30735584a4
The GD32VW55x I2C master (the STM32-style "v2" IP) never completed a real
transfer. Two bugs:
1. Wrong kernel clock. The protocol state machine is clocked by the I2C
kernel clock selected in RCU_CFG1.I2C0SEL, not by the APB1 bus clock that
only feeds the register interface. The driver left it at the APB1 default
and computed TIMING for PCLK1 (~80 MHz); the resulting prescaled period is
so short that the SDADEL/SCLDEL setup and hold times fall below the
analog-filter minimum of the IP, so the master latches START but never
drives SCL (STAT stuck with BUSY set). Route I2C0 to IRC16M (16 MHz) and
use it as clk_freq, and never let the prescaler drop below the value that
keeps the prescaled clock at/under 4 MHz (250 ns) so SDADEL/SCLDEL stay in
spec. This matches the vendor BSP (IRC16M, PSC=3).
2. Transfer timeout was zero. CONFIG_GD32VW55X_I2C_TIMEOTICKS has a Kconfig
default of 0 ("override when non-zero"), but the driver derived the timeout
with a plain #ifndef, which never triggers because the symbol is always
defined. The polled wait loop therefore ran a single iteration and gave
up. Address probes (NACK on the first pass) still worked and masked it;
only multi-byte transfers exercised the loop. Honour the "0 means derive
from seconds/milliseconds" contract.
Also make the interrupt wait immune to the ISR completing between startmsg()
and the wait (do not clobber a posted DONE), and drop a redundant cast.
To exercise this on hardware, add an "sht3x" configuration to the
gd32vw553k-start: the nsh base plus I2C0, the i2ctool and the Sensirion SHT3x
temperature/humidity driver, registered as /dev/i2c0 and /dev/temp0. I2C0 is
routed to PA2 (SCL) / PA3 (SDA) on AF4, the pins broken out on the J1 header
(datasheet Table 2-5); when SPI is enabled it claims PA2, so I2C0 falls back
to PB0/PB1, whose SDA pin is not broken out (the periph case).
Signed-off-by: Jorge Guzman <jorge.gzm@gmail.com>
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| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
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