[PATCH v2 1/2] drm/omap: panel-tpo-td028ttec1: add backlight support

[Andreas Kemnade <andreas@kemnade.info>]

This panel has a backlight, so fetch it from devicetree using the
corresponding property as documented in panel-common.txt. It is
implemented the same way as in panel-dpi.c
This ensures the backlight is also disabled when the display is
turned off like when doing xset dpms force off.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
Changes in v2: 
 - do not reorder initialisation
 - fix commit message

 drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c b/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c
index 7ddc8c574a61..1db8740f3c21 100644
--- a/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c
+++ b/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c
@@ -35,6 +35,8 @@ struct panel_drv_data {
 
 	struct videomode vm;
 
+	struct backlight_device *backlight;
+
 	struct spi_device *spi_dev;
 };
 
@@ -268,6 +270,8 @@ static int td028ttec1_panel_enable(struct omap_dss_device *dssdev)
 
 	r |= jbt_ret_write_0(ddata, JBT_REG_DISPLAY_ON);
 
+	backlight_enable(ddata->backlight);
+
 	dssdev->state = OMAP_DSS_DISPLAY_ACTIVE;
 
 transfer_err:
@@ -283,6 +287,8 @@ static void td028ttec1_panel_disable(struct omap_dss_device *dssdev)
 	if (!omapdss_device_is_enabled(dssdev))
 		return;
 
+	backlight_disable(ddata->backlight);
+
 	dev_dbg(dssdev->dev, "td028ttec1_panel_disable()\n");
 
 	jbt_ret_write_0(ddata, JBT_REG_DISPLAY_OFF);
@@ -334,6 +340,10 @@ static int td028ttec1_panel_probe(struct spi_device *spi)
 	if (ddata == NULL)
 		return -ENOMEM;
 
+	ddata->backlight = devm_of_find_backlight(&spi->dev);
+	if (IS_ERR(ddata->backlight))
+		return PTR_ERR(ddata->backlight);
+
 	dev_set_drvdata(&spi->dev, ddata);
 
 	ddata->spi_dev = spi;
-- 
2.11.0