Implement reset use to discard any changes which could have been
applied to DC before and can interfere with current configuration.

Tested-by: Agneli <po...@protonmail.ch> # Toshiba AC100 T20
Tested-by: Robert Eckelmann <longnose...@gmail.com> # ASUS TF101
Tested-by: Andreas Westman Dorcsak <hed...@yahoo.com> # ASUS Grouper E1565
Tested-by: Ion Agorria <i...@agorria.com> # HTC One X
Tested-by: Svyatoslav Ryhel <clamo...@gmail.com> # Nvidia Tegratab T114
Signed-off-by: Svyatoslav Ryhel <clamo...@gmail.com>
---
 drivers/video/tegra20/tegra-dc.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/video/tegra20/tegra-dc.c b/drivers/video/tegra20/tegra-dc.c
index 56a23b3c97..35abb6fe46 100644
--- a/drivers/video/tegra20/tegra-dc.c
+++ b/drivers/video/tegra20/tegra-dc.c
@@ -10,7 +10,9 @@
 #include <panel.h>
 #include <part.h>
 #include <pwm.h>
+#include <reset.h>
 #include <video.h>
+#include <linux/delay.h>
 #include <asm/cache.h>
 #include <asm/global_data.h>
 #include <asm/system.h>
@@ -342,6 +344,7 @@ static int tegra_lcd_probe(struct udevice *dev)
        struct video_uc_plat *plat = dev_get_uclass_plat(dev);
        struct video_priv *uc_priv = dev_get_uclass_priv(dev);
        struct tegra_lcd_priv *priv = dev_get_priv(dev);
+       struct reset_ctl reset_ctl;
        int ret;
 
        /* Initialize the Tegra display controller */
@@ -349,6 +352,20 @@ static int tegra_lcd_probe(struct udevice *dev)
        funcmux_select(PERIPH_ID_DISP1, FUNCMUX_DEFAULT);
 #endif
 
+       ret = reset_get_by_name(dev, "dc", &reset_ctl);
+       if (ret) {
+               log_err("reset_get_by_name() failed: %d\n", ret);
+               return ret;
+       }
+
+       clock_disable(priv->dc_clk[0]);
+
+       /* Reset everything set before */
+       reset_assert(&reset_ctl);
+       mdelay(4);
+       reset_deassert(&reset_ctl);
+       mdelay(4);
+
        if (tegra_display_probe(priv, (void *)plat->base)) {
                debug("%s: Failed to probe display driver\n", __func__);
                return -1;
-- 
2.40.1

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