Commit b2d57b56 authored by Peter Rosin's avatar Peter Rosin
Browse files

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



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: default avatarWolfram Sang <wsa@the-dreams.de>
Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
parent 8f7720b9

drivers/i2c/i2c-mux.c

+36 −8
Original line number Diff line number Diff line
@@ -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) {

		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);

				if (ret)

					continue;

			if (chan_id == reg) {

				priv->adap.dev.of_node = child;

				if (chan_id == reg)

					break;

			}

		}



		priv->adap.dev.of_node = child;

		of_node_put(mux_node);

	}



	/*

include/linux/i2c-mux.h

+6 −2
Original line number Diff line number Diff line
@@ -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;
@@ -52,6 +54,8 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, 


/* flags for i2c_mux_alloc */

#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)

{

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