[PATCH 04/22] phy: allwinner: phy-sun6i-mipi-dphy: Support D-PHY Rx mode for MIPI CSI-2

From: Paul Kocialkowski
Date: Fri Sep 10 2021 - 14:42:40 EST

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The Allwinner A31 D-PHY supports both Rx and Tx modes. While the latter
is already supported and used for MIPI DSI this adds support for the
former, to be used with MIPI CSI-2.

This implementation is inspired by Allwinner's V3s Linux SDK
implementation, which was used as a documentation base.

It uses the direction dt property to distinguish between tx and rx
directions.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
---
drivers/phy/allwinner/phy-sun6i-mipi-dphy.c | 166 +++++++++++++++++++-
1 file changed, 162 insertions(+), 4 deletions(-)

diff --git a/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c b/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
index f0bc87d654d4..3900f1650851 100644
--- a/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
+++ b/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
@@ -24,6 +24,14 @@
#define SUN6I_DPHY_TX_CTL_REG 0x04
#define SUN6I_DPHY_TX_CTL_HS_TX_CLK_CONT BIT(28)

+#define SUN6I_DPHY_RX_CTL_REG 0x08
+#define SUN6I_DPHY_RX_CTL_EN_DBC BIT(31)
+#define SUN6I_DPHY_RX_CTL_RX_CLK_FORCE BIT(24)
+#define SUN6I_DPHY_RX_CTL_RX_D3_FORCE BIT(23)
+#define SUN6I_DPHY_RX_CTL_RX_D2_FORCE BIT(22)
+#define SUN6I_DPHY_RX_CTL_RX_D1_FORCE BIT(21)
+#define SUN6I_DPHY_RX_CTL_RX_D0_FORCE BIT(20)
+
#define SUN6I_DPHY_TX_TIME0_REG 0x10
#define SUN6I_DPHY_TX_TIME0_HS_TRAIL(n) (((n) & 0xff) << 24)
#define SUN6I_DPHY_TX_TIME0_HS_PREPARE(n) (((n) & 0xff) << 16)
@@ -44,12 +52,29 @@
#define SUN6I_DPHY_TX_TIME4_HS_TX_ANA1(n) (((n) & 0xff) << 8)
#define SUN6I_DPHY_TX_TIME4_HS_TX_ANA0(n) ((n) & 0xff)

+#define SUN6I_DPHY_RX_TIME0_REG 0x30
+#define SUN6I_DPHY_RX_TIME0_HS_RX_SYNC(n) (((n) & 0xff) << 24)
+#define SUN6I_DPHY_RX_TIME0_HS_RX_CLK_MISS(n) (((n) & 0xff) << 16)
+#define SUN6I_DPHY_RX_TIME0_LP_RX(n) (((n) & 0xff) << 8)
+
+#define SUN6I_DPHY_RX_TIME1_REG 0x34
+#define SUN6I_DPHY_RX_TIME1_RX_DLY(n) (((n) & 0xfff) << 20)
+#define SUN6I_DPHY_RX_TIME1_LP_RX_ULPS_WP(n) ((n) & 0xfffff)
+
+#define SUN6I_DPHY_RX_TIME2_REG 0x38
+#define SUN6I_DPHY_RX_TIME2_HS_RX_ANA1(n) (((n) & 0xff) << 8)
+#define SUN6I_DPHY_RX_TIME2_HS_RX_ANA0(n) ((n) & 0xff)
+
+#define SUN6I_DPHY_RX_TIME3_REG 0x40
+#define SUN6I_DPHY_RX_TIME3_LPRST_DLY(n) (((n) & 0xffff) << 16)
+
#define SUN6I_DPHY_ANA0_REG 0x4c
#define SUN6I_DPHY_ANA0_REG_PWS BIT(31)
#define SUN6I_DPHY_ANA0_REG_DMPC BIT(28)
#define SUN6I_DPHY_ANA0_REG_DMPD(n) (((n) & 0xf) << 24)
#define SUN6I_DPHY_ANA0_REG_SLV(n) (((n) & 7) << 12)
#define SUN6I_DPHY_ANA0_REG_DEN(n) (((n) & 0xf) << 8)
+#define SUN6I_DPHY_ANA0_REG_SFB(n) (((n) & 3) << 2)

#define SUN6I_DPHY_ANA1_REG 0x50
#define SUN6I_DPHY_ANA1_REG_VTTMODE BIT(31)
@@ -84,6 +109,11 @@

