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>

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 0fb21c99a5e3d1230d7f40f99e0c2d360bbe80e8..d604aad90a89565a4a43c246f1d5d8d2d0164619 100644 (file)
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -230,6 +230,16 @@ config INPUT_M68K_BEEP
        tristate "M68k Beeper support"
        depends on M68K
 
+config INPUT_MAX7360_ROTARY
+       tristate "Maxim MAX7360 Rotary Encoder"
+       depends on MFD_MAX7360
+       help
+         If you say yes here you get support for the rotary encoder on the
+         Maxim MAX7360 I/O Expander.
+
+         To compile this driver as a module, choose M here: the module will be
+         called max7360_rotary.
+
 config INPUT_MAX77650_ONKEY
        tristate "Maxim MAX77650 ONKEY support"
        depends on MFD_MAX77650

diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index d468c8140b93da5bb537e8a3baea2b90e7bb4229..ac45cb9b5c998b1d8fda799b643e5b3c02546bb3 100644 (file)
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_INPUT_IQS7222)           += iqs7222.o
 obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)     += keyspan_remote.o
 obj-$(CONFIG_INPUT_KXTJ9)              += kxtj9.o
 obj-$(CONFIG_INPUT_M68K_BEEP)          += m68kspkr.o
+obj-$(CONFIG_INPUT_MAX7360_ROTARY)     += max7360-rotary.o
 obj-$(CONFIG_INPUT_MAX77650_ONKEY)     += max77650-onkey.o
 obj-$(CONFIG_INPUT_MAX77693_HAPTIC)    += max77693-haptic.o
 obj-$(CONFIG_INPUT_MAX8925_ONKEY)      += max8925_onkey.o

