[PATCH v3 06/10] video: tegra20: dc: add reset support

[Svyatoslav Ryhel]

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

Tested-by: Agneli <poczt at protonmail.ch> # Toshiba AC100 T20
Tested-by: Robert Eckelmann <longnoserob at gmail.com> # ASUS TF101
Tested-by: Andreas Westman Dorcsak <hedmoo at yahoo.com> # ASUS Grouper E1565
Tested-by: Ion Agorria <ion at agorria.com> # HTC One X
Tested-by: Svyatoslav Ryhel <clamor95 at gmail.com> # Nvidia Tegratab T114
Signed-off-by: Svyatoslav Ryhel <clamor95 at 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