Re: [PATCH] input: cpcap-pwrbutton: new driver

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

Hi Sebastian,

On Fri, Feb 24, 2017 at 09:59:09AM +0100, Sebastian Reichel wrote:
> Motorola CPCAP is a PMIC found in multiple smartphones.
> This driver adds support for the power/on button and has
> been tested with Droid 4.
> 
> Signed-off-by: Sebastian Reichel <sre@kernel.org>
> ---
>  .../devicetree/bindings/input/cpcap-pwrbutton.txt  |  20 ++++
>  drivers/input/misc/Kconfig                         |  10 ++
>  drivers/input/misc/Makefile                        |   1 +
>  drivers/input/misc/cpcap-pwrbutton.c               | 119 +++++++++++++++++++++
>  4 files changed, 150 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/cpcap-pwrbutton.txt
>  create mode 100644 drivers/input/misc/cpcap-pwrbutton.c
> 
> diff --git a/Documentation/devicetree/bindings/input/cpcap-pwrbutton.txt b/Documentation/devicetree/bindings/input/cpcap-pwrbutton.txt
> new file mode 100644
> index 000000000000..0dd0076daf71
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/cpcap-pwrbutton.txt
> @@ -0,0 +1,20 @@
> +Motorola CPCAP on key
> +
> +This module is part of the CPCAP. For more details about the whole
> +chip see Documentation/devicetree/bindings/mfd/motorola-cpcap.txt.
> +
> +This module provides a simple power button event via an Interrupt.
> +
> +Required properties:
> +- compatible: should be one of the following
> +   - "motorola,cpcap-pwrbutton"
> +- interrupts: irq specifier for CPCAP's ON IRQ
> +
> +Example:
> +
> +&cpcap {
> +	cpcap_pwrbutton: pwrbutton {
> +		compatible = "motorola,cpcap-pwrbutton";
> +		interrupts = <23 IRQ_TYPE_NONE>;
> +	};
> +};
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 5b6c52210d20..9f7b72249eac 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -316,6 +316,16 @@ config INPUT_COBALT_BTNS
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called cobalt_btns.
>  
> +config INPUT_CPCAP_PWRBUTTON
> +	tristate "CPCAP OnKey"
> +	depends on MFD_CPCAP
> +	help
> +	  Say Y here if you want to enable power key reporting via the
> +	  Motorola CPCAP chip.
> +
> +	  To compile this driver as a module, choose M here. The module will
> +	  be called cpcap-pwrbutton.
> +
>  config INPUT_WISTRON_BTNS
>  	tristate "x86 Wistron laptop button interface"
>  	depends on X86_32
> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> index b10523f2878e..b923a9828c88 100644
> --- a/drivers/input/misc/Makefile
> +++ b/drivers/input/misc/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_INPUT_CM109)		+= cm109.o
>  obj-$(CONFIG_INPUT_CMA3000)		+= cma3000_d0x.o
>  obj-$(CONFIG_INPUT_CMA3000_I2C)		+= cma3000_d0x_i2c.o
>  obj-$(CONFIG_INPUT_COBALT_BTNS)		+= cobalt_btns.o
> +obj-$(CONFIG_INPUT_CPCAP_PWRBUTTON)	+= cpcap-pwrbutton.o
>  obj-$(CONFIG_INPUT_DA9052_ONKEY)	+= da9052_onkey.o
>  obj-$(CONFIG_INPUT_DA9055_ONKEY)	+= da9055_onkey.o
>  obj-$(CONFIG_INPUT_DA9063_ONKEY)	+= da9063_onkey.o
> diff --git a/drivers/input/misc/cpcap-pwrbutton.c b/drivers/input/misc/cpcap-pwrbutton.c
> new file mode 100644
> index 000000000000..ed6674689e79
> --- /dev/null
> +++ b/drivers/input/misc/cpcap-pwrbutton.c
> @@ -0,0 +1,119 @@
> +/**
> + * CPCAP Power Button Input Driver
> + *
> + * Copyright (C) 2017 Sebastian Reichel <sre@kernel.org>
> + *
> + * This file is subject to the terms and conditions of the GNU General
> + * Public License. See the file "COPYING" in the main directory of this
> + * archive for more details.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/input.h>
> +#include <linux/interrupt.h>
> +#include <linux/regmap.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/motorola-cpcap.h>
> +
> +#define CPCAP_IRQ_ON 23
> +#define CPCAP_IRQ_ON_BITMASK (1 << (CPCAP_IRQ_ON % 16))

