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serial: stm32: Clear prev values before setting RTS delays

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The code lacks clearing of previous DEAT/DEDT values. Thus, changing
values on the fly results in garbage delays tending towards the maximum
value as more and more bits are ORed together. (Leaving RS485 mode
would have cleared the old values though).

Fixes: 1bcda09d29 ("serial: stm32: add support for RS485 hardware control mode")
Cc: stable@kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220627150753.34510-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Change-Id: I2f1f2c0675180f65c524948a9103d03abf8f4ee8
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/272029
Reviewed-by: CITOOLS <MDG-smet-aci-reviews@list.st.com>
Reviewed-by: CIBUILD <MDG-smet-aci-builds@list.st.com>
Reviewed-by: Eric FOURMONT <eric.fourmont-ext@st.com>
Domain-Review: Amelie DELAUNAY <amelie.delaunay@foss.st.com>
This commit is contained in:
Ilpo Järvinen
2022-06-27 18:07:52 +03:00
committed by Eric Fourmont
parent ef0c423932
commit 7f29f81666
1 changed files with 2 additions and 0 deletions
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2
drivers/tty/serial/stm32-usart.c
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@ -110,6 +110,8 @@ static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 baud,
*cr3 |= USART_CR3_DEM;
over8 = *cr1 & USART_CR1_OVER8;
*cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
/* Assertion time */
tmp = stm32_usart_config_delay_rs485(cr1, delay_ADE, baud, over8,
rs485_deat_dedt_max, rs485conf);