Am Donnerstag, 7. März 2019, 09:41:53 CET schrieb Christoph Muellner: > The rockchip-emmc PHY can be configured with different > drive impedance values. Currenlty a value of 50 Ohm is > hard coded into the driver. > > This patch introduces the DTS property 'drive-impedance-ohm' > for the rockchip-emmc phy node, which uses the value from the DTS > to setup the drive impedance accordingly. > > Signed-off-by: Christoph Muellner <[email protected]> > Signed-off-by: Philipp Tomsich <[email protected]>
change itself looks good Reviewed-by: Heiko Stuebner <[email protected]> Though I cannot say too much about the electrical side. Heiko > --- > drivers/phy/rockchip/phy-rockchip-emmc.c | 30 ++++++++++++++++++++++++++++-- > 1 file changed, 28 insertions(+), 2 deletions(-) > > diff --git a/drivers/phy/rockchip/phy-rockchip-emmc.c > b/drivers/phy/rockchip/phy-rockchip-emmc.c > index 19bf84f0bc67..b804c6bf4b55 100644 > --- a/drivers/phy/rockchip/phy-rockchip-emmc.c > +++ b/drivers/phy/rockchip/phy-rockchip-emmc.c > @@ -87,6 +87,7 @@ struct rockchip_emmc_phy { > unsigned int reg_offset; > struct regmap *reg_base; > struct clk *emmcclk; > + unsigned int drive_impedance; > }; > > static int rockchip_emmc_phy_power(struct phy *phy, bool on_off) > @@ -281,10 +282,10 @@ static int rockchip_emmc_phy_power_on(struct phy *phy) > { > struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy); > > - /* Drive impedance: 50 Ohm */ > + /* Drive impedance: from DTS */ > regmap_write(rk_phy->reg_base, > rk_phy->reg_offset + GRF_EMMCPHY_CON6, > - HIWORD_UPDATE(PHYCTRL_DR_50OHM, > + HIWORD_UPDATE(rk_phy->drive_impedance, > PHYCTRL_DR_MASK, > PHYCTRL_DR_SHIFT)); > > @@ -314,6 +315,26 @@ static const struct phy_ops ops = { > .owner = THIS_MODULE, > }; > > +static u32 convert_drive_impedance_ohm(struct platform_device *pdev, u32 > dr_ohm) > +{ > + switch (dr_ohm) { > + case 100: > + return PHYCTRL_DR_100OHM; > + case 66: > + return PHYCTRL_DR_66OHM; > + case 50: > + return PHYCTRL_DR_50OHM; > + case 40: > + return PHYCTRL_DR_40OHM; > + case 33: > + return PHYCTRL_DR_33OHM; > + } > + > + dev_warn(&pdev->dev, "Invalid value %u for drive-impedance-ohm.\n", > + dr_ohm); > + return PHYCTRL_DR_50OHM; > +} > + > static int rockchip_emmc_phy_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -322,6 +343,7 @@ static int rockchip_emmc_phy_probe(struct platform_device > *pdev) > struct phy_provider *phy_provider; > struct regmap *grf; > unsigned int reg_offset; > + u32 val; > > if (!dev->parent || !dev->parent->of_node) > return -ENODEV; > @@ -344,6 +366,10 @@ static int rockchip_emmc_phy_probe(struct > platform_device *pdev) > > rk_phy->reg_offset = reg_offset; > rk_phy->reg_base = grf; > + rk_phy->drive_impedance = PHYCTRL_DR_50OHM; > + > + if (!of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val)) > + rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, > val); > > generic_phy = devm_phy_create(dev, dev->of_node, &ops); > if (IS_ERR(generic_phy)) { >