Is this truly static or it could depend= on IRQ returned by
platform_get_irq()?

> +
> +struct cpcap_power_button {
> +	struct regmap *regmap;
> +	struct input_dev *idev;
> +	struct device *dev;
> +};
> +
> +static irqreturn_t powerbutton_irq(int irq, void *_button)
> +{
> +	struct cpcap_power_button *button = _button;
> +	bool key_pressed;
> +	int err, val;
> +
> +	err = regmap_read(button->regmap, CPCAP_REG_INTS2, &val);
> +	if (err) {
> +		dev_err(button->dev, "read failed: %d", err);
> +		return IRQ_HANDLED;
> +	}
> +	key_pressed = !!(val & CPCAP_IRQ_ON_BITMASK);

No need to do this, input_report_key() already "normalizes" the value,
so simply do

	input_report_key(button->idev, KEY_POWER, val & CPCAP_IRQ_ON_BITMASK);

> +
> +	pm_wakeup_event(button->dev, 0);
> +	input_report_key(button->idev, KEY_POWER, key_pressed);
> +	input_sync(button->idev);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int cpcap_power_button_probe(struct platform_device *pdev)
> +{
> +	struct cpcap_power_button *button;
> +	int irq = platform_get_irq(pdev, 0);
> +	int err;
> +
> +	button = devm_kmalloc(&pdev->dev, sizeof(*button), GFP_KERNEL);
> +	if (!button)
> +		return -ENOMEM;
> +
> +	button->idev = devm_input_allocate_device(&pdev->dev);
> +	if (!button->idev)
> +		return -ENOMEM;
> +
> +	button->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!button->regmap)
> +		return -ENODEV;
> +
> +	button->dev = &pdev->dev;
> +
> +	button->idev->name = "cpcap-pwrbutton";
> +	button->idev->phys = "cpcap-pwrbutton/input0";
> +	button->idev->dev.parent = button->dev;
> +	input_set_capability(button->idev, EV_KEY, KEY_POWER);
> +
> +	err = devm_request_threaded_irq(&button->idev->dev, irq, NULL,

This is wrong device to attach devm to: we never bind input device to a
driver, so interrupt will never be released. You want to use &pdev->dev
as with the rest of devm resources.

> +		powerbutton_irq, IRQF_ONESHOT, "cpcap_pwrbutton", button);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "IRQ request failed: %d\n", err);
> +		return err;
> +	}
> +
> +	err = input_register_device(button->idev);
> +	if (err) {
> +		dev_err(&pdev->dev, "Input register failed: %d\n", err);
> +		return err;
> +	}
> +
> +	device_init_wakeup(&pdev->dev, true);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id cpcap_pwrbutton_dt_match_table[] = {
> +	{ .compatible = "motorola,cpcap-pwrbutton" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, cpcap_pwrbutton_dt_match_table);
> +#endif
> +
> +static struct platform_driver cpcap_power_button_driver = {
> +	.probe		= cpcap_power_button_probe,
> +	.driver		= {
> +		.name	= "cpcap-pwrbutton",
> +		.of_match_table = of_match_ptr(cpcap_pwrbutton_dt_match_table),
> +	},
> +};
> +module_platform_driver(cpcap_power_button_driver);
> +
> +MODULE_ALIAS("platform:cpcap-pwrbutton");
> +MODULE_DESCRIPTION("CPCAP Power Button");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
> -- 
> 2.11.0
> 

Thanks.

-- 
Dmitry