Messages in this thread | | | From | Wells Lu 呂芳騰 <> | Subject | RE: [PATCH v2 2/2] net: ethernet: Add driver for Sunplus SP7021 | Date | Fri, 26 Nov 2021 19:13:23 +0000 |
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Hi Andrew,
I read specification of ICPlus IP101G (10M/100M PHY). Bits of register 0 (control) and register 1 (status) are R/W or RO type. They will not be cleared after read. No matter how many times they are read, the read-back value is the same.
For example, Value of register 0 (control) is 0x3100 Value of register 1 (status) is 0x786d
The read-back values are always the same unless you unplug the cable.
Besides, we use polling mode (phydev->irq = PHY_POLL) PHY state-machine is triggered by using 1-Hz work- queue, not interrupt.
We didn't find any problem after many tests after using 'force' mode.
Can we go with this approach?
Best regards, Wells
> > Hi Andrew, > > > > > > From data provided by ASIC engineer, MAC of SP7021 only reads the 4 > > registers of PHY: > > 0: Control register > > 1: Status register > > This is the register which has latching of the link status. genphy_update_link() expects > this latching behaviour, and if the hardware reads the register, that behaviour is not > going to happen. > > Andrew
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