#define SUN6I_DPHY_DBG5_REG 0xf4

+enum sun6i_dphy_direction {
+ SUN6I_DPHY_DIRECTION_TX,
+ SUN6I_DPHY_DIRECTION_RX,
+};
+
struct sun6i_dphy {
struct clk *bus_clk;
struct clk *mod_clk;
@@ -92,6 +122,8 @@ struct sun6i_dphy {

struct phy *phy;
struct phy_configure_opts_mipi_dphy config;
+
+ enum sun6i_dphy_direction direction;
};

static int sun6i_dphy_init(struct phy *phy)
@@ -119,9 +151,8 @@ static int sun6i_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
return 0;
}

-static int sun6i_dphy_power_on(struct phy *phy)
+static int sun6i_dphy_tx_power_on(struct sun6i_dphy *dphy)
{
- struct sun6i_dphy *dphy = phy_get_drvdata(phy);
u8 lanes_mask = GENMASK(dphy->config.lanes - 1, 0);

regmap_write(dphy->regs, SUN6I_DPHY_TX_CTL_REG,
@@ -211,12 +242,129 @@ static int sun6i_dphy_power_on(struct phy *phy)
return 0;
}

+static int sun6i_dphy_rx_power_on(struct sun6i_dphy *dphy)
+{
+ /* Physical clock rate is actually half of symbol rate with DDR. */
+ unsigned long mipi_symbol_rate = dphy->config.hs_clk_rate;
+ unsigned long dphy_clk_rate;
+ unsigned int rx_dly;
+ unsigned int lprst_dly;
+ u32 value;
+
+ dphy_clk_rate = clk_get_rate(dphy->mod_clk);
+ if (!dphy_clk_rate)
+ return -EINVAL;
+
+ /* Hardcoded timing parameters from the Allwinner BSP. */
+ regmap_write(dphy->regs, SUN6I_DPHY_RX_TIME0_REG,
+ SUN6I_DPHY_RX_TIME0_HS_RX_SYNC(255) |
+ SUN6I_DPHY_RX_TIME0_HS_RX_CLK_MISS(255) |
+ SUN6I_DPHY_RX_TIME0_LP_RX(255));
+
+ /*
+ * Formula from the Allwinner BSP, with hardcoded coefficients
+ * (probably internal divider/multiplier).
+ */
+ rx_dly = 8 * (unsigned int)(dphy_clk_rate / (mipi_symbol_rate / 8));
+
+ /*
+ * The Allwinner BSP has an alternative formula for LP_RX_ULPS_WP:
+ * lp_ulps_wp_cnt = lp_ulps_wp_ms * lp_clk / 1000
+ * but does not use it and hardcodes 255 instead.
+ */
+ regmap_write(dphy->regs, SUN6I_DPHY_RX_TIME1_REG,
+ SUN6I_DPHY_RX_TIME1_RX_DLY(rx_dly) |
+ SUN6I_DPHY_RX_TIME1_LP_RX_ULPS_WP(255));
+
+ /* HS_RX_ANA0 value is hardcoded in the Allwinner BSP. */
+ regmap_write(dphy->regs, SUN6I_DPHY_RX_TIME2_REG,
+ SUN6I_DPHY_RX_TIME2_HS_RX_ANA0(4));
+
+ /*
+ * Formula from the Allwinner BSP, with hardcoded coefficients
+ * (probably internal divider/multiplier).
+ */
+ lprst_dly = 4 * (unsigned int)(dphy_clk_rate / (mipi_symbol_rate / 2));
+
+ regmap_write(dphy->regs, SUN6I_DPHY_RX_TIME3_REG,
+ SUN6I_DPHY_RX_TIME3_LPRST_DLY(lprst_dly));
+
+ /* Analog parameters are hardcoded in the Allwinner BSP. */
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA0_REG,
+ SUN6I_DPHY_ANA0_REG_PWS |
+ SUN6I_DPHY_ANA0_REG_SLV(7) |
+ SUN6I_DPHY_ANA0_REG_SFB(2));
+
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA1_REG,
+ SUN6I_DPHY_ANA1_REG_SVTT(4));
+
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA4_REG,
+ SUN6I_DPHY_ANA4_REG_DMPLVC |
+ SUN6I_DPHY_ANA4_REG_DMPLVD(1));
+
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA2_REG,
+ SUN6I_DPHY_ANA2_REG_ENIB);
+
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA3_REG,
+ SUN6I_DPHY_ANA3_EN_LDOR |
+ SUN6I_DPHY_ANA3_EN_LDOC |
+ SUN6I_DPHY_ANA3_EN_LDOD);
+
+ /*
+ * Delay comes from the Allwinner BSP, likely for internal regulator
+ * ramp-up.
+ */
+ udelay(3);
+
+ value = SUN6I_DPHY_RX_CTL_EN_DBC | SUN6I_DPHY_RX_CTL_RX_CLK_FORCE;
+
+ /*
+ * Rx data lane force-enable bits are used as regular RX enable by the
+ * Allwinner BSP.
+ */
+ if (dphy->config.lanes >= 1)
+ value |= SUN6I_DPHY_RX_CTL_RX_D0_FORCE;
+ if (dphy->config.lanes >= 2)
+ value |= SUN6I_DPHY_RX_CTL_RX_D1_FORCE;
+ if (dphy->config.lanes >= 3)
+ value |= SUN6I_DPHY_RX_CTL_RX_D2_FORCE;
+ if (dphy->config.lanes == 4)
+ value |= SUN6I_DPHY_RX_CTL_RX_D3_FORCE;
+
+ regmap_write(dphy->regs, SUN6I_DPHY_RX_CTL_REG, value);
+
+ regmap_write(dphy->regs, SUN6I_DPHY_GCTL_REG,
+ SUN6I_DPHY_GCTL_LANE_NUM(dphy->config.lanes) |
+ SUN6I_DPHY_GCTL_EN);
+
+ return 0;
+}
+
+static int sun6i_dphy_power_on(struct phy *phy)
+{
+ struct sun6i_dphy *dphy = phy_get_drvdata(phy);
+
+ switch (dphy->direction) {
+ case SUN6I_DPHY_DIRECTION_TX:
+ return sun6i_dphy_tx_power_on(dphy);
+ case SUN6I_DPHY_DIRECTION_RX:
+ return sun6i_dphy_rx_power_on(dphy);
+ default:
+ return -EINVAL;
+ }
+}
+
static int sun6i_dphy_power_off(struct phy *phy)
{
struct sun6i_dphy *dphy = phy_get_drvdata(phy);

