[PATCH net-next v5 0/3] net: dsa: realtek: support reset controller and update docs

[PATCH net-next v5 0/3] net: dsa: realtek: support reset controller and update docs

[Luiz Angelo Daros de Luca]

The driver previously supported reset pins using GPIO, but it lacked
support for reset controllers. Although a reset method is generally not
required, the driver fails to detect the switch if the reset was kept
asserted by a previous driver.

This series adds support to reset a Realtek switch using a reset
controller. It also updates the binding documentation to remove the
requirement of a reset method and to add the new reset controller
property.

It was tested on a TL-WR1043ND v1 router (rtl8366rb via SMI).

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
---
Changes in v5:
- Fixed error checking logic when reset controller (de)assert fails
- Link to v4: https://lore.kernel.org/r/20240219-realtek-reset-v4-0-858b82a29503@gmail.com

Changes in v4:
- do not test for priv->reset,priv->reset_ctl
- updated commit message
- Link to v3: https://lore.kernel.org/r/20240213-realtek-reset-v3-0-37837e574713@gmail.com

Changes in v3:
- Rebased on the Realtek DSA driver refactoring (08f627164126)
- Dropped the reset controller example in bindings
- Used %pe in error printing
- Linked to v2: https://lore.kernel.org/r/20231027190910.27044-1-luizluca@gmail.com/

Changes in v2:
- Introduced a dedicated commit for removing the reset-gpios requirement
- Placed binding patches before code changes
- Removed the 'reset-names' property
- Moved the example from the commit message to realtek.yaml
- Split the reset function into _assert/_deassert variants
- Modified reset functions to return a warning instead of a value
- Utilized devm_reset_control_get_optional to prevent failure when the
  reset control is missing
- Used 'true' and 'false' for boolean values
- Removed the CONFIG_RESET_CONTROLLER check as stub methods are
  sufficient when undefined
- Linked to v1: https://lore.kernel.org/r/20231024205805.19314-1-luizluca@gmail.com/

---
Luiz Angelo Daros de Luca (3):
      dt-bindings: net: dsa: realtek: reset-gpios is not required
      dt-bindings: net: dsa: realtek: add reset controller
      net: dsa: realtek: support reset controller

 .../devicetree/bindings/net/dsa/realtek.yaml       |  4 ++-
 drivers/net/dsa/realtek/realtek.h                  |  2 ++
 drivers/net/dsa/realtek/rtl83xx.c                  | 42 +++++++++++++++++++---
 drivers/net/dsa/realtek/rtl83xx.h                  |  2 ++
 4 files changed, 44 insertions(+), 6 deletions(-)
---
base-commit: d1d77120bc2867b3e449e07ee656a26b2fb03d1e
change-id: 20240212-realtek-reset-88a0bf25bb22

Best regards,
-- 
Luiz Angelo Daros de Luca <luizluca@gmail.com>

[PATCH net-next v5 1/3] dt-bindings: net: dsa: realtek: reset-gpios is not required

[Luiz Angelo Daros de Luca]

The 'reset-gpios' should not be mandatory. although they might be
required for some devices if the switch reset was left asserted by a
previous driver, such as the bootloader.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Cc: devicetree@vger.kernel.org
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
---
 Documentation/devicetree/bindings/net/dsa/realtek.yaml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/realtek.yaml b/Documentation/devicetree/bindings/net/dsa/realtek.yaml
index cce692f57b08..46e113df77c8 100644
--- a/Documentation/devicetree/bindings/net/dsa/realtek.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/realtek.yaml
@@ -127,7 +127,6 @@ else:
     - mdc-gpios
     - mdio-gpios
     - mdio
-    - reset-gpios
 
 required:
   - compatible

-- 
2.43.0

[PATCH net-next v5 2/3] dt-bindings: net: dsa: realtek: add reset controller

[Luiz Angelo Daros de Luca]

