[PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[Daniel Mack]

This simplifies the error unwind pathes.

Also, don't call gpio_to_irq() on GPIOs before dev_gpio_request_one()
succeeded on them. This avoids Ooopses with incorrect DT bindings.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 drivers/input/misc/rotary_encoder.c |   67 +++++++++++------------------------
 1 file changed, 21 insertions(+), 46 deletions(-)

diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index f07f784..d4e0abb 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -145,6 +145,7 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
 	struct rotary_encoder *encoder;
 	struct input_dev *input;
+	struct device *dev = &pdev->dev;
 	irq_handler_t handler;
 	int err;
 
@@ -163,13 +164,11 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 
 	encoder->input = input;
 	encoder->pdata = pdata;
-	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
-	encoder->irq_b = gpio_to_irq(pdata->gpio_b);
 
 	/* create and register the input driver */
 	input->name = pdev->name;
 	input->id.bustype = BUS_HOST;
-	input->dev.parent = &pdev->dev;
+	input->dev.parent = dev;
 
 	if (pdata->relative_axis) {
 		input->evbit[0] = BIT_MASK(EV_REL);
@@ -182,38 +181,27 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 
 	err = input_register_device(input);
 	if (err) {
-		dev_err(&pdev->dev, "failed to register input device\n");
+		dev_err(dev, "failed to register input device\n");
 		goto exit_free_mem;
 	}
 
 	/* request the GPIOs */
-	err = gpio_request(pdata->gpio_a, DRV_NAME);
+	err = devm_gpio_request_one(dev, pdata->gpio_a,
+				    GPIOF_IN, dev_name(dev));
 	if (err) {
-		dev_err(&pdev->dev, "unable to request GPIO %d\n",
-			pdata->gpio_a);
+		dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
 		goto exit_unregister_input;
 	}
 
-	err = gpio_direction_input(pdata->gpio_a);
+	err = devm_gpio_request_one(dev, pdata->gpio_b,
+				    GPIOF_IN, dev_name(dev));
 	if (err) {
-		dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
-			pdata->gpio_a);
+		dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_b);
 		goto exit_unregister_input;
 	}
 
-	err = gpio_request(pdata->gpio_b, DRV_NAME);
-	if (err) {
-		dev_err(&pdev->dev, "unable to request GPIO %d\n",
-			pdata->gpio_b);
-		goto exit_free_gpio_a;
-	}
-
-	err = gpio_direction_input(pdata->gpio_b);
-	if (err) {
-		dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
-			pdata->gpio_b);
-		goto exit_free_gpio_a;
-	}
+	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
+	encoder->irq_b = gpio_to_irq(pdata->gpio_b);
 
 	/* request the IRQs */
 	if (pdata->half_period) {
@@ -223,34 +211,26 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 		handler = &rotary_encoder_irq;
 	}
 
-	err = request_irq(encoder->irq_a, handler,
-			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
-			  DRV_NAME, encoder);
+	err = devm_request_irq(dev, encoder->irq_a, handler,
+			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+			       dev_name(dev), encoder);
 	if (err) {
-		dev_err(&pdev->dev, "unable to request IRQ %d\n",
-			encoder->irq_a);
-		goto exit_free_gpio_b;
+		dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a);
+		goto exit_unregister_input;
 	}
 
-	err = request_irq(encoder->irq_b, handler,
-			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
-			  DRV_NAME, encoder);
+	err = devm_request_irq(dev, encoder->irq_b, handler,
+			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+			       dev_name(dev), encoder);
 	if (err) {
-		dev_err(&pdev->dev, "unable to request IRQ %d\n",
-			encoder->irq_b);
-		goto exit_free_irq_a;
+		dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b);
+		goto exit_unregister_input;
 	}
 
 	platform_set_drvdata(pdev, encoder);
 
 	return 0;
 
