From 34035db3450d08a7650cd201abef973e18e3bc74 Mon Sep 17 00:00:00 2001 From: Christoph Muellner Date: Thu, 28 Feb 2019 15:59:56 +0100 Subject: phy: rockchip-emmc: Allow to set drive impedance via DTS. 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 Signed-off-by: Philipp Tomsich Reviewed-by: Heiko Stuebner --- 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 b69a0a796473..0dc075cab886 100644 --- a/drivers/phy/rockchip/phy-rockchip-emmc.c +++ b/drivers/phy/rockchip/phy-rockchip-emmc.c @@ -90,6 +90,7 @@ 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) @@ -286,10 +287,10 @@ 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)); @@ -326,6 +327,26 @@ 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; @@ -334,6 +355,7 @@ 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; @@ -356,6 +378,10 @@ 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)) { -- cgit v1.2.3