| Message ID | 20210723223152.648326-1-sean.anderson@seco.com |
|---|---|
| Headers | show |
| Series | tty: serial: uartlite: Disable changing fixed parameters | expand |
+Shubhrajyoti On 7/24/21 12:31 AM, Sean Anderson wrote: > The uartlite device is a "soft" device and certain parameters (such as > data bits, parity, and baud) are configured at synthesis time, and > cannot be discovered at runtime. Fortunately, bindings for this device > typically include some of these parameters (especially baud rate). > Instead of silently letting Linux's termios drift away from what the > hardware is actually doing, make the termios reflect the hardware, and > prevent them from being changed. With this series applied, the user > recieves an error message the first time they try and change these > termios: > > # stty parity > [ 7.221696] uartlite 84000000.serial: only 'n' parity supported > [ 7.222139] uartlite 84000000.serial: only 8 data bits supported > stty: standard input: cannot perform all requested operations > > In addition, the configured baud/parity/bits/etc. are exposed through > the standard termios ioctls, instead of using the default termios for > unconfigured ttys. > > > Sean Anderson (5): > dt-bindings: serial: uartlite: Convert to json-schema > dt-bindings: serial: uartlite: Add properties for synthesis-time > parameters > sh: j2: Update uartlite binding with data and parity properties > tty: serial: uartlite: Initialize termios with fixed synthesis > parameters > tty: serial: uartlite: Prevent changing fixed parameters > > .../bindings/serial/xlnx,opb-uartlite.txt | 23 ---- > .../bindings/serial/xlnx,opb-uartlite.yaml | 92 ++++++++++++++ > arch/sh/boot/dts/j2_mimas_v2.dts | 2 + > drivers/tty/serial/uartlite.c | 118 ++++++++++++++++-- > 4 files changed, 203 insertions(+), 32 deletions(-) > delete mode 100644 Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.txt > create mode 100644 Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml >
The uartlite device is a "soft" device and certain parameters (such as data bits, parity, and baud) are configured at synthesis time, and cannot be discovered at runtime. Fortunately, bindings for this device typically include some of these parameters (especially baud rate). Instead of silently letting Linux's termios drift away from what the hardware is actually doing, make the termios reflect the hardware, and prevent them from being changed. With this series applied, the user recieves an error message the first time they try and change these termios: # stty parity [ 7.221696] uartlite 84000000.serial: only 'n' parity supported [ 7.222139] uartlite 84000000.serial: only 8 data bits supported stty: standard input: cannot perform all requested operations In addition, the configured baud/parity/bits/etc. are exposed through the standard termios ioctls, instead of using the default termios for unconfigured ttys. Sean Anderson (5): dt-bindings: serial: uartlite: Convert to json-schema dt-bindings: serial: uartlite: Add properties for synthesis-time parameters sh: j2: Update uartlite binding with data and parity properties tty: serial: uartlite: Initialize termios with fixed synthesis parameters tty: serial: uartlite: Prevent changing fixed parameters .../bindings/serial/xlnx,opb-uartlite.txt | 23 ---- .../bindings/serial/xlnx,opb-uartlite.yaml | 92 ++++++++++++++ arch/sh/boot/dts/j2_mimas_v2.dts | 2 + drivers/tty/serial/uartlite.c | 118 ++++++++++++++++-- 4 files changed, 203 insertions(+), 32 deletions(-) delete mode 100644 Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.txt create mode 100644 Documentation/devicetree/bindings/serial/xlnx,opb-uartlite.yaml