[PATCH V4 2/6] of/slimbus: OF helper for SLIMbus

[Sagar Dharia]

OF helper routine scans the SLIMbus DeviceTree, allocates resources,
and creates slim_devices according to the hierarchy.

Signed-off-by: Sagar Dharia <sdharia@xxxxxxxxxxxxxx>
---
 Documentation/devicetree/bindings/slimbus/bus.txt | 54 ++++++++++++++++
 drivers/slimbus/slim-core.c                       | 75 +++++++++++++++++++++++
 2 files changed, 129 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/slimbus/bus.txt

diff --git a/Documentation/devicetree/bindings/slimbus/bus.txt b/Documentation/devicetree/bindings/slimbus/bus.txt
new file mode 100644
index 0000000..71c769d
--- /dev/null
+++ b/Documentation/devicetree/bindings/slimbus/bus.txt
@@ -0,0 +1,54 @@
+SLIM(Serial Low Power Interchip Media Bus) bus
+
+SLIMbus is a 2-wire bus, and is used to communicate with peripheral
+components like audio-codec.
+
+Controller is a normal device using binding for whatever bus it is
+on (e.g. platform bus).
+Required property for SLIMbus controller node:
+- compatible	- name of SLIMbus controller following generic names
+		recommended practice.
+- #address-cells - should be 4 (number of cells required to define
+		4 fields of the enumeration address for the SLIMbus
+		slave device)
+- #size-cells	- should be 0
+
+No other properties are required in the SLIMbus controller bus node.
+
+Child nodes:
+Every SLIMbus controller node can contain zero or more child nodes
+representing slave devices on the bus. Every SLIMbus slave device is
+uniquely determined by the enumeration address containing 4 fields:
+Manufacturer ID, Product code, Device index, and Instance value for
+the device.
+
+Required property for SLIMbus child node:
+- reg		- enumeration address fields of the device
+
+Optional:
+- compatible	- Slave devices can use compatible field to have a name.
+		If this field is missing, name of the device will be
+		determined using slave's enumeration address.
+		(e.g. in the example below, slave's name will be:
+		0x217:0x60:0x1:0x0)
+		Note that the property is listed as optional since the
+		devices are discoverable when they are functional.
+		However, the device may need additional non-standard
+		way to power it up so that it can start functioning.
+		In that case, compatible property will be
+		needed for the corresponding driver to probe and
+		perform the required procedure to make it functional.
+
+SLIMbus example for Qualcomm's slimbus manager component:
+
+	slim@28080000 {
+		compatible = "qcom,slim-msm";
+		reg = <0x28080000 0x2000>,
+		interrupts = <0 33 0>;
+		clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;
+		clock-names = "iface_clk", "core_clk";
+
+		codec_slave@xxxxxxxxxxxxxxx {
+			reg = <0x217 0x60 0x1 0x0>;
+		};
+	};
diff --git a/drivers/slimbus/slim-core.c b/drivers/slimbus/slim-core.c
index 5b9fefa..4c2c646 100644
--- a/drivers/slimbus/slim-core.c
+++ b/drivers/slimbus/slim-core.c
@@ -18,6 +18,7 @@
 #include <linux/idr.h>
 #include <linux/pm_runtime.h>
 #include <linux/slimbus.h>
+#include <linux/of.h>
 
 static DEFINE_MUTEX(slim_lock);
 static DEFINE_IDR(ctrl_idr);
@@ -279,6 +280,79 @@ static LIST_HEAD(board_list);
 static LIST_HEAD(slim_ctrl_list);
 static DEFINE_MUTEX(board_lock);
 
+#if IS_ENABLED(CONFIG_OF)
+/* OF helpers for SLIMbus */
+static void of_register_slim_devices(struct slim_controller *ctrl)
+{
+	struct device_node *node;
+	struct slim_boardinfo *temp, *binfo = NULL;
+	int n = 0;
+
+	if (!ctrl->dev.of_node)
+		return;
+
+	for_each_child_of_node(ctrl->dev.of_node, node) {
+		int ret;
+		u32 ea[4];
+		struct slim_device *slim;
+		char *name;
+
+		ret = of_property_read_u32_array(node, "reg", ea, 4);
+		if (ret) {
+			dev_err(&ctrl->dev, "of_slim: E-addr err:%d\n", ret);
+			continue;
+		}
+		name = kcalloc(SLIMBUS_NAME_SIZE, sizeof(char), GFP_KERNEL);
+		if (!name)
+			goto of_slim_err;
+
+		slim = kzalloc(sizeof(struct slim_device), GFP_KERNEL);
+		if (!slim) {
+			kfree(name);
+			goto of_slim_err;
+		}
+		slim->e_addr.manf_id = (u16)ea[0];
+		slim->e_addr.prod_code = (u16)ea[1];
+		slim->e_addr.dev_index = (u8)ea[2];
+		slim->e_addr.instance = (u8)ea[3];
+
+		ret = of_modalias_node(node, name, SLIMBUS_NAME_SIZE);
+		if (ret < 0) {
+			/* use device address for name, if not specified */
+			snprintf(name, SLIMBUS_NAME_SIZE, "0x%x:0x%x:0x%x:0x%x",
+				 slim->e_addr.manf_id, slim->e_addr.prod_code,
+				 slim->e_addr.dev_index, slim->e_addr.instance);
+		}
+
+		temp = krealloc(binfo, (n + 1) * sizeof(struct slim_boardinfo),
+					GFP_KERNEL);
+		if (!temp) {
+			kfree(name);
+			kfree(slim);
+			goto of_slim_err;
+		}
+		binfo = temp;
+		slim->dev.of_node = of_node_get(node);
+		slim->name = name;
+		binfo[n].bus_num = ctrl->nr;
+		binfo[n].slim_slave = slim;
+		n++;
+	}
+	slim_register_board_info(binfo, n);
+	return;
+
+of_slim_err:
+	n--;
+	while (n >= 0) {
+		kfree(binfo[n].slim_slave->name);
+		kfree(binfo[n].slim_slave);
+	}
+	kfree(binfo);
+}
+#else
+static void of_register_slim_devices(struct slim_controller *ctrl) { }
+#endif
+
 /* If controller is not present, only add to boards list */
 static void slim_match_ctrl_to_boardinfo(struct slim_controller *ctrl,
 					 struct slim_boardinfo *bi)
@@ -328,6 +402,7 @@ static void slim_ctrl_add_boarddevs(struct slim_controller *ctrl)
 {
 	struct sbi_boardinfo *bi;
 
+	of_register_slim_devices(ctrl);
 	mutex_lock(&board_lock);
 	list_add_tail(&ctrl->list, &slim_ctrl_list);
 	list_for_each_entry(bi, &board_list, list)
-- 
1.8.2.1