drm/tinydrm/mipi-dbi: Add poweron-reset functions

Split out common poweron-reset functionality.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180110185940.53841-5-noralf@tronnes.org
diff --git a/drivers/gpu/drm/tinydrm/st7735r.c b/drivers/gpu/drm/tinydrm/st7735r.c
index 1f38e15..08b4fb1 100644
--- a/drivers/gpu/drm/tinydrm/st7735r.c
+++ b/drivers/gpu/drm/tinydrm/st7735r.c
@@ -40,19 +40,14 @@ static void jd_t18003_t01_pipe_enable(struct drm_simple_display_pipe *pipe,
 {
 	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
-	struct device *dev = tdev->drm->dev;
 	int ret;
 	u8 addr_mode;
 
 	DRM_DEBUG_KMS("\n");
 
-	mipi_dbi_hw_reset(mipi);
-
-	ret = mipi_dbi_command(mipi, MIPI_DCS_SOFT_RESET);
-	if (ret) {
-		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
+	ret = mipi_dbi_poweron_reset(mipi);
+	if (ret)
 		return;
-	}
 
 	msleep(150);