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Subject[PATCH 1/2] phy: rockchip: set pulldown for strobe line in dts
Date
This patch add support to set the internal pulldown via dt property
and allow simplify the board design for the trace from emmc-phy to
the eMMC chipset.
Default to not set the pull-down.

This patch was inspired from the 4.4 tree of the
Rockchip SDK, where it is enabled unconditional.
The patch had been tested with our rk3399 customized board.

Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
---
drivers/phy/rockchip/phy-rockchip-emmc.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/phy/rockchip/phy-rockchip-emmc.c b/drivers/phy/rockchip/phy-rockchip-emmc.c
index 2dc19ddd120f..d9bc45828f74 100644
--- a/drivers/phy/rockchip/phy-rockchip-emmc.c
+++ b/drivers/phy/rockchip/phy-rockchip-emmc.c
@@ -67,6 +67,10 @@
#define PHYCTRL_OTAPDLYENA_SHIFT 0xb
#define PHYCTRL_OTAPDLYSEL_MASK 0xf
#define PHYCTRL_OTAPDLYSEL_SHIFT 0x7
+#define PHYCTRL_REN_STRB_DISABLE 0x0
+#define PHYCTRL_REN_STRB_ENABLE 0x1
+#define PHYCTRL_REN_STRB_MASK 0x1
+#define PHYCTRL_REN_STRB_SHIFT 0x9

#define PHYCTRL_IS_CALDONE(x) \
((((x) >> PHYCTRL_CALDONE_SHIFT) & \
@@ -80,6 +84,7 @@ struct rockchip_emmc_phy {
struct regmap *reg_base;
struct clk *emmcclk;
unsigned int drive_impedance;
+ unsigned int enable_strobe_pulldown;
};

static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
@@ -295,6 +300,13 @@ static int rockchip_emmc_phy_power_on(struct phy *phy)
PHYCTRL_OTAPDLYSEL_MASK,
PHYCTRL_OTAPDLYSEL_SHIFT));

+ /* Internal pull-down for strobe line */
+ regmap_write(rk_phy->reg_base,
+ rk_phy->reg_offset + GRF_EMMCPHY_CON2,
+ HIWORD_UPDATE(rk_phy->enable_strobe_pulldown,
+ PHYCTRL_REN_STRB_MASK,
+ PHYCTRL_REN_STRB_SHIFT));
+
/* Power up emmc phy analog blocks */
return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_ON);
}
@@ -359,10 +371,14 @@ 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;
+ rk_phy->enable_strobe_pulldown = PHYCTRL_REN_STRB_DISABLE;

if (!of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val))
rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, val);

+ if (of_property_read_bool(dev->of_node, "enable-strobe-pulldown"))
+ rk_phy->enable_strobe_pulldown = PHYCTRL_REN_STRB_ENABLE;
+
generic_phy = devm_phy_create(dev, dev->of_node, &ops);
if (IS_ERR(generic_phy)) {
dev_err(dev, "failed to create PHY\n");
--
2.20.1
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