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From: luoj@codeaurora.org
To: Andrew Lunn <andrew@lunn.ch>
Cc: hkallweit1@gmail.com, davem@davemloft.net, kuba@kernel.org,
	p.zabel@pengutronix.de, agross@kernel.org,
	bjorn.andersson@linaro.org, robh+dt@kernel.org,
	robert.marko@sartura.hr, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	devicetree@vger.kernel.org, sricharan@codeaurora.org
Subject: Re: [PATCH 1/3] net: mdio-ipq4019: Add mdio reset function
Date: Mon, 02 Aug 2021 14:46:37 +0800	[thread overview]
Message-ID: <5eba90f41162cc19625025776fbdd0a2@codeaurora.org> (raw)
In-Reply-To: <YQKsnqWCfoTpTuxI@lunn.ch>

On 2021-07-29 21:26, Andrew Lunn wrote:
> Hi Luo
> 
> For a patchset, netdev wants to see a patch 0/X which describes the
> big picture. What is the patchset as a whole doing.
> 
> Hi Andrew,
> Thanks for reminder, will provide it in the next patch set.
> 
>> +static int ipq_mdio_reset(struct mii_bus *bus)
>> +{
>> +	struct ipq4019_mdio_data *priv = bus->priv;
>> +	struct device *dev = bus->parent;
>> +	struct gpio_desc *reset_gpio;
>> +	u32 val;
>> +	int i, ret;
>> +
>> +	/* To indicate CMN_PLL that ethernet_ldo has been ready if needed */
>> +	if (!IS_ERR(priv->eth_ldo_rdy)) {
>> +		val = readl(priv->eth_ldo_rdy);
>> +		val |= BIT(0);
>> +		writel(val, priv->eth_ldo_rdy);
>> +		fsleep(QCA_PHY_SET_DELAY_US);
>> +	}
>> +
>> +	/* Reset GEPHY if need */
>> +	if (!IS_ERR(priv->reset_ctrl)) {
>> +		reset_control_assert(priv->reset_ctrl);
>> +		fsleep(QCA_PHY_SET_DELAY_US);
>> +		reset_control_deassert(priv->reset_ctrl);
>> +		fsleep(QCA_PHY_SET_DELAY_US);
>> +	}
> 
> What exactly is being reset here? Which is GEPHY?
> 
> The MDIO bus master driver should not be touching any Ethernet
> PHYs. All it provides is a bus, nothing more.
> 
> The GEPHY is the embedded Giga Ethernet PHY in the chipset IPQ50xx, 
> there is a dedicated MDIO bus for this internal PHY.
> what the reset function does here is for resetting this dedicated MDIO 
> bus and this embedded PHY DSP hardware.
> because this dedicated MDIO bus is only connected with this internal 
> PHY on chip set IPQ50xx, so i put this
> code in the MDIO reset function.
> 
>> +
>> +	/* Configure MDIO clock frequency */
>> +	if (!IS_ERR(priv->mdio_clk)) {
>> +		ret = clk_set_rate(priv->mdio_clk, QCA_MDIO_CLK_RATE);
>> +		if (ret)
>> +			return ret;
>> +
>> +		ret = clk_prepare_enable(priv->mdio_clk);
>> +		if (ret)
>> +			return ret;
>> +	}
> 
>> +
>> +	/* Reset PHYs by gpio pins */
>> +	for (i = 0; i < gpiod_count(dev, "phy-reset"); i++) {
>> +		reset_gpio = gpiod_get_index_optional(dev, "phy-reset", i, 
>> GPIOD_OUT_HIGH);
>> +		if (IS_ERR(reset_gpio))
>> +			continue;
>> +		gpiod_set_value_cansleep(reset_gpio, 0);
>> +		fsleep(QCA_PHY_SET_DELAY_US);
>> +		gpiod_set_value_cansleep(reset_gpio, 1);
>> +		fsleep(QCA_PHY_SET_DELAY_US);
>> +		gpiod_put(reset_gpio);
>> +	}
> 
> No, there is common code in phylib to do that.
> 
> Hi Andrew,
> The common code in phylib for resetting PHY by GPIO pin is high active, 
> which is not suitable for the PHY reset here.
> for resetting the PHY, calling gpiod_set_value_cansleep(reset_gpio, 1), 
> then gpiod_set_value_cansleep(reset_gpio, 0).
> but as for resetting the PHY by GPIO pin in IPQ chipset, this is the 
> opposite process(low active) from the phylib code,
> which needs to set the GPIO output value to 0, then to 1 for reset as 
> the code above.
> 
>>  static int ipq4019_mdio_probe(struct platform_device *pdev)
>>  {
>>  	struct ipq4019_mdio_data *priv;
>>  	struct mii_bus *bus;
>> +	struct resource *res;
>>  	int ret;
>> 
>>  	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*priv));
>> @@ -182,14 +244,23 @@ static int ipq4019_mdio_probe(struct 
>> platform_device *pdev)
>>  		return -ENOMEM;
>> 
>>  	priv = bus->priv;
>> +	priv->eth_ldo_rdy = IOMEM_ERR_PTR(-EINVAL);
>> 
>>  	priv->membase = devm_platform_ioremap_resource(pdev, 0);
>>  	if (IS_ERR(priv->membase))
>>  		return PTR_ERR(priv->membase);
>> 
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>> +	if (res)
>> +		priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);
>> +
>> +	priv->reset_ctrl = devm_reset_control_get_exclusive(&pdev->dev, 
>> "gephy_mdc_rst");
>> +	priv->mdio_clk = devm_clk_get(&pdev->dev, "gcc_mdio_ahb_clk");
> 
> You probably want to use devm_clk_get_optional().
> 
>     Andrew
> 
> thanks for the comment, will update it in the next patch set.

      reply	other threads:[~2021-08-02  6:47 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 12:53 Luo Jie
2021-07-29 12:53 ` [PATCH 2/3] net: mdio-ipq4019: rename mdio_ipq4019 to mdio_ipq Luo Jie
2021-07-29 13:15   ` Andrew Lunn
2021-08-02  5:56     ` luoj
2021-07-29 12:53 ` [PATCH 3/3] dt-bindings: net: rename Qualcomm IPQ MDIO bindings Luo Jie
2021-07-29 13:17   ` Andrew Lunn
2021-08-02  6:02     ` luoj
2021-07-29 13:57   ` Rob Herring
2021-07-29 17:29   ` Rob Herring
2021-08-02  7:19     ` luoj
2021-08-02 13:39       ` Andrew Lunn
2021-08-04  2:37         ` Jie Luo
2021-07-29 13:26 ` [PATCH 1/3] net: mdio-ipq4019: Add mdio reset function Andrew Lunn
2021-08-02  6:46   ` luoj [this message]

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