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authorChristoph Muellner <christoph.muellner@theobroma-systems.com>2019-03-22 12:34:50 +0100
committerKishon Vijay Abraham I <kishon@ti.com>2019-04-17 14:12:58 +0530
commit043f42edbf2953ea45d0413ac998cff3dae6b268 (patch)
treef0cbd386fdccdc59ffc771cb0bd6bd83a004089b /drivers/phy
parent3f6d1767b1a011165cb404df1acdf003252df153 (diff)
downloadlinux-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>
Diffstat (limited to 'drivers/phy')
-rw-r--r--drivers/phy/rockchip/phy-rockchip-emmc.c30
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)) {