The it66121_ctx structure has a gpio_reset field, and it66121_hw_reset()
calls gpiod_set_value() on it. However, the GPIO descriptor is never
acquired via devm_gpiod_get(), leaving gpio_reset as NULL throughout
the driver lifetime.
gpiod_set_value() silently returns when passed a NULL descriptor, so
the hardware reset sequence in it66121_hw_reset() is a no-op. This
leaves the chip in an undefined state at probe time, which can prevent
it from responding on the I2C bus.
The DT binding marks reset-gpios as a required property, so all
compliant device trees provide this GPIO. Add the missing
devm_gpiod_get() call after enabling power supplies and before the
hardware reset, so the chip is properly reset with power applied.
Fixes: 988156dc2fc9 ("drm: bridge: add it66121 driver")
Cc: [email protected]
Signed-off-by: Julien Chauveau <[email protected]>
---
drivers/gpu/drm/bridge/ite-it66121.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/bridge/ite-it66121.c
b/drivers/gpu/drm/bridge/ite-it66121.c
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -1559,6 +1559,11 @@ static int it66121_probe(struct i2c_client *client)
return ret;
}
+ ctx->gpio_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(ctx->gpio_reset))
+ return dev_err_probe(dev, PTR_ERR(ctx->gpio_reset),
+ "Failed to get reset GPIO\n");
+
it66121_hw_reset(ctx);
