| Message ID | 20230405094149.1513209-1-jk@codeconstruct.com.au (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | i3c: Allow OF-alias-based persistent bus numbering | expand |
On 05/04/2023 10:41, Jeremy Kerr wrote: > 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@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) would it be worth passing the struct i3c_master_controller through this in case other info is needed at a later date? Does ACPI have anything similar? > { > - 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; >
Hi Ben, > > @@ -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) > > would it be worth passing the struct i3c_master_controller through > this in case other info is needed at a later date? Does ACPI have > anything similar? We could certainly add other platform enumeration data in future, but I don't know enough about ACPI device discovery to cater for everything at this stage. I'm just passing the OF node because that's all we need now; we can certainly extend once we have a concrete pattern for other platforms - this is just a static function, so it'll be easy to update. If we want to follow i2c: for non-OF-based static bus numbering, it's up to whatever is instantiating the i2c bus device to provide an id for i2c_add_numbered_adapter(). We don't have any users for that in i3c at present though, so it's probably a bit premature to add an equivalent API. Cheers, Jeremy
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;
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@codeconstruct.com.au> --- drivers/i3c/master.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-)