From: Andrzej Hajda <a.hajda@samsung.com>
Date: Fri, 8 Jun 2018 08:04:57 +0200
Subject: drm/bridge/sii8620: simplify hardware reset procedure
Git-commit: 8efaac07d7e6694f39521f9fb8a5c848b712ecee
Patch-mainline: v4.18-rc2
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

There is no need to flip reset pin twice. Also delays can be changed to
values present in vendor's code.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Maciej Purski <m.purski@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180608060457.18357-1-a.hajda@samsung.com

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/bridge/sil-sii8620.c |   23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -971,8 +971,17 @@ static int sii8620_hw_on(struct sii8620
 	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
 	if (ret)
 		return ret;
+
 	usleep_range(10000, 20000);
-	return clk_prepare_enable(ctx->clk_xtal);
+	ret = clk_prepare_enable(ctx->clk_xtal);
+	if (ret)
+		return ret;
+
+	msleep(100);
+	gpiod_set_value(ctx->gpio_reset, 0);
+	msleep(100);
+
+	return 0;
 }
 
 static int sii8620_hw_off(struct sii8620 *ctx)
@@ -982,17 +991,6 @@ static int sii8620_hw_off(struct sii8620
 	return regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
 }
 
-static void sii8620_hw_reset(struct sii8620 *ctx)
-{
-	usleep_range(10000, 20000);
-	gpiod_set_value(ctx->gpio_reset, 0);
-	usleep_range(5000, 20000);
-	gpiod_set_value(ctx->gpio_reset, 1);
-	usleep_range(10000, 20000);
-	gpiod_set_value(ctx->gpio_reset, 0);
-	msleep(300);
-}
-
 static void sii8620_cbus_reset(struct sii8620 *ctx)
 {
 	sii8620_write(ctx, REG_PWD_SRST, BIT_PWD_SRST_CBUS_RST
@@ -2112,7 +2110,6 @@ static void sii8620_cable_in(struct sii8
 		dev_err(dev, "Error powering on, %d.\n", ret);
 		return;
 	}
-	sii8620_hw_reset(ctx);
 
 	sii8620_read_buf(ctx, REG_VND_IDL, ver, ARRAY_SIZE(ver));
 	ret = sii8620_clear_error(ctx);