linux-kernel - [PATCH 5/9] drm/bridge: tc358767: Simplify polling in tc_link

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Date:   Tue, 26 Feb 2019 11:36:05 -0800
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Archit Taneja <architt@...eaurora.org>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Chris Healy <cphealy@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 5/9] drm/bridge: tc358767: Simplify polling in tc_link_training()

Replace explicit polling in tc_link_training() with equivalent call to
regmap_read_poll_timeout() for simplicity. No functional change
intended (not including slightly altered debug output).

Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
Cc: Archit Taneja <architt@...eaurora.org>
Cc: Andrzej Hajda <a.hajda@...sung.com>
Cc: Laurent Pinchart <Laurent.pinchart@...asonboard.com>
Cc: Chris Healy <cphealy@...il.com>
Cc: Lucas Stach <l.stach@...gutronix.de>
Cc: dri-devel@...ts.freedesktop.org
Cc: linux-kernel@...r.kernel.org
---
 drivers/gpu/drm/bridge/tc358767.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 6455e6484722..ea30cec4a0c3 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -735,7 +735,6 @@ static int tc_link_training(struct tc_data *tc, int pattern)
 	const char * const *errors;
 	u32 srcctrl = tc_srcctrl(tc) | DP0_SRCCTRL_SCRMBLDIS |
 		      DP0_SRCCTRL_AUTOCORRECT;
-	int timeout;
 	int retry;
 	u32 value;
 	int ret;
@@ -765,20 +764,17 @@ static int tc_link_training(struct tc_data *tc, int pattern)
 		tc_write(DP0CTL, DP_EN);
 
 		/* wait */
-		timeout = 1000;
-		do {
-			tc_read(DP0_LTSTAT, &value);
-			udelay(1);
-		} while ((!(value & LT_LOOPDONE)) && (--timeout));
-		if (timeout == 0) {
+		ret = regmap_read_poll_timeout(tc->regmap, DP0_LTSTAT, value,
+					       value & LT_LOOPDONE, 1, 1000);
+		if (ret) {
 			dev_err(tc->dev, "Link training timeout!\n");
 		} else {
 			int pattern = (value >> 11) & 0x3;
 			int error = (value >> 8) & 0x7;
 
 			dev_dbg(tc->dev,
-				"Link training phase %d done after %d uS: %s\n",
-				pattern, 1000 - timeout, errors[error]);
+				"Link training phase %d done: %s\n",
+				pattern, errors[error]);
 			if (pattern == DP_TRAINING_PATTERN_1 && error == 0)
 				break;
 			if (pattern == DP_TRAINING_PATTERN_2) {
-- 
2.20.1