[PATCH v4 8/9] i2c: atr: add static flag

Cosmin Tanislav
2025-04-28T10:25:38Z

Some I2C ATRs do not support dynamic remapping, only static mapping
of direct children.

Add a new flag that prevents old mappings to be replaced or new mappings
to be created in the alias finding code paths.

Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
---
drivers/i2c/i2c-atr.c | 6 +++++-
include/linux/i2c-atr.h | 3 +++
2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-atr.c b/drivers/i2c/i2c-atr.c
index e2350fcf3d68..721dd680f2ac 100644
--- a/drivers/i2c/i2c-atr.c
+++ b/drivers/i2c/i2c-atr.c
@@ -341,12 +341,16 @@ i2c_atr_create_mapping_by_addr(struct i2c_atr_chan *chan, u16 addr)
static struct i2c_atr_alias_pair *
i2c_atr_get_mapping_by_addr(struct i2c_atr_chan *chan, u16 addr)
{
+ struct i2c_atr *atr = chan->atr;
struct i2c_atr_alias_pair *c2a;

c2a = i2c_atr_find_mapping_by_addr(chan, addr);
if (c2a)
return c2a;

+ if (atr->flags & I2C_ATR_F_STATIC)
+ return NULL;
+
c2a = i2c_atr_create_mapping_by_addr(chan, addr);
if (c2a)
return c2a;
@@ -545,7 +549,7 @@ static int i2c_atr_attach_addr(struct i2c_adapter *adapter,
mutex_lock(&chan->alias_pairs_lock);

c2a = i2c_atr_create_mapping_by_addr(chan, addr);
- if (!c2a)
+ if (!c2a && !(atr->flags & I2C_ATR_F_STATIC))
c2a = i2c_atr_replace_mapping_by_addr(chan, addr);

if (!c2a) {
diff --git a/include/linux/i2c-atr.h b/include/linux/i2c-atr.h
index 5082f4dd0e23..7c6a9627191d 100644
--- a/include/linux/i2c-atr.h
+++ b/include/linux/i2c-atr.h
@@ -20,8 +20,11 @@ struct i2c_atr;

/**
* enum i2c_atr_flags - Flags for an I2C ATR driver
+ *
+ * @I2C_ATR_F_STATIC: ATR does not support dynamic mapping, use static mapping
*/
enum i2c_atr_flags {
+ I2C_ATR_F_STATIC = BIT(0),
};

/**
--
2.49.0