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Subject[PATCH v6 2/4] soundwire: core: add device tree support for slave devices
Date
This patch adds support to parsing device tree based
SoundWire slave devices.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
drivers/soundwire/bus.c | 2 ++
drivers/soundwire/bus.h | 1 +
drivers/soundwire/slave.c | 52 +++++++++++++++++++++++++++++++++++++++
3 files changed, 55 insertions(+)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 728db3ebad6e..d83d89b3b15a 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -79,6 +79,8 @@ int sdw_add_bus_master(struct sdw_bus *bus)
*/
if (IS_ENABLED(CONFIG_ACPI) && ACPI_HANDLE(bus->dev))
ret = sdw_acpi_find_slaves(bus);
+ else if (IS_ENABLED(CONFIG_OF) && bus->dev->of_node)
+ ret = sdw_of_find_slaves(bus);
else
ret = -ENOTSUPP; /* No ACPI/DT so error out */

diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
index 9d6ea7e447ff..cb482da914da 100644
--- a/drivers/soundwire/bus.h
+++ b/drivers/soundwire/bus.h
@@ -15,6 +15,7 @@ static inline int sdw_acpi_find_slaves(struct sdw_bus *bus)
}
#endif

+int sdw_of_find_slaves(struct sdw_bus *bus);
void sdw_extract_slave_id(struct sdw_bus *bus,
u64 addr, struct sdw_slave_id *id);

diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index 4b522f6d1238..48a63ca130d2 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -2,6 +2,7 @@
// Copyright(c) 2015-17 Intel Corporation.

#include <linux/acpi.h>
+#include <linux/of.h>
#include <linux/soundwire/sdw.h>
#include <linux/soundwire/sdw_type.h>
#include "bus.h"
@@ -35,6 +36,7 @@ static int sdw_slave_add(struct sdw_bus *bus,

slave->dev.release = sdw_slave_release;
slave->dev.bus = &sdw_bus_type;
+ slave->dev.of_node = of_node_get(to_of_node(fwnode));
slave->bus = bus;
slave->status = SDW_SLAVE_UNATTACHED;
slave->dev_num = 0;
@@ -113,3 +115,53 @@ int sdw_acpi_find_slaves(struct sdw_bus *bus)
}

#endif
+
+/*
+ * sdw_of_find_slaves() - Find Slave devices in master device tree node
+ * @bus: SDW bus instance
+ *
+ * Scans Master DT node for SDW child Slave devices and registers it.
+ */
+int sdw_of_find_slaves(struct sdw_bus *bus)
+{
+ struct device *dev = bus->dev;
+ struct device_node *node;
+
+ for_each_child_of_node(bus->dev->of_node, node) {
+ int link_id, sdw_version, ret, len;
+ const char *compat = NULL;
+ struct sdw_slave_id id;
+ const __be32 *addr;
+
+ compat = of_get_property(node, "compatible", NULL);
+ if (!compat)
+ continue;
+
+ ret = sscanf(compat, "sdw%01x%04hx%04hx%02hhx", &sdw_version,
+ &id.mfg_id, &id.part_id, &id.class_id);
+
+ if (ret != 4) {
+ dev_err(dev, "Invalid compatible string found %s\n",
+ compat);
+ continue;
+ }
+
+ addr = of_get_property(node, "reg", &len);
+ if (!addr || (len < 2 * sizeof(u32))) {
+ dev_err(dev, "Invalid Link and Instance ID\n");
+ continue;
+ }
+
+ link_id = be32_to_cpup(addr++);
+ id.unique_id = be32_to_cpup(addr);
+ id.sdw_version = sdw_version;
+
+ /* Check for link_id match */
+ if (link_id != bus->link_id)
+ continue;
+
+ sdw_slave_add(bus, &id, of_fwnode_handle(node));
+ }
+
+ return 0;
+}
--
2.21.0
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