linux-kernel - Re: [PATCH] HID: i2c-hid: set power sleep before shutdown

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Date:	Mon, 20 Jun 2016 11:34:57 +0200
From:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:	Guohua Zhong <ghzhong@...angdigital.com>
Cc:	Jiri Kosina <jikos@...nel.org>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Dmitry Torokhov <dtor@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Andrew Duggan <aduggan@...aptics.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] HID: i2c-hid: set power sleep before shutdown

On Jun 18 2016 or thereabouts, Guohua Zhong wrote:
> Add i2c_hid_shutdown for i2c-hid driver to send suspend cmd &
> disable irq before device shutdown.
> 
> Some HW design is that the power to i2c hid device won't down
> after device shutdown. Also the i2c-hid driver do not send suspend
> cmd to the hid i2c device and disable its irq before shutdown.So
> if We touch the touchscreen or some other i2c hid device ,the power
> consumtion will be go up even when the device is in shutdown state.

Wow, that's a new one! Could you tell us which device board is behaving
that way (if not under NDA or such)?

> 
> Though the root cause maybe a HW issue. But it seems that it is a
> good pratice to set power sleep for i2c-hid device before shutdown.

Works for me:
Acked-By: Benjamin Tissoires <benjamin.tissoires@...hat.com>

Cheers,
Benjamin

> 
> Signed-off-by: Guohua Zhong <ghzhong@...angdigital.com>
> ---
>  drivers/hid/i2c-hid/i2c-hid.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 2e021ba..d6ea97b 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -1106,6 +1106,12 @@ static int i2c_hid_remove(struct i2c_client *client)
>  	return 0;
>  }
>  
> +static void i2c_hid_shutdown(struct i2c_client *client)
> +{
> +	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
> +	disable_irq(client->irq);
> +}
> +
>  #ifdef CONFIG_PM_SLEEP
>  static int i2c_hid_suspend(struct device *dev)
>  {
> @@ -1230,7 +1236,7 @@ static struct i2c_driver i2c_hid_driver = {
>  
>  	.probe		= i2c_hid_probe,
>  	.remove		= i2c_hid_remove,
> -
> +	.shutdown	= i2c_hid_shutdown,
>  	.id_table	= i2c_hid_id_table,
>  };
>  
> -- 
> 1.9.1
> 
>