Set an ACPI companion for I2C mux channels enumerated through ACPI and
ensure they are scanned for devices.
Signed-off-by: Dustin Byford <dus...@cumulusnetworks.com>
---
drivers/i2c/i2c-core.c | 10 ++++++++++
drivers/i2c/i2c-mux.c | 8 ++++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index c83e4d1..23cc8e9 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -171,8 +171,18 @@ static void acpi_i2c_register_devices(struct i2c_adapter
*adap)
if (!adap->dev.parent)
return;
+ /*
+ * Determine where to start walking the ACPI namespace. The common
+ * case is to start at the adapter's parent device. However, in
+ * the case of a "virtual" I2C adapter created to represent a mux
+ * channel the parent dev (pointing to the mux device) does not
+ * have an ACPI handle. Walk starting at the adapter instead.
+ */
handle = ACPI_HANDLE(adap->dev.parent);
if (!handle)
+ handle = ACPI_HANDLE(&adap->dev);
+
+ if (!handle)
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 2ba7c0f..2731b99 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -25,6 +25,7 @@
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/of.h>
+#include <linux/acpi.h>
/* multiplexer per channel data */
struct i2c_mux_priv {
@@ -173,6 +174,13 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter
*parent,
}
}
+ /*
+ * Now try to populate the mux adapter's ACPI node.
+ */
+ if (has_acpi_companion(mux_dev))
+ acpi_preset_companion(&priv->adap.dev, ACPI_COMPANION(mux_dev),
+ chan_id);
+
if (force_nr) {
priv->adap.nr = force_nr;
ret = i2c_add_numbered_adapter(&priv->adap);
--
2.1.4
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