[PATCH] i3c: Allow OF-alias-based persistent bus numbering
Jeremy Kerr
jk at codeconstruct.com.au
Wed Apr 5 02:41:49 PDT 2023
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: Jeremy Kerr <jk at codeconstruct.com.au>
---
drivers/i3c/master.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index af8b9ebaec34..6a3169e4606e 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -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)
@@ -2618,7 +2630,7 @@ 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;
@@ -2846,8 +2858,16 @@ 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;
--
2.39.1
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