[PATCH 4/4] phy: rockchip-samsung-dcphy: add MIPI D-PHY receiver support

[Jason Yang via B4 Relay <devnull+jason98166.gmail.com@kernel.org>]

From: Jason Yang <jason98166@gmail.com>

Implement the receiver (CSI) direction of the D-PHY. Add the RX
register layout and the HS-frequency settle table, and hook the
receiver bring-up and teardown into the per-direction power_on(),
power_off() and configure() paths, all serialized on the provider
mutex alongside the transmitter.

Only the D-PHY receiver is implemented, with fixed RK3588 tuning
defaults. The RX register layout and field definitions follow the
RK3588 TRM (section 22.4); what the TRM does not publish are the
per-data-rate HS settle values (it points to a separate timing-table
supplement and gives only a single example point) and the analog
tuning values, both of which are taken from the Rockchip vendor
kernel. The PLL is left untouched on the receive path: the sensor
supplies the link clock, and the TRM start-up sequence (figure 22-8)
allows the PLL sequence to be skipped when only the receiver (slave)
lanes are used. configure() only records the incoming rate so the
settle table can be indexed.

Signed-off-by: Jason Yang <jason98166@gmail.com>
Assisted-by: Claude:claude-opus-4-8
---
 drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c | 330 +++++++++++++++++++++-
 1 file changed, 320 insertions(+), 10 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
index 0248424929bb..49243ba93bd0 100644
--- a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
+++ b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
@@ -237,6 +237,63 @@
 #define DPHY_MD3_TIME_CON4	0x0740
 #define DPHY_MD3_DATA_CON0	0x0744
 
