max7360-rotary.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright 2025 Bootlin
  4 *
  5 * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
  6 */
  7
  8#include <linux/bitfield.h>
  9#include <linux/device/devres.h>
 10#include <linux/dev_printk.h>
 11#include <linux/init.h>
 12#include <linux/input.h>
 13#include <linux/interrupt.h>
 14#include <linux/mfd/max7360.h>
 15#include <linux/property.h>
 16#include <linux/platform_device.h>
 17#include <linux/pm_wakeirq.h>
 18#include <linux/regmap.h>
 19#include <linux/types.h>
 20
 21#define MAX7360_ROTARY_DEFAULT_STEPS 24
 22
 23struct max7360_rotary {
 24	struct input_dev *input;
 25	struct regmap *regmap;
 26	unsigned int debounce_ms;
 27
 28	unsigned int pos;
 29
 30	u32 steps;
 31	u32 axis;
 32	bool relative_axis;
 33	bool rollover;
 34};
 35
 36static void max7360_rotary_report_event(struct max7360_rotary *max7360_rotary, int steps)
 37{
 38	if (max7360_rotary->relative_axis) {
 39		input_report_rel(max7360_rotary->input, max7360_rotary->axis, steps);
 40	} else {
 41		int pos = max7360_rotary->pos;
 42		int maxval = max7360_rotary->steps;
 43
 44		/*
 45		 * Add steps to the position.
 46		 * Make sure added steps are always in ]-maxval; maxval[
 47		 * interval, so (pos + maxval) is always >= 0.
 48		 * Then set back pos to the [0; maxval[ interval.
 49		 */
 50		pos += steps % maxval;
 51		if (max7360_rotary->rollover)
 52			pos = (pos + maxval) % maxval;
 53		else
 54			pos = clamp(pos, 0, maxval - 1);
 55
 56		max7360_rotary->pos = pos;
 57		input_report_abs(max7360_rotary->input, max7360_rotary->axis, max7360_rotary->pos);
 58	}
 59
 60	input_sync(max7360_rotary->input);
 61}
 62
 63static irqreturn_t max7360_rotary_irq(int irq, void *data)
 64{
 65	struct max7360_rotary *max7360_rotary = data;
 66	struct device *dev = max7360_rotary->input->dev.parent;
 67	unsigned int val;
 68	int error;
 69
 70	error = regmap_read(max7360_rotary->regmap, MAX7360_REG_RTR_CNT, &val);
 71	if (error < 0) {
 72		dev_err(dev, "Failed to read rotary counter\n");
 73		return IRQ_NONE;
 74	}
 75
 76	if (val == 0)
 77		return IRQ_NONE;
 78
 79	max7360_rotary_report_event(max7360_rotary, sign_extend32(val, 7));
 80
 81	return IRQ_HANDLED;
 82}
 83
 84static int max7360_rotary_hw_init(struct max7360_rotary *max7360_rotary)
 85{
 86	struct device *dev = max7360_rotary->input->dev.parent;
 87	int val;
 88	int error;
 89
 90	val = FIELD_PREP(MAX7360_ROT_DEBOUNCE, max7360_rotary->debounce_ms) |
 91	      FIELD_PREP(MAX7360_ROT_INTCNT, 1) | MAX7360_ROT_INTCNT_DLY;
 92	error = regmap_write(max7360_rotary->regmap, MAX7360_REG_RTRCFG, val);
 93	if (error)
 94		dev_err(dev, "Failed to set max7360 rotary encoder configuration\n");
 95
 96	return error;
 97}
 98
 99static int max7360_rotary_probe(struct platform_device *pdev)
100{
101	struct max7360_rotary *max7360_rotary;
102	struct device *dev = &pdev->dev;
103	struct input_dev *input;
104	struct regmap *regmap;
105	int irq;
106	int error;
107
108	regmap = dev_get_regmap(dev->parent, NULL);
109	if (!regmap)
110		return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
111
112	irq = fwnode_irq_get_byname(dev_fwnode(dev->parent), "inti");
113	if (irq < 0)
114		return dev_err_probe(dev, irq, "Failed to get IRQ\n");
115
116	max7360_rotary = devm_kzalloc(dev, sizeof(*max7360_rotary), GFP_KERNEL);
117	if (!max7360_rotary)
118		return -ENOMEM;
119
120	max7360_rotary->regmap = regmap;
121
122	device_property_read_u32(dev->parent, "linux,axis", &max7360_rotary->axis);
123	max7360_rotary->rollover = device_property_read_bool(dev->parent,
124							     "rotary-encoder,rollover");
125	max7360_rotary->relative_axis =
126		device_property_read_bool(dev->parent, "rotary-encoder,relative-axis");
127
128	error = device_property_read_u32(dev->parent, "rotary-encoder,steps",
129					 &max7360_rotary->steps);
130	if (error)
131		max7360_rotary->steps = MAX7360_ROTARY_DEFAULT_STEPS;
132
133	device_property_read_u32(dev->parent, "rotary-debounce-delay-ms",
134				 &max7360_rotary->debounce_ms);
135	if (max7360_rotary->debounce_ms > MAX7360_ROT_DEBOUNCE_MAX)
136		return dev_err_probe(dev, -EINVAL, "Invalid debounce timing: %u\n",
137				     max7360_rotary->debounce_ms);
138
139	input = devm_input_allocate_device(dev);
140	if (!input)
141		return -ENOMEM;
142
143	max7360_rotary->input = input;
144
145	input->id.bustype = BUS_I2C;
146	input->name = pdev->name;
147
148	if (max7360_rotary->relative_axis)
149		input_set_capability(input, EV_REL, max7360_rotary->axis);
150	else
151		input_set_abs_params(input, max7360_rotary->axis, 0, max7360_rotary->steps, 0, 1);
152
153	error = devm_request_threaded_irq(dev, irq, NULL, max7360_rotary_irq,
154					  IRQF_ONESHOT | IRQF_SHARED,
155					  "max7360-rotary", max7360_rotary);
156	if (error)
157		return dev_err_probe(dev, error, "Failed to register interrupt\n");
158
159	error = input_register_device(input);
160	if (error)
161		return dev_err_probe(dev, error, "Could not register input device\n");
162
163	error = max7360_rotary_hw_init(max7360_rotary);
164	if (error)
165		return dev_err_probe(dev, error, "Failed to initialize max7360 rotary\n");
166
167	device_init_wakeup(dev, true);
168	error = dev_pm_set_wake_irq(dev, irq);
169	if (error)
170		dev_warn(dev, "Failed to set up wakeup irq: %d\n", error);
171
172	return 0;
173}
174
175static void max7360_rotary_remove(struct platform_device *pdev)
176{
177	dev_pm_clear_wake_irq(&pdev->dev);
178	device_init_wakeup(&pdev->dev, false);
179}
180
181static struct platform_driver max7360_rotary_driver = {
182	.driver = {
183		.name	= "max7360-rotary",
184	},
185	.probe		= max7360_rotary_probe,
186	.remove		= max7360_rotary_remove,
187};
188module_platform_driver(max7360_rotary_driver);
189
190MODULE_DESCRIPTION("MAX7360 Rotary driver");
191MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
192MODULE_LICENSE("GPL");