diff --git a/drivers/input/misc/max7360-rotary.c b/drivers/input/misc/max7360-rotary.c
new file mode 100644 (file)
index 0000000..385831e
--- /dev/null
+++ b/drivers/input/misc/max7360-rotary.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 Bootlin
+ *
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device/devres.h>
+#include <linux/dev_printk.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/max7360.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+#define MAX7360_ROTARY_DEFAULT_STEPS 24
+
+struct max7360_rotary {
+       struct input_dev *input;
+       struct regmap *regmap;
+       unsigned int debounce_ms;
+
+       unsigned int pos;
+
+       u32 steps;
+       u32 axis;
+       bool relative_axis;
+       bool rollover;
+};
+
+static void max7360_rotary_report_event(struct max7360_rotary *max7360_rotary, int steps)
+{
+       if (max7360_rotary->relative_axis) {
+               input_report_rel(max7360_rotary->input, max7360_rotary->axis, steps);
+       } else {
+               int pos = max7360_rotary->pos;
+               int maxval = max7360_rotary->steps;
+
+               /*
+                * Add steps to the position.
+                * Make sure added steps are always in ]-maxval; maxval[
+                * interval, so (pos + maxval) is always >= 0.
+                * Then set back pos to the [0; maxval[ interval.
+                */
+               pos += steps % maxval;
+               if (max7360_rotary->rollover)
+                       pos = (pos + maxval) % maxval;
+               else
+                       pos = clamp(pos, 0, maxval - 1);
+
+               max7360_rotary->pos = pos;
+               input_report_abs(max7360_rotary->input, max7360_rotary->axis, max7360_rotary->pos);
+       }
+
+       input_sync(max7360_rotary->input);
+}
+
+static irqreturn_t max7360_rotary_irq(int irq, void *data)
+{
+       struct max7360_rotary *max7360_rotary = data;
+       struct device *dev = max7360_rotary->input->dev.parent;
+       unsigned int val;
+       int error;
+
+       error = regmap_read(max7360_rotary->regmap, MAX7360_REG_RTR_CNT, &val);
+       if (error < 0) {
+               dev_err(dev, "Failed to read rotary counter\n");
+               return IRQ_NONE;
+       }
+
+       if (val == 0)
+               return IRQ_NONE;
+
+       max7360_rotary_report_event(max7360_rotary, sign_extend32(val, 7));
+
+       return IRQ_HANDLED;
+}
+
+static int max7360_rotary_hw_init(struct max7360_rotary *max7360_rotary)
+{
+       struct device *dev = max7360_rotary->input->dev.parent;
+       int val;
+       int error;
+
+       val = FIELD_PREP(MAX7360_ROT_DEBOUNCE, max7360_rotary->debounce_ms) |
+             FIELD_PREP(MAX7360_ROT_INTCNT, 1) | MAX7360_ROT_INTCNT_DLY;
+       error = regmap_write(max7360_rotary->regmap, MAX7360_REG_RTRCFG, val);
+       if (error)
+               dev_err(dev, "Failed to set max7360 rotary encoder configuration\n");
+
+       return error;
+}
+
+static int max7360_rotary_probe(struct platform_device *pdev)
+{
+       struct max7360_rotary *max7360_rotary;
+       struct device *dev = &pdev->dev;
+       struct input_dev *input;
+       struct regmap *regmap;
+       int irq;
+       int error;
+
+       regmap = dev_get_regmap(dev->parent, NULL);
+       if (!regmap)
+               return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
+
+       irq = fwnode_irq_get_byname(dev_fwnode(dev->parent), "inti");
+       if (irq < 0)
+               return dev_err_probe(dev, irq, "Failed to get IRQ\n");
+
+       max7360_rotary = devm_kzalloc(dev, sizeof(*max7360_rotary), GFP_KERNEL);
+       if (!max7360_rotary)
+               return -ENOMEM;
+
+       max7360_rotary->regmap = regmap;
+
+       device_property_read_u32(dev->parent, "linux,axis", &max7360_rotary->axis);
+       max7360_rotary->rollover = device_property_read_bool(dev->parent,
+                                                            "rotary-encoder,rollover");
+       max7360_rotary->relative_axis =
+               device_property_read_bool(dev->parent, "rotary-encoder,relative-axis");
+
+       error = device_property_read_u32(dev->parent, "rotary-encoder,steps",
+                                        &max7360_rotary->steps);
+       if (error)
+               max7360_rotary->steps = MAX7360_ROTARY_DEFAULT_STEPS;
+
+       device_property_read_u32(dev->parent, "rotary-debounce-delay-ms",
+                                &max7360_rotary->debounce_ms);
+       if (max7360_rotary->debounce_ms > MAX7360_ROT_DEBOUNCE_MAX)
+               return dev_err_probe(dev, -EINVAL, "Invalid debounce timing: %u\n",
+                                    max7360_rotary->debounce_ms);
+
+       input = devm_input_allocate_device(dev);
+       if (!input)
+               return -ENOMEM;
+
+       max7360_rotary->input = input;
+
+       input->id.bustype = BUS_I2C;
+       input->name = pdev->name;
+
+       if (max7360_rotary->relative_axis)
+               input_set_capability(input, EV_REL, max7360_rotary->axis);
+       else
+               input_set_abs_params(input, max7360_rotary->axis, 0, max7360_rotary->steps, 0, 1);
+
+       error = devm_request_threaded_irq(dev, irq, NULL, max7360_rotary_irq,
+                                         IRQF_ONESHOT | IRQF_SHARED,
+                                         "max7360-rotary", max7360_rotary);
+       if (error)
+               return dev_err_probe(dev, error, "Failed to register interrupt\n");
+
+       error = input_register_device(input);
+       if (error)
+               return dev_err_probe(dev, error, "Could not register input device\n");
+
+       error = max7360_rotary_hw_init(max7360_rotary);
+       if (error)
+               return dev_err_probe(dev, error, "Failed to initialize max7360 rotary\n");
+
+       device_init_wakeup(dev, true);
+       error = dev_pm_set_wake_irq(dev, irq);
+       if (error)
+               dev_warn(dev, "Failed to set up wakeup irq: %d\n", error);
+
+       return 0;
+}
+
+static void max7360_rotary_remove(struct platform_device *pdev)
+{
+       dev_pm_clear_wake_irq(&pdev->dev);
+       device_init_wakeup(&pdev->dev, false);
+}
+
+static struct platform_driver max7360_rotary_driver = {
+       .driver = {
+               .name   = "max7360-rotary",
+       },
+       .probe          = max7360_rotary_probe,
+       .remove         = max7360_rotary_remove,
+};
+module_platform_driver(max7360_rotary_driver);
+
+MODULE_DESCRIPTION("MAX7360 Rotary driver");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
+MODULE_LICENSE("GPL");