Each bridge instance creates up to four auxiliary devices with different
names. However, their IDs are always zero, causing duplicate filename
errors when a system has multiple bridges:
sysfs: cannot create duplicate filename
'/bus/auxiliary/devices/ti_sn65dsi86.gpio.0'
Fix this by using a unique instance ID per bridge instance. The
instance ID is derived from the I2C adapter number and the bridge's I2C
address, to support multiple instances on the same bus.
Fixes: bf73537f411b0d4f ("drm/bridge: ti-sn65dsi86: Break GPIO and MIPI-to-eDP
bridge into sub-drivers")
Signed-off-by: Geert Uytterhoeven <[email protected]>
---
On the White Hawk development board:
/sys/bus/auxiliary/devices/
|-- ti_sn65dsi86.aux.1068
|-- ti_sn65dsi86.aux.4140
|-- ti_sn65dsi86.bridge.1068
|-- ti_sn65dsi86.bridge.4140
|-- ti_sn65dsi86.gpio.1068
|-- ti_sn65dsi86.gpio.4140
|-- ti_sn65dsi86.pwm.1068
`-- ti_sn65dsi86.pwm.4140
Discussion after v1:
-
https://lore.kernel.org/8c2df6a903f87d4932586b25f1d3bd548fe8e6d1.1729180470.git.geert+rene...@glider.be
Notes:
- While the bridge supports only two possible I2C addresses, I2C
translators may be present, increasing the address space. Hence the
instance ID calculation assumes 10-bit addressing. Perhaps it makes
sense to introduce a global I2C helper function for this?
- I think this is the simplest solution. If/when the auxiliary bus
receives support à la PLATFORM_DEVID_AUTO, the driver can be
updated.
v2:
- Use I2C adapter/address instead of ida_alloc().
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 9e31f750fd889745..fb452d1b46995673 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -480,6 +480,7 @@ static int ti_sn65dsi86_add_aux_device(struct ti_sn65dsi86
*pdata,
const char *name)
{
struct device *dev = pdata->dev;
+ const struct i2c_client *client = to_i2c_client(dev);
struct auxiliary_device *aux;
int ret;
@@ -488,6 +489,7 @@ static int ti_sn65dsi86_add_aux_device(struct ti_sn65dsi86
*pdata,
return -ENOMEM;
aux->name = name;
+ aux->id = (client->adapter->nr << 10) | client->addr;
aux->dev.parent = dev;
aux->dev.release = ti_sn65dsi86_aux_device_release;
device_set_of_node_from_dev(&aux->dev, dev);
--
2.34.1
