The device ignores any levels or transitions on the SCL pin when the device
is idle, asleep or during waking up.
Linux kernel driver for atsha204a (atmel-sha204a.ko) also ignores return
value from i2c wakeup send command, see:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/crypto/atmel-i2c.c?h=v5.19#n174
And also userspace Turris libatsha204 library ignores return value from
wakeup send command, see:
https://gitlab.nic.cz/turris/libatsha204/-/blob/v29.2/src/libatsha204/layer_ni2c.c#L75-76
U-Boot driver should do same thing.
Fixes waking up ATSHA204 on Turris 1.x boards.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Paweł Anikiel <pan@semihalf.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
for (try = 1; try <= 10; ++try) {
debug("Try %i... ", try);
+ /*
+ * The device ignores any levels or transitions on the SCL pin
+ * when the device is idle, asleep or during waking up.
+ * Don't check for error when waking up the device.
+ */
memset(req, 0, 4);
- res = atsha204a_send(dev, req, 4);
- if (res) {
- debug("failed on I2C send, trying again\n");
- continue;
- }
+ atsha204a_send(dev, req, 4);
udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US);