linux-kernel - [PATCH 1/2] mfd: madera: Allow more time for hardware reset

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Date:   Mon, 6 Jan 2020 10:28:33 +0000
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     <lee.jones@...aro.org>
CC:     <linux-kernel@...r.kernel.org>, <patches@...nsource.cirrus.com>
Subject: [PATCH 1/2] mfd: madera: Allow more time for hardware reset

Both manual and power on resets have a brief period where the chip will
not be accessible immediately afterwards. Extend the time allowed for
this from a minimum of 1mS to 2mS based on newer evaluation of the
hardware and ensure this reset happens in all reset conditions. Whilst
making the change also remove the redundant NULL checks in the reset
functions as the GPIO functions already check for this.

Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
---
 drivers/mfd/madera-core.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index a8cfadc1fc01e..f41ce408259fb 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -238,6 +238,11 @@ static int madera_wait_for_boot(struct madera *madera)
 	return ret;
 }
 
+static inline void madera_reset_delay(void)
+{
+	usleep_range(2000, 3000);
+}
+
 static int madera_soft_reset(struct madera *madera)
 {
 	int ret;
@@ -249,16 +254,13 @@ static int madera_soft_reset(struct madera *madera)
 	}
 
 	/* Allow time for internal clocks to startup after reset */
-	usleep_range(1000, 2000);
+	madera_reset_delay();
 
 	return 0;
 }
 
 static void madera_enable_hard_reset(struct madera *madera)
 {
-	if (!madera->pdata.reset)
-		return;
-
 	/*
 	 * There are many existing out-of-tree users of these codecs that we
 	 * can't break so preserve the expected behaviour of setting the line
@@ -269,11 +271,9 @@ static void madera_enable_hard_reset(struct madera *madera)
 
 static void madera_disable_hard_reset(struct madera *madera)
 {
-	if (!madera->pdata.reset)
-		return;
-
 	gpiod_set_raw_value_cansleep(madera->pdata.reset, 1);
-	usleep_range(1000, 2000);
+
+	madera_reset_delay();
 }
 
 static int __maybe_unused madera_runtime_resume(struct device *dev)
@@ -292,6 +292,8 @@ static int __maybe_unused madera_runtime_resume(struct device *dev)
 	regcache_cache_only(madera->regmap, false);
 	regcache_cache_only(madera->regmap_32bit, false);
 
+	madera_reset_delay();
+
 	ret = madera_wait_for_boot(madera);
 	if (ret)
 		goto err;
-- 
2.11.0