On Fri, Apr 24, 2020 at 10:05 PM Tomasz Duszynski <tomasz.duszynski@xxxxxxxxxxx> wrote: > On Wed, Apr 22, 2020 at 10:49:44PM +0300, Andy Shevchenko wrote: > > On Wed, Apr 22, 2020 at 5:22 PM Tomasz Duszynski > > <tomasz.duszynski@xxxxxxxxxxx> wrote: ... > > > Add Sensirion SCD30 carbon dioxide core driver. > > > > And DocLink tar of Datasheet: with a link? > > I never do this. These files change their location way too often to be > worthwhile putting here. Nobody has that much time to fallow all this > and keep respective files up to date. > > But that doesn't mean I can't drop a link here. > https://developer.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/9.5_CO2/Sensirion_CO2_Sensors_SCD30_Interface_Description.pdf Yes, just make it a tag DocLink: .... ... > > > +int scd30_probe(struct device *dev, int irq, const char *name, void *priv, > > > + int (*command)(struct scd30_state *state, enum scd30_cmd cmd, > > > + u16 arg, char *rsp, int size)); > > > > My gosh. > > Please, supply proper structure member in priv or alike. > > Not sure it's worth the fuss. Wrapping all into structure means either > copying respective members or more dereferences later on. At least you may introduce a typedef, because above really hurts my eyes. ... > > > +enum { > > > + CONC, > > > + TEMP, > > > + HR, > > > +}; > > > > Way too generic names for anonymous enum. > > I'd argue that they are pretty well understood abbreviations in iio generally > and here specifically. But adding some prefix won't harm. Yes, prefix is what I was talking about. ... > > > +static int scd30_wait_meas_poll(struct scd30_state *state) > > > +{ > > > + int tries = 5; > > > + > > > + while (tries--) { > > > + int ret; > > > + u16 val; > > > + > > > + ret = scd30_command(state, CMD_MEAS_READY, 0, (char *)&val, > > > + sizeof(val)); > > > + if (ret) > > > + return -EIO; > > > + > > > + /* new measurement available */ > > > + if (val) > > > + break; > > > + > > > + msleep_interruptible(state->meas_interval * 250); > > > + } > > > + > > > + if (tries == -1) > > > + return -ETIMEDOUT; > > > > unsigned int tries = ...; > > > > do { > > ... > > } while (--tries); > > if (!tries) > > return ...; > > > > looks better and I guess less code in asm. > > > > You mean that one extra branch in case of while? There are few things: a) do {} while notation immediately tells that at least one cycle of body will be done (unconditionally); b) it makes a loop variable unsigned and no need to check for specific negative numbers; c) it quite likely will generate slightly better assembly code. > But it comes to code > itself it looks more compact. And I am okay with that. > > > > + return 0; > > > +} ... > > > + if (kstrtou16(buf, 0, &val)) > > > + return -EINVAL; > > > > Shadowed error code. Don't do like this. > > Integer parsing either returns EINVAL or ERANGE. Passing the latter to > the user is not worth the trouble, especially because majority of writable attrs > have a fellow _available attr. It's simple a bad coding practice. Please, change. > > > + if (kstrtou16(buf, 0, &val)) > > > + return -EINVAL; > > > > Ditto. > > > > > + if (kstrtou16(buf, 0, &val)) > > > + return -EINVAL; > > > > Ditto. ... > > > + if (kstrtou16(buf, 0, &val)) > > > + return -EINVAL; > > > > No shadowed error code, please. Check entire code. Same here. ... > > > +static IIO_DEVICE_ATTR_RW(pressure_comp, 0); > > > +static IIO_DEVICE_ATTR_RO(pressure_comp_available, 0); > > > +static IIO_DEVICE_ATTR_RW(meas_interval, 0); > > > +static IIO_DEVICE_ATTR_RO(meas_interval_available, 0); > > > +static IIO_DEVICE_ATTR_RW(asc, 0); > > > +static IIO_DEVICE_ATTR_RW(frc, 0); > > > +static IIO_DEVICE_ATTR_RO(frc_available, 0); > > > +static IIO_DEVICE_ATTR_RW(temp_offset, 0); > > > +static IIO_CONST_ATTR(temp_offset_available, "[0 1 65535]"); > > > +static IIO_DEVICE_ATTR_WO(reset, 0); > > > > Do you need all of them? Doesn't IIO core provides a tons of helpers for these? > > Btw, where is ABI documentation? It's a show stopper. > > They are sensor specific and none falls into a category of iio generic > attrs. Maybe, except the measurement interval which could be represented as > a SAMP_FREQ. IIO ABI becomes already a big pile of nodes and I hope we will become stricter about adding new ones. > But given that measurement interval spans from 2s to 1800s > it becomes a little bit awkward to have it in Hz. > As for ABI that's in > a separate patch. It's not good from bisectability point of view. If by some reason this patch or documentation patch gets reverted, the other one will be dangling. Please, unify them. -- With Best Regards, Andy Shevchenko
