Messages in this thread Patch in this message | | | Date | Fri, 3 Feb 2023 23:48:44 +0200 | From | Vladimir Oltean <> | Subject | Re: [PATCH 2/9] net: ethernet: mtk_eth_soc: set MDIO bus clock frequency |
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On Fri, Feb 03, 2023 at 07:01:01AM +0000, Daniel Golle wrote: > Set MDIO bus clock frequency and allow setting a custom maximum > frequency from device tree. > > Signed-off-by: Daniel Golle <daniel@makrotopia.org> > --- > drivers/net/ethernet/mediatek/mtk_eth_soc.c | 25 +++++++++++++++++++++ > drivers/net/ethernet/mediatek/mtk_eth_soc.h | 5 +++++ > 2 files changed, 30 insertions(+) > > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > index a44ffff48c7b..9050423821dc 100644 > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c > @@ -790,7 +790,9 @@ static const struct phylink_mac_ops mtk_phylink_ops = { > static int mtk_mdio_init(struct mtk_eth *eth) > { > struct device_node *mii_np; > + int clk = 25000000, max_clk = 2500000, divider = 1;
Would be good if constant values (clk) weren't put in variables.
> int ret; > + u32 val; > > mii_np = of_get_child_by_name(eth->dev->of_node, "mdio-bus"); > if (!mii_np) { > @@ -818,6 +820,29 @@ static int mtk_mdio_init(struct mtk_eth *eth) > eth->mii_bus->parent = eth->dev; > > snprintf(eth->mii_bus->id, MII_BUS_ID_SIZE, "%pOFn", mii_np); > + > + if (!of_property_read_u32(mii_np, "clock-frequency", &val)) > + max_clk = val;
Checking for valid range? There should also probably be a dt-bindings patch for this.
> + > + while (clk / divider > max_clk) { > + if (divider >= 63) > + break; > + > + divider++; > + };
uhm, "divider = min(DIV_ROUND_UP(25000000, max_clk), 63);"? I don't think the compiler is smart enough to optimize away this loop.
> + > + val = mtk_r32(eth, MTK_PPSC); > + val |= PPSC_MDC_TURBO; > + mtk_w32(eth, val, MTK_PPSC);
What does "TURBO" do and why do you set it unconditionally?
> + > + /* Configure MDC Divider */ > + val = mtk_r32(eth, MTK_PPSC); > + val &= ~PPSC_MDC_CFG; > + val |= FIELD_PREP(PPSC_MDC_CFG, divider); > + mtk_w32(eth, val, MTK_PPSC); > + > + dev_dbg(eth->dev, "MDC is running on %d Hz\n", clk / divider); > + > ret = of_mdiobus_register(eth->mii_bus, mii_np); > err_put_node: > diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > index 7230dcb29315..724815ae18a0 100644 > --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h > +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h > @@ -363,6 +363,11 @@ > #define RX_DMA_VTAG_V2 BIT(0) > #define RX_DMA_L4_VALID_V2 BIT(2) > > +/* PHY Polling and SMI Master Control registers */ > +#define MTK_PPSC 0x10000 > +#define PPSC_MDC_CFG GENMASK(29, 24) > +#define PPSC_MDC_TURBO BIT(20) > + > /* PHY Indirect Access Control registers */ > #define MTK_PHY_IAC 0x10004 > #define PHY_IAC_ACCESS BIT(31) > -- > 2.39.1 >
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