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From: Douglas Anderson <dianders@chromium.org>
To: Neil Armstrong <neil.armstrong@linaro.org>,
	Jessica Zhang <quic_jesszhan@quicinc.com>,
	Sam Ravnborg <sam@ravnborg.org>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Douglas Anderson <dianders@chromium.org>,
	Cong Yang <yangcong5@huaqin.corp-partner.google.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	David Airlie <airlied@gmail.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 5/8] drm/panel: ilitek-ili9882t: Check for errors on the NOP in prepare()
Date: Fri, 17 May 2024 14:36:40 -0700
Message-ID: <20240517143643.5.I323476ba9fa8cc7a5adee4c1ec95202785cc5686@changeid>
In-Reply-To: <20240517213712.3135166-1-dianders@chromium.org>
References: <20240517213712.3135166-1-dianders@chromium.org>
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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@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