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input: misc: Add support for MAX7360 rotary
Add driver for Maxim Integrated MAX7360 rotary encoder controller, supporting a single rotary switch. Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com> Link: https://lore.kernel.org/r/20250824-mdb-max7360-support-v14-9-435cfda2b1ea@bootlin.com Signed-off-by: Lee Jones <lee@kernel.org>
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‎drivers/input/misc/Kconfig‎

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@@ -230,6 +230,16 @@ config INPUT_M68K_BEEP
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tristate "M68k Beeper support"
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depends on M68K
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config INPUT_MAX7360_ROTARY
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tristate "Maxim MAX7360 Rotary Encoder"
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depends on MFD_MAX7360
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help
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If you say yes here you get support for the rotary encoder on the
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Maxim MAX7360 I/O Expander.
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To compile this driver as a module, choose M here: the module will be
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called max7360_rotary.
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config INPUT_MAX77650_ONKEY
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tristate "Maxim MAX77650 ONKEY support"
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depends on MFD_MAX77650

‎drivers/input/misc/Makefile‎

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@@ -51,6 +51,7 @@ obj-$(CONFIG_INPUT_IQS7222) += iqs7222.o
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obj-$(CONFIG_INPUT_KEYSPAN_REMOTE) += keyspan_remote.o
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obj-$(CONFIG_INPUT_KXTJ9) += kxtj9.o
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obj-$(CONFIG_INPUT_M68K_BEEP) += m68kspkr.o
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obj-$(CONFIG_INPUT_MAX7360_ROTARY) += max7360-rotary.o
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obj-$(CONFIG_INPUT_MAX77650_ONKEY) += max77650-onkey.o
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obj-$(CONFIG_INPUT_MAX77693_HAPTIC) += max77693-haptic.o
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obj-$(CONFIG_INPUT_MAX8925_ONKEY) += max8925_onkey.o

