netdev - [PATCH net-next v3 1/2] net: dsa: realtek: realtek-smi: clean-up reset

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Date:   Sun, 13 Feb 2022 23:20:11 -0300
From:   Luiz Angelo Daros de Luca <luizluca@...il.com>
To:     netdev@...r.kernel.org
Cc:     linus.walleij@...aro.org, andrew@...n.ch, vivien.didelot@...il.com,
        f.fainelli@...il.com, olteanv@...il.com, davem@...emloft.net,
        kuba@...nel.org, alsi@...g-olufsen.dk, arinc.unal@...nc9.com,
        Luiz Angelo Daros de Luca <luizluca@...il.com>
Subject: [PATCH net-next v3 1/2] net: dsa: realtek: realtek-smi: clean-up reset

When reset GPIO was missing, the driver was still printing an info
message and still trying to assert the reset. Although gpiod_set_value()
will silently ignore calls with NULL gpio_desc, it is better to make it
clear the driver might allow gpio_desc to be NULL.

The initial value for the reset pin was changed to GPIOD_OUT_LOW,
followed by a gpiod_set_value() asserting the reset. This way, it will
be easier to spot if and where the reset really happens.

A new "asserted RESET" message was added just after the reset is
asserted, similar to the existing "deasserted RESET" message. Both
messages were demoted to dbg. The code comment is not needed anymore.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@...il.com>
---
 drivers/net/dsa/realtek/realtek-smi.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/net/dsa/realtek/realtek-smi.c b/drivers/net/dsa/realtek/realtek-smi.c
index 946fbbd70153..33cf5a0692de 100644
--- a/drivers/net/dsa/realtek/realtek-smi.c
+++ b/drivers/net/dsa/realtek/realtek-smi.c
@@ -420,16 +420,19 @@ static int realtek_smi_probe(struct platform_device *pdev)
 
 	/* TODO: if power is software controlled, set up any regulators here */
 
-	/* Assert then deassert RESET */
-	priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	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");
 		return PTR_ERR(priv->reset);
 	}
-	msleep(REALTEK_SMI_HW_STOP_DELAY);
-	gpiod_set_value(priv->reset, 0);
-	msleep(REALTEK_SMI_HW_START_DELAY);
-	dev_info(dev, "deasserted RESET\n");
+	if (priv->reset) {
+		gpiod_set_value(priv->reset, 1);
+		dev_dbg(dev, "asserted RESET\n");
+		msleep(REALTEK_SMI_HW_STOP_DELAY);
+		gpiod_set_value(priv->reset, 0);
+		msleep(REALTEK_SMI_HW_START_DELAY);
+		dev_dbg(dev, "deasserted RESET\n");
+	}
 
 	/* Fetch MDIO pins */
 	priv->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);
@@ -474,7 +477,10 @@ static int realtek_smi_remove(struct platform_device *pdev)
 	dsa_unregister_switch(priv->ds);
 	if (priv->slave_mii_bus)
 		of_node_put(priv->slave_mii_bus->dev.of_node);
-	gpiod_set_value(priv->reset, 1);
+
+	/* leave the device reset asserted */
+	if (priv->reset)
+		gpiod_set_value(priv->reset, 1);
 
 	platform_set_drvdata(pdev, NULL);
 
-- 
2.35.1