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 <christoph.muellner@xxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Philipp Tomsich <philipp.tomsich@xxxxxxxxxxxxxxxxxxxxx>
change itself looks good
Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
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)) {
>
