kernel_samsung_a53x/drivers/tty
Hugo Villeneuve 973fdf7efa serial: max310x: improve crystal stable clock detection
commit 93cd256ab224c2519e7c4e5f58bb4f1ac2bf0965 upstream.

Some people are seeing a warning similar to this when using a crystal:

    max310x 11-006c: clock is not stable yet

The datasheet doesn't mention the maximum time to wait for the clock to be
stable when using a crystal, and it seems that the 10ms delay in the driver
is not always sufficient.

Jan Kundrát reported that it took three tries (each separated by 10ms) to
get a stable clock.

Modify behavior to check stable clock ready bit multiple times (20), and
waiting 10ms between each try.

Note: the first draft of the driver originally used a 50ms delay, without
checking the clock stable bit.
Then a loop with 1000 retries was implemented, each time reading the clock
stable bit.

Fixes: 4cf9a888fd3c ("serial: max310x: Check the clock readiness")
Cc: stable@vger.kernel.org
Suggested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Link: https://www.spinics.net/lists/linux-serial/msg35773.html
Link: https://lore.kernel.org/all/20240110174015.6f20195fde08e5c9e64e5675@hugovil.com/raw
Link: e5dfe3e4a7
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240116213001.3691629-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-18 12:13:31 +01:00
..
hvc
ipwireless
serdev
serial serial: max310x: improve crystal stable clock detection 2024-11-18 12:13:31 +01:00
vt
amiserial.c
cyclades.c
ehv_bytechan.c
goldfish.c
isicom.c
Kconfig
Makefile
mips_ejtag_fdc.c
moxa.c
moxa.h
mxser.c
mxser.h
n_gsm.c
n_hdlc.c
n_null.c
n_r3964.c
n_tracerouter.c
n_tracesink.c
n_tracesink.h
n_tty.c
nozomi.c
pty.c
rocket.c
rocket.h
rocket_int.h
synclink.c
synclink_gt.c
synclinkmp.c
sysrq.c
tty.h tty: change tty_write_lock()'s ndelay parameter to bool 2024-11-18 12:12:49 +01:00
tty_audit.c
tty_baudrate.c
tty_buffer.c
tty_io.c usb: cdc-acm: return correct error code on unsupported break 2024-11-18 12:12:50 +01:00
tty_ioctl.c tty: allow TIOCSLCKTRMIOS with CAP_CHECKPOINT_RESTORE 2024-11-18 12:13:20 +01:00
tty_jobctrl.c
tty_ldisc.c
tty_ldsem.c
tty_mutex.c
tty_port.c
ttynull.c
vcc.c