‎drivers/input/misc/max7360-rotary.c‎

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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2025 Bootlin
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*
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* Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
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*/
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#include <linux/bitfield.h>
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#include <linux/device/devres.h>
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#include <linux/dev_printk.h>
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#include <linux/init.h>
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#include <linux/input.h>
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#include <linux/interrupt.h>
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#include <linux/mfd/max7360.h>
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#include <linux/property.h>
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#include <linux/platform_device.h>
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#include <linux/pm_wakeirq.h>
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#include <linux/regmap.h>
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#include <linux/types.h>
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#define MAX7360_ROTARY_DEFAULT_STEPS 24
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struct max7360_rotary {
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struct input_dev *input;
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struct regmap *regmap;
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unsigned int debounce_ms;
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unsigned int pos;
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u32 steps;
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u32 axis;
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bool relative_axis;
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bool rollover;
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};
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static void max7360_rotary_report_event(struct max7360_rotary *max7360_rotary, int steps)
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{
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if (max7360_rotary->relative_axis) {
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input_report_rel(max7360_rotary->input, max7360_rotary->axis, steps);
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} else {
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int pos = max7360_rotary->pos;
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int maxval = max7360_rotary->steps;
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/*
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* Add steps to the position.
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* Make sure added steps are always in ]-maxval; maxval[
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* interval, so (pos + maxval) is always >= 0.
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* Then set back pos to the [0; maxval[ interval.
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*/
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pos += steps % maxval;
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if (max7360_rotary->rollover)
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pos = (pos + maxval) % maxval;
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else
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pos = clamp(pos, 0, maxval - 1);
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max7360_rotary->pos = pos;
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input_report_abs(max7360_rotary->input, max7360_rotary->axis, max7360_rotary->pos);
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}
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input_sync(max7360_rotary->input);
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}
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static irqreturn_t max7360_rotary_irq(int irq, void *data)
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{
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struct max7360_rotary *max7360_rotary = data;
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struct device *dev = max7360_rotary->input->dev.parent;
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unsigned int val;
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int error;
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error = regmap_read(max7360_rotary->regmap, MAX7360_REG_RTR_CNT, &val);
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if (error < 0) {
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dev_err(dev, "Failed to read rotary counter\n");
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return IRQ_NONE;
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}
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if (val == 0)
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return IRQ_NONE;
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max7360_rotary_report_event(max7360_rotary, sign_extend32(val, 7));
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return IRQ_HANDLED;
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}
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static int max7360_rotary_hw_init(struct max7360_rotary *max7360_rotary)
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{
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struct device *dev = max7360_rotary->input->dev.parent;
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int val;
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int error;
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val = FIELD_PREP(MAX7360_ROT_DEBOUNCE, max7360_rotary->debounce_ms) |
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FIELD_PREP(MAX7360_ROT_INTCNT, 1) | MAX7360_ROT_INTCNT_DLY;
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error = regmap_write(max7360_rotary->regmap, MAX7360_REG_RTRCFG, val);
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if (error)
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dev_err(dev, "Failed to set max7360 rotary encoder configuration\n");
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return error;
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}
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static int max7360_rotary_probe(struct platform_device *pdev)
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{
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struct max7360_rotary *max7360_rotary;
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struct device *dev = &pdev->dev;
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struct input_dev *input;
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struct regmap *regmap;
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int irq;
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int error;
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regmap = dev_get_regmap(dev->parent, NULL);
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if (!regmap)
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return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
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irq = fwnode_irq_get_byname(dev_fwnode(dev->parent), "inti");
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if (irq < 0)
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return dev_err_probe(dev, irq, "Failed to get IRQ\n");
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max7360_rotary = devm_kzalloc(dev, sizeof(*max7360_rotary), GFP_KERNEL);
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if (!max7360_rotary)
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return -ENOMEM;
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max7360_rotary->regmap = regmap;
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device_property_read_u32(dev->parent, "linux,axis", &max7360_rotary->axis);
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max7360_rotary->rollover = device_property_read_bool(dev->parent,
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"rotary-encoder,rollover");
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max7360_rotary->relative_axis =
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device_property_read_bool(dev->parent, "rotary-encoder,relative-axis");
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error = device_property_read_u32(dev->parent, "rotary-encoder,steps",
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&max7360_rotary->steps);
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if (error)
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max7360_rotary->steps = MAX7360_ROTARY_DEFAULT_STEPS;
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device_property_read_u32(dev->parent, "rotary-debounce-delay-ms",
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&max7360_rotary->debounce_ms);
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if (max7360_rotary->debounce_ms > MAX7360_ROT_DEBOUNCE_MAX)
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return dev_err_probe(dev, -EINVAL, "Invalid debounce timing: %u\n",
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max7360_rotary->debounce_ms);
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input = devm_input_allocate_device(dev);
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if (!input)
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return -ENOMEM;
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max7360_rotary->input = input;
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input->id.bustype = BUS_I2C;
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input->name = pdev->name;
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if (max7360_rotary->relative_axis)
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input_set_capability(input, EV_REL, max7360_rotary->axis);
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else
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input_set_abs_params(input, max7360_rotary->axis, 0, max7360_rotary->steps, 0, 1);
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error = devm_request_threaded_irq(dev, irq, NULL, max7360_rotary_irq,
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IRQF_ONESHOT | IRQF_SHARED,
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"max7360-rotary", max7360_rotary);
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if (error)
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return dev_err_probe(dev, error, "Failed to register interrupt\n");
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error = input_register_device(input);
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if (error)
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return dev_err_probe(dev, error, "Could not register input device\n");
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error = max7360_rotary_hw_init(max7360_rotary);
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if (error)
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return dev_err_probe(dev, error, "Failed to initialize max7360 rotary\n");
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device_init_wakeup(dev, true);
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error = dev_pm_set_wake_irq(dev, irq);
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if (error)
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dev_warn(dev, "Failed to set up wakeup irq: %d\n", error);
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return 0;
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}
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static void max7360_rotary_remove(struct platform_device *pdev)
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{
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dev_pm_clear_wake_irq(&pdev->dev);
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device_init_wakeup(&pdev->dev, false);
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}
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static struct platform_driver max7360_rotary_driver = {
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.driver = {
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.name = "max7360-rotary",
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},
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.probe = max7360_rotary_probe,
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.remove = max7360_rotary_remove,
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};
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module_platform_driver(max7360_rotary_driver);
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MODULE_DESCRIPTION("MAX7360 Rotary driver");
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MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
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MODULE_LICENSE("GPL");

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