[PATCH 04/12] i3c: master: Support ACPI enumeration

[Akhil R <akhilrajeev@nvidia.com>]

Support ACPI enumeration for I2C and I3C devices on an I3C bus.
Read _ADR and LVR from the ACPI resources and extract the data
as per the ACPI specification for an I3C bus. Also read
mipi-i3c-static-address as per the MIPI DISCO specifications [1]
to get the static address to be used.

Although the existing subsystem allows host controllers to register
through the ACPI table, it was not possible to describe I3C or I2C
devices there. This change enables describing the I3C or I2C devices
in the ACPI table, which is required if the device is using a static
address or if it needs some specific properties to be attached to it.

[1] https://www.mipi.org/specifications/disco

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
 drivers/i3c/master.c | 101 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 93 insertions(+), 8 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 2c479fecbfdf..15a356a2b3c8 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2404,12 +2404,31 @@ EXPORT_SYMBOL_GPL(i3c_master_add_i3c_dev_locked);
 
 #define OF_I3C_REG1_IS_I2C_DEV			BIT(31)
 
+static int i3c_acpi_get_i2c_resource(struct acpi_resource *ares, void *data)
+{
+	struct i2c_dev_boardinfo *boardinfo = data;
+	struct acpi_resource_i2c_serialbus *sb;
+
+	if (!i2c_acpi_get_i2c_resource(ares, &sb))
+		return 1;
+
+	boardinfo->base.addr = sb->slave_address;
+	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+		boardinfo->base.flags |= I2C_CLIENT_TEN;
+
+	boardinfo->lvr = sb->lvr;
+
+	return 0;
+}
+
 static int
 i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
 			     struct fwnode_handle *fwnode, u32 *reg)
 {
 	struct i2c_dev_boardinfo *boardinfo;
 	struct device *dev = &master->dev;
+	struct acpi_device *adev;
+	LIST_HEAD(resources);
 	int ret;
 
 	boardinfo = devm_kzalloc(dev, sizeof(*boardinfo), GFP_KERNEL);
@@ -2420,6 +2439,23 @@ i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
 		ret = of_i2c_get_board_info(dev, to_of_node(fwnode), &boardinfo->base);
 		if (ret)
 			return ret;
+
+		/* LVR is encoded in reg[2] for Device Tree. */
+		boardinfo->lvr = reg[2];
+	} else if (is_acpi_device_node(fwnode)) {
+		adev = to_acpi_device_node(fwnode);
+		boardinfo->base.fwnode = acpi_fwnode_handle(adev);
+
+		ret = acpi_dev_get_resources(adev, &resources,
+					     i3c_acpi_get_i2c_resource, boardinfo);
+
+		if (ret < 0)
+			return ret;
+
+		acpi_dev_free_resource_list(&resources);
+
+		if (!boardinfo->base.addr)
+			return -ENODEV;
 	} else {
 		return -EINVAL;
 	}
@@ -2434,9 +2470,6 @@ i3c_master_add_i2c_boardinfo(struct i3c_master_controller *master,
 		return -EOPNOTSUPP;
 	}
 
-	/* LVR is encoded in reg[2]. */
-	boardinfo->lvr = reg[2];
-
 	list_add_tail(&boardinfo->node, &master->boardinfo.i2c);
 	fwnode_handle_get(fwnode);
 
@@ -2491,8 +2524,8 @@ i3c_master_add_i3c_boardinfo(struct i3c_master_controller *master,
 	return 0;
 }
 
-static int i3c_master_add_dev(struct i3c_master_controller *master,
-			      struct fwnode_handle *fwnode)
+static int i3c_master_add_of_dev(struct i3c_master_controller *master,
+				 struct fwnode_handle *fwnode)
 {
 	u32 reg[3];
 	int ret;
@@ -2516,6 +2549,31 @@ static int i3c_master_add_dev(struct i3c_master_controller *master,
 	return ret;
 }
 
+static int i3c_master_add_acpi_dev(struct i3c_master_controller *master,
+				   struct fwnode_handle *fwnode)
+{
+	struct acpi_device *adev = to_acpi_device_node(fwnode);
+	acpi_bus_address adr;
+	u32 reg[3] = { 0 };
+
+	/*
+	 * If the ACPI table entry does not have _ADR method, it's an I2C device
+	 * If the ACPI table entry has _ADR method, it's an I3C device
+	 */
+	if (!acpi_has_method(adev->handle, "_ADR"))
+		return i3c_master_add_i2c_boardinfo(master, fwnode, reg);
+
+	adr = acpi_device_adr(adev);
+
+	/* For I3C devices, _ADR will have the 48 bit PID of the device  */
+	reg[1] = upper_32_bits(adr);
+	reg[2] = lower_32_bits(adr);
+
+	fwnode_property_read_u32(fwnode, "mipi-i3c-static-address", &reg[0]);
+
+	return i3c_master_add_i3c_boardinfo(master, fwnode, reg);
+}
+
 static int fwnode_populate_i3c_bus(struct i3c_master_controller *master)
 {
 	struct device *dev = &master->dev;
@@ -2527,7 +2585,13 @@ static int fwnode_populate_i3c_bus(struct i3c_master_controller *master)
 		return 0;
 
 	fwnode_for_each_available_child_node_scoped(fwnode, child) {
-		ret = i3c_master_add_dev(master, child);
+		if (is_of_node(child))
+			ret = i3c_master_add_of_dev(master, child);
+		else if (is_acpi_device_node(child))
+			ret = i3c_master_add_acpi_dev(master, child);
+		else
+			continue;
+
 		if (ret)
 			return ret;
 	}
@@ -2593,10 +2657,31 @@ static u8 i3c_master_i2c_get_lvr(struct i2c_client *client)
 {
 	/* Fall back to no spike filters and FM bus mode. */
 	u8 lvr = I3C_LVR_I2C_INDEX(2) | I3C_LVR_I2C_FM_MODE;
+	struct i2c_dev_boardinfo boardinfo;
+	struct acpi_device *adev;
+	LIST_HEAD(resources);
 	u32 reg[3];
+	int ret;
+
+	if (is_of_node(client->dev.fwnode)) {
+		if (!fwnode_property_read_u32_array(client->dev.fwnode, "reg",
+						    reg, ARRAY_SIZE(reg)))
+			lvr = reg[2];
+	} else if (is_acpi_device_node(client->dev.fwnode)) {
+		adev = to_acpi_device_node(client->dev.fwnode);
+		memset(&boardinfo, 0, sizeof(boardinfo));
+
+		ret = acpi_dev_get_resources(adev, &resources,
+					     i3c_acpi_get_i2c_resource, &boardinfo);
 
-	if (!fwnode_property_read_u32_array(client->dev.fwnode, "reg", reg, ARRAY_SIZE(reg)))
-		lvr = reg[2];
+		if (ret < 0)
+			return lvr;
+
+		if (boardinfo.base.addr)
+			lvr = boardinfo.lvr;
+
+		acpi_dev_free_resource_list(&resources);
+	}
 
 	return lvr;
 }
-- 
2.50.1