[PATCH] video: stm32-ltdc: reset the controller on probe

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Linux resets the LTDC on probe. Let's do the same in barebox, so
a chainloaded barebox doesn't attempt reconfiguration of the DSI host
while the LTDC is still streaming to it.

Tested by chainloading the generic BL33 image on an STM32MP157C-DK2 and
observing it doesn't hang when framebuffer support is enabled.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/video/stm32_ltdc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/video/stm32_ltdc.c b/drivers/video/stm32_ltdc.c
index 43d443788364..5165bbf01749 100644
--- a/drivers/video/stm32_ltdc.c
+++ b/drivers/video/stm32_ltdc.c
@@ -272,6 +272,10 @@ static int ltdc_probe(struct device *dev)
 	if (IS_ERR(hw->pclk))
 		return dev_errp_probe(dev, hw->pclk, "peripheral clock get\n");
 
+	ret = device_reset_us(dev, 10);
+	if (ret)
+		return dev_err_probe(dev, ret, "peripheral reset\n");
+
 	for_each_available_child_of_node(dev->of_node, np) {
 		struct ltdc_fb *priv;
 		struct of_endpoint ep;
-- 
2.47.3