Realtek switches can use a reset controller instead of reset-gpios.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Cc: devicetree@vger.kernel.org
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/net/dsa/realtek.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/dsa/realtek.yaml b/Documentation/devicetree/bindings/net/dsa/realtek.yaml
index 46e113df77c8..70b6bda3cf98 100644
--- a/Documentation/devicetree/bindings/net/dsa/realtek.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/realtek.yaml
@@ -59,6 +59,9 @@ properties:
     description: GPIO to be used to reset the whole device
     maxItems: 1
 
+  resets:
+    maxItems: 1
+
   realtek,disable-leds:
     type: boolean
     description: |

-- 
2.43.0

[PATCH net-next v5 3/3] net: dsa: realtek: support reset controller

[Luiz Angelo Daros de Luca]

Add support for resetting the device using a reset controller,
complementing the existing GPIO reset functionality (reset-gpios).

Although the reset is optional and the driver performs a soft reset
during setup, if the initial reset pin state was asserted, the driver
will not detect the device until the reset is deasserted.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/dsa/realtek/realtek.h |  2 ++
 drivers/net/dsa/realtek/rtl83xx.c | 42 ++++++++++++++++++++++++++++++++++-----
 drivers/net/dsa/realtek/rtl83xx.h |  2 ++
 3 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/realtek/realtek.h b/drivers/net/dsa/realtek/realtek.h
index b80bfde1ad04..e0b1aa01337b 100644
--- a/drivers/net/dsa/realtek/realtek.h
+++ b/drivers/net/dsa/realtek/realtek.h
@@ -12,6 +12,7 @@
 #include <linux/platform_device.h>
 #include <linux/gpio/consumer.h>
 #include <net/dsa.h>
+#include <linux/reset.h>
 
 #define REALTEK_HW_STOP_DELAY		25	/* msecs */
 #define REALTEK_HW_START_DELAY		100	/* msecs */
@@ -48,6 +49,7 @@ struct rtl8366_vlan_4k {
 
 struct realtek_priv {
 	struct device		*dev;
+	struct reset_control    *reset_ctl;
 	struct gpio_desc	*reset;
 	struct gpio_desc	*mdc;
 	struct gpio_desc	*mdio;
diff --git a/drivers/net/dsa/realtek/rtl83xx.c b/drivers/net/dsa/realtek/rtl83xx.c
index 801873754df2..d2e876805393 100644
--- a/drivers/net/dsa/realtek/rtl83xx.c
+++ b/drivers/net/dsa/realtek/rtl83xx.c
@@ -184,6 +184,13 @@ rtl83xx_probe(struct device *dev,
 						    "realtek,disable-leds");
 
 	/* TODO: if power is software controlled, set up any regulators here */
+	priv->reset_ctl = devm_reset_control_get_optional(dev, NULL);
+	if (IS_ERR(priv->reset_ctl)) {
+		ret = PTR_ERR(priv->reset_ctl);
+		dev_err_probe(dev, ret, "failed to get reset control\n");
+		return ERR_CAST(priv->reset_ctl);
+	}
+
 	priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(priv->reset)) {
 		dev_err(dev, "failed to get RESET GPIO\n");
@@ -192,11 +199,11 @@ rtl83xx_probe(struct device *dev,
 
 	dev_set_drvdata(dev, priv);
 
-	if (priv->reset) {
-		gpiod_set_value(priv->reset, 1);
+	if (priv->reset_ctl || priv->reset) {
+		rtl83xx_reset_assert(priv);
 		dev_dbg(dev, "asserted RESET\n");
 		msleep(REALTEK_HW_STOP_DELAY);
-		gpiod_set_value(priv->reset, 0);
+		rtl83xx_reset_deassert(priv);
 		msleep(REALTEK_HW_START_DELAY);
 		dev_dbg(dev, "deasserted RESET\n");
 	}
@@ -292,11 +299,36 @@ EXPORT_SYMBOL_NS_GPL(rtl83xx_shutdown, REALTEK_DSA);
 void rtl83xx_remove(struct realtek_priv *priv)
 {
 	/* leave the device reset asserted */
-	if (priv->reset)
-		gpiod_set_value(priv->reset, 1);
+	rtl83xx_reset_assert(priv);
 }
 EXPORT_SYMBOL_NS_GPL(rtl83xx_remove, REALTEK_DSA);
 
