Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Charles Keepax <ckeepax@opensource.cirrus.com>
To:     <lee.jones@linaro.org>
CC:     <linux-kernel@vger.kernel.org>, <patches@opensource.cirrus.com>
Subject: [PATCH RESEND 2/3] mfd: madera: Wait for boot done before accessing any other registers
Date:   Tue, 14 Jan 2020 15:10:47 +0000
Message-ID: <20200114151048.20282-2-ckeepax@opensource.cirrus.com>
In-Reply-To: <20200114151048.20282-1-ckeepax@opensource.cirrus.com>
References: <20200114151048.20282-1-ckeepax@opensource.cirrus.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

It is advised to wait for the boot done bit to be set before reading
any other register, update the driver to respect this.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

This patch can be applied separately from the other patches in the series,
if needed. Just resending to keep everything together in one chain.

Thanks,
Charles

 drivers/mfd/madera-core.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index a8cfadc1fc01e..a7d50a7fa625d 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -199,7 +199,7 @@ EXPORT_SYMBOL_GPL(madera_name_from_type);
 #define MADERA_BOOT_POLL_INTERVAL_USEC		5000
 #define MADERA_BOOT_POLL_TIMEOUT_USEC		25000
 
-static int madera_wait_for_boot(struct madera *madera)
+static int madera_wait_for_boot_noack(struct madera *madera)
 {
 	ktime_t timeout;
 	unsigned int val = 0;
@@ -226,6 +226,13 @@ static int madera_wait_for_boot(struct madera *madera)
 		ret = -ETIMEDOUT;
 	}
 
+	return ret;
+}
+
+static int madera_wait_for_boot(struct madera *madera)
+{
+	int ret = madera_wait_for_boot_noack(madera);
+
 	/*
 	 * BOOT_DONE defaults to unmasked on boot so we must ack it.
 	 * Do this even after a timeout to avoid interrupt storms.
@@ -545,6 +552,12 @@ int madera_dev_init(struct madera *madera)
 	regcache_cache_only(madera->regmap, false);
 	regcache_cache_only(madera->regmap_32bit, false);
 
+	ret = madera_wait_for_boot_noack(madera);
+	if (ret) {
+		dev_err(madera->dev, "Device failed initial boot: %d\n", ret);
+		goto err_reset;
+	}
+
 	/*
 	 * Now we can power up and verify that this is a chip we know about
 	 * before we start doing any writes to its registers.
@@ -650,7 +663,7 @@ int madera_dev_init(struct madera *madera)
 
 	ret = madera_wait_for_boot(madera);
 	if (ret) {
-		dev_err(madera->dev, "Device failed initial boot: %d\n", ret);
+		dev_err(madera->dev, "Failed to clear boot done: %d\n", ret);
 		goto err_reset;
 	}
 
-- 
2.11.0