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Message-ID: <f2b54fc5-81a6-45ae-0218-193a993333ab@starfivetech.com>
Date:   Sat, 6 May 2023 15:13:51 +0800
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Subject: Re: [PATCH v2 2/2] net: phy: motorcomm: Add pad drive strength cfg
 support
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To:     Andrew Lunn <andrew@lunn.ch>
CC:     <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <netdev@vger.kernel.org>, Peter Geis <pgwipeout@gmail.com>,
        Frank <Frank.Sae@motor-comm.com>,
        "David S . Miller" <davem@davemloft.net>,
        "Eric Dumazet" <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Yanhong Wang <yanhong.wang@starfivetech.com>
References: <20230505090558.2355-1-samin.guo@starfivetech.com>
 <20230505090558.2355-3-samin.guo@starfivetech.com>
 <fc516e65-cde2-4a65-a3c5-bd8c939e7eb1@lunn.ch>
From:   Guo Samin <samin.guo@starfivetech.com>
In-Reply-To: <fc516e65-cde2-4a65-a3c5-bd8c939e7eb1@lunn.ch>
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Re: [PATCH v2 2/2] net: phy: motorcomm: Add pad drive strength cfg support
From: Andrew Lunn <andrew@lunn.ch>
to: Samin Guo <samin.guo@starfivetech.com>
data: 2023/5/5

>>  #define YTPHY_DTS_OUTPUT_CLK_DIS		0
>> @@ -1495,6 +1504,7 @@ static int yt8531_config_init(struct phy_device *phydev)
>>  {
>>  	struct device_node *node = phydev->mdio.dev.of_node;
>>  	int ret;
>> +	u32 ds, val;
> 
> Reverse Christmas tree.  Sort these longest first, shortest last.
> 
Thanks, will fix.
> Otherwise this looks O.K.
> 
> The only open question is if real unit should be used, uA, not some
> magic numbers. Lets see what the DT Maintainers say.
> 
>       Andrew

Hi Andrew,

As I communicated with Frank, Motorcomm doesn't give specific units on their datasheet, except for magic numbers.
Tried to ask Motorcomm last week, but it seems that they themselves do not know what the unit is and have no response so far.


Below is all the relevant information I found：

Pad Drive Strength Cfg (EXT_0xA010)

Bit   |  Symbol           |  Access |  Default |  Description
15:13 |  Rgmii_sw_dr_rx   |  RW     |  0x3     |  Drive strenght of rx_clk pad.
                                               |  3'b111: strongest; 3'b000: weakest.

12    |  Rgmii_sw_dr[2]   |  RW     |  0x0     |  Bit 2 of Rgmii_sw_dr[2:0], refer to ext A010[5:4]

5:4   |  Rgmii_sw_dr[1:0] |  RW     |  0x3     |  Bit 1 and 0 of Rgmii_sw_dr, Drive strenght of rxd/rx_ctl rgmii pad.
                                               |  3'b111: strongest; 3'b000: weakest


Best regards,
Samin