+void rtl83xx_reset_assert(struct realtek_priv *priv)
+{
+	int ret;
+
+	ret = reset_control_assert(priv->reset_ctl);
+	if (ret)
+		dev_warn(priv->dev,
+			 "Failed to assert the switch reset control: %pe\n",
+			 ERR_PTR(ret));
+
+	gpiod_set_value(priv->reset, true);
+}
+
+void rtl83xx_reset_deassert(struct realtek_priv *priv)
+{
+	int ret;
+
+	ret = reset_control_deassert(priv->reset_ctl);
+	if (ret)
+		dev_warn(priv->dev,
+			 "Failed to deassert the switch reset control: %pe\n",
+			 ERR_PTR(ret));
+
+	gpiod_set_value(priv->reset, false);
+}
+
 MODULE_AUTHOR("Luiz Angelo Daros de Luca <luizluca@gmail.com>");
 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 MODULE_DESCRIPTION("Realtek DSA switches common module");
diff --git a/drivers/net/dsa/realtek/rtl83xx.h b/drivers/net/dsa/realtek/rtl83xx.h
index 0ddff33df6b0..c8a0ff8fd75e 100644
--- a/drivers/net/dsa/realtek/rtl83xx.h
+++ b/drivers/net/dsa/realtek/rtl83xx.h
@@ -18,5 +18,7 @@ int rtl83xx_register_switch(struct realtek_priv *priv);
 void rtl83xx_unregister_switch(struct realtek_priv *priv);
 void rtl83xx_shutdown(struct realtek_priv *priv);
 void rtl83xx_remove(struct realtek_priv *priv);
+void rtl83xx_reset_assert(struct realtek_priv *priv);
+void rtl83xx_reset_deassert(struct realtek_priv *priv);
 
 #endif /* _RTL83XX_H */

-- 
2.43.0

Re: [PATCH net-next v5 3/3] net: dsa: realtek: support reset controller

[Alvin Šipraga]

On Sun, Feb 25, 2024 at 01:29:55PM -0300, Luiz Angelo Daros de Luca wrote:
> Add support for resetting the device using a reset controller,
> complementing the existing GPIO reset functionality (reset-gpios).
> 
> Although the reset is optional and the driver performs a soft reset
> during setup, if the initial reset pin state was asserted, the driver
> will not detect the device until the reset is deasserted.
> 
> Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> ---

Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>

>  drivers/net/dsa/realtek/realtek.h |  2 ++
>  drivers/net/dsa/realtek/rtl83xx.c | 42 ++++++++++++++++++++++++++++++++++-----
>  drivers/net/dsa/realtek/rtl83xx.h |  2 ++
>  3 files changed, 41 insertions(+), 5 deletions(-)

Re: [PATCH net-next v5 0/3] net: dsa: realtek: support reset controller and update docs

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Sun, 25 Feb 2024 13:29:52 -0300 you wrote:
> The driver previously supported reset pins using GPIO, but it lacked
> support for reset controllers. Although a reset method is generally not
> required, the driver fails to detect the switch if the reset was kept
> asserted by a previous driver.
> 
> This series adds support to reset a Realtek switch using a reset
> controller. It also updates the binding documentation to remove the
> requirement of a reset method and to add the new reset controller
> property.
> 
> [...]

Here is the summary with links:
  - [net-next,v5,1/3] dt-bindings: net: dsa: realtek: reset-gpios is not required
    https://git.kernel.org/netdev/net-next/c/28001bb1955f
  - [net-next,v5,2/3] dt-bindings: net: dsa: realtek: add reset controller
    https://git.kernel.org/netdev/net-next/c/5fc2d68fc818
  - [net-next,v5,3/3] net: dsa: realtek: support reset controller
    https://git.kernel.org/netdev/net-next/c/56998aa6b7f0

You are awesome, thank you!
-- 
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