net: phy: realtek: Support external PHY clock

net: phy: realtek: Support external PHY clock

[Detlev Casanova]

Some PHYs can use an external clock that must be enabled before
communicating with them.

Changes since v2:
 * Reword documentation commit message

Changes since v1:
 * Remove the clock name as it is not guaranteed to be identical across
   different PHYs
 * Disable/Enable the clock when suspending/resuming

[PATCH v3 1/3] net: phy: realtek: Add optional external PHY clock

[Detlev Casanova]

In some cases, the PHY can use an external clock source instead of a
crystal.

Add an optional clock in the phy node to make sure that the clock source
is enabled, if specified, before probing.

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 drivers/net/phy/realtek.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 3d99fd6664d7..b13dd0b3c99e 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -12,6 +12,7 @@
 #include <linux/phy.h>
 #include <linux/module.h>
 #include <linux/delay.h>
+#include <linux/clk.h>
 
 #define RTL821x_PHYSR				0x11
 #define RTL821x_PHYSR_DUPLEX			BIT(13)
@@ -80,6 +81,7 @@ struct rtl821x_priv {
 	u16 phycr1;
 	u16 phycr2;
 	bool has_phycr2;
+	struct clk *clk;
 };
 
 static int rtl821x_read_page(struct phy_device *phydev)
@@ -103,6 +105,11 @@ static int rtl821x_probe(struct phy_device *phydev)
 	if (!priv)
 		return -ENOMEM;
 
+	priv->clk = devm_clk_get_optional_enabled(dev, NULL);
+	if (IS_ERR(priv->clk))
+		return dev_err_probe(dev, PTR_ERR(priv->clk),
+				     "failed to get phy clock\n");
+
 	ret = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR1);
 	if (ret < 0)
 		return ret;
-- 
2.39.3

[PATCH v3 2/3] dt-bindings: net: phy: Document support for external PHY clk

[Detlev Casanova]

Ethern PHYs can have external an clock that needs to be activated before
communicating with the PHY.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 Documentation/devicetree/bindings/net/ethernet-phy.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
index 4f574532ee13..c1241c8a3b77 100644
--- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
@@ -93,6 +93,12 @@ properties:
       the turn around line low at end of the control phase of the
       MDIO transaction.
 
+  clocks:
+    maxItems: 1
+    description:
+      External clock connected to the PHY. If not specified it is assumed
+      that the PHY uses a fixed crystal or an internal oscillator.
+
   enet-phy-lane-swap:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
-- 
2.39.3

[PATCH v3 3/3] net: phy: realtek: Disable clock on suspend

[Detlev Casanova]

For PHYs that call rtl821x_probe() where an external clock can be
configured, make sure that the clock is disabled
when ->suspend() is called and enabled on resume.

The PHY_ALWAYS_CALL_SUSPEND is added to ensure that the suspend function
is actually always called.

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
 drivers/net/phy/realtek.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index b13dd0b3c99e..62eac4835def 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -426,10 +426,28 @@ static int rtl8211f_config_init(struct phy_device *phydev)
 	return genphy_soft_reset(phydev);
 }
 
+static int rtl821x_suspend(struct phy_device *phydev)
+{
+	struct rtl821x_priv *priv = phydev->priv;
+	int ret = genphy_suspend(phydev);
+
+	if (ret)
+		return ret;
+
+	if (!phydev->wol_enabled)
+		clk_disable_unprepare(priv->clk);
+
+	return ret;
+}
+
 static int rtl821x_resume(struct phy_device *phydev)
 {
+	struct rtl821x_priv *priv = phydev->priv;
 	int ret;
 
