[PATCH] net: dwmac-rk: MAC clock should be truned off

[PATCH] net: dwmac-rk: MAC clock should be truned off

[李哲]

if PHY power-on fails, clockassociated the MAC should
be disabled during the MAC initialization process

Signed-off-by: 李哲 <sensor1010@163.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
index 700858ff6f7c..036e45be5828 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
@@ -1648,7 +1648,7 @@ static int gmac_clk_enable(struct rk_priv_data *bsp_priv, bool enable)
 static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 {
 	struct regulator *ldo = bsp_priv->regulator;
-	int ret;
+	int ret = 0;
 	struct device *dev = &bsp_priv->pdev->dev;
 
 	if (enable) {
@@ -1661,7 +1661,7 @@ static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 			dev_err(dev, "fail to disable phy-supply\n");
 	}
 
-	return 0;
+	return ret;
 }
 
 static struct rk_priv_data *rk_gmac_setup(struct platform_device *pdev,
-- 
2.17.1

Re: [PATCH] net: dwmac-rk: MAC clock should be truned off

[Andrew Lunn]

On Fri, May 23, 2025 at 08:15:21AM -0700, 李哲 wrote:
> if PHY power-on fails, clockassociated the MAC should
> be disabled during the MAC initialization process

The Subject: line has a typo.

> Signed-off-by: 李哲 <sensor1010@163.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> index 700858ff6f7c..036e45be5828 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> @@ -1648,7 +1648,7 @@ static int gmac_clk_enable(struct rk_priv_data *bsp_priv, bool enable)
>  static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
>  {
>  	struct regulator *ldo = bsp_priv->regulator;
> -	int ret;
> +	int ret = 0;
>  	struct device *dev = &bsp_priv->pdev->dev;
>  
>  	if (enable) {
> @@ -1661,7 +1661,7 @@ static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
>  			dev_err(dev, "fail to disable phy-supply\n");
>  	}
>  
> -	return 0;
> +	return ret;

This does not make much sense to me. How do you get here with ret not
being 0?

    Andrew

---
pw-bot: cr

Re: Re: [PATCH] net: dwmac-rk: MAC clock should be truned off

[Andrew Lunn]

On Sat, May 24, 2025 at 10:05:47PM +0800, lizhe wrote:
> Hi， Anerdw
> The following is the logic for calling this function： 
> 
> 
> rk_gmac_powerup() {
> 
> ret = phy_power_on(bsp_priv, true);      // here.
> 
> if (ret) {
> 
> gmac_clk_enable(bsp_priv, false);
> 
> return ret;
> 
> }
> 
> }

Ah, there is something funny with your patch. Look at the diff:

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
index 700858ff6f7c..036e45be5828 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
@@ -1648,7 +1648,7 @@  static int gmac_clk_enable(struct rk_priv_data *bsp_priv, bool enable)

This line tells you where in the file you are patching, and the
function to be patched. This is what i looked at,
gmac_clk_enable(). And gmac_clk_enable() has a similar structure, ret
declared at the beginning, return 0 at the end. But the only way to
that return 0 is without error.

But patch is actually for:

 static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 {
 	struct regulator *ldo = bsp_priv->regulator;
-	int ret;
+	int ret = 0;
 	struct device *dev = &bsp_priv->pdev->dev;
 
 	if (enable) {
@@ -1661,7 +1661,7 @@  static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 			dev_err(dev, "fail to disable phy-supply\n");
 	}
 
-	return 0;
+	return ret;
 }

And agree, the error codes are ignored in phy_power_on().

But i have a few questions:

How did you generate this diff? This is the first time i've made this
mistake, as far as i know. I trust the context information when
reviewing patches. Yet here it is wrong. Why? Is this actually normal?
I know diff gets it wrong for python, i don't trust it at all with
that language, but i've not noticed such problems with C.

Did you look at the history of phy_power_on()? It looks pretty
deliberate ignoring errors. Maybe there is a reason why this happens?
git blame and git log might explain why it is like this.

	Andrew

Re: Re: [PATCH] net: dwmac-rk: MAC clock should be truned off

[Russell King (Oracle)]

On Sat, May 24, 2025 at 04:48:15PM +0200, Andrew Lunn wrote:
> On Sat, May 24, 2025 at 10:05:47PM +0800, lizhe wrote:
> > Hi， Anerdw
> > The following is the logic for calling this function： 
> > 
> > 
> > rk_gmac_powerup() {
> > 
> > ret = phy_power_on(bsp_priv, true);      // here.
> > 
> > if (ret) {
> > 
> > gmac_clk_enable(bsp_priv, false);
> > 
> > return ret;
> > 
> > }
> > 
> > }
> 
> Ah, there is something funny with your patch. Look at the diff:
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> index 700858ff6f7c..036e45be5828 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
> @@ -1648,7 +1648,7 @@  static int gmac_clk_enable(struct rk_priv_data *bsp_priv, bool enable)
> 
> This line tells you where in the file you are patching, and the
> function to be patched. This is what i looked at,
> gmac_clk_enable(). And gmac_clk_enable() has a similar structure, ret
> declared at the beginning, return 0 at the end. But the only way to
> that return 0 is without error.
> 
> But patch is actually for:
> 
>  static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)

Andrew, this is not a problem. This is how diffs work. If the function
hasn't actually started at the point the context starts, then the
previous function will appear in the comment after the line numbers.

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