linux-kernel - [PATCH v3 8/9] i2c: atr: add static flag

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Message-ID: <20250228151730.1874916-9-demonsingur@gmail.com>
Date: Fri, 28 Feb 2025 17:17:25 +0200
From: Cosmin Tanislav <demonsingur@...il.com>
To: 
Cc: Wolfram Sang <wsa+renesas@...g-engineering.com>,
	Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Romain Gantois <romain.gantois@...tlin.com>,
	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org,
	Cosmin Tanislav <demonsingur@...il.com>
Subject: [PATCH v3 8/9] i2c: atr: add static flag

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@...il.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 b3ad70a9d5f8..699cf23185c0 100644
--- a/drivers/i2c/i2c-atr.c
+++ b/drivers/i2c/i2c-atr.c
@@ -337,12 +337,16 @@ 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;
@@ -541,7 +545,7 @@ 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),
 };
 
 /**
-- 
2.48.1