- regmap_update_bits(dphy->regs, SUN6I_DPHY_ANA1_REG,
- SUN6I_DPHY_ANA1_REG_VTTMODE, 0);
+ regmap_write(dphy->regs, SUN6I_DPHY_GCTL_REG, 0);
+
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA0_REG, 0);
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA1_REG, 0);
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA2_REG, 0);
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA3_REG, 0);
+ regmap_write(dphy->regs, SUN6I_DPHY_ANA4_REG, 0);

return 0;
}
@@ -253,7 +401,9 @@ static int sun6i_dphy_probe(struct platform_device *pdev)
{
struct phy_provider *phy_provider;
struct sun6i_dphy *dphy;
+ const char *direction;
void __iomem *regs;
+ int ret;

dphy = devm_kzalloc(&pdev->dev, sizeof(*dphy), GFP_KERNEL);
if (!dphy)
@@ -290,6 +440,14 @@ static int sun6i_dphy_probe(struct platform_device *pdev)
return PTR_ERR(dphy->phy);
}

+ dphy->direction = SUN6I_DPHY_DIRECTION_TX;
+
+ ret = of_property_read_string(pdev->dev.of_node, "allwinner,direction",
+ &direction);
+
+ if (!ret && !strncmp(direction, "rx", 2))
+ dphy->direction = SUN6I_DPHY_DIRECTION_RX;
+
phy_set_drvdata(dphy->phy, dphy);
phy_provider = devm_of_phy_provider_register(&pdev->dev, of_phy_simple_xlate);

--
2.32.0

Next message: Paul Kocialkowski: "[PATCH 05/22] dt-bindings: media: sun6i-a31-csi: Add MIPI CSI-2 input port"
Previous message: Paul Kocialkowski: "[PATCH 02/22] ARM: dts: sun8i: v3s: Parent the CSI module clock to the ISP PLL"
In reply to: Paul Kocialkowski: "[PATCH 02/22] ARM: dts: sun8i: v3s: Parent the CSI module clock to the ISP PLL"
Next in thread: Paul Kocialkowski: "[PATCH 05/22] dt-bindings: media: sun6i-a31-csi: Add MIPI CSI-2 input port"
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