[PATCH 1/2] drm/dsi: Implement DCS get display mode

[Vinay Simha BN]

Provide a small convenience wrapper that transmits
a DCS get_display_mode command.

Signed-off-by: Vinay Simha BN <simhavcs at gmail.com>
---
 drivers/gpu/drm/drm_mipi_dsi.c | 24 ++++++++++++++++++++++++
 include/drm/drm_mipi_dsi.h     |  1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index f5d8083..2e032ea 100644
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -792,6 +792,30 @@ int mipi_dsi_dcs_get_power_mode(struct mipi_dsi_device *dsi, u8 *mode)
 EXPORT_SYMBOL(mipi_dsi_dcs_get_power_mode);
 
 /**
+ * mipi_dsi_dcs_get_display_mode() - query the display module's image mode
+ * @dsi: DSI peripheral device
+ * @mode: return location for the display image mode
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int mipi_dsi_dcs_get_display_mode(struct mipi_dsi_device *dsi, u8 *mode)
+{
+	ssize_t err;
+
+	err = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_MODE, mode,
+				sizeof(*mode));
+	if (err <= 0) {
+		if (err == 0)
+			err = -ENODATA;
+
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_get_display_mode);
+
+/**
  * mipi_dsi_dcs_get_pixel_format() - gets the pixel format for the RGB image
  *    data used by the interface
  * @dsi: DSI peripheral device
diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 7a9840f..48fcd65 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -254,6 +254,7 @@ ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
 int mipi_dsi_dcs_nop(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_soft_reset(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_get_power_mode(struct mipi_dsi_device *dsi, u8 *mode);
+int mipi_dsi_dcs_get_display_mode(struct mipi_dsi_device *dsi, u8 *mode);
 int mipi_dsi_dcs_get_pixel_format(struct mipi_dsi_device *dsi, u8 *format);
 int mipi_dsi_dcs_enter_sleep_mode(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_exit_sleep_mode(struct mipi_dsi_device *dsi);
-- 
2.1.2