Re: [PATCH 2/2] input: misc: add driver for max16150

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Marc,

On Mon, Feb 23, 2026 at 07:03:40PM +0800, Marc Paolo Sosa via B4 Relay wrote:
> From: Marc Paolo Sosa <marcpaolo.sosa@analog.com>
> 
> MAX16150/MAX16169 nanoPower Pushbutton On/Off Controller
> 
> Signed-off-by: Marc Paolo Sosa <marcpaolo.sosa@analog.com>
> ---
>  drivers/input/misc/Kconfig    |   9 +++
>  drivers/input/misc/Makefile   |   1 +
>  drivers/input/misc/max16150.c | 161 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 171 insertions(+)
> 
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 94a753fcb64f..a31d3d2a7fd6 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -178,6 +178,15 @@ config INPUT_E3X0_BUTTON
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called e3x0_button.
>  
> +config INPUT_MAX16150_PWRBUTTON
> +	tristate "MAX16150/MAX16169 Pushbutton driver"
> +	help
> +	  Say Y here if you want to enable power key reporting via
> +	  MAX16150/MAX16169 nanoPower Pushbutton On/Off Controller.
> +
> +	  To compile this driver as a module, choose M here. The module will
> +	  be called max16150.
> +
>  config INPUT_PCSPKR
>  	tristate "PC Speaker support"
>  	depends on PCSPKR_PLATFORM
> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> index 415fc4e2918b..c2c1c45f2df6 100644
> --- a/drivers/input/misc/Makefile
> +++ b/drivers/input/misc/Makefile
> @@ -52,6 +52,7 @@ 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-$(CONFIG_INPUT_MAX16150_PWRBUTTON)	+= max16150.o
>  obj-$(CONFIG_INPUT_MAX7360_ROTARY)	+= max7360-rotary.o
>  obj-$(CONFIG_INPUT_MAX77650_ONKEY)	+= max77650-onkey.o
>  obj-$(CONFIG_INPUT_MAX77693_HAPTIC)	+= max77693-haptic.o
> diff --git a/drivers/input/misc/max16150.c b/drivers/input/misc/max16150.c
> new file mode 100644
> index 000000000000..ae353b926afc
> --- /dev/null
> +++ b/drivers/input/misc/max16150.c
> @@ -0,0 +1,161 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Analog Devices MAX16150/MAX16169 Pushbutton Driver
> + *
> + * Copyright 2025 Analog Devices Inc.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/input.h>
> +#include <linux/interrupt.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +
> +#define MAX16150_LONG_INTERRUPT 120000000
> +
> +struct max16150_chip_info {
> +	bool has_clr_gpio;
> +};
> +
> +struct max16150_device {
> +	struct input_dev *input;
> +	struct gpio_desc *gpiod;
> +	struct gpio_desc *clr_gpiod;
> +	const struct max16150_chip_info *chip_info;
> +	u64 low, high, duration;

I do not think you need to store "high" and "duration", just "press"
time. I also do not think you need nanosecond resilution, jiffies will
do.

> +	unsigned int keycode;
> +};
> +
> +static irqreturn_t max16150_irq_handler(int irq, void *_max16150)
> +{
> +	struct max16150_device *max16150 = _max16150;
> +	int value;
> +
> +	value = gpiod_get_value(max16150->gpiod);
> +
> +	if (!value) {
> +		max16150->low = ktime_get_ns();
> +		return IRQ_HANDLED;
> +	}
> +
> +	max16150->high = ktime_get_ns();
> +	if (max16150->low) {
> +		max16150->duration = max16150->high - max16150->low;
> +
> +		if (max16150->duration > MAX16150_LONG_INTERRUPT) {

time_after() is probably what you need here.

> +			gpiod_set_value(max16150->clr_gpiod, 1);
> +			input_report_key(max16150->input, max16150->keycode, 1);
> +			input_sync(max16150->input);

Why is press not reported right away?

