This series adds sanitization to serial_rs485 struct before passing it to driver's rs485_config. This takes the work Lino Sanfilippo started (0ed12afa5655^..60efd0513916) a bit further. By moving sanitization of the rs485 struct into the serial core, per driver rs485_config() is more into the point, that is, setting up the hw to realize RS485. The other benefit is that with the sanitization, the other drivers no longer need to care when new things are added to serial_rs485 as serial core handles them on the other drivers' behalf. The addressing mode changes I'll submit separately will take advantage of this. The addressing mode changes were the main motivator for doing the changes, however, I believe these changes stand on their feet even w/o considering the addressing mode changes. The series is long because per driver changes are split into two different stages. The key objectives here for the split have been to keep things bisect safe and to do changes per driver rather than in one large block. This required 4 stages: 1) Add datastructure entries & other preps (01-03) 2) Per driver rs485_supported (04-21) 3) Sanitization, core taking advantage of rs485_supported (22-24) 4) Cleanup per driver custom sanitization code (25-36) As you can see, the downside of this split is that the per driver code is split to 2+4 patches which makes some things moving less obvious. Merging them is only possible if the stages 2-4 are done in one large change (little bits here and there could be left out from it but not much). In stage 3 patches, there are a few userspace interface impacting changes with userspace api regression potential: a) Some drivers have not cleared flags/fields in per driver code while other drivers have. The old behavior is inconsistent. Now the bits will get cleaned up by serial core. I don't believe it's going to cause issues. b) Init path now sanitizes configuration if rs485_config is being called from the init path (mainly coming from dt). It attempts to repair some incorrect configurations which seems ok. However, if RS485 mode is not enabled at boot, serial_rs485 struct gets cleared in order for it to match what the port is configured with (RS232). Such clearing implies losing values that were configured through dt and that could perhaps be seen as unwanted side-effect from having consistent serial_rs485? There is also impact for the ioctl path from this clearing of serial_rs485 when RS485 is disabled but impact seems minor at most. c) Returning -EINVAL for non-legacy flags. This also affects setting bits that were previously padding (that is, all flags bits currently not defined in include/uapi/linux/serial.h). It was possible to put garbage into them earlier but no more. I guess this is not very likely a big issue. No non-legacy flags are added in this series (the addressing mode changes submitted separately will add new flags). Cc: alexandre.belloni@xxxxxxxxxxx Cc: alexandre.torgue@xxxxxxxxxxx Cc: andriy.shevchenko@xxxxxxxxxxxxxxx Cc: bcm-kernel-feedback-list@xxxxxxxxxxxx Cc: claudiu.beznea@xxxxxxxxxxxxx Cc: corbet@xxxxxxx Cc: festevam@xxxxxxxxx Cc: f.fainelli@xxxxxxxxx Cc: kernel@xxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: linux@xxxxxxxxxxxxxxx Cc: linux-doc@xxxxxxxxxxxxxxx Cc: linux-imx@xxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: linux-rpi-kernel@xxxxxxxxxxxxxxxxxxx Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx Cc: mcoquelin.stm32@xxxxxxxxx Cc: nicolas.ferre@xxxxxxxxxxxxx Cc: nsaenz@xxxxxxxxxx Cc: richard.genoud@xxxxxxxxx Cc: rjui@xxxxxxxxxxxx Cc: sbranden@xxxxxxxxxxxx Cc: s.hauer@xxxxxxxxxxxxxx Cc: shawnguo@xxxxxxxxxx Cc: vz@xxxxxxxxx Ilpo Järvinen (36): serial: Add uart_rs485_config() serial: Move serial_rs485 sanitization into separate function serial: Add rs485_supported to uart_port serial: 8250: Create serial8250_em485_supported for em485 users serial: 8250_bcm2835aux: Use serial8250_em485_supported serial: 8250_dwlib: Fill in rs485_supported serial: 8250_exar: Fill in rs485_supported serial: 8250_fintek: Fill in rs485_supported serial: 8250_lpc18cc: Fill in rs485_supported serial: 8250_of: Use serial8250_em485_supported serial: 8250_pci: Fill in rs485_supported for pci_fintek serial: pl011: Fill in rs485_supported serial: ar933x: Fill in rs485_supported serial: atmel: Fill in rs485_supported serial: fsl_lpuart: Fill in rs485_supported serial: imx: Fill in rs485_supported serial: max310x: Fill in rs485_supported serial: mcf: Fill in rs485_supported serial: omap: Fill in rs485_supported serial: sc16is7xx: Fill in rs485_supported serial: stm32: Fill in rs485_supported serial: Sanitize rs485_struct serial: Clear rs485 struct when non-RS485 mode is set serial: return -EINVAL for non-legacy RS485 flags serial: 8250_dwlib: Remove serial_rs485 sanitization serial: 8250_fintek: Remove serial_rs485 sanitization serial: 8250: lpc18xx: Remove serial_rs485 sanitization serial: 8250_pci: Remove serial_rs485 sanitization serial: pl011: Remove serial_rs485 sanitization serial: fsl_lpuart: Call core's sanitization and remove custom one serial: imx: Remove serial_rs485 sanitization serial: max310x: Remove serial_rs485 sanitization serial: 8250_exar: Remove serial_rs485 assignment serial: mcf: Remove serial_rs485 assignment serial: sc16is7xx: Remove serial_rs485 assignment serial: 8250: Remove serial_rs485 sanitization from em485 .../driver-api/serial/serial-rs485.rst | 12 +- drivers/tty/serial/8250/8250.h | 1 + drivers/tty/serial/8250/8250_bcm2835aux.c | 1 + drivers/tty/serial/8250/8250_core.c | 1 + drivers/tty/serial/8250/8250_dwlib.c | 17 +-- drivers/tty/serial/8250/8250_exar.c | 14 +- drivers/tty/serial/8250/8250_fintek.c | 29 +++-- drivers/tty/serial/8250/8250_lpc18xx.c | 20 +-- drivers/tty/serial/8250/8250_of.c | 1 + drivers/tty/serial/8250/8250_pci.c | 24 +--- drivers/tty/serial/8250/8250_port.c | 28 ++-- drivers/tty/serial/amba-pl011.c | 13 +- drivers/tty/serial/ar933x_uart.c | 7 + drivers/tty/serial/atmel_serial.c | 7 + drivers/tty/serial/fsl_lpuart.c | 25 +--- drivers/tty/serial/imx.c | 19 ++- drivers/tty/serial/max310x.c | 9 +- drivers/tty/serial/mcf.c | 7 +- drivers/tty/serial/omap-serial.c | 8 ++ drivers/tty/serial/sc16is7xx.c | 8 +- drivers/tty/serial/serial_core.c | 120 ++++++++++++++---- drivers/tty/serial/stm32-usart.c | 8 ++ include/linux/serial_core.h | 2 + 23 files changed, 247 insertions(+), 134 deletions(-) -- 2.30.2