diff options
| author | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2019-02-28 15:59:56 +0100 |
|---|---|---|
| committer | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2019-05-21 18:23:42 +0200 |
| commit | 34035db3450d08a7650cd201abef973e18e3bc74 (patch) | |
| tree | c2588973d2a633f5388010473a16834e1d1f0d91 | |
| parent | 7df3822fe667840da178e7f2b7ce398b3cd6c2a4 (diff) | |
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 <christoph.muellner@theobroma-systems.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
| -rw-r--r-- | drivers/phy/rockchip/phy-rockchip-emmc.c | 30 |
1 files 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)) { |