The device might be described in the device tree but not connected to
the I2C bus. Update the status property so that the DRM panel logic
returns -ENODEV when someone tries to get the panel attached to this
DT node.
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
---
.../gpu/drm/panel/panel-raspberrypi-touchscreen.c | 35 ++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
index 2c9c9722734f..b8fcb1acef75 100644
--- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
+++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
@@ -358,6 +358,39 @@ static const struct drm_panel_funcs rpi_touchscreen_funcs = {
.get_modes = rpi_touchscreen_get_modes,
};
+static void rpi_touchscreen_set_status_fail(struct i2c_client *i2c)
+{
+ struct property *newprop;
+
+ newprop = kzalloc(sizeof(*newprop), GFP_KERNEL);
+ if (!newprop)
+ return;
+
+ newprop->name = kstrdup("status", GFP_KERNEL);
+ if (!newprop->name)
+ goto err;
+
+ newprop->value = kstrdup("fail", GFP_KERNEL);
+ if (!newprop->value)
+ goto err;
+
+ newprop->length = sizeof("fail");
+
+ if (of_update_property(i2c->dev.of_node, newprop))
+ goto err;
+
+ /* We intentionally leak the memory we allocate here, because the new
+ * OF property might live longer than the underlying dev, so no way
+ * we can use devm_kzalloc() here.
+ */
+ return;
+
+err:
+ kfree(newprop->value);
+ kfree(newprop->name);
+ kfree(newprop);
+}
+
static int rpi_touchscreen_probe(struct i2c_client *i2c,
const struct i2c_device_id *id)
{
@@ -382,6 +415,7 @@ static int rpi_touchscreen_probe(struct i2c_client *i2c,
ver = rpi_touchscreen_i2c_read(ts, REG_ID);
if (ver < 0) {
+ rpi_touchscreen_set_status_fail(i2c);
dev_err(dev, "Atmel I2C read failed: %d\n", ver);
return -ENODEV;
}
@@ -391,6 +425,7 @@ static int rpi_touchscreen_probe(struct i2c_client *i2c,
case 0xc3: /* ver 2 */
break;
default:
+ rpi_touchscreen_set_status_fail(i2c);
dev_err(dev, "Unknown Atmel firmware revision: 0x%02x\n", ver);
return -ENODEV;
}
--
2.14.1
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