-exit_free_irq_a:
-	free_irq(encoder->irq_a, encoder);
-exit_free_gpio_b:
-	gpio_free(pdata->gpio_b);
-exit_free_gpio_a:
-	gpio_free(pdata->gpio_a);
 exit_unregister_input:
 	input_unregister_device(input);
 	input = NULL; /* so we don't try to free it */
@@ -263,12 +243,7 @@ exit_free_mem:
 static int __devexit rotary_encoder_remove(struct platform_device *pdev)
 {
 	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
-	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
 
-	free_irq(encoder->irq_a, encoder);
-	free_irq(encoder->irq_b, encoder);
-	gpio_free(pdata->gpio_a);
-	gpio_free(pdata->gpio_b);
 	input_unregister_device(encoder->input);
 	platform_set_drvdata(pdev, NULL);
 	kfree(encoder);
-- 
1.7.10.4

[PATCH v2 2/2] input: rotary-encoder: add DT bindings

[Daniel Mack]

This adds devicetree bindings to the rotary encoder driver and some
documenation about how to use them. Tested on a PXA3xx platform.

Signed-off-by: Daniel Mack <zonque@gmail.com>
---
 .../devicetree/bindings/input/rotary-encoder.txt   |   37 ++++++++++++
 drivers/input/misc/rotary_encoder.c                |   63 +++++++++++++++++++-
 2 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/input/rotary-encoder.txt

diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.txt b/Documentation/devicetree/bindings/input/rotary-encoder.txt
new file mode 100644
index 0000000..dd1f634
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/rotary-encoder.txt
@@ -0,0 +1,37 @@
+Rotary encoder DT bindings
+
+Required properties:
+- gpios: a spec for two GPIOs to be used
+
+Optional properties:
+- linux,axis: the input subsystem axis to map to this rotary encoder.
+  Defaults to 0 (ABS_X / REL_X)
+- rotary-encoder,steps: Number of steps in a full turnaround of the
+  encoder. Only relevant for absolute axis. Defaults to 24 which is a
+  typical value for such devices.
+- rotary-encoder,relative-axis: register a relative axis rather than an
+  absolute one. Relative axis will only generate +1/-1 events on the input
+  device, hence no steps need to be passed.
+- rotary-encoder,rollover: Automatic rollove when the rotary value becomes
+  greater than the specified steps or smaller than 0. For absolute axis only.
+- rotary-encoder,half-period: Makes the driver work on half-period mode.
+
+See Documentation/input/rotary-encoder.txt for more information.
+
+Example:
+
+		rotary@0 {
+			compatible = "rotary-encoder";
+			gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
+			linux,axis = <0>; /* REL_X */
+			rotary-encoder,relative-axis;
+		};
+
+		rotary@1 {
+			compatible = "rotary-encoder";
+			gpios = <&gpio 21 0>, <&gpio 22 0>;
+			linux,axis = <1>; /* ABS_Y */
+			rotary-encoder,steps = <24>;
+			rotary-encoder,rollover;
+		};
+
diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index d4e0abb..6a14fef 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -24,6 +24,8 @@
 #include <linux/gpio.h>
 #include <linux/rotary_encoder.h>
 #include <linux/slab.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
 
 #define DRV_NAME "rotary-encoder"
 
@@ -140,15 +142,73 @@ static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id rotary_encoder_of_match[] = {
+	{ .compatible = "rotary-encoder", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
+
+static int rotary_encoder_probe_dt(struct platform_device *pdev)
+{
+	int tmp;
+	enum of_gpio_flags flags;
+	struct rotary_encoder_platform_data *pdata;
+	struct device_node *np = pdev->dev.of_node;
+	const struct of_device_id *of_id =
+		of_match_device(rotary_encoder_of_match, &pdev->dev);
+
+	if (!of_id)
+		return 0;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	if (of_property_read_u32(np, "rotary-encoder,steps", &tmp) == 0)
+		pdata->steps = tmp;
+	if (of_property_read_u32(np, "linux,axis", &tmp) == 0)
+		pdata->axis = tmp;
+
+	pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
+	pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
+
+	pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
+	pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
+
+	if (of_get_property(np, "rotary-encoder,relative-axis", NULL))
+		pdata->relative_axis = 1;
+	if (of_get_property(np, "rotary-encoder,rollover", NULL))
+		pdata->rollover = 1;
+	if (of_get_property(np, "rotary-encoder,half-period", NULL))
+		pdata->half_period = 1;
+
+	pdev->dev.platform_data = pdata;
+
+	return 0;
+}
+#else
+static inline int rotary_encoder_probe_dt(struct platform_device *)
+{
+	return 0;
+}
+#endif
+
 static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 {
-	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
+	struct rotary_encoder_platform_data *pdata;
 	struct rotary_encoder *encoder;
 	struct input_dev *input;
 	struct device *dev = &pdev->dev;
 	irq_handler_t handler;
 	int err;
 