+/* D-PHY receiver direction registers (clock lane + four data lanes) */
+#define DPHY_SC_GNR_CON0	0x0b00
+#define DPHY_SC_GNR_CON1	0x0b04
+#define DPHY_SC_ANA_CON1	0x0b0c
+#define HS_RX_BIAS_CON(x)	FIELD_PREP(GENMASK(15, 11), x)
+#define DPHY_SC_ANA_CON2	0x0b10
+#define HS_TERM_SW(x)		FIELD_PREP(GENMASK(2, 0), x)
+#define DPHY_SC_ANA_CON3	0x0b14
+#define ULPS_HYS_SW_DPHY(x)	FIELD_PREP(GENMASK(10, 8), x)
+#define DPHY_SC_TIME_CON0	0x0b30
+#define T_CLK_SETTLE(x)		FIELD_PREP(GENMASK(7, 0), x)
+#define T_CLK_MISS(x)		FIELD_PREP(GENMASK(11, 8), x)
+#define COMBO_SD0_GNR_CON0	0x0c00
+#define COMBO_SD0_GNR_CON1	0x0c04
+#define COMBO_SD0_ANA_CON1	0x0c0c
+#define COMBO_SD0_ANA_CON2	0x0c10
+#define SKEW_DLYSEL(x)		FIELD_PREP(GENMASK(9, 8), x)
+#define RX_TERM_SW(x)		FIELD_PREP(GENMASK(2, 0), x)
+#define COMBO_SD0_ANA_CON3	0x0c14
+#define SEL_ESCPOL		BIT(11)
+#define LP_HYS_SW(x)		FIELD_PREP(GENMASK(5, 4), x)
+#define COMBO_SD0_ANA_CON7	0x0c24
+#define CLK_DBL_CTRL(x)		FIELD_PREP(GENMASK(7, 6), x)
+#define COMBO_SD0_TIME_CON0	0x0c30
+#define T_HS_SETTLE(x)		FIELD_PREP(GENMASK(7, 0), x)
+#define SETTLE_CLK_SEL		BIT(8)
+#define COMBO_SD0_TIME_CON1	0x0c34
+#define T_ERR_SOT_SYNC(x)	FIELD_PREP(GENMASK(7, 0), x)
+#define COMBO_SD0_DESKEW_CON2	0x0c48
+#define SKEW_CAL_CLK_COARSE_SET(x) FIELD_PREP(GENMASK(4, 0), x)
+#define COMBO_SD1_GNR_CON0	0x0d00
+#define COMBO_SD1_GNR_CON1	0x0d04
+#define COMBO_SD1_ANA_CON1	0x0d0c
+#define COMBO_SD1_ANA_CON2	0x0d10
+#define COMBO_SD1_ANA_CON3	0x0d14
+#define COMBO_SD1_ANA_CON7	0x0d24
+#define COMBO_SD1_TIME_CON0	0x0d30
+#define COMBO_SD1_TIME_CON1	0x0d34
+#define COMBO_SD1_DESKEW_CON2	0x0d48
+#define COMBO_SD2_GNR_CON0	0x0e00
+#define COMBO_SD2_GNR_CON1	0x0e04
+#define COMBO_SD2_ANA_CON1	0x0e0c
+#define COMBO_SD2_ANA_CON2	0x0e10
+#define COMBO_SD2_ANA_CON3	0x0e14
+#define COMBO_SD2_ANA_CON7	0x0e24
+#define COMBO_SD2_TIME_CON0	0x0e30
+#define COMBO_SD2_TIME_CON1	0x0e34
+#define COMBO_SD2_DESKEW_CON2	0x0e48
+#define DPHY_SD3_GNR_CON0	0x0f00
+#define DPHY_SD3_GNR_CON1	0x0f04
+#define DPHY_SD3_ANA_CON1	0x0f0c
+#define DPHY_SD3_ANA_CON2	0x0f10
+#define DPHY_SD3_ANA_CON3	0x0f14
+#define DPHY_SD3_TIME_CON0	0x0f30
+#define DPHY_SD3_TIME_CON1	0x0f34
+#define DPHY_SD3_DESKEW_CON2	0x0f48
+
 #define T_LP_EXIT_SKEW(x)	FIELD_PREP(GENMASK(3, 2), x)
 #define T_LP_ENTRY_SKEW(x)	FIELD_PREP(GENMASK(1, 0), x)
 #define T_HS_ZERO(x)		FIELD_PREP(GENMASK(15, 8), x)
@@ -303,6 +360,7 @@ struct samsung_mipi_dcphy {
 	struct reset_control *apb_rst;
 	struct reset_control *grf_apb_rst;
 	unsigned int lanes;
+	unsigned long long hs_clk_rate;
 	struct samsung_mipi_dcphy_dir phys[2];
 	/* Serialises the two directions' access to the shared PHY state. */
 	struct mutex lock;
@@ -986,6 +1044,210 @@ struct samsung_mipi_dphy_timing samsung_mipi_dphy_timing_table[] = {
 	{  80,  2,   0,  0, 28,  5,  0, 22,  2,  0,  5},
 };
 
