Re: [PATCH 3/3] HID: i2c-hid: Add support for ACPI GPIO interrupts

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

On Feb 23 2015 or thereabouts, Mika Westerberg wrote:
> The HID over I2C specification allows to have the interrupt for a HID
> device to be GPIO instead of directly connected to the IO-APIC.
> 
> Add support for this so that when the driver does not find proper interrupt
> number from the I2C client structure we check if it has ACPI GpioInt()
> resource listed in _CRS. If it is found we convert it to an interrupt
> number and use it instead.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---

I know this has been already discussed, so don't take this as a request
for a change. I however hoped that the acpi subsystem would provide the
irq directly in the i2c client without having to deal with it in
i2c_hid. For me, declaring the GPIO as an interrupt means that the irq
should be created in the first place. However, if we also have access to
the gpio, that means that we can read the value of it, which is better in
our case. So I am fine with all the solutions - as long as it works :)

I don't know enough of the use of gpios in acpi to properly review the
code. So I'll just add my:
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Cheers,
Benjamin

>  drivers/hid/i2c-hid/i2c-hid.c | 68 +++++++++++++++++++++++++++++++------------
>  1 file changed, 50 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 404ccde49acd..c6cad72f6296 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -37,6 +37,7 @@
>  #include <linux/mutex.h>
>  #include <linux/acpi.h>
>  #include <linux/of.h>
> +#include <linux/gpio/consumer.h>
>  
>  #include <linux/i2c/i2c-hid.h>
>  
> @@ -144,6 +145,8 @@ struct i2c_hid {
>  	unsigned long		flags;		/* device flags */
>  
>  	wait_queue_head_t	wait;		/* For waiting the interrupt */
> +	struct gpio_desc	*desc;
> +	int			irq;
>  
>  	struct i2c_hid_platform_data pdata;
>  };
> @@ -790,16 +793,16 @@ static int i2c_hid_init_irq(struct i2c_client *client)
>  	struct i2c_hid *ihid = i2c_get_clientdata(client);
>  	int ret;
>  
> -	dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
> +	dev_dbg(&client->dev, "Requesting IRQ: %d\n", ihid->irq);
>  
> -	ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
> +	ret = request_threaded_irq(ihid->irq, NULL, i2c_hid_irq,
>  			IRQF_TRIGGER_LOW | IRQF_ONESHOT,
>  			client->name, ihid);
>  	if (ret < 0) {
>  		dev_warn(&client->dev,
>  			"Could not register for %s interrupt, irq = %d,"
>  			" ret = %d\n",
> -			client->name, client->irq, ret);
> +			client->name, ihid->irq, ret);
>  
>  		return ret;
>  	}
> @@ -846,6 +849,14 @@ static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
>  }
>  
>  #ifdef CONFIG_ACPI
> +
> +/* Default GPIO mapping */
> +static const struct acpi_gpio_params i2c_hid_irq_gpio = { 0, 0, true };
> +static const struct acpi_gpio_mapping i2c_hid_acpi_gpios[] = {
> +	{ "gpios", &i2c_hid_irq_gpio, 1 },
> +	{ },
> +};
> +
>  static int i2c_hid_acpi_pdata(struct i2c_client *client,
>  		struct i2c_hid_platform_data *pdata)
>  {
> @@ -871,7 +882,7 @@ static int i2c_hid_acpi_pdata(struct i2c_client *client,
>  	pdata->hid_descriptor_address = obj->integer.value;
>  	ACPI_FREE(obj);
>  
> -	return 0;
> +	return acpi_dev_add_driver_gpios(adev, i2c_hid_acpi_gpios);
>  }
>  
>  static const struct acpi_device_id i2c_hid_acpi_match[] = {
