Hello,I've been debugging the Gigabit Ethernet chip KSZ9021RN.I'm using the I.MX RT1176 platform. I understand that most of the KSZ9021 examples are for the I.MX Linux platform, but initializing this chip basically involves configuring some registers. I've referred to some of the code in U-Boot for initializing the KSZ9021.
My initialization process is as follows:
1.Successfully read the correct chip ID from register 0x02.
2.Software PHY reset: Set bit 15 of register 0x00.
3.Set RGMII RX/TX Data Pad Skew:
(1) Write register 0x0B as 0x8105, write register 0x0C as 0.
(2) Write register 0x0B as 0x8104, write register 0x0C as 0xa0d0.(I am unsure how these skew values should be set and whether they may affect auto-negotiation.)
4.Read register 0x1B (Interrupt Control/Status) to clear interrupts.
5.Set bit 8 (enable link up interrupt) and bit 10 (enable link down interrupt) of register 0x1B to 1.
6.Set bit 14 of register 0x1F to 0 (interrupt pin active low).
7.Set bits 5 to 8 of register 0x04 to 1 (10/100M full/half duplex capable).
8.Set bit 9 (Restart auto-negotiation process) of register 0x00 to 1 and bit 12 (Auto-Negotiation Enable) to 1.
After initializing these registers, I am waiting for bit 2 (Link Status) in register 0x01 to become 'link up.' I have connected an Ethernet cable to the computer on the hardware side, but the value of this register always remains at 0x7949, and the LEDs on both sides of the RJ45 connector do not light up.
If I turn off Auto-negotiate and use the default 10Mbps speed, I can establish a normal link-up. However, when I manually set the speed to 100Mbps or 1000Mbps, it fails.
There is another issue as well: when operating at 10Mbps, If register 0x104 is not properly configured, the computer also cannot ping the board.
I'm not sure how these parameters should be configured.
Additionally, auto-negotiation doesn't work properly. I'm not sure if it's due to the configuration of these registers or if there's an issue in my hardware circuit, such as an inaccurate crystal oscillator.
I would greatly appreciate your response.
