[0/3] adc-joystick: Add polled support

From: Chris Morgan <macromorgan@hotmail.com>

Add support to the existing adc-joystick driver to support polling
rather than relying on triggered buffers. This is useful for devices
that do not offer triggered buffers in hardware. Code adapted from
changes made by Maya Matuszczyk <maccraft123mc@gmail.com>.

Chris Morgan (3):
  dt-bindings: adc-joystick: bindings for adc-joystick-polled
  Input: adc-joystick - Add polled input device support
  arm64: dts: rockchip: Update joystick to polled for Odroid-Go2

 .../bindings/input/adc-joystick.yaml          |  8 ++-
 .../boot/dts/rockchip/rk3326-odroid-go2.dts   |  2 +-
 drivers/input/joystick/adc-joystick.c         | 53 +++++++++++++++----
 3 files changed, 49 insertions(+), 14 deletions(-)

On 2022-06-01 21:17, Chris Morgan wrote:
> From: Chris Morgan <macromorgan@hotmail.com>

Hi Chris,

Thanks for your patch. Here's some things I spotted on a quick glance. 
I'll test this patch against the existing (non-poll) devices over, or 
after the weekend.

> 
> 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>
> ---
>  drivers/input/joystick/adc-joystick.c | 53 +++++++++++++++++++++------
>  1 file changed, 42 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/input/joystick/adc-joystick.c
> b/drivers/input/joystick/adc-joystick.c
> index 78ebca7d400a..83a5a420141e 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 (of_device_is_compatible(dev->of_node, "adc-joystick-polled"))
> +		joy->polled = 1;
Don't use a new compatible for that (see my comment for patch 1/3). Keep 
it as a property and then you can access it through 
`fwnode_property_read_bool`.

> +
> +	if (joy->polled == 1) {
It's a bool, so just do `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 == 0) {
Same here. Just do `if (!joy->polled)`.

Cheers,
Artur

> +		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);
> +		}
> 
> -	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);
> +		if (error)  {
> +			dev_err(dev, "Unable to add action\n");
> +			return error;
> +		}
>  	}
> 
>  	return 0;
> @@ -246,6 +276,7 @@ static int adc_joystick_probe(struct 
> platform_device *pdev)
> 
>  static const struct of_device_id adc_joystick_of_match[] = {
>  	{ .compatible = "adc-joystick", },
> +	{ .compatible = "adc-joystick-polled", },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(of, adc_joystick_of_match);