+/* D-PHY receiver HS-RX configuration lookup */
+struct samsung_mipi_dphy_rx_hsfreq_range {
+	u32 range_h_mbps;
+	u16 cfg_bit;
+};
+
+/*
+ * HS RX settle values taken from the rk3588 vendor kernel. The TRM
+ * defines these fields but does not publish the per-data-rate table
+ * (it defers to a separate timing-table supplement). Each cfg_bit is a
+ * pre-combined SETTLE_CLK_SEL | T_HS_SETTLE value written to the
+ * data-lane TIME_CON0. Sorted by .range_h_mbps ascending.
+ */
+static const struct samsung_mipi_dphy_rx_hsfreq_range samsung_mipi_dphy_rx_hsfreq_ranges[] = {
+	{   80, 0x105 }, {  100, 0x106 }, {  120, 0x107 }, {  140, 0x108 },
+	{  160, 0x109 }, {  180, 0x10a }, {  200, 0x10b }, {  220, 0x10c },
+	{  240, 0x10d }, {  270, 0x10e }, {  290, 0x10f }, {  310, 0x110 },
+	{  330, 0x111 }, {  350, 0x112 }, {  370, 0x113 }, {  390, 0x114 },
+	{  410, 0x115 }, {  430, 0x116 }, {  450, 0x117 }, {  470, 0x118 },
+	{  490, 0x119 }, {  510, 0x11a }, {  540, 0x11b }, {  560, 0x11c },
+	{  580, 0x11d }, {  600, 0x11e }, {  620, 0x11f }, {  640, 0x120 },
+	{  660, 0x121 }, {  680, 0x122 }, {  700, 0x123 }, {  720, 0x124 },
+	{  740, 0x125 }, {  760, 0x126 }, {  790, 0x127 }, {  810, 0x128 },
+	{  830, 0x129 }, {  850, 0x12a }, {  870, 0x12b }, {  890, 0x12c },
+	{  910, 0x12d }, {  930, 0x12e }, {  950, 0x12f }, {  970, 0x130 },
+	{  990, 0x131 }, { 1010, 0x132 }, { 1030, 0x133 }, { 1060, 0x134 },
+	{ 1080, 0x135 }, { 1100, 0x136 }, { 1120, 0x137 }, { 1140, 0x138 },
+	{ 1160, 0x139 }, { 1180, 0x13a }, { 1200, 0x13b }, { 1220, 0x13c },
+	{ 1240, 0x13d }, { 1260, 0x13e }, { 1280, 0x13f }, { 1310, 0x140 },
+	{ 1330, 0x141 }, { 1350, 0x142 }, { 1370, 0x143 }, { 1390, 0x144 },
+	{ 1410, 0x145 }, { 1430, 0x146 }, { 1450, 0x147 }, { 1470, 0x148 },
+	{ 1490, 0x149 }, { 1580, 0x007 }, { 1740, 0x008 }, { 1910, 0x009 },
+	{ 2070, 0x00a }, { 2240, 0x00b }, { 2410, 0x00c }, { 2570, 0x00d },
+	{ 2740, 0x00e }, { 2910, 0x00f }, { 3070, 0x010 }, { 3240, 0x011 },
+	{ 3410, 0x012 }, { 3570, 0x013 }, { 3740, 0x014 }, { 3890, 0x015 },
+	{ 4070, 0x016 }, { 4240, 0x017 }, { 4400, 0x018 }, { 4500, 0x019 },
+};
+
+static int samsung_mipi_dphy_rx_lookup_hsfreq(u32 lane_mbps, u16 *cfg_bit)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(samsung_mipi_dphy_rx_hsfreq_ranges); i++) {
+		if (lane_mbps <= samsung_mipi_dphy_rx_hsfreq_ranges[i].range_h_mbps) {
+			*cfg_bit = samsung_mipi_dphy_rx_hsfreq_ranges[i].cfg_bit;
+			return 0;
+		}
+	}
+
+	return -ERANGE;
+}
+
+/* SKEW_DLYSEL per data rate, from the RK3588 TRM ANA_CON2 description */
+static u32 samsung_mipi_dphy_rx_data_lane_dlysel(u32 lane_mbps)
+{
+	if (lane_mbps < 1500)
+		return 0;
+	if (lane_mbps < 2000)
+		return SKEW_DLYSEL(3);
+	if (lane_mbps < 3000)
+		return SKEW_DLYSEL(2);
+	if (lane_mbps < 4000)
+		return SKEW_DLYSEL(1);
+	return 0;
+}
+
+/*
+ * Per-data-lane register bases, indexed by lane number. The clock lane is
+ * programmed separately; its enable/settle registers do not follow this
+ * regular spacing.
+ */
+static const u32 rx_data_lane_gnr_con0[] = {
+	COMBO_SD0_GNR_CON0, COMBO_SD1_GNR_CON0,
+	COMBO_SD2_GNR_CON0, DPHY_SD3_GNR_CON0,
+};
+
+static const u32 rx_lane_time_con0[] = {
+	COMBO_SD0_TIME_CON0, COMBO_SD1_TIME_CON0,
+	COMBO_SD2_TIME_CON0, DPHY_SD3_TIME_CON0,
+};
+
+static const u32 rx_lane_time_con1[] = {
+	COMBO_SD0_TIME_CON1, COMBO_SD1_TIME_CON1,
+	COMBO_SD2_TIME_CON1, DPHY_SD3_TIME_CON1,
+};
+
+/*
+ * These RX analog tuning values come from the vendor BSP; the
+ * termination (RX_TERM_SW/HS_TERM_SW = 2, 96.6 ohm) additionally
+ * matches the TRM ANA_CON2 default.
+ */
+static void samsung_mipi_dphy_rx_config_common(struct samsung_mipi_dcphy *samsung)
+{
+	u32 dlysel = samsung_mipi_dphy_rx_data_lane_dlysel(div_u64(samsung->hs_clk_rate,
+							      1000000));
+	u32 ana_con2_common = dlysel | RX_TERM_SW(2);
+
+	/* Clock lane */
+	regmap_write(samsung->regmap, DPHY_SC_GNR_CON1, T_PHY_READY(0x1450));
+	regmap_write(samsung->regmap, DPHY_SC_ANA_CON1, HS_RX_BIAS_CON(0x10));
+	regmap_write(samsung->regmap, DPHY_SC_ANA_CON2, HS_TERM_SW(2));
