linux-kernel - Re: [PATCH v2] eeprom: at24: fix I2C device selection for runtime PM

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Message-ID: <20171202144837.mmnv5i2dyzg72xwf@kekkonen.localdomain>
Date:   Sat, 2 Dec 2017 16:48:38 +0200
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Sven Van Asbroeck <svendev@...x.com>
Cc:     linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org,
        divagar.mohandass@...el.com, brgl@...ev.pl
Subject: Re: [PATCH v2] eeprom: at24: fix I2C device selection for runtime PM

Hi,

On Fri, Dec 01, 2017 at 01:37:12PM -0500, Sven Van Asbroeck wrote:
> From: Sakari Ailus <sakari.ailus@...ux.intel.com>
> 
> The at24 driver creates dummy I2C devices to access offsets in the chip
> that are outside the area supported using a single I2C address. It is not
> meaningful to use runtime PM to such devices; the system firmware (ACPI)
> does not know about these devices nor runtime PM was enabled for them.
> Always use the real device instead of the dummy ones.
> 
> Fixes: 98e8201039af ("eeprom: at24: enable runtime pm support")
> Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> Tested-by: Sven Van Asbroeck on a 24AA16/24LC16B <svendev@...x.com>
> [Bartosz: rebased on top of previous fixes for 4.15, tweaked the
>           commit message]
> [Sven: fixed Bartosz's rebase]
> Signed-off-by: Sven Van Asbroeck <svendev@...x.com>
> Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>

I presume this is the final one. Yeah, the client variable was effectively
unused in the earlier version. Seems good to me.

> ---
>  drivers/misc/eeprom/at24.c | 24 ++++++++++--------------
>  1 file changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 305a7a4..20b4f26 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -562,7 +562,7 @@ static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,
>  static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  {
>  	struct at24_data *at24 = priv;
> -	struct i2c_client *client;
> +	struct device *dev = &at24->client[0]->dev;
>  	char *buf = val;
>  	int ret;
>  
> @@ -572,11 +572,9 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  	if (off + count > at24->chip.byte_len)
>  		return -EINVAL;
>  
> -	client = at24_translate_offset(at24, &off);
> -
> -	ret = pm_runtime_get_sync(&client->dev);
> +	ret = pm_runtime_get_sync(dev);
>  	if (ret < 0) {
> -		pm_runtime_put_noidle(&client->dev);
> +		pm_runtime_put_noidle(dev);
>  		return ret;
>  	}
>  
> @@ -592,7 +590,7 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  		status = at24->read_func(at24, buf, off, count);
>  		if (status < 0) {
>  			mutex_unlock(&at24->lock);
> -			pm_runtime_put(&client->dev);
> +			pm_runtime_put(dev);
>  			return status;
>  		}
>  		buf += status;
> @@ -602,7 +600,7 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  
>  	mutex_unlock(&at24->lock);
>  
> -	pm_runtime_put(&client->dev);
> +	pm_runtime_put(dev);
>  
>  	return 0;
>  }
> @@ -610,7 +608,7 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count)
>  static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>  {
>  	struct at24_data *at24 = priv;
> -	struct i2c_client *client;
> +	struct device *dev = &at24->client[0]->dev;
>  	char *buf = val;
>  	int ret;
>  
> @@ -620,11 +618,9 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>  	if (off + count > at24->chip.byte_len)
>  		return -EINVAL;
>  
> -	client = at24_translate_offset(at24, &off);
> -
> -	ret = pm_runtime_get_sync(&client->dev);
> +	ret = pm_runtime_get_sync(dev);
>  	if (ret < 0) {
> -		pm_runtime_put_noidle(&client->dev);
> +		pm_runtime_put_noidle(dev);
>  		return ret;
>  	}
>  
> @@ -640,7 +636,7 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>  		status = at24->write_func(at24, buf, off, count);
>  		if (status < 0) {
>  			mutex_unlock(&at24->lock);
> -			pm_runtime_put(&client->dev);
> +			pm_runtime_put(dev);
>  			return status;
>  		}
>  		buf += status;
> @@ -650,7 +646,7 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>  
>  	mutex_unlock(&at24->lock);
>  
> -	pm_runtime_put(&client->dev);
> +	pm_runtime_put(dev);
>  
>  	return 0;
>  }
> -- 
> 1.9.1
> 

-- 
Sakari Ailus
sakari.ailus@...ux.intel.com