media: i2c: ds90ub9xx: Set serializer temperature ramp

For continuous PLL lock, it is recommended to extend the temperature
ramp down range of the DS90UB953-Q1 serializer based on the device's
initial temperature [1].

The serializer's die temperature is reported only to the deserializer
through the sensor status registers, and for UB9702, it is recommended
to set the temperature ramp during the link setup sequence, i.e. before
we even probe the ub953 driver.

Add support to the deserializer driver to configure ub953's temperature
ramp.

[1]: Section 7.3.1.1 - https://www.ti.com/lit/gpn/ds90ub953-q1

Signed-off-by: Jai Luthra <[e-mail]>
Signed-off-by: Sakari Ailus <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/i2c/ds90ub953.h

···
 
 /* Indirect register blocks */
 #define UB953_IND_TARGET_PAT_GEN		0x00
-#define UB953_IND_TARGET_FPD3_TX		0x01
+#define UB953_IND_TARGET_ANALOG			0x01
 #define UB953_IND_TARGET_DIE_ID			0x02
 
 #define UB953_IND_PGEN_CTL			0x01
···
 #define UB953_IND_PGEN_VBP			0x0e
 #define UB953_IND_PGEN_VFP			0x0f
 #define UB953_IND_PGEN_COLOR(n)			(0x10 + (n)) /* n <= 15 */
+
+#define UB953_IND_ANA_TEMP_DYNAMIC_CFG		0x4b
+#define UB953_IND_ANA_TEMP_DYNAMIC_CFG_OV	BIT(5)
+#define UB953_IND_ANA_TEMP_STATIC_CFG		0x4c
+#define UB953_IND_ANA_TEMP_STATIC_CFG_MASK	GENMASK(6, 4)
 
 /* UB971 Registers */
 

drivers/media/i2c/ds90ub960.c

···
 	return ret;
 }
 
+static int ub960_rxport_serializer_read(struct ub960_rxport *rxport, u8 reg,
+					u8 *val, int *err)
+{
+	struct ub960_data *priv = rxport->priv;
+	struct device *dev = &priv->client->dev;
+	union i2c_smbus_data data = { 0 };
+	int ret;
+
+	if (err && *err)
+		return *err;
+
+	ret = i2c_smbus_xfer(priv->client->adapter, rxport->ser.alias,
+			     priv->client->flags, I2C_SMBUS_READ, reg,
+			     I2C_SMBUS_BYTE_DATA, &data);
+	if (ret)
+		dev_err(dev,
+			"rx%u: cannot read serializer register 0x%02x (%d)!\n",
+			rxport->nport, reg, ret);
+	else
+		*val = data.byte;
+
+	if (ret && err)
+		*err = ret;
+
+	return ret;
+}
+
+static int ub960_serializer_temp_ramp(struct ub960_rxport *rxport)
+{
+	struct ub960_data *priv = rxport->priv;
+	short temp_dynamic_offset[] = {-1, -1, 0, 0, 1, 1, 1, 3};
+	u8 temp_dynamic_cfg;
+	u8 nport = rxport->nport;
+	u8 ser_temp_code;
+	int ret;
+
+	/* Configure temp ramp only on UB953 */
+	if (!fwnode_device_is_compatible(rxport->ser.fwnode, "ti,ds90ub953-q1"))
+		return 0;
+
+	/* Read current serializer die temperature */
+	ub960_rxport_read(priv, nport, UB960_RR_SENSOR_STS_2, &ser_temp_code,
+			  &ret);
+
+	/* Enable I2C passthrough on back channel */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH, &ret);
+
+	if (ret)
+		return ret;
+
+	/* Select indirect page for analog regs on the serializer */
+	ub960_rxport_serializer_write(rxport, UB953_REG_IND_ACC_CTL,
+				      UB953_IND_TARGET_ANALOG << 2, &ret);
+
+	/* Set temperature ramp dynamic and static config */
+	ub960_rxport_serializer_write(rxport, UB953_REG_IND_ACC_ADDR,
+				      UB953_IND_ANA_TEMP_DYNAMIC_CFG, &ret);
+	ub960_rxport_serializer_read(rxport, UB953_REG_IND_ACC_DATA,
+				     &temp_dynamic_cfg, &ret);
+
+	if (ret)
+		return ret;
+
+	temp_dynamic_cfg |= UB953_IND_ANA_TEMP_DYNAMIC_CFG_OV;
+	temp_dynamic_cfg += temp_dynamic_offset[ser_temp_code];
+
+	/* Update temp static config */
+	ub960_rxport_serializer_write(rxport, UB953_REG_IND_ACC_ADDR,
+				      UB953_IND_ANA_TEMP_STATIC_CFG, &ret);
+	ub960_rxport_serializer_write(rxport, UB953_REG_IND_ACC_DATA,
+				      UB953_IND_ANA_TEMP_STATIC_CFG_MASK, &ret);
+
+	/* Update temperature ramp dynamic config */
+	ub960_rxport_serializer_write(rxport, UB953_REG_IND_ACC_ADDR,
+				      UB953_IND_ANA_TEMP_DYNAMIC_CFG, &ret);
+
+	/* Enable I2C auto ack on BC before we set dynamic cfg and reset */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG,
+				 UB960_RR_BCC_CONFIG_AUTO_ACK_ALL,
+				 UB960_RR_BCC_CONFIG_AUTO_ACK_ALL, &ret);
+
+	ub960_rxport_serializer_write(rxport, UB953_REG_IND_ACC_DATA,
+				      temp_dynamic_cfg, &ret);
+
+	if (ret)
+		return ret;
+
+	/* Soft reset to apply PLL updates */
+	ub960_rxport_serializer_write(rxport, UB953_REG_RESET_CTL,
+				      UB953_REG_RESET_CTL_DIGITAL_RESET_0,
+				      &ret);
+	msleep(20);
+
+	/* Disable I2C passthrough and auto-ack on BC */
+	ub960_rxport_update_bits(priv, nport, UB960_RR_BCC_CONFIG,
+				 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH |
+					 UB960_RR_BCC_CONFIG_AUTO_ACK_ALL,
+				 0x0, &ret);
+
+	return ret;
+}
+
 static int ub960_rxport_bc_ser_config(struct ub960_rxport *rxport)
 {
 	struct ub960_data *priv = rxport->priv;
···
 		ret = -EIO;
 		dev_err_probe(dev, ret, "Failed to lock all RX ports\n");
 		return ret;
+	}
+
+	/* Set temperature ramp on serializer */
+	for_each_active_rxport(priv, it) {
+		ret = ub960_serializer_temp_ramp(it.rxport);
+		if (ret)
+			return ret;
+
+		ub960_rxport_update_bits(priv, it.nport, UB960_RR_BCC_CONFIG,
+					 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH,
+					 UB960_RR_BCC_CONFIG_I2C_PASS_THROUGH,
+					 &ret);
+		if (ret)
+			return ret;
 	}
 
 	/*
···
 
 	/* Wait time for stable lock */
 	fsleep(15000);
+
+	/* Set temperature ramp on serializer */
+	for_each_active_rxport(priv, it) {
+		ret = ub960_serializer_temp_ramp(it.rxport);
+		if (ret)
+			return ret;
+	}
 
 	for_each_active_rxport_fpd4(priv, it) {
 		ret = ub960_enable_dfe_lms_ub9702(priv, it.nport);