> @@ -935,12 +946,6 @@ static int i2c_hid_probe(struct i2c_client *client,
>  
>  	dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
>  
> -	if (!client->irq) {
> -		dev_err(&client->dev,
> -			"HID over i2c has not been provided an Int IRQ\n");
> -		return -EINVAL;
> -	}
> -
>  	ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
>  	if (!ihid)
>  		return -ENOMEM;
> @@ -960,6 +965,23 @@ static int i2c_hid_probe(struct i2c_client *client,
>  		ihid->pdata = *platform_data;
>  	}
>  
> +	if (client->irq > 0) {
> +		ihid->irq = client->irq;
> +	} else if (ACPI_COMPANION(&client->dev)) {
> +		ihid->desc = gpiod_get(&client->dev, NULL, GPIOD_IN);
> +		if (IS_ERR(ihid->desc)) {
> +			dev_err(&client->dev, "Failed to get GPIO interrupt\n");
> +			return PTR_ERR(ihid->desc);
> +		}
> +
> +		ihid->irq = gpiod_to_irq(ihid->desc);
> +		if (ihid->irq < 0) {
> +			gpiod_put(ihid->desc);
> +			dev_err(&client->dev, "Failed to convert GPIO to IRQ\n");
> +			return ihid->irq;
> +		}
> +	}
> +
>  	i2c_set_clientdata(client, ihid);
>  
>  	ihid->client = client;
> @@ -1022,13 +1044,16 @@ err_mem_free:
>  	hid_destroy_device(hid);
>  
>  err_irq:
> -	free_irq(client->irq, ihid);
> +	free_irq(ihid->irq, ihid);
>  
>  err_pm:
>  	pm_runtime_put_noidle(&client->dev);
>  	pm_runtime_disable(&client->dev);
>  
>  err:
> +	if (ihid->desc)
> +		gpiod_put(ihid->desc);
> +
>  	i2c_hid_free_buffers(ihid);
>  	kfree(ihid);
>  	return ret;
> @@ -1047,13 +1072,18 @@ static int i2c_hid_remove(struct i2c_client *client)
>  	hid = ihid->hid;
>  	hid_destroy_device(hid);
>  
> -	free_irq(client->irq, ihid);
> +	free_irq(ihid->irq, ihid);
>  
>  	if (ihid->bufsize)
>  		i2c_hid_free_buffers(ihid);
>  
> +	if (ihid->desc)
> +		gpiod_put(ihid->desc);
> +
>  	kfree(ihid);
>  
> +	acpi_dev_remove_driver_gpios(ACPI_COMPANION(&client->dev));
> +
>  	return 0;
>  }
>  
> @@ -1065,9 +1095,9 @@ static int i2c_hid_suspend(struct device *dev)
>  	struct hid_device *hid = ihid->hid;
>  	int ret = 0;
>  
> -	disable_irq(client->irq);
> +	disable_irq(ihid->irq);
>  	if (device_may_wakeup(&client->dev))
> -		enable_irq_wake(client->irq);
> +		enable_irq_wake(ihid->irq);
>  
>  	if (hid->driver && hid->driver->suspend)
>  		ret = hid->driver->suspend(hid, PMSG_SUSPEND);
> @@ -1085,13 +1115,13 @@ static int i2c_hid_resume(struct device *dev)
>  	struct i2c_hid *ihid = i2c_get_clientdata(client);
>  	struct hid_device *hid = ihid->hid;
>  
> -	enable_irq(client->irq);
> +	enable_irq(ihid->irq);
>  	ret = i2c_hid_hwreset(client);
>  	if (ret)
>  		return ret;
>  
>  	if (device_may_wakeup(&client->dev))
> -		disable_irq_wake(client->irq);
> +		disable_irq_wake(ihid->irq);
>  
>  	if (hid->driver && hid->driver->reset_resume) {
>  		ret = hid->driver->reset_resume(hid);
> @@ -1106,17 +1136,19 @@ static int i2c_hid_resume(struct device *dev)
>  static int i2c_hid_runtime_suspend(struct device *dev)
>  {
>  	struct i2c_client *client = to_i2c_client(dev);
> +	struct i2c_hid *ihid = i2c_get_clientdata(client);
>  
>  	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
> -	disable_irq(client->irq);
> +	disable_irq(ihid->irq);
>  	return 0;
>  }
>  
>  static int i2c_hid_runtime_resume(struct device *dev)
>  {
>  	struct i2c_client *client = to_i2c_client(dev);
> +	struct i2c_hid *ihid = i2c_get_clientdata(client);
>  
> -	enable_irq(client->irq);
> +	enable_irq(ihid->irq);
>  	i2c_hid_set_power(client, I2C_HID_PWR_ON);
>  	return 0;
>  }
> -- 
> 2.1.4
>