Commit b2d57b56 authored by Peter Rosin's avatar Peter Rosin

i2c: mux: add support for 'i2c-mux', 'i2c-arb' and 'i2c-gate' DT subnodes

Backwards compatibility is preserved; the subnodes are in practice

However, the mux core needs to know what subnode it should examine, so add
a couple of new flags for i2c_mux_alloc for this purpose.

The rule is that if the mux core finds a 'reg' property in the appropriate
subnode, e.g. if 'reg' exists in the 'i2c-mux' subnode, then the mux core
will assume that this is an old style entry and not an i2c-mux subnode
(correspondingly for arbitrators and gates with 'i2c-arb' and 'i2c-gate').
Reviewed-by: default avatarWolfram Sang <>
Signed-off-by: Peter Rosin's avatarPeter Rosin <>
parent 8f7720b9
......@@ -255,6 +255,10 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
muxc->dev = dev;
if (flags & I2C_MUX_LOCKED)
muxc->mux_locked = true;
if (flags & I2C_MUX_ARBITRATOR)
muxc->arbitrator = true;
if (flags & I2C_MUX_GATE)
muxc->gate = true;
muxc->select = select;
muxc->deselect = deselect;
muxc->max_adapters = max_adapters;
......@@ -335,18 +339,42 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
* nothing if !CONFIG_OF.
if (muxc->dev->of_node) {
struct device_node *child;
struct device_node *dev_node = muxc->dev->of_node;
struct device_node *mux_node, *child = NULL;
u32 reg;
for_each_child_of_node(muxc->dev->of_node, child) {
ret = of_property_read_u32(child, "reg", &reg);
if (ret)
if (chan_id == reg) {
priv-> = child;
if (muxc->arbitrator)
mux_node = of_get_child_by_name(dev_node, "i2c-arb");
else if (muxc->gate)
mux_node = of_get_child_by_name(dev_node, "i2c-gate");
mux_node = of_get_child_by_name(dev_node, "i2c-mux");
if (mux_node) {
/* A "reg" property indicates an old-style DT entry */
if (!of_property_read_u32(mux_node, "reg", &reg)) {
mux_node = NULL;
if (!mux_node)
mux_node = of_node_get(dev_node);
else if (muxc->arbitrator || muxc->gate)
child = of_node_get(mux_node);
if (!child) {
for_each_child_of_node(mux_node, child) {
ret = of_property_read_u32(child, "reg", &reg);
if (ret)
if (chan_id == reg)
priv-> = child;
......@@ -32,7 +32,9 @@
struct i2c_mux_core {
struct i2c_adapter *parent;
struct device *dev;
bool mux_locked;
unsigned int mux_locked:1;
unsigned int arbitrator:1;
unsigned int gate:1;
void *priv;
......@@ -51,7 +53,9 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
int (*deselect)(struct i2c_mux_core *, u32));
/* flags for i2c_mux_alloc */
#define I2C_MUX_LOCKED BIT(0)
#define I2C_MUX_LOCKED BIT(0)
#define I2C_MUX_GATE BIT(2)
static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
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