Re: [alsa-devel] [RESEND PATCH v4 2/4] soundwire: core: add device tree support for slave devices

On 8/22/19 6:37 PM, Srinivas Kandagatla wrote:

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 49f64b2115b9..c2eaeb5c38ed 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -77,6 +77,8 @@ 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 3048ca153f22..ee46befedbd1 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 f39a5815e25d..3ef265d2ee89 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;

@@ -112,3 +114,53 @@ 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 Instance and Link ID\n");
  

• 	continue;
  

• }
  

• id.unique_id = be32_to_cpup(addr++);
  

• link_id = be32_to_cpup(addr);
  

So here the link ID is obviously not in the address, so you are not using the MIPI spec as we discussed initially?

• 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;

+}