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phy: rockchip-emmc: Allow to set drive impedance via DTS.

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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>
This commit is contained in:
Christoph Muellner 2019-03-22 12:34:50 +01:00 committed by Kishon Vijay Abraham I
parent 3f6d1767b1
commit 043f42edbf
1 changed files with 28 additions and 2 deletions
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30
drivers/phy/rockchip/phy-rockchip-emmc.c
View file

@ -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)) {