[PATCH v6 5/9] phy: rockchip-samsung-dcphy: Move block-level setup to runtime resume

[Jason Yang]

The APB reset and the BIAS references have to be treated as block-level
[1]: both the transmitter and the receiver need them, and they only have
to be programmed once. They are programmed from the transmitter's
power-on path today.

A later change registers one struct phy for each of them, and a second
consumer coming up would then reset the block underneath a PHY that is
already running.

Program them from runtime resume instead, where whichever of the two
comes up first brings the block up and a second one no longer resets it.

This puts the BIAS writes ahead of the per-PHY reset assert, where the
TRM's worked example has them after [1]. That is safe: neither M_RESETN
nor S_RESETN covers the BIAS registers, and the values written are those
registers' reset defaults.

[1] RK3588 TRM: sections 22.4.1 (address map), 22.4.2 (reset values),
    22.6.1.2 (reset) and 22.6.4.1 (D-PHY transmitter start-up)

Signed-off-by: Jason Yang <jason98166 at gmail.com>
---
 drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
index 7a009d87a665..d6acc3e2d448 100644
--- a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
+++ b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
@@ -1346,7 +1346,6 @@ static int samsung_mipi_dphy_power_on(struct samsung_mipi_dcphy *samsung)
 
 	reset_control_assert(samsung->m_phy_rst);
 
-	samsung_mipi_dcphy_bias_block_enable(samsung);
 	samsung_mipi_dcphy_pll_configure(samsung);
 	samsung_mipi_dphy_clk_lane_timing_init(samsung);
 	samsung_mipi_dphy_data_lane_timing_init(samsung);
@@ -1373,10 +1372,6 @@ static int samsung_mipi_dcphy_power_on(struct phy *phy)
 {
 	struct samsung_mipi_dcphy *samsung = phy_get_drvdata(phy);
 
-	reset_control_assert(samsung->apb_rst);
-	udelay(1);
-	reset_control_deassert(samsung->apb_rst);
-
 	switch (samsung->type) {
 	case PHY_TYPE_DPHY:
 		return samsung_mipi_dphy_power_on(samsung);
@@ -1667,6 +1662,12 @@ static __maybe_unused int samsung_mipi_dcphy_runtime_resume(struct device *dev)
 		return ret;
 	}
 
+	reset_control_assert(samsung->apb_rst);
+	udelay(1);
+	reset_control_deassert(samsung->apb_rst);
+
+	samsung_mipi_dcphy_bias_block_enable(samsung);
+
 	return 0;
 }
 

-- 
2.43.0