> +			input_report_key(max16150->input, max16150->keycode, 0);
> +			input_sync(max16150->input);
> +		}
> +
> +		max16150->low = 0;
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct max16150_chip_info max16150_variant_a = {
> +	.has_clr_gpio = true,
> +};
> +
> +static const struct max16150_chip_info max16150_variant_b = {
> +	.has_clr_gpio = false,
> +};
> +
> +static int max16150_probe(struct platform_device *pdev)
> +{
> +	const struct max16150_chip_info *chip_info;
> +	struct max16150_device *max16150;
> +	struct device *dev = &pdev->dev;
> +	int err, irq, ret;

Why do you need both err and ret?

> +	u32 keycode;
> +
> +	chip_info = device_get_match_data(dev);
> +	if (!chip_info)
> +		return -EINVAL;
> +
> +	max16150 = devm_kzalloc(dev, sizeof(*max16150), GFP_KERNEL);
> +	if (!max16150)
> +		return -ENOMEM;
> +
> +	max16150->chip_info = chip_info;
> +
> +	max16150->input = devm_input_allocate_device(dev);
> +	if (!max16150->input)
> +		return -ENOMEM;
> +
> +	max16150->input->name = "MAX16150 Pushbutton";
> +	max16150->input->phys = "max16150/input0";
> +	max16150->input->id.bustype = BUS_HOST;
> +
> +	keycode = KEY_POWER;
> +	ret = device_property_read_u32(dev, "linux,code", &keycode);

	err = ...

> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to get keycode\n");
> +
> +	max16150->keycode = keycode;
> +
> +	input_set_capability(max16150->input, EV_KEY, max16150->keycode);
> +
> +	max16150->gpiod = devm_gpiod_get(dev, "interrupt", GPIOD_IN);
> +	if (IS_ERR(max16150->gpiod))
> +		return dev_err_probe(dev, PTR_ERR(max16150->gpiod),
> +				     "Failed to get interrupt GPIO\n");
> +
> +	if (chip_info->has_clr_gpio) {
> +		max16150->clr_gpiod = devm_gpiod_get(dev, "clr", GPIOD_OUT_HIGH);
> +		if (IS_ERR(max16150->clr_gpiod))
> +			return dev_err_probe(dev, PTR_ERR(max16150->clr_gpiod),
> +					     "Failed to get clr GPIO\n");
> +
> +		if (!max16150->clr_gpiod)


How would we end up here? You are using devm_gpiod_get() which will
never return NULL GPIO descriptor.

> +			return dev_err_probe(dev, -ENODEV,
> +						 "clr GPIO is mandatory\n");
> +
> +		if (max16150->clr_gpiod) {
> +			fsleep(1000);
> +			gpiod_set_value(max16150->clr_gpiod, 0);
> +		}
> +	}
> +
> +	irq = gpiod_to_irq(max16150->gpiod);
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq,
> +				     "MAX16150: Failed to map GPIO to IRQ");

As Rob said in DT binding review use interrupts property and separate
IRQ and GPIO handling.

> +
> +	err = devm_request_irq(dev, irq, max16150_irq_handler,
> +			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +			       "max16150_irq", max16150);
> +	if (err)
> +		return err;
> +
> +	return input_register_device(max16150->input);

	err = input_register_device(...);
	if (err)
		return err;
	
	return 0;

> +}
> +
> +static const struct of_device_id max16150_of_match[] = {
> +	{ .compatible = "adi,max16150a", .data = &max16150_variant_a },
> +	{ .compatible = "adi,max16150b", .data = &max16150_variant_b },
> +	{ .compatible = "adi,max16169a", .data = &max16150_variant_a },
> +	{ .compatible = "adi,max16169b", .data = &max16150_variant_b },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, max16150_of_match);
> +
> +static struct platform_driver max16150_driver = {
> +	.probe  = max16150_probe,
> +	.driver = {
> +		.name = "max16150",
> +		.of_match_table = max16150_of_match,
> +	},
> +};
> +module_platform_driver(max16150_driver);
> +
> +MODULE_AUTHOR("Marc Paolo Sosa <marcpaolo.sosa@analog.com>");
> +MODULE_DESCRIPTION("MAX16150/MAX16169 Pushbutton Driver");
> +MODULE_LICENSE("GPL");

Thanks.

-- 
Dmitry