+	regmap_write(samsung->regmap, DPHY_SC_ANA_CON3, ULPS_HYS_SW_DPHY(6));
+
+	/* Data lane 0 */
+	if (samsung->lanes > 0) {
+		regmap_write(samsung->regmap, COMBO_SD0_GNR_CON1, T_PHY_READY(0x1450));
+		regmap_write(samsung->regmap, COMBO_SD0_ANA_CON1, HS_RX_BIAS_CON(0x10));
+		regmap_write(samsung->regmap, COMBO_SD0_ANA_CON2, ana_con2_common);
+		regmap_write(samsung->regmap, COMBO_SD0_ANA_CON3,
+			     ULPS_HYS_SW_DPHY(6) | LP_HYS_SW(3) | SEL_ESCPOL);
+		regmap_write(samsung->regmap, COMBO_SD0_ANA_CON7, CLK_DBL_CTRL(1));
+		regmap_write(samsung->regmap, COMBO_SD0_DESKEW_CON2, SKEW_CAL_CLK_COARSE_SET(0));
+	}
+
+	/* Data lane 1 */
+	if (samsung->lanes > 1) {
+		regmap_write(samsung->regmap, COMBO_SD1_GNR_CON1, T_PHY_READY(0x1450));
+		regmap_write(samsung->regmap, COMBO_SD1_ANA_CON1, HS_RX_BIAS_CON(0x10));
+		regmap_write(samsung->regmap, COMBO_SD1_ANA_CON2, ana_con2_common);
+		regmap_write(samsung->regmap, COMBO_SD1_ANA_CON3, ULPS_HYS_SW_DPHY(6));
+		regmap_write(samsung->regmap, COMBO_SD1_ANA_CON7, CLK_DBL_CTRL(1));
+		regmap_write(samsung->regmap, COMBO_SD1_DESKEW_CON2, SKEW_CAL_CLK_COARSE_SET(3));
+	}
+
+	/* Data lane 2 */
+	if (samsung->lanes > 2) {
+		regmap_write(samsung->regmap, COMBO_SD2_GNR_CON1, T_PHY_READY(0x1450));
+		regmap_write(samsung->regmap, COMBO_SD2_ANA_CON1, HS_RX_BIAS_CON(0x10));
+		regmap_write(samsung->regmap, COMBO_SD2_ANA_CON2, ana_con2_common);
+		regmap_write(samsung->regmap, COMBO_SD2_ANA_CON3, ULPS_HYS_SW_DPHY(6));
+		regmap_write(samsung->regmap, COMBO_SD2_ANA_CON7, CLK_DBL_CTRL(1));
+		regmap_write(samsung->regmap, COMBO_SD2_DESKEW_CON2, SKEW_CAL_CLK_COARSE_SET(3));
+	}
+
+	/* Data lane 3 */
+	if (samsung->lanes > 3) {
+		regmap_write(samsung->regmap, DPHY_SD3_GNR_CON1, T_PHY_READY(0x1450));
+		regmap_write(samsung->regmap, DPHY_SD3_ANA_CON1, HS_RX_BIAS_CON(0x10));
+		regmap_write(samsung->regmap, DPHY_SD3_ANA_CON2, ana_con2_common);
+		regmap_write(samsung->regmap, DPHY_SD3_ANA_CON3, ULPS_HYS_SW_DPHY(6));
+		regmap_write(samsung->regmap, DPHY_SD3_DESKEW_CON2, SKEW_CAL_CLK_COARSE_SET(3));
+	}
+}
+
+static int samsung_mipi_dphy_rx_config_settle(struct samsung_mipi_dcphy *samsung)
+{
+	u32 lane_mbps = div_u64(samsung->hs_clk_rate, 1000000);
+	u16 cfg_bit;
+	int ret, i;
+
+	ret = samsung_mipi_dphy_rx_lookup_hsfreq(lane_mbps, &cfg_bit);
+	if (ret) {
+		dev_err(samsung->dev,
+			"no RX hsfreq cfg for %u Mbps (limit ~4500 Mbps)\n",
+			lane_mbps);
+		return ret;
+	}
+
+	/*
+	 * Clock-lane settle uses the fixed value from the TRM RX bring-up
+	 * example, unlike the per-rate data-lane settle below.
+	 */
+	regmap_write(samsung->regmap, DPHY_SC_TIME_CON0,
+		     T_CLK_SETTLE(0x01) | T_CLK_MISS(0x03));
+
+	for (i = 0; i < samsung->lanes; i++) {
+		regmap_update_bits(samsung->regmap, rx_lane_time_con0[i],
+				   T_HS_SETTLE(0xff) | SETTLE_CLK_SEL, cfg_bit);
+		regmap_update_bits(samsung->regmap, rx_lane_time_con1[i],
+				   T_ERR_SOT_SYNC(0xff), T_ERR_SOT_SYNC(0x03));
+	}
+
+	return 0;
+}
+
+static int samsung_mipi_dphy_rx_lane_enable(struct samsung_mipi_dcphy *samsung)
+{
+	u32 sts;
+	int ret, i;
+
+	regmap_update_bits(samsung->regmap, DPHY_SC_GNR_CON0, PHY_ENABLE, PHY_ENABLE);
+	for (i = 0; i < samsung->lanes; i++)
+		regmap_update_bits(samsung->regmap, rx_data_lane_gnr_con0[i],
+				   PHY_ENABLE, PHY_ENABLE);
+
+	ret = regmap_read_poll_timeout(samsung->regmap, DPHY_SC_GNR_CON0,
+				       sts, sts & PHY_READY, 200, 4000);
+	if (ret) {
+		dev_err(samsung->dev, "RX clock lane not ready\n");
+		return ret;
+	}
+
+	for (i = 0; i < samsung->lanes; i++) {
+		ret = regmap_read_poll_timeout(samsung->regmap, rx_data_lane_gnr_con0[i],
+					       sts, sts & PHY_READY, 200, 2000);
+		if (ret) {
+			dev_err(samsung->dev, "RX data lane %d not ready\n", i);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 static void samsung_mipi_dcphy_bias_block_enable(struct samsung_mipi_dcphy *samsung)
 {
 	regmap_write(samsung->regmap, BIAS_CON0, I_DEV_DIV_6 | I_RES_100_2UA);
@@ -1002,6 +1264,50 @@ static void samsung_mipi_dcphy_bias_block_enable(struct samsung_mipi_dcphy *sams
 			   I_MUX_SEL_MASK, I_MUX_400MV);
 }
 
