: linux-input@vger.kernel.org
> ---
> v2:
>  * support compatible property for wacom, with specific "vdd-supply"
>  * name
>  * support the 100ms delay needed for this digitizer
>  * target regulator support only at specific device
> 
> v3:
>  * drop Wacom specifics and allow this to be used generically
>  * add "init-delay-ms" property support
> 
> v4:
>  * use devm_regulator_get() (with a 'dummy' regulator for most cases)
>    instead of _optional() version, to make code less conditional (Dmitry)
>  * fix but where 'init_delay_ms' wasn't getting assigned properly
>  * disable regulator in probe() failure path
> ---
>  drivers/hid/i2c-hid/i2c-hid.c | 44 +++++++++++++++++++++++++++++++++++++++++--
>  include/linux/i2c/i2c-hid.h   |  6 ++++++
>  2 files changed, 48 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index b3ec4f2de875..5c6e037613d7 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -38,6 +38,7 @@
>  #include <linux/acpi.h>
>  #include <linux/of.h>
>  #include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
>  
>  #include <linux/i2c/i2c-hid.h>
>  
> @@ -937,6 +938,10 @@ static int i2c_hid_of_probe(struct i2c_client *client,
>  	}
>  	pdata->hid_descriptor_address = val;
>  
> +	ret = of_property_read_u32(dev->of_node, "init-delay-ms", &val);
> +	if (!ret)
> +		pdata->init_delay_ms = val;
> +
>  	return 0;
>  }
>  
> @@ -983,6 +988,15 @@ static int i2c_hid_probe(struct i2c_client *client,
>  		ihid->pdata = *platform_data;
>  	}
>  
> +	ihid->pdata.supply = devm_regulator_get(&client->dev, "vdd");

Oh, haveni't noticed that the rest of the driver does not use devm.
Well, I'll leave it up to hid-i2c folks to decide if they are OK with
mixing up the managed and non-managed resources, it seems safe to me in
this case.

Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Thanks.

-- 
Dmitry

Re: [PATCH 1/2] devicetree: i2c-hid: Add regulator support

[Benjamin Tissoires]

On Dec 02 2016 or thereabouts, Brian Norris wrote:
> From: Caesar Wang <wxt@rock-chips.com>
> 
> Document a "vdd-supply" and an initialization delay. Can be used for
> powering on/off a HID.
> 
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: linux-input@vger.kernel.org
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
> v2:
>  * add compatible property for wacom, per Rob's request
>  * name the regulator property specifically (VDD)
> 
> v3:
>  * remove wacom property, per Benjamin's request
>  * add delay property
> 
> v4: no change
> ---
>  Documentation/devicetree/bindings/input/hid-over-i2c.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.txt b/Documentation/devicetree/bindings/input/hid-over-i2c.txt
> index 488edcb264c4..1ea290167652 100644
> --- a/Documentation/devicetree/bindings/input/hid-over-i2c.txt
> +++ b/Documentation/devicetree/bindings/input/hid-over-i2c.txt
> @@ -17,6 +17,11 @@ Required properties:
>  - interrupt-parent: the phandle for the interrupt controller
>  - interrupts: interrupt line
>  
> +Optional properties:
> +- vdd-supply: phandle of the regulator that provides the supply voltage.
> +- init-delay-ms: time required by the device after power-on before it is ready
> +  for communication.

Nitpick: maybe we should say that the power-on applies to the vdd-supply
parameter, not the SET_POWER HID command. I am just worried people will
misuse this parameter.

Otherwise, Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

> +
>  Example:
>  
>  	i2c-hid-dev@2c {
> -- 
> 2.8.0.rc3.226.g39d4020
> 

Re: [PATCH 2/2] HID: i2c-hid: support regulator power on/off

[Benjamin Tissoires]

