Input: adc-joystick - add polled input device support

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>
Link: https://lore.kernel.org/r/20220816210440.14260-3-macroalpha82@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/joystick/adc-joystick.c b/drivers/input/joystick/adc-joystick.c
index e0cfdc8..c0deff5 100644 (file)
--- 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)
@@ -192,8 +208,25 @@ static int adc_joystick_probe(struct platform_device *pdev)
                return error;
        }
 
-       /* Count how many channels we got. NULL terminated. */
+       error = device_property_read_u32(dev, "poll-interval", &poll_interval);
+       if (error) {
+               /* -EINVAL means the property is absent. */
+               if (error != -EINVAL)
+                       return error;
+       } else if (poll_interval == 0) {
+               dev_err(dev, "Unable to get poll-interval\n");
+               return -EINVAL;
+       } else {
+               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");
@@ -215,23 +248,31 @@ 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;
 
        error = adc_joystick_set_axes(dev, joy);
        if (error)
                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) {
+               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;
+
+               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;
+               }
        }
 
        input_set_drvdata(input, joy);