Wolfram Sang <wsa@xxxxxxxxxxxxx> writes: > On Mon, Nov 02, 2015 at 02:03:37AM +0000, Mans Rullgard wrote: >> The BYTECNT register holds the transfer size minus one. Setting it >> to the correct value requires a dummy read/write only for zero-length >> transfers as it is impossible to request one from the hardware. If a >> zero-length transfer is requested, changing the length to 1 and setting >> "buf" to a dummy location allows making the main loops less convoluted. >> >> In other words, this patch makes the driver transfer the number of bytes >> requested unless this is zero, which is not supported by the hardware, >> in which case one byte is transferred instead. > > Uh, this is wrong, zero byte should really not transfer anything. We > need to fix that and bail out, so probably something like > > if (!len) > return -EOPNOTSUPP; So the existing driver is wrong to allow it. Makes sense to drop that. > Also, the xlr_func() should mask out I2C_FUNC_SMBUS_QUICK. OK. > Other than that, the patch looks good to me. > > Out of curiosity, your first driver had the registers 32bit apart. Now > you can deal with 8bit. Is this configurable on this SoC? It's all 32 bits. The XLR driver uses a u32 * to access the registers. -- Måns Rullgård -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
