On 30. 04. 24, 22:04, Hugo Villeneuve wrote:
From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
When using a high speed clock with a low baud rate, the 4x prescaler is
automatically selected if required. In that case, sc16is7xx_set_baud()
properly configures the chip registers, but returns an incorrect baud
rate by not taking into account the prescaler value. This incorrect baud
rate is then fed to uart_update_timeout().
For example, with an input clock of 80MHz, and a selected baud rate of 50,
sc16is7xx_set_baud() will return 200 instead of 50.
Fix this by first changing the prescaler variable to hold the selected
prescaler value instead of the MCR bitfield. Then properly take into
account the selected prescaler value in the return value computation.
Also add better documentation about the divisor value computation.
Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
---
Changes for V2:
- Change prescaler type to "unsigned int" (Jiri S.)
Thanks.
Reviewed-by: Jiri Slaby <jirislaby@xxxxxxxxxx>
--
js
suse labs