+	err = rotary_encoder_probe_dt(pdev);
+	if (err)
+		return err;
+
+	pdata = pdev->dev.platform_data;
+
 	if (!pdata) {
 		dev_err(&pdev->dev, "missing platform data\n");
 		return -ENOENT;
@@ -257,6 +317,7 @@ static struct platform_driver rotary_encoder_driver = {
 	.driver		= {
 		.name	= DRV_NAME,
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(rotary_encoder_of_match),
 	}
 };
 module_platform_driver(rotary_encoder_driver);
-- 
1.7.10.4

Re: [PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[Dmitry Torokhov]

On Wed, Jul 25, 2012 at 09:43:47AM +0200, Daniel Mack wrote:
> @@ -263,12 +243,7 @@ exit_free_mem:
>  static int __devexit rotary_encoder_remove(struct platform_device *pdev)
>  {
>  	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
> -	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
>  
> -	free_irq(encoder->irq_a, encoder);
> -	free_irq(encoder->irq_b, encoder);
> -	gpio_free(pdata->gpio_a);
> -	gpio_free(pdata->gpio_b);
>  	input_unregister_device(encoder->input);

Another botched devm_ conversion. *sigh*

Input device gone, IRQ arrives, kernel goes oops, machine hangs hard.

Please, do not use devm_ interfaces unless... Actually, just do not use
nor suggest devm_interfaces until all resources are devm-ized. Mixing 2
styles of releasing resources leads to trouble.

Thanks.

-- 
Dmitry

Re: [PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[Daniel Mack]

On 25.07.2012 18:05, Dmitry Torokhov wrote:
> On Wed, Jul 25, 2012 at 09:43:47AM +0200, Daniel Mack wrote:
>> @@ -263,12 +243,7 @@ exit_free_mem:
>>  static int __devexit rotary_encoder_remove(struct platform_device *pdev)
>>  {
>>  	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
>> -	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
>>  
>> -	free_irq(encoder->irq_a, encoder);
>> -	free_irq(encoder->irq_b, encoder);
>> -	gpio_free(pdata->gpio_a);
>> -	gpio_free(pdata->gpio_b);
>>  	input_unregister_device(encoder->input);
> 
> Another botched devm_ conversion. *sigh*
> 
> Input device gone, IRQ arrives, kernel goes oops, machine hangs hard.
> 
> Please, do not use devm_ interfaces unless... Actually, just do not use
> nor suggest devm_interfaces until all resources are devm-ized. Mixing 2
> styles of releasing resources leads to trouble.

Ok, makes sense. Thanks for noticing. Are you happy with the first
version I submitted then?


Daniel

RE: [PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[H Hartley Sweeten]

On Wednesday, July 25, 2012 9:05 AM, Dmitry Torokhov wrote:
> On Wed, Jul 25, 2012 at 09:43:47AM +0200, Daniel Mack wrote:
>> @@ -263,12 +243,7 @@ exit_free_mem:
>>  static int __devexit rotary_encoder_remove(struct platform_device *pdev)
>>  {
>>  	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
>> -	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
>>  
>> -	free_irq(encoder->irq_a, encoder);
>> -	free_irq(encoder->irq_b, encoder);
>> -	gpio_free(pdata->gpio_a);
>> -	gpio_free(pdata->gpio_b);
>>  	input_unregister_device(encoder->input);
>
> Another botched devm_ conversion. *sigh*
>
> Input device gone, IRQ arrives, kernel goes oops, machine hangs hard.
>
> Please, do not use devm_ interfaces unless... Actually, just do not use
> nor suggest devm_interfaces until all resources are devm-ized. Mixing 2
> styles of releasing resources leads to trouble.

