linux-kernel - Re: [PATCH 2/5] watchdog: ziirave_wdt: Be verbose about errors in probe()

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Date:   Wed, 31 Jul 2019 14:42:54 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Andrey Smirnov <andrew.smirnov@...il.com>
Cc:     linux-watchdog@...r.kernel.org, Chris Healy <cphealy@...il.com>,
        Rick Ramstetter <rick@...eaterllc.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] watchdog: ziirave_wdt: Be verbose about errors in
 probe()

On Wed, Jul 31, 2019 at 10:42:49AM -0700, Andrey Smirnov wrote:
> The driver is quite silent in case of probe failure, which makes it
> more difficult to diagnose problem from the kernel log. Add logging to
> all of the silent error paths ziirave_wdt_probe() to improve that.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
> Cc: Chris Healy <cphealy@...il.com>
> Cc: Guenter Roeck <linux@...ck-us.net>
> Cc: Rick Ramstetter <rick@...eaterllc.com>
> Cc: linux-watchdog@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/watchdog/ziirave_wdt.c | 32 ++++++++++++++++++++++++--------
>  1 file changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
> index 6ec028fb2635..8c71341a9c1c 100644
> --- a/drivers/watchdog/ziirave_wdt.c
> +++ b/drivers/watchdog/ziirave_wdt.c
> @@ -658,8 +658,10 @@ static int ziirave_wdt_probe(struct i2c_client *client,
>  	 */
>  	if (w_priv->wdd.timeout == 0) {
>  		val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
> -		if (val < 0)
> +		if (val < 0) {
> +			dev_err(&client->dev, "Failed to read timeout\n");
>  			return val;
> +		}
>  
>  		if (val < ZIIRAVE_TIMEOUT_MIN)
>  			return -ENODEV;
> @@ -668,8 +670,10 @@ static int ziirave_wdt_probe(struct i2c_client *client,
>  	} else {
>  		ret = ziirave_wdt_set_timeout(&w_priv->wdd,
>  					      w_priv->wdd.timeout);
> -		if (ret)
> +		if (ret) {
> +			dev_err(&client->dev, "Failed to set timeout\n");
>  			return ret;
> +		}
>  
>  		dev_info(&client->dev, "Timeout set to %ds\n",
>  			 w_priv->wdd.timeout);
> @@ -681,34 +685,46 @@ static int ziirave_wdt_probe(struct i2c_client *client,
>  
>  	/* If in unconfigured state, set to stopped */
>  	val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
> -	if (val < 0)
> +	if (val < 0) {
> +		dev_err(&client->dev, "Failed to read state\n");
>  		return val;
> +	}
>  
>  	if (val == ZIIRAVE_STATE_INITIAL)
>  		ziirave_wdt_stop(&w_priv->wdd);
>  
>  	ret = ziirave_wdt_init_duration(client);
> -	if (ret)
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to init duration\n");
>  		return ret;
> +	}
>  
>  	ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
>  				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
> -	if (ret)
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to read firmware version\n");
>  		return ret;
> +	}
>  
>  	ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
>  				   ZIIRAVE_WDT_BOOT_VER_MAJOR);
> -	if (ret)
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to read bootloader version\n");
>  		return ret;
> +	}
>  
>  	w_priv->reset_reason = i2c_smbus_read_byte_data(client,
>  						ZIIRAVE_WDT_RESET_REASON);
> -	if (w_priv->reset_reason < 0)
> +	if (w_priv->reset_reason < 0) {
> +		dev_err(&client->dev, "Failed to read reset reason\n");
>  		return w_priv->reset_reason;
> +	}
>  
>  	if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
> -	    !ziirave_reasons[w_priv->reset_reason])
> +	    !ziirave_reasons[w_priv->reset_reason]) {
> +		dev_err(&client->dev, "Invalid reset reason\n");
>  		return -ENODEV;
> +	}
>  
>  	ret = watchdog_register_device(&w_priv->wdd);
>  
> -- 
> 2.21.0
>