Commit 7dc2e0a8 authored by Jeremy Kerr's avatar Jeremy Kerr Committed by Alexandre Belloni
Browse files

i3c: Allow OF-alias-based persistent bus numbering 



Parse the /aliases node to assign any fixed bus numbers, as is done with
the i2c subsystem. Numbering for non-aliased busses will start after the
highest fixed bus number.

This allows an alias node such as:

    aliases {
        i3c0 = &bus_a,
	i3c4 = &bus_b,
    };

to set the numbering for a set of i3c controllers:

    /* fixed-numbered bus, assigned "i3c-0" */
    bus_a: i3c-master {
    };

    /* another fixed-numbered bus, assigned "i3c-4" */
    bus_b: i3c-master {
    };

    /* dynamic-numbered bus, likely assigned "i3c-5" */
    bus_c: i3c-master {
    };

If no i3c device aliases are present, the numbering will stay as-is,
starting from 0.

Signed-off-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20230405094149.1513209-1-jk@codeconstruct.com.au


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 58445641

drivers/i3c/master.c

+25 −5
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 


static DEFINE_IDR(i3c_bus_idr);

static DEFINE_MUTEX(i3c_core_lock);

static int __i3c_first_dynamic_bus_num;



/**

 * i3c_bus_maintenance_lock - Lock the bus for a maintenance operation
@@ -419,9 +420,9 @@ static void i3c_bus_cleanup(struct i3c_bus *i3cbus) 
	mutex_unlock(&i3c_core_lock);

}



static int i3c_bus_init(struct i3c_bus *i3cbus)

static int i3c_bus_init(struct i3c_bus *i3cbus, struct device_node *np)

{

	int ret;

	int ret, start, end, id = -1;



	init_rwsem(&i3cbus->lock);

	INIT_LIST_HEAD(&i3cbus->devs.i2c);
@@ -429,8 +430,19 @@ static int i3c_bus_init(struct i3c_bus *i3cbus) 
	i3c_bus_init_addrslots(i3cbus);

	i3cbus->mode = I3C_BUS_MODE_PURE;



	if (np)

		id = of_alias_get_id(np, "i3c");



	mutex_lock(&i3c_core_lock);

	ret = idr_alloc(&i3c_bus_idr, i3cbus, 0, 0, GFP_KERNEL);

	if (id >= 0) {

		start = id;

		end = start + 1;

	} else {

		start = __i3c_first_dynamic_bus_num;

		end = 0;

	}



	ret = idr_alloc(&i3c_bus_idr, i3cbus, start, end, GFP_KERNEL);

	mutex_unlock(&i3c_core_lock);



	if (ret < 0)
@@ -2606,7 +2618,7 @@ int i3c_master_register(struct i3c_master_controller *master, 
	INIT_LIST_HEAD(&master->boardinfo.i2c);

	INIT_LIST_HEAD(&master->boardinfo.i3c);



	ret = i3c_bus_init(i3cbus);

	ret = i3c_bus_init(i3cbus, master->dev.of_node);

	if (ret)

		return ret;
@@ -2830,8 +2842,16 @@ void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev) 


static int __init i3c_init(void)

{

	int res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);

	int res;



	res = of_alias_get_highest_id("i3c");

	if (res >= 0) {

		mutex_lock(&i3c_core_lock);

		__i3c_first_dynamic_bus_num = res + 1;

		mutex_unlock(&i3c_core_lock);

	}



	res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);

	if (res)

		return res;