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authorRichard Fitzgerald <rf@opensource.cirrus.com>2018-08-27 14:51:15 +0100
committerLee Jones <lee.jones@linaro.org>2018-10-23 08:58:34 +0100
commitb04e68d16605dcde1c21b5df5f86a5372e53ae97 (patch)
tree539c884321e9b00d65e6a1d1b52773a342ced999 /drivers/mfd
parent6b269a41a4520f7eb639e61a45ebbb9c9267d5e0 (diff)
mfd: madera: Don't use regmap_read_poll_timeout to poll for BOOT_DONE
While polling for BOOT_DONE the chip could NAK a read because it is still booting, which would terminate the regmap_read_poll_timeout() with an error. Instead implement a polling loop that ignores read errors so we always poll until the chip signals boot or the loop times out. Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/madera-core.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index 8cfea969b060..440030cecbbd 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -132,32 +132,39 @@ const char *madera_name_from_type(enum madera_type type)
}
EXPORT_SYMBOL_GPL(madera_name_from_type);
-#define MADERA_BOOT_POLL_MAX_INTERVAL_US 5000
-#define MADERA_BOOT_POLL_TIMEOUT_US 25000
+#define MADERA_BOOT_POLL_INTERVAL_USEC 5000
+#define MADERA_BOOT_POLL_TIMEOUT_USEC 25000
static int madera_wait_for_boot(struct madera *madera)
{
+ ktime_t timeout;
unsigned int val;
- int ret;
+ int ret = 0;
/*
* We can't use an interrupt as we need to runtime resume to do so,
* so we poll the status bit. This won't race with the interrupt
* handler because it will be blocked on runtime resume.
+ * The chip could NAK a read request while it is booting so ignore
+ * errors from regmap_read.
*/
- ret = regmap_read_poll_timeout(madera->regmap,
- MADERA_IRQ1_RAW_STATUS_1,
- val,
- (val & MADERA_BOOT_DONE_STS1),
- MADERA_BOOT_POLL_MAX_INTERVAL_US,
- MADERA_BOOT_POLL_TIMEOUT_US);
-
- if (ret)
- dev_err(madera->dev, "Polling BOOT_DONE_STS failed: %d\n", ret);
+ timeout = ktime_add_us(ktime_get(), MADERA_BOOT_POLL_TIMEOUT_USEC);
+ regmap_read(madera->regmap, MADERA_IRQ1_RAW_STATUS_1, &val);
+ while (!(val & MADERA_BOOT_DONE_STS1) &&
+ !ktime_after(ktime_get(), timeout)) {
+ usleep_range(MADERA_BOOT_POLL_INTERVAL_USEC / 2,
+ MADERA_BOOT_POLL_INTERVAL_USEC);
+ regmap_read(madera->regmap, MADERA_IRQ1_RAW_STATUS_1, &val);
+ };
+
+ if (!(val & MADERA_BOOT_DONE_STS1)) {
+ dev_err(madera->dev, "Polling BOOT_DONE_STS timed out\n");
+ ret = -ETIMEDOUT;
+ }
/*
* BOOT_DONE defaults to unmasked on boot so we must ack it.
- * Do this unconditionally to avoid interrupt storms.
+ * Do this even after a timeout to avoid interrupt storms.
*/
regmap_write(madera->regmap, MADERA_IRQ1_STATUS_1,
MADERA_BOOT_DONE_EINT1);