Oops.. Sorry about that. I didn't think about the interaction with
input_unregister_device.

Regards,
Hartley

Re: [PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[Dmitry Torokhov]

On Wed, Jul 25, 2012 at 06:07:24PM +0200, Daniel Mack wrote:
> On 25.07.2012 18:05, Dmitry Torokhov wrote:
> > On Wed, Jul 25, 2012 at 09:43:47AM +0200, Daniel Mack wrote:
> >> @@ -263,12 +243,7 @@ exit_free_mem:
> >>  static int __devexit rotary_encoder_remove(struct platform_device *pdev)
> >>  {
> >>  	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
> >> -	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
> >>  
> >> -	free_irq(encoder->irq_a, encoder);
> >> -	free_irq(encoder->irq_b, encoder);
> >> -	gpio_free(pdata->gpio_a);
> >> -	gpio_free(pdata->gpio_b);
> >>  	input_unregister_device(encoder->input);
> > 
> > Another botched devm_ conversion. *sigh*
> > 
> > Input device gone, IRQ arrives, kernel goes oops, machine hangs hard.
> > 
> > Please, do not use devm_ interfaces unless... Actually, just do not use
> > nor suggest devm_interfaces until all resources are devm-ized. Mixing 2
> > styles of releasing resources leads to trouble.
> 
> Ok, makes sense. Thanks for noticing. Are you happy with the first
> version I submitted then?

I have a few issues with that version as well:

1. It writes over platform_data field in the device which does nto
belong to the driver (this field belongs to the platform/board code);

2. I believe we should favor kernel supplied data over firmware
allowing users to override DT bindings, if needed;

3. It still uses devm_* to allocate memory and as I said I do not like
mixing 2 styles of managign resources in one driver.

Thanks.

-- 
Dmitry

Re: [PATCH v2 1/2] input: rotary-encoder: switch to devm_* allocation of GPIOs and IRQs

[Daniel Mack]

On 25.07.2012 18:29, Dmitry Torokhov wrote:
> On Wed, Jul 25, 2012 at 06:07:24PM +0200, Daniel Mack wrote:
>> On 25.07.2012 18:05, Dmitry Torokhov wrote:
>>> On Wed, Jul 25, 2012 at 09:43:47AM +0200, Daniel Mack wrote:
>>>> @@ -263,12 +243,7 @@ exit_free_mem:
>>>>  static int __devexit rotary_encoder_remove(struct platform_device *pdev)
>>>>  {
>>>>  	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
>>>> -	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
>>>>  
>>>> -	free_irq(encoder->irq_a, encoder);
>>>> -	free_irq(encoder->irq_b, encoder);
>>>> -	gpio_free(pdata->gpio_a);
>>>> -	gpio_free(pdata->gpio_b);
>>>>  	input_unregister_device(encoder->input);
>>>
>>> Another botched devm_ conversion. *sigh*
>>>
>>> Input device gone, IRQ arrives, kernel goes oops, machine hangs hard.
>>>
>>> Please, do not use devm_ interfaces unless... Actually, just do not use
>>> nor suggest devm_interfaces until all resources are devm-ized. Mixing 2
>>> styles of releasing resources leads to trouble.
>>
>> Ok, makes sense. Thanks for noticing. Are you happy with the first
>> version I submitted then?
> 
> I have a few issues with that version as well:
> 
> 1. It writes over platform_data field in the device which does nto
> belong to the driver (this field belongs to the platform/board code);
> 
> 2. I believe we should favor kernel supplied data over firmware
> allowing users to override DT bindings, if needed;

Ok, this is different from what I saw in other drivers, but I'm fine
with that.

> 3. It still uses devm_* to allocate memory and as I said I do not like
> mixing 2 styles of managign resources in one driver.

Ok, sorry again. I didn't closely follow that new development, hence I
wasn't aware of these pitfalls.

New patch series coming up.