The second address can be used as a shortcut to access register pages
2+3. The driver does not use this feature yet. The second address should
still be marked as used, otherwise userspace could interfere with the
driver.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---

Change since v2: add comment in the code as well

 drivers/mfd/da9063-i2c.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mfd/da9063-i2c.c b/drivers/mfd/da9063-i2c.c
index 1ec9ab56442d..a803b7440f09 100644
--- a/drivers/mfd/da9063-i2c.c
+++ b/drivers/mfd/da9063-i2c.c
@@ -469,6 +469,9 @@ static int da9063_i2c_probe(struct i2c_client *i2c)
 		}
 	}
 
+	/* Reserve our unused second address so userspace won't interfere */
+	devm_i2c_new_dummy_device(&i2c->dev, i2c->adapter, i2c->addr + 1);
+
 	return da9063_device_init(da9063, i2c->irq);
 }
 
-- 
2.47.2

On Thu, 23 Oct 2025 08:55:59 +0200, Wolfram Sang wrote:
> The second address can be used as a shortcut to access register pages
> 2+3. The driver does not use this feature yet. The second address should
> still be marked as used, otherwise userspace could interfere with the
> driver.
> 
> 

Applied, thanks!

[1/1] mfd: da9063: occupy second I2C address, too
      commit: 3bf76786c95c52bd8cd065061126b3006a0177ed

--
Lee Jones [李琼斯]