From: Josep Orga <jorga@somdevices.com>
Date: Sat, 18 Apr 2020 11:33:39 +0000 (+0200)
Subject: net: ethernet: fec_main: Add "phy-reset-in-suspend" device tree option. When this... 
X-Git-Tag: rel_imx_4.19.35_1.1.0-somdevices.0~32
X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=06f023d1295f74bf55e2473e9881cd191666b4de;p=linux.git

net: ethernet: fec_main: Add "phy-reset-in-suspend" device tree option. When this option is
present, the driver will assert the phy reset line during suspend.
There are two main reasons to set this configuration:
- Avoid that the phy reset line "powers" the phy when the phy power
  is turned off.
- Ensure that the phy is reset when waking up from suspend, what
  helps to ensure proper operation when the phy power is turned off.

Based on: https://github.com/digi-embedded/linux/commit/f0ddbc0153b269bfd21b84dbd4ad16acdfd21f29

Signed-off-by: Josep Orga <jorga@somdevices.com>
---

diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt
index 87f570dd98c1..051a22358a29 100644
--- a/Documentation/devicetree/bindings/net/fsl-fec.txt
+++ b/Documentation/devicetree/bindings/net/fsl-fec.txt
@@ -22,6 +22,8 @@ Optional properties:
 - phy-reset-active-high : If present then the reset sequence using the GPIO
   specified in the "phy-reset-gpios" property is reversed (H=reset state,
   L=operation state).
+- phy-reset-in-suspend : keeps the phy in reset during suspend mode to
+  avoid back-drives through the reset line.
 - phy-reset-post-delay : Post reset delay in milliseconds. If present then
   a delay of phy-reset-post-delay milliseconds will be observed after the
   phy-reset-gpios has been toggled. Can be omitted thus no delay is
diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 0052fbb42740..b5ec76c2ca3f 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -590,6 +590,9 @@ struct fec_enet_private {
 	int	wake_irq;
 	u32	quirks;
 	u32	fixups;
+	int	phy_reset_gpio;
+	bool	active_high;
+	bool	phy_reset_in_suspend;
 
 	struct	napi_struct napi;
 	int	csum_flags;
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 8bce5a045245..1de1801dfab5 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3519,10 +3519,11 @@ static void fec_reset_phy_init(void)
 
 static int fec_reset_phy(struct platform_device *pdev)
 {
-	int err, phy_reset;
-	bool active_high = false;
+	int err;
 	int msec = 1, phy_post_delay = 0;
 	struct device_node *np = pdev->dev.of_node;
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct fec_enet_private *fep = netdev_priv(ndev);
 
 	if (!np)
 		return 0;
@@ -3532,33 +3533,38 @@ static int fec_reset_phy(struct platform_device *pdev)
 	if (!err && msec > 1000)
 		msec = 1;
 
-	phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
-	if (phy_reset == -EPROBE_DEFER)
-		return phy_reset;
-	else if (!gpio_is_valid(phy_reset))
+	fep->phy_reset_gpio = of_get_named_gpio(np, "phy-reset-gpios", 0);
+	if (fep->phy_reset_gpio == -EPROBE_DEFER)
+		return fep->phy_reset_gpio;
+	else if (!gpio_is_valid(fep->phy_reset_gpio)) {
+		fep->phy_reset_gpio = -1;
 		return 0;
+	}
 
 	err = of_property_read_u32(np, "phy-reset-post-delay", &phy_post_delay);
 	/* valid reset duration should be less than 1s */
 	if (!err && phy_post_delay > 1000)
 		return -EINVAL;
 
-	active_high = of_property_read_bool(np, "phy-reset-active-high");
+	fep->active_high = of_property_read_bool(np, "phy-reset-active-high");
 
-	err = devm_gpio_request_one(&pdev->dev, phy_reset,
-			active_high ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
+	err = devm_gpio_request_one(&pdev->dev, fep->phy_reset_gpio,
+			fep->active_high ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
 			"phy-reset");
 	if (err) {
 		dev_err(&pdev->dev, "failed to get phy-reset-gpios: %d\n", err);
 		return err;
 	}
 
+	fep->phy_reset_in_suspend = of_property_read_bool(np,
+							  "phy-reset-in-suspend");
+
 	if (msec > 20)
 		msleep(msec);
 	else
 		usleep_range(msec * 1000, msec * 1000 + 1000);
 
-	gpio_set_value_cansleep(phy_reset, !active_high);
+	gpio_set_value_cansleep(fep->phy_reset_gpio, !fep->active_high);
 
 	if (!phy_post_delay)
 		return 0;
@@ -3984,6 +3990,8 @@ static int __maybe_unused fec_suspend(struct device *dev)
 		fec_stop(ndev);
 		if (!(fep->wol_flag & FEC_WOL_FLAG_ENABLE)) {
 			fec_irqs_disable(ndev);
+			if (fep->phy_reset_in_suspend)
+				gpio_set_value_cansleep(fep->phy_reset_gpio, fep->active_high);
 			pinctrl_pm_select_sleep_state(&fep->pdev->dev);
 		} else {
 			disable_irq(fep->wake_irq);
@@ -3996,6 +4004,8 @@ static int __maybe_unused fec_suspend(struct device *dev)
 		if (ret < 0)
 			return ret;
 	} else if (fep->mii_bus_share && !ndev->phydev) {
+		if (fep->phy_reset_in_suspend)
+				gpio_set_value_cansleep(fep->phy_reset_gpio, fep->active_high);
 		pinctrl_pm_select_sleep_state(&fep->pdev->dev);
 	}
 	rtnl_unlock();
@@ -4044,6 +4054,8 @@ static int __maybe_unused fec_resume(struct device *dev)
 			writel(val, fep->hwp + FEC_ECNTRL);
 			fep->wol_flag &= ~FEC_WOL_FLAG_SLEEP_ON;
 		} else {
+			if (fep->phy_reset_in_suspend)
+				gpio_set_value_cansleep(fep->phy_reset_gpio, !fep->active_high);
 			pinctrl_pm_select_default_state(&fep->pdev->dev);
 		}
 		fec_restart(ndev);
@@ -4053,6 +4065,8 @@ static int __maybe_unused fec_resume(struct device *dev)
 		napi_enable(&fep->napi);
 		phy_start(ndev->phydev);
 	} else if (fep->mii_bus_share && !ndev->phydev) {
+		if (fep->phy_reset_in_suspend)
+				gpio_set_value_cansleep(fep->phy_reset_gpio, !fep->active_high);
 		pinctrl_pm_select_default_state(&fep->pdev->dev);
 		/* And then recovery mii bus */
 		ret = fec_restore_mii_bus(ndev);