Linux kernel mirror (for testing)
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linux
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");