linux-kernel - [PATCH v2 3/3] mfd: madera: Allow more time for hardware reset

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Date:   Tue, 14 Jan 2020 15:10:48 +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 v2 3/3] 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>
---

Changes since v1:
 - Switch from a helper function to defines for the delay

This patch can be applied separately from the other patches in the series,
if needed.

Thanks,
Charles

 drivers/mfd/madera-core.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index a7d50a7fa625d..7e0835cb062b1 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -35,6 +35,9 @@
 
 #define MADERA_32KZ_MCLK2	1
 
+#define MADERA_RESET_MIN_US	2000
+#define MADERA_RESET_MAX_US	3000
+
 static const char * const madera_core_supplies[] = {
 	"AVDD",
 	"DBVDD1",
@@ -256,16 +259,13 @@ static int madera_soft_reset(struct madera *madera)
 	}
 
 	/* Allow time for internal clocks to startup after reset */
-	usleep_range(1000, 2000);
+	usleep_range(MADERA_RESET_MIN_US, MADERA_RESET_MAX_US);
 
 	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
@@ -276,11 +276,9 @@ 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);
+
+	usleep_range(MADERA_RESET_MIN_US, MADERA_RESET_MAX_US);
 }
 
 static int __maybe_unused madera_runtime_resume(struct device *dev)
@@ -299,6 +297,8 @@ static int __maybe_unused madera_runtime_resume(struct device *dev)
 	regcache_cache_only(madera->regmap, false);
 	regcache_cache_only(madera->regmap_32bit, false);
 
+	usleep_range(MADERA_RESET_MIN_US, MADERA_RESET_MAX_US);
+
 	ret = madera_wait_for_boot(madera);
 	if (ret)
 		goto err;
-- 
2.11.0