+static int samsung_mipi_dphy_rx_power_on(struct samsung_mipi_dcphy *samsung,
+					 struct phy *peer)
+{
+	bool first = peer->power_count == 0;
+	int ret;
+
+	if (!samsung->hs_clk_rate)
+		return -EINVAL;
+
+	reset_control_assert(samsung->s_phy_rst);
+
+	if (first)
+		samsung_mipi_dcphy_bias_block_enable(samsung);
+	samsung_mipi_dphy_rx_config_common(samsung);
+
+	ret = samsung_mipi_dphy_rx_config_settle(samsung);
+	if (ret)
+		goto out_deassert;
+
+	ret = samsung_mipi_dphy_rx_lane_enable(samsung);
+
+out_deassert:
+	reset_control_deassert(samsung->s_phy_rst);
+
+	return ret;
+}
+
+static int samsung_mipi_dphy_rx_power_off(struct samsung_mipi_dcphy *samsung)
+{
+	int i;
+
+	reset_control_assert(samsung->s_phy_rst);
+
+	regmap_update_bits(samsung->regmap, DPHY_SC_GNR_CON0, PHY_ENABLE, 0);
+	for (i = 0; i < samsung->lanes; i++)
+		regmap_update_bits(samsung->regmap, rx_data_lane_gnr_con0[i],
+				   PHY_ENABLE, 0);
+
+	reset_control_deassert(samsung->s_phy_rst);
+	usleep_range(500, 1000);
+
+	return 0;
+}
+
 static void samsung_mipi_dphy_lane_enable(struct samsung_mipi_dcphy *samsung)
 {
 	regmap_write(samsung->regmap, DPHY_MC_GNR_CON1, T_PHY_READY(0x2000));
@@ -1404,7 +1710,7 @@ static int samsung_mipi_dcphy_power_on(struct phy *phy)
 
