netdev - Re: [PATCH v4 1/5] net: mdio: ipq4019: move eth_ldo

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Date: Sat, 30 Dec 2023 11:15:08 +0800
From: Jie Luo <quic_luoj@...cinc.com>
To: Konrad Dybcio <konrad.dybcio@...aro.org>, <agross@...nel.org>,
        <andersson@...nel.org>, <davem@...emloft.net>, <edumazet@...gle.com>,
        <kuba@...nel.org>, <pabeni@...hat.com>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <andrew@...n.ch>, <hkallweit1@...il.com>, <linux@...linux.org.uk>,
        <robert.marko@...tura.hr>
CC: <linux-arm-msm@...r.kernel.org>, <netdev@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <quic_srichara@...cinc.com>
Subject: Re: [PATCH v4 1/5] net: mdio: ipq4019: move eth_ldo_rdy before MDIO
 bus register



On 12/28/2023 5:49 PM, Konrad Dybcio wrote:
> On 25.12.2023 09:44, Luo Jie wrote:
>> The ethernet LDO provides the clock for the ethernet PHY that
>> is connected with PCS, each LDO enables the clock output to
>> each PCS, after the clock output enablement, the PHY GPIO reset
>> can take effect.
>>
>> For the PHY taking the MDIO bus level GPIO reset, the ethernet
>> LDO should be enabled before the MDIO bus register.
>>
>> For example, the qca8084 PHY takes the MDIO bus level GPIO
>> reset for quad PHYs, there is another reason for qca8084 PHY
>> using MDIO bus level GPIO reset instead of PHY level GPIO
>> reset as below.
>>
>> The work sequence of qca8084:
>> 1. enable ethernet LDO.
>> 2. GPIO reset on quad PHYs.
>> 3. register clock provider based on MDIO device of qca8084.
>> 4. PHY probe function called for initializing common clocks.
>> 5. PHY capabilities acquirement.
>>
>> If qca8084 takes PHY level GPIO reset in the step 4, the clock
>> provider of qca8084 can't be registered correctly, since the
>> clock parent(reading the current qca8084 hardware registers in
>> step 3) of the registered clocks is deserted after GPIO reset.
>>
>> There are two PCS(UNIPHY) supported in SOC side on ipq5332,
>> and three PCS(UNIPHY) supported on ipq9574.
>>
>> Signed-off-by: Luo Jie <quic_luoj@...cinc.com>
>> ---
>>   drivers/net/mdio/mdio-ipq4019.c | 51 +++++++++++++++++++++------------
>>   1 file changed, 32 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/net/mdio/mdio-ipq4019.c b/drivers/net/mdio/mdio-ipq4019.c
>> index abd8b508ec16..5273864fabb3 100644
>> --- a/drivers/net/mdio/mdio-ipq4019.c
>> +++ b/drivers/net/mdio/mdio-ipq4019.c
>> @@ -37,9 +37,12 @@
>>   
>>   #define IPQ_PHY_SET_DELAY_US	100000
>>   
>> +/* Maximum SOC PCS(uniphy) number on IPQ platform */
>> +#define ETH_LDO_RDY_CNT				3
>> +
>>   struct ipq4019_mdio_data {
>> -	void __iomem	*membase;
>> -	void __iomem *eth_ldo_rdy;
>> +	void __iomem *membase;
>> +	void __iomem *eth_ldo_rdy[ETH_LDO_RDY_CNT];
>>   	struct clk *mdio_clk;
>>   };
>>   
>> @@ -206,19 +209,8 @@ static int ipq4019_mdio_write_c22(struct mii_bus *bus, int mii_id, int regnum,
>>   static int ipq_mdio_reset(struct mii_bus *bus)
>>   {
>>   	struct ipq4019_mdio_data *priv = bus->priv;
>> -	u32 val;
>>   	int ret;
>>   
>> -	/* To indicate CMN_PLL that ethernet_ldo has been ready if platform resource 1
>> -	 * is specified in the device tree.
>> -	 */
>> -	if (priv->eth_ldo_rdy) {
>> -		val = readl(priv->eth_ldo_rdy);
>> -		val |= BIT(0);
>> -		writel(val, priv->eth_ldo_rdy);
>> -		fsleep(IPQ_PHY_SET_DELAY_US);
>> -	}
>> -
>>   	/* Configure MDIO clock source frequency if clock is specified in the device tree */
>>   	ret = clk_set_rate(priv->mdio_clk, IPQ_MDIO_CLK_RATE);
>>   	if (ret)
>> @@ -236,7 +228,7 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
>>   	struct ipq4019_mdio_data *priv;
>>   	struct mii_bus *bus;
>>   	struct resource *res;
>> -	int ret;
>> +	int ret, index;
>>   
>>   	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*priv));
>>   	if (!bus)
>> @@ -252,11 +244,32 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
>>   	if (IS_ERR(priv->mdio_clk))
>>   		return PTR_ERR(priv->mdio_clk);
>>   
>> -	/* The platform resource is provided on the chipset IPQ5018 */
>> -	/* This resource is optional */
>> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>> -	if (res)
>> -		priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);
>> +	/* These platform resources are provided on the chipset IPQ5018 or
>> +	 * IPQ5332.
>> +	 */
>> +	/* This resource are optional */
>> +	for (index = 0; index < ETH_LDO_RDY_CNT; index++) {
>> +		res = platform_get_resource(pdev, IORESOURCE_MEM, index + 1);
>> +		if (res) {
> if (!res)
> 	break

will update this.

> 
>> +			priv->eth_ldo_rdy[index] = devm_ioremap(&pdev->dev,
>> +								res->start,
>> +								resource_size(res));
>> +
>> +			/* The ethernet LDO enable is necessary to reset PHY
>> +			 * by GPIO, some PHY(such as qca8084) GPIO reset uses
>> +			 * the MDIO level reset, so this function should be
>> +			 * called before the MDIO bus register.
>> +			 */
>> +			if (priv->eth_ldo_rdy[index]) {
>> +				u32 val;
>> +
>> +				val = readl(priv->eth_ldo_rdy[index]);
>> +				val |= BIT(0);
>> +				writel(val, priv->eth_ldo_rdy[index]);
>> +				fsleep(IPQ_PHY_SET_DELAY_US);
> fsleep should only be used when the argument is variable
> 
> Konrad

Ok, will update to use usleep_range, Thanks.