[PATCH RESEND 2/3] mfd: madera: Wait for boot done before accessing any other registers

From: Charles Keepax
Date: Tue Jan 14 2020 - 10:10:57 EST


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@xxxxxxxxxxxxxxxxxxxxx>
---

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