2015-05-11 13:30:54

by Niklas Cassel

Subject: [PATCH v3] net: phy: micrel: Fix regression in kszphy_probe

Don't do clock-mode-select if clk == NULL,
since when building without CONFIG_HAVE_CLK,
clk_get returns NULL and clk_get_rate returns 0.

Doing clock-mode-select in this cause causes kszphy_probe to
return -EINVAL and thus prevents the device from being probed.

The original code (before regression) would return 0
when building without CONFIG_HAVE_CLK.

Cc: stable <[email protected]> # 3.19+
Fixes: 63f44b2bfccd ("net: phy: micrel: add generic clock-mode-select
support")
Signed-off-by: Niklas Cassel <[email protected]>
---
drivers/net/phy/micrel.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 1190fd8..f6a34e3 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -548,7 +548,11 @@ static int kszphy_probe(struct phy_device *phydev)
}

clk = devm_clk_get(&phydev->dev, "rmii-ref");
- if (!IS_ERR(clk)) {
+ /* Don't check rate if clk == NULL, since when CONFIG_HAVE_CLK is not
+ * set, clk_get returns NULL and clk_get_rate returns 0. Doing so
+ * would return -EINVAL and prevent the device from being probed.
+ */
+ if (!IS_ERR_OR_NULL(clk)) {
unsigned long rate = clk_get_rate(clk);
bool rmii_ref_clk_sel_25_mhz;

--
2.1.4

2015-05-11 13:50:48

by Johan Hovold

Subject: Re: [PATCH v3] net: phy: micrel: Fix regression in kszphy_probe

On Mon, May 11, 2015 at 03:30:15PM +0200, Niklas Cassel wrote:
> Don't do clock-mode-select if clk == NULL,
> since when building without CONFIG_HAVE_CLK,
> clk_get returns NULL and clk_get_rate returns 0.
>
> Doing clock-mode-select in this cause causes kszphy_probe to
> return -EINVAL and thus prevents the device from being probed.
>
> The original code (before regression) would return 0
> when building without CONFIG_HAVE_CLK.
>
> Cc: stable <[email protected]> # 3.19+
> Fixes: 63f44b2bfccd ("net: phy: micrel: add generic clock-mode-select
> support")

You're blaming the wrong commit here -- the regression was introduced by
1fadee0c3645 ("net/phy: micrel: Add clock support for KSZ8021/KSZ8031")
and then the commit you mention made even more devices fail without
CONFIG_HAVE_CLK.

Thought I mentioned this commit explicitly in my last mail but see now
that I only wrote that the offending commit went into 3.18 (i.e. not
3.19).

> Signed-off-by: Niklas Cassel <[email protected]>
> ---
> drivers/net/phy/micrel.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index 1190fd8..f6a34e3 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -548,7 +548,11 @@ static int kszphy_probe(struct phy_device *phydev)
> }
>
> clk = devm_clk_get(&phydev->dev, "rmii-ref");
> - if (!IS_ERR(clk)) {
> + /* Don't check rate if clk == NULL, since when CONFIG_HAVE_CLK is not
> + * set, clk_get returns NULL and clk_get_rate returns 0. Doing so
> + * would return -EINVAL and prevent the device from being probed.
> + */

Why not simply

/* NOTE: clk may be NULL if building without CONFIG_HAVE_CLK */

> + if (!IS_ERR_OR_NULL(clk)) {
> unsigned long rate = clk_get_rate(clk);
> bool rmii_ref_clk_sel_25_mhz;

Johan