David Brownell wrote: > The reason single-bit operations don't provide error paths is twofold. > First, they started as wrappers for can't-fail register accessors. > Second, it's extremely unrealisitic to expect much code to handle any > kind of faults in the middle of bitbanging loops ... or even just in > classic "set this bit and continue" configuration code. That's interesting. I'm not sure it's a good idea not to return an error code. The caller can just ignore it if they don't care, and it's extremely cheap to "return 0" in GPIO drivers which can't error. If I were bit-banging on GPIOs reached via some peripheral chip (such a GPIO-fanout chip over I2C/SPI, where that chip is itself feeding a secondary I2C or similar bit-banging bus), I probably would like to check for errors and take emergency action if the peripheral chip isn't responding, or just report to userspace. This has actually happened on a board I worked with, where the primary I2C failed due to a plugged in peripheral loading it too much, and a secondary bit-banging bus was not then reachable. -- Jamie -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
