From b04e68d16605dcde1c21b5df5f86a5372e53ae97 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Mon, 27 Aug 2018 14:51:15 +0100 Subject: [PATCH] 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 Signed-off-by: Lee Jones --- drivers/mfd/madera-core.c | 33 ++++++++++++++++++++------------- 1 file 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); -- 2.30.2