Re: [PATCH net-next 01/11] net: stmmac: provide set_clk_tx_rate() hook
From: Andrew Lunn <andrew@lunn.ch>
Date: 2025-02-27 14:02:45
Also in:
linux-arm-kernel
On Thu, Feb 27, 2025 at 09:16:23AM +0000, Russell King (Oracle) wrote:
Several stmmac sub-drivers which support RGMII follow the same pattern. They calculate the transmit clock rate, and then call clk_set_rate(). Analysis of several implementation documents suggests that the platform is responsible for providing the transmit clock to the DWMAC core's clk_tx_i. The expected rates are: 10Mbps 100Mbps 1Gbps MII 2.5MHz 25MHz RMII 2.5MHz 25MHz GMII 125MHz RGMI 2.5MHz 25MHz 125MHz It seems some platforms require this clock to be manually configured, but there are outputs from the MAC core that indicate the speed, so a platform may use these to automatically configure the clock. Thus, we can't just provide one solution to configure this clock rate. Moreover, the clock may need to be derived from one of several sources depending on the interface mode. Provide a platform hook that is passed the transmit clock, interface mode and speed. Reviewed-by: Thierry Reding <redacted> Signed-off-by: Russell King (Oracle) <redacted>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew