Add driver for Maxim Integrated MAX7360 rotary encoder controller,
supporting a single rotary switch.
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
drivers/input/misc/Kconfig | 10 ++
drivers/input/misc/Makefile | 1 +
drivers/input/misc/max7360-rotary.c | 198 ++++++++++++++++++++++++++++++++++++
3 files changed, 209 insertions(+)
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index f5496ca0c0d2..0bc9d121c984 100644
--- 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 6d91804d0a6f..c454fba3a3ae 100644
--- 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
index 000000000000..d547ed222a2f
--- /dev/null
+++ b/drivers/input/misc/max7360-rotary.c
@@ -0,0 +1,198 @@
+// 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;
+ unsigned int debounce_ms;
+ struct regmap *regmap;
+
+ u32 steps;
+ u32 axis;
+ bool relative_axis;
+ bool rollover;
+
+ unsigned int pos;
+};
+
+static void max7360_rotaty_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 {
+ unsigned int pos = max7360_rotary->pos;
+
+ if (steps < 0) {
+ /* turning counter-clockwise */
+ if (max7360_rotary->rollover)
+ pos += max7360_rotary->steps + steps;
+ else
+ pos = max(0, (int)pos + steps);
+ } else {
+ /* turning clockwise */
+ if (max7360_rotary->rollover)
+ pos += steps;
+ else
+ pos = min(max7360_rotary->steps, pos + steps);
+ }
+
+ if (max7360_rotary->rollover)
+ pos %= max7360_rotary->steps;
+
+ 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) {
+ dev_dbg(dev, "Got a spurious interrupt\n");
+
+ return IRQ_NONE;
+ }
+
+ max7360_rotaty_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)
+ 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);
+}
+
+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");
--
2.39.5On Mon, Apr 28, 2025 at 01:57:28PM +0200, Mathieu Dubois-Briand wrote:
> Add driver for Maxim Integrated MAX7360 rotary encoder controller,
> supporting a single rotary switch.
...
> +struct max7360_rotary {
> + struct input_dev *input;
> + unsigned int debounce_ms;
> + struct regmap *regmap;
> +
> + u32 steps;
> + u32 axis;
> + bool relative_axis;
> + bool rollover;
> +
> + unsigned int pos;
> +};
I believe `pahole` can recommend better layout (look for the better position
of debounce_ms).
...
> +static void max7360_rotaty_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 {
> + unsigned int pos = max7360_rotary->pos;
> +
> + if (steps < 0) {
> + /* turning counter-clockwise */
> + if (max7360_rotary->rollover)
> + pos += max7360_rotary->steps + steps;
> + else
> + pos = max(0, (int)pos + steps);
Please, no castings for min()/max()/clamp(). It diminishes the use of those
macros.
> + } else {
> + /* turning clockwise */
> + if (max7360_rotary->rollover)
> + pos += steps;
> + else
> + pos = min(max7360_rotary->steps, pos + steps);
> + }
> +
> + if (max7360_rotary->rollover)
> + pos %= max7360_rotary->steps;
> +
> + 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) {
> + dev_dbg(dev, "Got a spurious interrupt\n");
This contradicts with the IRQF_SHARED. Drop one of them.
> + return IRQ_NONE;
> + }
> +
> + max7360_rotaty_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;
Indentation is incorrect.
> + 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)
> + dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
Missing return. Copy'n'paste error over all drivers?
> + 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);
Shouldn't be here
device_init_wakeup(dev, false);
?
> +}
--
With Best Regards,
Andy Shevchenko
On Fri May 2, 2025 at 12:52 PM CEST, Andy Shevchenko wrote:
> On Mon, Apr 28, 2025 at 01:57:28PM +0200, Mathieu Dubois-Briand wrote:
>> Add driver for Maxim Integrated MAX7360 rotary encoder controller,
>> supporting a single rotary switch.
>
> ...
>
>> +struct max7360_rotary {
>> + struct input_dev *input;
>> + unsigned int debounce_ms;
>> + struct regmap *regmap;
>> +
>> + u32 steps;
>> + u32 axis;
>> + bool relative_axis;
>> + bool rollover;
>> +
>> + unsigned int pos;
>> +};
>
> I believe `pahole` can recommend better layout (look for the better position
> of debounce_ms).
>
> ...
>
Oh yes it does on arm64. Moving it after the regmap pointer, it should
be better.
>> +static void max7360_rotaty_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 {
>> + unsigned int pos = max7360_rotary->pos;
>> +
>> + if (steps < 0) {
>> + /* turning counter-clockwise */
>> + if (max7360_rotary->rollover)
>> + pos += max7360_rotary->steps + steps;
>> + else
>
>> + pos = max(0, (int)pos + steps);
>
> Please, no castings for min()/max()/clamp(). It diminishes the use of those
> macros.
>
Sorry, I'm not sure to get the point. Should I use MIN_T() instead?
>
> ...
>
>> +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)
>> + dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
>
> Missing return. Copy'n'paste error over all drivers?
>
Probably more an error while replacing all dev_err()+return by
dev_err_probe(), but yes. I will look for similar issues.
> ...
OK with all other comments.
Thanks for your review.
Mathieu
--
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
On Fri, May 02, 2025 at 03:58:04PM +0200, Mathieu Dubois-Briand wrote: > On Fri May 2, 2025 at 12:52 PM CEST, Andy Shevchenko wrote: > > On Mon, Apr 28, 2025 at 01:57:28PM +0200, Mathieu Dubois-Briand wrote: ... > >> + pos = max(0, (int)pos + steps); > > > > Please, no castings for min()/max()/clamp(). It diminishes the use of those > > macros. > > Sorry, I'm not sure to get the point. Should I use MIN_T() instead? Are the second argument is compile-time constant? I don't think so. Hence no use for MIN*()/MAX*(). First of all, try to answer to the Q: Why is the explicit casting being used? The second Q: How can it be easily fixed without using _t() variants of the macros? -- With Best Regards, Andy Shevchenko
On Fri May 2, 2025 at 4:09 PM CEST, Andy Shevchenko wrote: > On Fri, May 02, 2025 at 03:58:04PM +0200, Mathieu Dubois-Briand wrote: >> On Fri May 2, 2025 at 12:52 PM CEST, Andy Shevchenko wrote: >> > On Mon, Apr 28, 2025 at 01:57:28PM +0200, Mathieu Dubois-Briand wrote: > > ... > >> >> + pos = max(0, (int)pos + steps); >> > >> > Please, no castings for min()/max()/clamp(). It diminishes the use of those >> > macros. >> >> Sorry, I'm not sure to get the point. Should I use MIN_T() instead? > > Are the second argument is compile-time constant? I don't think so. Hence no > use for MIN*()/MAX*(). First of all, try to answer to the Q: Why is the explicit > casting being used? The second Q: How can it be easily fixed without using _t() > variants of the macros? Err right, no MIN/MAX of course. Explicit cast is here because the unsigned int + int sum would result in an unsigned int. I will use an intermediate signed value. Also the whole logic here can be simplified a bit, so I will rework the whole block. Best regards, Mathieu -- Mathieu Dubois-Briand, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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