Re: [PATCH v10 2/3] Input: adc-joystick - Add polled input device support

[Artur Rojek <contact@artur-rojek.eu>]

On 2022-08-04 20:40, Chris Morgan wrote:
> On Wed, Aug 03, 2022 at 08:03:17PM +0200, Artur Rojek wrote:
>> On 2022-08-03 19:45, Chris Morgan wrote:
>> > From: Chris Morgan <macromorgan@hotmail.com>
>> >
>> > Add polled input device support to the adc-joystick driver. This is
>> > useful for devices which do not have hardware capable triggers on
>> > their SARADC. Code modified from adc-joystick.c changes made by Maya
>> > Matuszczyk.
>> >
>> > Signed-off-by: Maya Matuszczyk <maccraft123mc@gmail.com>
>> > Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
>> > ---
>> Chris,
>> some minor details inline.
>> >  drivers/input/joystick/adc-joystick.c | 53 ++++++++++++++++++++++++---
>> >  1 file changed, 47 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/drivers/input/joystick/adc-joystick.c
>> > b/drivers/input/joystick/adc-joystick.c
>> > index 78ebca7d400a..a288ebfe254e 100644
>> > --- a/drivers/input/joystick/adc-joystick.c
>> > +++ b/drivers/input/joystick/adc-joystick.c
>> > @@ -26,8 +26,23 @@ struct adc_joystick {
>> >  	struct adc_joystick_axis *axes;
>> >  	struct iio_channel *chans;
>> >  	int num_chans;
>> > +	bool polled;
>> >  };
>> >
>> > +static void adc_joystick_poll(struct input_dev *input)
>> > +{
>> > +	struct adc_joystick *joy = input_get_drvdata(input);
>> > +	int i, val, ret;
>> > +
>> > +	for (i = 0; i < joy->num_chans; i++) {
>> > +		ret = iio_read_channel_raw(&joy->chans[i], &val);
>> > +		if (ret < 0)
>> > +			return;
>> > +		input_report_abs(input, joy->axes[i].code, val);
>> > +	}
>> > +	input_sync(input);
>> > +}
>> > +
>> >  static int adc_joystick_handle(const void *data, void *private)
>> >  {
>> >  	struct adc_joystick *joy = private;
>> > @@ -179,6 +194,7 @@ static int adc_joystick_probe(struct platform_device
>> > *pdev)
>> >  	int error;
>> >  	int bits;
>> >  	int i;
>> > +	unsigned int poll_interval;
>> >
>> >  	joy = devm_kzalloc(dev, sizeof(*joy), GFP_KERNEL);
>> >  	if (!joy)
>> > @@ -192,11 +208,25 @@ static int adc_joystick_probe(struct
>> > platform_device *pdev)
>> >  		return error;
>> >  	}
>> >
>> > -	/* Count how many channels we got. NULL terminated. */
>> > +	if (device_property_present(dev, "poll-interval")) {
>> > +		error = device_property_read_u32(dev, "poll-interval",
>> > +						 &poll_interval);
>> > +		if (error)
>> > +			return error;
>> > +		joy->polled = true;
>> > +	}
>> > +
>> > +	/*
>> > +	 * Count how many channels we got. NULL terminated.
>> > +	 * Do not check the storage size if using polling.
>> > +	 */
>> >  	for (i = 0; joy->chans[i].indio_dev; i++) {
>> > +		if (joy->polled)
>> > +			continue;
>> >  		bits = joy->chans[i].channel->scan_type.storagebits;
>> >  		if (!bits || bits > 16) {
>> > -			dev_err(dev, "Unsupported channel storage size\n");
>> > +			dev_err(dev,
>> > +				"Unsupported channel storage size\n");
>> This change is now unnecessary, as the line can fit in 80 chars again.
>> >  			return -EINVAL;
>> >  		}
>> >  		if (bits != joy->chans[0].channel->scan_type.storagebits) {
>> > @@ -215,8 +245,14 @@ static int adc_joystick_probe(struct
>> > platform_device *pdev)
>> >  	joy->input = input;
>> >  	input->name = pdev->name;
>> >  	input->id.bustype = BUS_HOST;
>> > -	input->open = adc_joystick_open;
>> > -	input->close = adc_joystick_close;
>> > +
>> > +	if (joy->polled) {
>> > +		input_setup_polling(input, adc_joystick_poll);
>> > +		input_set_poll_interval(input, poll_interval);
>> > +	} else {
>> > +		input->open = adc_joystick_open;
>> > +		input->close = adc_joystick_close;
>> > +	}
>> >
>> >  	error = adc_joystick_set_axes(dev, joy);
>> >  	if (error)
>> > @@ -229,13 +265,18 @@ static int adc_joystick_probe(struct
>> > platform_device *pdev)
>> >  		return error;
>> >  	}
>> >
>> > -	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
>> > +	if (joy->polled)
>> > +		return 0;
>> > +
>> > +	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle,
>> > +					     joy);
>> Same here.
>> >  	if (IS_ERR(joy->buffer)) {
>> >  		dev_err(dev, "Unable to allocate callback buffer\n");
>> >  		return PTR_ERR(joy->buffer);
>> >  	}
>> >
>> > -	error = devm_add_action_or_reset(dev, adc_joystick_cleanup,
>> > joy->buffer);
>> > +	error = devm_add_action_or_reset(dev, adc_joystick_cleanup,
>> > +					 joy->buffer);
>> And here.
> 
> This one comes in at 82 when I make it a one-liner. I'll update the 
> others but
> leave this one here alone.
It doesn't relate to the polled input functionality anymore, so please
remove it. I'll correct such minor mistakes with a larger cleanup patch
eventually.

Cheers,
Artur
> 
> Thank you.
> 
>> >  	if (error)  {
>> >  		dev_err(dev, "Unable to add action\n");
>> >  		return error;