Re: [PATCH 1/8] Input: elan_i2c - Use PM subsystem to manage wake irq

Rafael J. Wysocki
2022-08-31T18:01:35Z

On Wed, Aug 31, 2022 at 1:16 AM Raul E Rangel <rrangel@chromium.org> wrote:
>
> The Elan I2C touchpad driver is currently manually managing the wake
> IRQ. This change removes the explicit enable_irq_wake/disable_irq_wake
> and instead relies on the PM subsystem. This is done by calling
> dev_pm_set_wake_irq.
>
> i2c_device_probe already calls dev_pm_set_wake_irq when using device
> tree, so it's only required when using ACPI. The net result is that this
> change should be a no-op. i2c_device_remove also already calls
> dev_pm_clear_wake_irq, so we don't need to do that in this driver.
>
> I tested this on an ACPI system where the touchpad doesn't have _PRW
> defined. I verified I can still wake the system and that the wake source
> was the touchpad IRQ GPIO.
>
> Signed-off-by: Raul E Rangel <rrangel@chromium.org>

I like this a lot, but the assumption in the wakeirq code is that the
IRQ in question will be dedicated for signaling wakeup. Does it hold
here?

> ---
>
> drivers/input/mouse/elan_i2c_core.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
> index e1758d5ffe4218..7d997d2b56436b 100644
> --- a/drivers/input/mouse/elan_i2c_core.c
> +++ b/drivers/input/mouse/elan_i2c_core.c
> @@ -33,6 +33,7 @@
> #include <linux/jiffies.h>
> #include <linux/completion.h>
> #include <linux/of.h>
> +#include <linux/pm_wakeirq.h>
> #include <linux/property.h>
> #include <linux/regulator/consumer.h>
> #include <asm/unaligned.h>
> @@ -86,8 +87,6 @@ struct elan_tp_data {
> u16 fw_page_size;
> u32 fw_signature_address;
>
> - bool irq_wake;
> -
> u8 min_baseline;
> u8 max_baseline;
> bool baseline_ready;
> @@ -1337,8 +1336,10 @@ static int elan_probe(struct i2c_client *client,
> * Systems using device tree should set up wakeup via DTS,
> * the rest will configure device as wakeup source by default.
> */
> - if (!dev->of_node)
> + if (!dev->of_node) {
> device_init_wakeup(dev, true);
> + dev_pm_set_wake_irq(dev, client->irq);
> + }
>
> return 0;
> }
> @@ -1362,8 +1363,6 @@ static int __maybe_unused elan_suspend(struct device *dev)
>
> if (device_may_wakeup(dev)) {
> ret = elan_sleep(data);
> - /* Enable wake from IRQ */
> - data->irq_wake = (enable_irq_wake(client->irq) == 0);
> } else {
> ret = elan_set_power(data, false);
> if (ret)
> @@ -1394,9 +1393,6 @@ static int __maybe_unused elan_resume(struct device *dev)
> dev_err(dev, "error %d enabling regulator\n", error);
> goto err;
> }
> - } else if (data->irq_wake) {
> - disable_irq_wake(client->irq);
> - data->irq_wake = false;
> }
>
> error = elan_set_power(data, true);
> --
> 2.37.2.672.g94769d06f0-goog
>