Re: [PATCH 5/5] platform/x86: lenovo-yogabook-wmi: Add support for hall sensor on the back

From: Yauhen Kharuzhy <jekhor@gmail.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <markgross@kernel.org>,
	Andy Shevchenko <andy@infradead.org>,
	platform-driver-x86@vger.kernel.org
Subject: Re: [PATCH 5/5] platform/x86: lenovo-yogabook-wmi: Add support for hall sensor on the back
Date: Mon, 29 Nov 2021 00:09:13 +0300	[thread overview]
Message-ID: <YaPv+W6MYK30FvPO@jeknote.loshitsa1.net> (raw)
In-Reply-To: <20211128190031.405620-5-hdegoede@redhat.com>

On Sun, Nov 28, 2021 at 08:00:31PM +0100, Hans de Goede wrote:
> On the back of the device there is a hall sensor connected to the
> "INT33FF:02" GPIO controller pin 18, which gets triggered when the
> device is fully folded into tablet-mode (when the back of the display
> touched the back of the keyboard).
> 
> Use this to disable both the touch-keyboard and the digitizer when
> the tablet is fully folded into tablet-mode.

Wonderful. I knew that this device would still bring surprises...I
didn't find this sensor in my investigation :)

In your opinion, is it possible to use this sensor to correct of the custom
hinge angle sensor readings from the Intel sensor hub? The hinge angle sensor
uses accelerometers to calculate the angle and cannot reliably
distinquish between 0 and 360 degrees. I used the lid switch status in a my
patch for iio-sensors-proxy but this sensor looks like a yet another candidate.
The lid switch is more generic soultion, of course.

> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/platform/x86/lenovo-yogabook-wmi.c | 71 +++++++++++++++++++++-
>  1 file changed, 70 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/lenovo-yogabook-wmi.c b/drivers/platform/x86/lenovo-yogabook-wmi.c
> index ecd624d9108f..65dd1ed97762 100644
> --- a/drivers/platform/x86/lenovo-yogabook-wmi.c
> +++ b/drivers/platform/x86/lenovo-yogabook-wmi.c
> @@ -3,6 +3,9 @@
>  
>  #include <linux/acpi.h>
>  #include <linux/devm-helpers.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/gpio/machine.h>
> +#include <linux/interrupt.h>
>  #include <linux/module.h>
>  #include <linux/leds.h>
>  #include <linux/wmi.h>
> @@ -22,6 +25,7 @@ enum {
>  	YB_KBD_IS_ON,
>  	YB_DIGITIZER_IS_ON,
>  	YB_DIGITIZER_MODE,
> +	YB_TABLET_MODE,
>  	YB_SUSPENDED,
>  };
>  
> @@ -31,6 +35,8 @@ struct yogabook_wmi {
>  	struct acpi_device *dig_adev;
>  	struct device *kbd_dev;
>  	struct device *dig_dev;
> +	struct gpio_desc *backside_hall_gpio;
> +	int backside_hall_irq;
>  	struct work_struct work;
>  	struct led_classdev kbd_bl_led;
>  	unsigned long flags;
> @@ -109,7 +115,10 @@ static void yogabook_wmi_work(struct work_struct *work)
>  	if (test_bit(YB_SUSPENDED, &data->flags))
>  		return;
>  
> -	if (test_bit(YB_DIGITIZER_MODE, &data->flags)) {
> +	if (test_bit(YB_TABLET_MODE, &data->flags)) {
> +		kbd_on = false;
> +		digitizer_on = false;
> +	} else if (test_bit(YB_DIGITIZER_MODE, &data->flags)) {
>  		digitizer_on = true;
>  		kbd_on = false;
>  	} else {
> @@ -171,6 +180,20 @@ static void yogabook_wmi_notify(struct wmi_device *wdev, union acpi_object *dumm
>  	schedule_work(&data->work);
>  }
>  
> +static irqreturn_t yogabook_backside_hall_irq(int irq, void *_data)
> +{
> +	struct yogabook_wmi *data = _data;
> +
> +	if (gpiod_get_value(data->backside_hall_gpio))
> +		set_bit(YB_TABLET_MODE, &data->flags);
> +	else
> +		clear_bit(YB_TABLET_MODE, &data->flags);
> +
> +	schedule_work(&data->work);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static enum led_brightness kbd_brightness_get(struct led_classdev *cdev)
>  {
>  	struct yogabook_wmi *data =
> @@ -197,6 +220,19 @@ static int kbd_brightness_set(struct led_classdev *cdev,
>  	return yogabook_wmi_set_kbd_backlight(wdev, data->brightness);
>  }
>  
> +static struct gpiod_lookup_table yogabook_wmi_gpios = {
> +	.dev_id		= "243FEC1D-1963-41C1-8100-06A9D82A94B4",
> +	.table		= {
> +		GPIO_LOOKUP("INT33FF:02", 18, "backside_hall_sw", GPIO_ACTIVE_LOW),
> +		{}
> +	},
> +};
> +
> +static void yogabook_wmi_rm_gpio_lookup(void *unused)
> +{
> +	gpiod_remove_lookup_table(&yogabook_wmi_gpios);
> +}
> +
>  static int yogabook_wmi_probe(struct wmi_device *wdev, const void *context)
>  {
>  	struct yogabook_wmi *data;
> @@ -242,6 +278,36 @@ static int yogabook_wmi_probe(struct wmi_device *wdev, const void *context)
>  		goto error_put_devs;
>  	}
>  
> +	gpiod_add_lookup_table(&yogabook_wmi_gpios);
> +
> +	r = devm_add_action_or_reset(&wdev->dev, yogabook_wmi_rm_gpio_lookup, NULL);
> +	if (r)
> +		goto error_put_devs;
> +
> +	data->backside_hall_gpio =
> +		devm_gpiod_get(&wdev->dev, "backside_hall_sw", GPIOD_IN);
> +	if (IS_ERR(data->backside_hall_gpio)) {
> +		r = PTR_ERR(data->backside_hall_gpio);
> +		dev_err_probe(&wdev->dev, r, "Getting backside_hall_sw GPIO\n");
> +		goto error_put_devs;
> +	}
> +
> +	r = gpiod_to_irq(data->backside_hall_gpio);
> +	if (r < 0) {
> +		dev_err_probe(&wdev->dev, r, "Getting backside_hall_sw IRQ\n");
> +		goto error_put_devs;
> +	}
> +	data->backside_hall_irq = r;
> +
> +	r = devm_request_irq(&wdev->dev, data->backside_hall_irq,
> +			     yogabook_backside_hall_irq,
> +			     IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +			     "backside_hall_sw", data);
> +	if (r) {
> +		dev_err_probe(&wdev->dev, r, "Requesting backside_hall_sw IRQ\n");
> +		goto error_put_devs;
> +	}
> +
>  	schedule_work(&data->work);
>  
>  	data->kbd_bl_led.name = "ybwmi::kbd_backlight";
> @@ -307,6 +373,9 @@ __maybe_unused int yogabook_wmi_resume(struct device *dev)
>  
>  	clear_bit(YB_SUSPENDED, &data->flags);
>  
> +	/* Check for YB_TABLET_MODE changes made during suspend */
> +	schedule_work(&data->work);
> +
>  	return 0;
>  }
>  
> -- 
> 2.33.1
> 

-- 
Yauhen Kharuzhy