 	mutex_lock(&samsung->lock);
 	if (pd->dir == RK_DCPHY_DIR_RX)
-		ret = -EOPNOTSUPP;
+		ret = samsung_mipi_dphy_rx_power_on(samsung, peer);
 	else
 		ret = samsung_mipi_dphy_tx_power_on(samsung, peer);
 	mutex_unlock(&samsung->lock);
@@ -1421,11 +1727,11 @@ static int samsung_mipi_dcphy_power_off(struct phy *phy)
 	if (pd->type != PHY_TYPE_DPHY)
 		return -EOPNOTSUPP;
 
-	if (pd->dir == RK_DCPHY_DIR_RX)
-		return -EOPNOTSUPP;
-
 	mutex_lock(&samsung->lock);
-	ret = samsung_mipi_dphy_tx_power_off(samsung);
+	if (pd->dir == RK_DCPHY_DIR_RX)
+		ret = samsung_mipi_dphy_rx_power_off(samsung);
+	else
+		ret = samsung_mipi_dphy_tx_power_off(samsung);
 	mutex_unlock(&samsung->lock);
 
 	return ret;
@@ -1525,13 +1831,17 @@ static int samsung_mipi_dcphy_configure(struct phy *phy,
 	struct samsung_mipi_dcphy *samsung = pd->parent;
 	unsigned long long target_rate = opts->mipi_dphy.hs_clk_rate;
 
+	mutex_lock(&samsung->lock);
 	samsung->lanes = opts->mipi_dphy.lanes > 4 ? 4 : opts->mipi_dphy.lanes;
 
-	if (pd->dir == RK_DCPHY_DIR_RX)
-		return -EOPNOTSUPP;
-
-	samsung_mipi_dcphy_pll_calc_rate(samsung, target_rate);
-	opts->mipi_dphy.hs_clk_rate = samsung->pll.rate;
+	if (pd->dir == RK_DCPHY_DIR_RX) {
+		/* The sensor supplies the link clock; the PLL stays off. */
+		samsung->hs_clk_rate = target_rate;
+	} else {
+		samsung_mipi_dcphy_pll_calc_rate(samsung, target_rate);
+		opts->mipi_dphy.hs_clk_rate = samsung->pll.rate;
+	}
+	mutex_unlock(&samsung->lock);
 
 	return 0;
 }

-- 
2.43.0



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