1 // SPDX-License-Identifier: GPL-2.0-only
3  * Input driver for resistor ladder connected on ADC
11 #include <linux/input.h>
32 static void adc_keys_poll(struct input_dev *input)  in adc_keys_poll()  argument
34 	struct adc_keys_state *st = input_get_drvdata(input);  in adc_keys_poll()
39 	ret = iio_read_channel_processed(st->channel, &value);  in adc_keys_poll()
42 		value = st->keyup_voltage;  in adc_keys_poll()
44 		for (i = 0; i < st->num_keys; i++) {  in adc_keys_poll()
45 			diff = abs(st->map[i].voltage - value);  in adc_keys_poll()
48 				keycode = st->map[i].keycode;  in adc_keys_poll()
53 	if (abs(st->keyup_voltage - value) < closest)  in adc_keys_poll()
56 	if (st->last_key && st->last_key != keycode)  in adc_keys_poll()
57 		input_report_key(input, st->last_key, 0);  in adc_keys_poll()
60 		input_report_key(input, keycode, 1);  in adc_keys_poll()
62 	input_sync(input);  in adc_keys_poll()
63 	st->last_key = keycode;  in adc_keys_poll()
71 	st->num_keys = device_get_child_node_count(dev);  in adc_keys_load_keymap()
72 	if (st->num_keys == 0) {  in adc_keys_load_keymap()
74 		return -EINVAL;  in adc_keys_load_keymap()
77 	map = devm_kmalloc_array(dev, st->num_keys, sizeof(*map), GFP_KERNEL);  in adc_keys_load_keymap()
79 		return -ENOMEM;  in adc_keys_load_keymap()
83 		if (fwnode_property_read_u32(child, "press-threshold-microvolt",  in adc_keys_load_keymap()
86 			return -EINVAL;  in adc_keys_load_keymap()
93 			return -EINVAL;  in adc_keys_load_keymap()
99 	st->map = map;  in adc_keys_load_keymap()
105 	struct device *dev = &pdev->dev;  in adc_keys_probe()
107 	struct input_dev *input;  in adc_keys_probe()  local
114 		return -ENOMEM;  in adc_keys_probe()
116 	st->channel = devm_iio_channel_get(dev, "buttons");  in adc_keys_probe()
117 	if (IS_ERR(st->channel))  in adc_keys_probe()
118 		return PTR_ERR(st->channel);  in adc_keys_probe()
120 	if (!st->channel->indio_dev)  in adc_keys_probe()
121 		return -ENXIO;  in adc_keys_probe()
123 	error = iio_get_channel_type(st->channel, &type);  in adc_keys_probe()
129 		return -EINVAL;  in adc_keys_probe()
132 	if (device_property_read_u32(dev, "keyup-threshold-microvolt",  in adc_keys_probe()
133 				     &st->keyup_voltage)) {  in adc_keys_probe()
135 		return -EINVAL;  in adc_keys_probe()
137 	st->keyup_voltage /= 1000;  in adc_keys_probe()
143 	input = devm_input_allocate_device(dev);  in adc_keys_probe()
144 	if (!input) {  in adc_keys_probe()
145 		dev_err(dev, "failed to allocate input device\n");  in adc_keys_probe()
146 		return -ENOMEM;  in adc_keys_probe()
149 	input_set_drvdata(input, st);  in adc_keys_probe()
151 	input->name = pdev->name;  in adc_keys_probe()
152 	input->phys = "adc-keys/input0";  in adc_keys_probe()
154 	input->id.bustype = BUS_HOST;  in adc_keys_probe()
155 	input->id.vendor = 0x0001;  in adc_keys_probe()
156 	input->id.product = 0x0001;  in adc_keys_probe()
157 	input->id.version = 0x0100;  in adc_keys_probe()
159 	__set_bit(EV_KEY, input->evbit);  in adc_keys_probe()
160 	for (i = 0; i < st->num_keys; i++)  in adc_keys_probe()
161 		__set_bit(st->map[i].keycode, input->keybit);  in adc_keys_probe()
164 		__set_bit(EV_REP, input->evbit);  in adc_keys_probe()
167 	error = input_setup_polling(input, adc_keys_poll);  in adc_keys_probe()
173 	if (!device_property_read_u32(dev, "poll-interval", &value))  in adc_keys_probe()
174 		input_set_poll_interval(input, value);  in adc_keys_probe()
176 	error = input_register_device(input);  in adc_keys_probe()
178 		dev_err(dev, "Unable to register input device: %d\n", error);  in adc_keys_probe()
187 	{ .compatible = "adc-keys", },
202 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
203 MODULE_DESCRIPTION("Input driver for resistor ladder connected on ADC");