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

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Backwards compatibility is preserved; the subnodes are in practice
optional.

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: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Peter Rosin <peda@axentia.se>
This commit is contained in:
Peter Rosin 2016-07-09 21:53:42 +02:00
parent 8f7720b950
commit b2d57b5604
2 changed files with 42 additions and 10 deletions
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36
drivers/i2c/i2c-mux.c
View File

@ -255,6 +255,10 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
muxc->dev = dev; muxc->dev = dev;
if (flags & I2C_MUX_LOCKED) if (flags & I2C_MUX_LOCKED)
muxc->mux_locked = true; muxc->mux_locked = true;
if (flags & I2C_MUX_ARBITRATOR)
muxc->arbitrator = true;
if (flags & I2C_MUX_GATE)
muxc->gate = true;
muxc->select = select; muxc->select = select;
muxc->deselect = deselect; muxc->deselect = deselect;
muxc->max_adapters = max_adapters; muxc->max_adapters = max_adapters;
@ -335,18 +339,42 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
* nothing if !CONFIG_OF. * nothing if !CONFIG_OF.
*/ */
if (muxc->dev->of_node) { 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; u32 reg;
for_each_child_of_node(muxc->dev->of_node, 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");
else
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)) {
of_node_put(mux_node);
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); ret = of_property_read_u32(child, "reg", &reg);
if (ret) if (ret)
continue; continue;
if (chan_id == reg) { if (chan_id == reg)
priv->adap.dev.of_node = child;
break; break;
} }
} }
priv->adap.dev.of_node = child;
of_node_put(mux_node);
} }
/* /*

6
include/linux/i2c-mux.h
View File

@ -32,7 +32,9 @@
struct i2c_mux_core { struct i2c_mux_core {
struct i2c_adapter *parent; struct i2c_adapter *parent;
struct device *dev; struct device *dev;
bool mux_locked; unsigned int mux_locked:1;
unsigned int arbitrator:1;
unsigned int gate:1;
void *priv; void *priv;
@ -52,6 +54,8 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
/* flags for i2c_mux_alloc */ /* flags for i2c_mux_alloc */
#define I2C_MUX_LOCKED BIT(0) #define I2C_MUX_LOCKED BIT(0)
#define I2C_MUX_ARBITRATOR BIT(1)
#define I2C_MUX_GATE BIT(2)
static inline void *i2c_mux_priv(struct i2c_mux_core *muxc) static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
{ {