+	if (!phydev->wol_enabled)
+		clk_prepare_enable(priv->clk);
+
 	ret = genphy_resume(phydev);
 	if (ret < 0)
 		return ret;
@@ -934,10 +952,11 @@ static struct phy_driver realtek_drvs[] = {
 		.read_status	= rtlgen_read_status,
 		.config_intr	= &rtl8211f_config_intr,
 		.handle_interrupt = rtl8211f_handle_interrupt,
-		.suspend	= genphy_suspend,
+		.suspend	= rtl821x_suspend,
 		.resume		= rtl821x_resume,
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
+		.flags		= PHY_ALWAYS_CALL_SUSPEND,
 	}, {
 		PHY_ID_MATCH_EXACT(RTL_8211FVD_PHYID),
 		.name		= "RTL8211F-VD Gigabit Ethernet",
@@ -946,10 +965,11 @@ static struct phy_driver realtek_drvs[] = {
 		.read_status	= rtlgen_read_status,
 		.config_intr	= &rtl8211f_config_intr,
 		.handle_interrupt = rtl8211f_handle_interrupt,
-		.suspend	= genphy_suspend,
+		.suspend	= rtl821x_suspend,
 		.resume		= rtl821x_resume,
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
+		.flags		= PHY_ALWAYS_CALL_SUSPEND,
 	}, {
 		.name		= "Generic FE-GE Realtek PHY",
 		.match_phy_device = rtlgen_match_phy_device,
-- 
2.39.3

Re: [PATCH v3 3/3] net: phy: realtek: Disable clock on suspend

[Florian Fainelli]

On 6/5/23 08:19, Detlev Casanova wrote:
> For PHYs that call rtl821x_probe() where an external clock can be
> configured, make sure that the clock is disabled
> when ->suspend() is called and enabled on resume.
> 
> The PHY_ALWAYS_CALL_SUSPEND is added to ensure that the suspend function
> is actually always called.
> 
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>   drivers/net/phy/realtek.c | 24 ++++++++++++++++++++++--
>   1 file changed, 22 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index b13dd0b3c99e..62eac4835def 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -426,10 +426,28 @@ static int rtl8211f_config_init(struct phy_device *phydev)
>   	return genphy_soft_reset(phydev);
>   }
>   
> +static int rtl821x_suspend(struct phy_device *phydev)
> +{
> +	struct rtl821x_priv *priv = phydev->priv;
> +	int ret = genphy_suspend(phydev);

Sorry I missed that part, if Wake-on-LAN is enabled you cannot suspend 
the PHY as this will typically prevent it from passing received frames 
up the MAC where Wake-on-LAN can be done. You need to move 
genphy_suspend() into the !phydev->wol_enabled clause.
-- 
Florian

Re: net: phy: realtek: Support external PHY clock

[Jakub Kicinski]

On Mon,  5 Jun 2023 11:19:50 -0400 Detlev Casanova wrote:
> Some PHYs can use an external clock that must be enabled before
> communicating with them.

Please add a [PATCH v4 0/0] prefix to the subject of the cover letter
(or use --cover-letter with git format-patch to generate the template).
Otherwise patchwork doesn't realize this is a cover letter.

Re: net: phy: realtek: Support external PHY clock

[Jakub Kicinski]

On Mon, 5 Jun 2023 14:45:01 -0700 Jakub Kicinski wrote:
> On Mon,  5 Jun 2023 11:19:50 -0400 Detlev Casanova wrote:
> > Some PHYs can use an external clock that must be enabled before
> > communicating with them.  
> 
> Please add a [PATCH v4 0/0] prefix to the subject of the cover letter
> (or use --cover-letter with git format-patch to generate the template).
> Otherwise patchwork doesn't realize this is a cover letter.

And so it didn't realize you already sent a v4...
FWIW we ask people not to repost within 24h, confuses reviewers.

net: phy: realtek: Support external PHY clock

[Detlev Casanova]

Hi, thank you for your comments ! HEre are the changes that were
discussed.

Some PHYs can use an external clock that must be enabled before probing
it.

Changes since v1:
 * Remove the clock name as it is not guaranteed to be identical across
   different PHYs
 * Disable/Enable the clock when suspending/resuming