From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: <lee.jones@linaro.org>
Cc: <patches@opensource.cirrus.com>, <linux-kernel@vger.kernel.org>,
"Richard Fitzgerald" <rf@opensource.cirrus.com>
Subject: [PATCH 1/2] mfd: madera: Increase wait for silicon reset
Date: Mon, 1 Oct 2018 15:33:56 +0100 [thread overview]
Message-ID: <20181001143357.28428-1-rf@opensource.cirrus.com> (raw)
Based on latest silicon validation we should allow at least
2 milliseconds after DCVDD enable or hard reset released before
trying to communicate with the silicon.
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
drivers/mfd/madera-core.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index 440030cecbbd..3ff9a0615658 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -135,6 +135,15 @@ EXPORT_SYMBOL_GPL(madera_name_from_type);
#define MADERA_BOOT_POLL_INTERVAL_USEC 5000
#define MADERA_BOOT_POLL_TIMEOUT_USEC 25000
+static void madera_por_delay(void)
+{
+ /*
+ * After DCVDD enable or hard reset released wait for internal
+ * POR (power-on-reset) before trying to communicate with the silicon
+ */
+ usleep_range(2000, 3000);
+}
+
static int madera_wait_for_boot(struct madera *madera)
{
ktime_t timeout;
@@ -209,7 +218,7 @@ static void madera_disable_hard_reset(struct madera *madera)
return;
gpiod_set_raw_value_cansleep(madera->pdata.reset, 1);
- usleep_range(1000, 2000);
+ madera_por_delay();
}
static int __maybe_unused madera_runtime_resume(struct device *dev)
@@ -225,6 +234,7 @@ static int __maybe_unused madera_runtime_resume(struct device *dev)
return ret;
}
+ madera_por_delay();
regcache_cache_only(madera->regmap, false);
regcache_cache_only(madera->regmap_32bit, false);
--
2.11.0
next reply other threads:[~2018-10-01 14:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-01 14:33 Richard Fitzgerald [this message]
2018-10-01 14:33 ` [PATCH 2/2] mfd: madera: Wait for BOOT_DONE before reading device ID Richard Fitzgerald
2018-10-02 8:52 ` Charles Keepax
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