Re: [PATCH v3 2/3] Input: adc-joystick - Add polled input device support

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 15 Jun 2022 03:43:07 +0200
Artur Rojek <contact@artur-rojek.eu> wrote:

> On 2022-06-13 21:23, 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>  
> 
> Hi Chris,
> 
> Comments inline. I also Cc'd Paul and Jonathan, who were attached in v2.

Please cc linux-iio@vger.kernel.org on future versions.

> 
> > ---
> >  drivers/input/joystick/adc-joystick.c | 52 +++++++++++++++++++++------
> >  1 file changed, 41 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/input/joystick/adc-joystick.c
> > b/drivers/input/joystick/adc-joystick.c
> > index 78ebca7d400a..dc01cd0214d2 100644
> > --- a/drivers/input/joystick/adc-joystick.c
> > +++ b/drivers/input/joystick/adc-joystick.c
> > @@ -13,6 +13,10 @@
> > 
> >  #include <asm/unaligned.h>
> > 
> > +#define ADC_JSK_POLL_INTERVAL	16
> > +#define ADC_JSK_POLL_MIN	8
> > +#define ADC_JSK_POLL_MAX	32
> > +
> >  struct adc_joystick_axis {
> >  	u32 code;
> >  	s32 range[2];
> > @@ -26,8 +30,21 @@ 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;
> > +
> > +	for (i = 0; i < joy->num_chans; i++) {
> > +		iio_read_channel_raw(&joy->chans[i], &val);
> > +		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;
> > @@ -215,8 +232,19 @@ 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 (device_property_read_bool(dev, 
> > "adc-joystick,no-hardware-trigger"))
> > +		joy->polled = 1;  
> As mentioned in v2, I don't think a DT property is required here. 
> Assuming the polled mode is a fallback for devices with no buffers, just 
> do:
> ```
> 	joy->polled = !(joy->chans[0].indio_dev->modes &
> 			INDIO_ALL_BUFFER_MODES);
> ```
> > +
> > +	if (joy->polled) {
> > +		input_setup_polling(input, adc_joystick_poll);
> > +		input_set_poll_interval(input, ADC_JSK_POLL_INTERVAL);
> > +		input_set_min_poll_interval(input, ADC_JSK_POLL_MIN);
> > +		input_set_max_poll_interval(input, ADC_JSK_POLL_MAX);
> > +	} else {
> > +		input->open = adc_joystick_open;
> > +		input->close = adc_joystick_close;
> > +	}
> > 
> >  	error = adc_joystick_set_axes(dev, joy);
> >  	if (error)
> > @@ -229,16 +257,18 @@ static int adc_joystick_probe(struct
> > platform_device *pdev)
> >  		return error;
> >  	}
> > 
> > -	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
> > -	if (IS_ERR(joy->buffer)) {
> > -		dev_err(dev, "Unable to allocate callback buffer\n");
> > -		return PTR_ERR(joy->buffer);
> > -	}
> > +	if (!joy->polled) {
> > +		joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);  
> Please maintain line discipline of 80 chars to stay consistent with the 
> rest of this driver.
> > +		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);
> > -	if (error)  {
> > -		dev_err(dev, "Unable to add action\n");
> > -		return error;
> > +		error = devm_add_action_or_reset(dev, adc_joystick_cleanup, 
> > joy->buffer);  
> Same here.
> 
> Cheers,
> Artur
> > +		if (error)  {
> > +			dev_err(dev, "Unable to add action\n");
> > +			return error;
> > +		}
> >  	}
> > 
> >  	return 0;