[PATCH] net: lpc_eth: Check clk_prepare_enable() error

[PATCH] net: lpc_eth: Check clk_prepare_enable() error

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@nxp.com>

clk_prepare_enable() may fail, so we should better check its return
value and propagate it in the case of failure.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
---
 drivers/net/ethernet/nxp/lpc_eth.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/nxp/lpc_eth.c b/drivers/net/ethernet/nxp/lpc_eth.c
index 4d4ecba..7c796f7 100644
--- a/drivers/net/ethernet/nxp/lpc_eth.c
+++ b/drivers/net/ethernet/nxp/lpc_eth.c
@@ -475,12 +475,19 @@ static void __lpc_get_mac(struct netdata_local *pldat, u8 *mac)
 	mac[5] = tmp >> 8;
 }
 
-static void __lpc_eth_clock_enable(struct netdata_local *pldat, bool enable)
+static int __lpc_eth_clock_enable(struct netdata_local *pldat, bool enable)
 {
-	if (enable)
-		clk_prepare_enable(pldat->clk);
-	else
+	int ret;
+
+	if (enable) {
+		ret = clk_prepare_enable(pldat->clk);
+		if (ret)
+			return ret;
+	} else {
 		clk_disable_unprepare(pldat->clk);
+	}
+
+	return 0;
 }
 
 static void __lpc_params_setup(struct netdata_local *pldat)
@@ -1039,6 +1046,7 @@ static int lpc_eth_close(struct net_device *ndev)
 {
 	unsigned long flags;
 	struct netdata_local *pldat = netdev_priv(ndev);
+	int ret;
 
 	if (netif_msg_ifdown(pldat))
 		dev_dbg(&pldat->pdev->dev, "shutting down %s\n", ndev->name);
@@ -1056,7 +1064,9 @@ static int lpc_eth_close(struct net_device *ndev)
 	writel(0, LPC_ENET_MAC2(pldat->net_base));
 	spin_unlock_irqrestore(&pldat->lock, flags);
 
-	__lpc_eth_clock_enable(pldat, false);
+	ret = __lpc_eth_clock_enable(pldat, false);
+	if (ret)
+		return ret;
 
 	return 0;
 }
@@ -1197,11 +1207,14 @@ static int lpc_eth_ioctl(struct net_device *ndev, struct ifreq *req, int cmd)
 static int lpc_eth_open(struct net_device *ndev)
 {
 	struct netdata_local *pldat = netdev_priv(ndev);
+	int ret;
 
 	if (netif_msg_ifup(pldat))
 		dev_dbg(&pldat->pdev->dev, "enabling %s\n", ndev->name);
 
-	__lpc_eth_clock_enable(pldat, true);
+	ret = __lpc_eth_clock_enable(pldat, true);
+	if (ret)
+		return ret;
 
 	/* Suspended PHY makes LPC ethernet core block, so resume now */
 	phy_resume(ndev->phydev);
@@ -1320,7 +1333,9 @@ static int lpc_eth_drv_probe(struct platform_device *pdev)
 	}
 
 	/* Enable network clock */
-	__lpc_eth_clock_enable(pldat, true);
+	ret = __lpc_eth_clock_enable(pldat, true);
+	if (ret)
+		goto err_out_free_dev;
 
 	/* Map IO space */
 	pldat->net_base = ioremap(res->start, resource_size(res));
-- 
1.9.1

Re: [PATCH] net: lpc_eth: Check clk_prepare_enable() error

[Vladimir Zapolskiy]

Hi Fabio,

On 23.08.2016 05:01, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@nxp.com>
> 
> clk_prepare_enable() may fail, so we should better check its return
> value and propagate it in the case of failure.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> ---
>  drivers/net/ethernet/nxp/lpc_eth.c | 29 ++++++++++++++++++++++-------
>  1 file changed, 22 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/nxp/lpc_eth.c b/drivers/net/ethernet/nxp/lpc_eth.c
> index 4d4ecba..7c796f7 100644
> --- a/drivers/net/ethernet/nxp/lpc_eth.c
> +++ b/drivers/net/ethernet/nxp/lpc_eth.c
> @@ -475,12 +475,19 @@ static void __lpc_get_mac(struct netdata_local *pldat, u8 *mac)
>  	mac[5] = tmp >> 8;
>  }
>  
> -static void __lpc_eth_clock_enable(struct netdata_local *pldat, bool enable)
> +static int __lpc_eth_clock_enable(struct netdata_local *pldat, bool enable)
>  {
> -	if (enable)
> -		clk_prepare_enable(pldat->clk);
> -	else
> +	int ret;
> +
> +	if (enable) {
> +		ret = clk_prepare_enable(pldat->clk);
> +		if (ret)
> +			return ret;
> +	} else {
>  		clk_disable_unprepare(pldat->clk);
> +	}
> +
> +	return 0;
>  }

The change is correct, but let me ask you to replace all instances of
__lpc_eth_clock_enable() with plain clk_prepare_enable() or
clk_disable_unprepare(). It should save one redundant error check also.