linux-kernel - Re: [PATCH v5 3/3] eeprom: at24: enable runtime pm support

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Message-ID: <20170904073850.i77nk36k5extin56@valkosipuli.retiisi.org.uk>
Date:   Mon, 4 Sep 2017 10:38:51 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Divagar Mohandass <divagar.mohandass@...el.com>
Cc:     robh+dt@...nel.org, mark.rutland@....com, wsa@...-dreams.de,
        devicetree@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org, rajmohan.mani@...el.com
Subject: Re: [PATCH v5 3/3] eeprom: at24: enable runtime pm support

Hi Divagar,

On Mon, Sep 04, 2017 at 12:10:45PM +0530, Divagar Mohandass wrote:
> Currently the device is kept in D0, there is an opportunity
> to save power by enabling runtime pm.
> 
> Device can be daisy chained from PMIC and we can't rely on I2C core
> for auto resume/suspend. Driver will decide when to resume/suspend.
> 
> Signed-off-by: Divagar Mohandass <divagar.mohandass@...el.com>
> ---
>  drivers/misc/eeprom/at24.c | 40 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 2199c42..03f5cb7 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -750,9 +782,12 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	err = at24_read(at24, 0, &test_byte, 1);

You do pm_runtime_put()s here and drop the ones below as it's needed
unconditionally. Then I think we're done.

>  	if (err) {
>  		err = -ENODEV;
> +		pm_runtime_put(&client->dev);
>  		goto err_clients;
>  	}
>  
> +	pm_runtime_put(&client->dev);
> +
>  	at24->nvmem_config.name = dev_name(&client->dev);
>  	at24->nvmem_config.dev = &client->dev;
>  	at24->nvmem_config.read_only = !writable;

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@....fi