Based on latest silicon validation, we should allow at least 2 milliseconds after DCVDD enable or hard reset before trying to communicate with the silicon.
Previously the delay was done as a side-effect of madera_disable_hard_reset(). As we also need this delay when enabling DCVDD (with or without hard reset) it is better for it to be obvious where it happens in every power-up sequence rather than hidden within another call in some cases. So it has been moved out into a separate function call. Signed-off-by: Richard Fitzgerald <[email protected]> --- drivers/mfd/madera-core.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c index 440030cecbbd..1dedfe68a3dc 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) +{ + /* + * Delay after DCVDD enable or hard reset to allow for silicon POR + * (power-on reset). + */ + usleep_range(2000, 3000); +} + static int madera_wait_for_boot(struct madera *madera) { ktime_t timeout; @@ -209,7 +218,6 @@ static void madera_disable_hard_reset(struct madera *madera) return; gpiod_set_raw_value_cansleep(madera->pdata.reset, 1); - usleep_range(1000, 2000); } static int __maybe_unused madera_runtime_resume(struct device *dev) @@ -225,6 +233,8 @@ 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); @@ -440,6 +450,7 @@ int madera_dev_init(struct madera *madera) } madera_disable_hard_reset(madera); + madera_por_delay(); regcache_cache_only(madera->regmap, false); regcache_cache_only(madera->regmap_32bit, false); -- 2.11.0
