From the ATSHA204A datasheet (document DS40002025A):
Wake: If SDA is held low for a period greater than tWLO, the device exits low-power mode and, after a delay of tWHI, is ready to receive I2C commands.
tWHI value can be found in table 7-2.
Signed-off-by: Paweł Anikiel pan@semihalf.com --- drivers/misc/atsha204a-i2c.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/atsha204a-i2c.c b/drivers/misc/atsha204a-i2c.c index aa6acf0f9a..81ecb5b617 100644 --- a/drivers/misc/atsha204a-i2c.c +++ b/drivers/misc/atsha204a-i2c.c @@ -21,7 +21,8 @@ #include <linux/bitrev.h> #include <u-boot/crc.h>
-#define ATSHA204A_TWLO 60 +#define ATSHA204A_TWLO_US 60 +#define ATSHA204A_TWHI_US 2500 #define ATSHA204A_TRANSACTION_TIMEOUT 100000 #define ATSHA204A_TRANSACTION_RETRY 5 #define ATSHA204A_EXECTIME 5000 @@ -109,7 +110,7 @@ int atsha204a_wakeup(struct udevice *dev) continue; }
- udelay(ATSHA204A_TWLO); + udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US);
res = atsha204a_recv_resp(dev, &resp); if (res) {