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 <[email protected]>
Signed-off-by: Philipp Tomsich <[email protected]>
Reviewed-by: Heiko Stuebner <[email protected]>
---
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 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)) {
--
2.11.0
A previous patch introduced the property 'drive-impedance-ohm'
for the RK3399's emmc phy node. This patch sets this value
explicitly to the default value of 50 Ohm.
Signed-off-by: Christoph Muellner <[email protected]>
Signed-off-by: Philipp Tomsich <[email protected]>
---
arch/arm64/boot/dts/rockchip/rk3399.dtsi | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
index db9d948c0b03..1f1f7732ae76 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
@@ -1450,6 +1450,7 @@
clock-names = "refclk";
#phy-cells = <1>;
resets = <&cru SRST_PCIEPHY>;
+ drive-impedance-ohm = <50>;
reset-names = "phy";
status = "disabled";
};
--
2.11.0
The RK3399-Q7 (Puma) requires 33 Ohm drive strength to ensure signal
integrity at HS-400 (200MHz clock, DDR signalling).
A repeated EMC testing run validates that this increase does not
negatively impact EMC compliance (emissions have ample distance to
the regulatory limits).
Signed-off-by: Christoph Muellner <[email protected]>
Signed-off-by: Philipp Tomsich <[email protected]>
Tested-by: Jakob Unterwurzacher <[email protected]>
Tested-by: Klaus Goger <[email protected]>
---
arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
index 0130b9f98c9d..4f75bb6b2f14 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
@@ -146,6 +146,7 @@
&emmc_phy {
status = "okay";
+ drive-impedance-ohm = <33>;
};
&gmac {
--
2.11.0
This patch documents the new proprty drive-impedance-ohm for
Rockchip's eMMC PHY node.
Signed-off-by: Christoph Muellner <[email protected]>
Signed-off-by: Philipp Tomsich <[email protected]>
---
Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
index e3ea55763b0a..e728786f21e0 100644
--- a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
+++ b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
@@ -7,12 +7,15 @@ Required properties:
- reg: PHY register address offset and length in "general
register files"
-Optional clocks using the clock bindings (see ../clock/clock-bindings.txt),
-specified by name:
+Optional properties:
- clock-names: Should contain "emmcclk". Although this is listed as optional
(because most boards can get basic functionality without having
access to it), it is strongly suggested.
+ See ../clock/clock-bindings.txt for details.
- clocks: Should have a phandle to the card clock exported by the SDHCI driver.
+ - drive-impedance-ohm: Specifies the drive impedance in Ohm.
+ Possible values are 33, 40, 50, 66 and 100.
+ If not set, the default value of 50 will be applied.
Example:
@@ -29,6 +32,7 @@ grf: syscon@ff770000 {
reg = <0xf780 0x20>;
clocks = <&sdhci>;
clock-names = "emmcclk";
+ drive-impedance-ohm = <50>;
#phy-cells = <0>;
};
};
--
2.11.0
Am Freitag, 22. M?rz 2019, 12:34:52 CET schrieb Christoph Muellner:
> A previous patch introduced the property 'drive-impedance-ohm'
> for the RK3399's emmc phy node. This patch sets this value
> explicitly to the default value of 50 Ohm.
>
> Signed-off-by: Christoph Muellner <[email protected]>
> Signed-off-by: Philipp Tomsich <[email protected]>
applied patches 3+4 for 5.2
Thanks
Heiko