[PATCH v4 04/24] drm/mipi-dsi: Create devm device attachment

[Maxime Ripard <maxime@cerno.tech>]

MIPI-DSI devices need to call mipi_dsi_attach() when their probe is done
to attach against their host.

However, at removal or when an error occurs, that attachment needs to be
undone through a call to mipi_dsi_detach().

Let's create a device-managed variant of the attachment function that
will automatically detach the device at unbind.

Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/drm_mipi_dsi.c | 35 ++++++++++++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  1 +
 2 files changed, 36 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index ddf67463eaa1..18cef04df2f2 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -391,6 +391,41 @@ int mipi_dsi_detach(struct mipi_dsi_device *dsi)
 }
 EXPORT_SYMBOL(mipi_dsi_detach);
 
+static void devm_mipi_dsi_detach(void *arg)
+{
+	struct mipi_dsi_device *dsi = arg;
+
+	mipi_dsi_detach(dsi);
+}
+
+/**
+ * devm_mipi_dsi_attach - Attach a MIPI-DSI device to its DSI Host
+ * @dev: device to tie the MIPI-DSI device attachment lifetime to
+ * @dsi: DSI peripheral
+ *
+ * This is the managed version of mipi_dsi_attach() which automatically
+ * calls mipi_dsi_detach() when @dev is unbound.
+ *
+ * Returns:
+ * 0 on success, a negative error code on failure.
+ */
+int devm_mipi_dsi_attach(struct device *dev,
+			 struct mipi_dsi_device *dsi)
+{
+	int ret;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, devm_mipi_dsi_detach, dsi);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_mipi_dsi_attach);
+
 static ssize_t mipi_dsi_device_transfer(struct mipi_dsi_device *dsi,
 					struct mipi_dsi_msg *msg)
 {
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index d0032e435e08..147e51b6d241 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -233,6 +233,7 @@ devm_mipi_dsi_device_register_full(struct device *dev, struct mipi_dsi_host *hos
 struct mipi_dsi_device *of_find_mipi_dsi_device_by_node(struct device_node *np);
 int mipi_dsi_attach(struct mipi_dsi_device *dsi);
 int mipi_dsi_detach(struct mipi_dsi_device *dsi);
+int devm_mipi_dsi_attach(struct device *dev, struct mipi_dsi_device *dsi);
 int mipi_dsi_shutdown_peripheral(struct mipi_dsi_device *dsi);
 int mipi_dsi_turn_on_peripheral(struct mipi_dsi_device *dsi);
 int mipi_dsi_set_maximum_return_packet_size(struct mipi_dsi_device *dsi,
-- 
2.31.1