linux-kernel - RE: [PATCH] net: fec: add post PHY reset delay DT property

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Message-ID: <VI1PR0401MB2271F7EB07C80F470D783B30FFF90@VI1PR0401MB2271.eurprd04.prod.outlook.com>
Date:   Tue, 23 May 2017 02:04:43 +0000
From:   Andy Duan <fugang.duan@....com>
To:     Quentin Schulz <quentin.schulz@...e-electrons.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "thomas.petazzoni@...e-electrons.com" 
        <thomas.petazzoni@...e-electrons.com>
Subject: RE: [PATCH] net: fec: add post PHY reset delay DT property

From: Quentin Schulz <quentin.schulz@...e-electrons.com> Sent: Monday, May 22, 2017 5:15 PM
>Some PHY require to wait for a bit after the reset GPIO has been toggled. This
>adds support for the DT property `phy-reset-post-delay` which gives the delay
>in milliseconds to wait after reset.
>
>If the DT property is not given, no delay is observed. Post reset delay greater
>than 1000ms are invalid and are default to 1ms.
>
>Signed-off-by: Quentin Schulz <quentin.schulz@...e-electrons.com>
>---
> Documentation/devicetree/bindings/net/fsl-fec.txt |  5 +++++
> drivers/net/ethernet/freescale/fec_main.c         | 17 +++++++++++++++--
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
>diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt
>b/Documentation/devicetree/bindings/net/fsl-fec.txt
>index a1e3693cca16..8795e8ca5793 100644
>--- a/Documentation/devicetree/bindings/net/fsl-fec.txt
>+++ b/Documentation/devicetree/bindings/net/fsl-fec.txt
>@@ -15,6 +15,11 @@ 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-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
>+  observed. Delay is in range of 1ms to 1000ms. If given delay is
>+higher
>+  than 1000ms, 1ms delay is done instead.
> - phy-supply : regulator that powers the Ethernet PHY.
> - phy-handle : phandle to the PHY device connected to this device.
> - fixed-link : Assume a fixed link. See fixed-link.txt in the same directory.
>diff --git a/drivers/net/ethernet/freescale/fec_main.c
>b/drivers/net/ethernet/freescale/fec_main.c
>index 56a563f90b0b..00a7fd0bcd59 100644
>--- a/drivers/net/ethernet/freescale/fec_main.c
>+++ b/drivers/net/ethernet/freescale/fec_main.c
>@@ -3192,7 +3192,7 @@ static int fec_reset_phy(struct platform_device
>*pdev)  {
> 	int err, phy_reset;
> 	bool active_high = false;
>-	int msec = 1;
>+	int msec = 1, phy_post_delay = 0;
> 	struct device_node *np = pdev->dev.of_node;
>
> 	if (!np)
>@@ -3210,7 +3210,6 @@ static int fec_reset_phy(struct platform_device
>*pdev)
> 		return 0;
>
> 	active_high = of_property_read_bool(np, "phy-reset-active-high");
>-

No necessary change here.

> 	err = devm_gpio_request_one(&pdev->dev, phy_reset,
> 			active_high ? GPIOF_OUT_INIT_HIGH :
>GPIOF_OUT_INIT_LOW,
> 			"phy-reset");
>@@ -3219,6 +3218,11 @@ static int fec_reset_phy(struct platform_device
>*pdev)
> 		return err;
> 	}
>
>+	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)
>+		phy_post_delay = 1;
>+
Put the dt parse before  . devm_gpio_request_one() that seems better.
Others are fine.


> 	if (msec > 20)
> 		msleep(msec);
> 	else
>@@ -3226,6 +3230,15 @@ static int fec_reset_phy(struct platform_device
>*pdev)
>
> 	gpio_set_value_cansleep(phy_reset, !active_high);
>
>+	if (!phy_post_delay)
>+		return 0;
>+
>+	if (phy_post_delay > 20)
>+		msleep(phy_post_delay);
>+	else
>+		usleep_range(phy_post_delay * 1000,
>+			     phy_post_delay * 1000 + 1000);
>+
> 	return 0;
> }
> #else /* CONFIG_OF */
>--
>2.11.0