diff options
| author | Christoph Muellner <christoph.muellner@theobroma-systems.com> | 2019-03-22 12:34:50 +0100 |
|---|---|---|
| committer | Kishon Vijay Abraham I <kishon@ti.com> | 2019-04-17 14:12:58 +0530 |
| commit | 043f42edbf2953ea45d0413ac998cff3dae6b268 (patch) | |
| tree | f0cbd386fdccdc59ffc771cb0bd6bd83a004089b | |
| parent | 3f6d1767b1a011165cb404df1acdf003252df153 (diff) | |
| download | linux-043f42edbf2953ea45d0413ac998cff3dae6b268.tar.bz2 | |
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>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
| -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 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)) { |