On Dec 02 2016 or thereabouts, Dmitry Torokhov wrote:
> On Fri, Dec 02, 2016 at 02:19:00PM -0800, Brian Norris wrote:
> > On some boards, we need to enable a regulator before using the HID, and
> > it's also nice to save power in suspend by disabling it. Support an
> > optional "vdd-supply" and a companion initialization delay.
> > 
> > Signed-off-by: Brian Norris <briannorris@chromium.org>
> > Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> > Cc: Jiri Kosina <jikos@kernel.org>
> > Cc: linux-input@vger.kernel.org
> > ---
> > v2:
> >  * support compatible property for wacom, with specific "vdd-supply"
> >  * name
> >  * support the 100ms delay needed for this digitizer
> >  * target regulator support only at specific device
> > 
> > v3:
> >  * drop Wacom specifics and allow this to be used generically
> >  * add "init-delay-ms" property support
> > 
> > v4:
> >  * use devm_regulator_get() (with a 'dummy' regulator for most cases)
> >    instead of _optional() version, to make code less conditional (Dmitry)
> >  * fix but where 'init_delay_ms' wasn't getting assigned properly
> >  * disable regulator in probe() failure path
> > ---
> >  drivers/hid/i2c-hid/i2c-hid.c | 44 +++++++++++++++++++++++++++++++++++++++++--
> >  include/linux/i2c/i2c-hid.h   |  6 ++++++
> >  2 files changed, 48 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> > index b3ec4f2de875..5c6e037613d7 100644
> > --- a/drivers/hid/i2c-hid/i2c-hid.c
> > +++ b/drivers/hid/i2c-hid/i2c-hid.c
> > @@ -38,6 +38,7 @@
> >  #include <linux/acpi.h>
> >  #include <linux/of.h>
> >  #include <linux/gpio/consumer.h>
> > +#include <linux/regulator/consumer.h>
> >  
> >  #include <linux/i2c/i2c-hid.h>
> >  
> > @@ -937,6 +938,10 @@ static int i2c_hid_of_probe(struct i2c_client *client,
> >  	}
> >  	pdata->hid_descriptor_address = val;
> >  
> > +	ret = of_property_read_u32(dev->of_node, "init-delay-ms", &val);
> > +	if (!ret)
> > +		pdata->init_delay_ms = val;
> > +
> >  	return 0;
> >  }
> >  
> > @@ -983,6 +988,15 @@ static int i2c_hid_probe(struct i2c_client *client,
> >  		ihid->pdata = *platform_data;
> >  	}
> >  
> > +	ihid->pdata.supply = devm_regulator_get(&client->dev, "vdd");
> 
> Oh, haveni't noticed that the rest of the driver does not use devm.
> Well, I'll leave it up to hid-i2c folks to decide if they are OK with
> mixing up the managed and non-managed resources, it seems safe to me in
> this case.

Yeah, it looks good to me as well. However, I think that will be the
trigger to request a devm conversion of the i2c-hid driver. Something
I'll add to my list of things to consider for v4.11 then :)

Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Cheers,
Benjamin

> 
> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> 
> Thanks.
> 
> -- 
> Dmitry

Re: [PATCH 1/2] devicetree: i2c-hid: Add regulator support

[Jiri Kosina]

On Fri, 2 Dec 2016, Brian Norris wrote:

> From: Caesar Wang <wxt@rock-chips.com>
> 
> Document a "vdd-supply" and an initialization delay. Can be used for
> powering on/off a HID.
> 
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: linux-input@vger.kernel.org
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
> v2:
>  * add compatible property for wacom, per Rob's request
>  * name the regulator property specifically (VDD)
> 
> v3:
>  * remove wacom property, per Benjamin's request
>  * add delay property
> 
> v4: no change

Applied both patches to for-4.10/i2c-hid.

Thanks,

-- 
Jiri Kosina
SUSE Labs

Re: [PATCH 1/2] devicetree: i2c-hid: Add regulator support

[Rob Herring]

On Fri, Dec 9, 2016 at 6:17 AM, Jiri Kosina <jikos@kernel.org> wrote:
> On Fri, 2 Dec 2016, Brian Norris wrote:
>
>> From: Caesar Wang <wxt@rock-chips.com>
>>
>> Document a "vdd-supply" and an initialization delay. Can be used for
>> powering on/off a HID.
>>
>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Jiri Kosina <jikos@kernel.org>
>> Cc: linux-input@vger.kernel.org
>> Signed-off-by: Brian Norris <briannorris@chromium.org>
>> ---
>> v2:
>>  * add compatible property for wacom, per Rob's request
>>  * name the regulator property specifically (VDD)
>>
>> v3:
>>  * remove wacom property, per Benjamin's request
>>  * add delay property
>>
>> v4: no change
>
> Applied both patches to for-4.10/i2c-hid.

In case it wasn't clear: NAK

This is still under discussion[1].

Rob

[1] https://lkml.org/lkml/2016/12/8/362