[PATCH 5/8] drm/panel: ilitek-ili9882t: Check for errors on the NOP in prepare()

[Douglas Anderson]

The mipi_dsi_dcs_nop() function returns an error but we weren't
checking it in ili9882t_prepare(). Add a check. This is highly
unlikely to matter in practice. If the NOP failed then likely later
MIPI commands would fail too.

Found by code inspection.

Fixes: e2450d32e5fb ("drm/panel: ili9882t: Break out as separate driver")
Signed-off-by: Douglas Anderson <dianders at chromium.org>
---

 drivers/gpu/drm/panel/panel-ilitek-ili9882t.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9882t.c b/drivers/gpu/drm/panel/panel-ilitek-ili9882t.c
index a2ea25bb6624..266a087fe14c 100644
--- a/drivers/gpu/drm/panel/panel-ilitek-ili9882t.c
+++ b/drivers/gpu/drm/panel/panel-ilitek-ili9882t.c
@@ -478,7 +478,11 @@ static int ili9882t_prepare(struct drm_panel *panel)
 	usleep_range(10000, 11000);
 
 	// MIPI needs to keep the LP11 state before the lcm_reset pin is pulled high
-	mipi_dsi_dcs_nop(ili->dsi);
+	ret = mipi_dsi_dcs_nop(ili->dsi);
+	if (ret < 0) {
+		dev_err(&ili->dsi->dev, "Failed to send NOP: %d\n", ret);
+		goto poweroff;
+	}
 	usleep_range(1000, 2000);
 
 	gpiod_set_value(ili->enable_gpio, 1);
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog