Hello Andy,
On Tue, Jun 02, 2020 at 08:14:13PM +0300, Andy Shevchenko wrote:
> On Tue, Jun 2, 2020 at 7:49 PM Tomasz Duszynski
> <tomasz.duszynski@xxxxxxxxxxx> wrote:
> >
> > Add I2C interface driver for the SCD30 sensor.
>
> ...
>
> > +static u16 scd30_i2c_cmd_lookup_tbl[] = {
> > + [CMD_START_MEAS] = 0x0010,
> > + [CMD_STOP_MEAS] = 0x0104,
> > + [CMD_MEAS_INTERVAL] = 0x4600,
> > + [CMD_MEAS_READY] = 0x0202,
> > + [CMD_READ_MEAS] = 0x0300,
> > + [CMD_ASC] = 0x5306,
> > + [CMD_FRC] = 0x5204,
> > + [CMD_TEMP_OFFSET] = 0x5403,
> > + [CMD_FW_VERSION] = 0xd100,
> > + [CMD_RESET] = 0xd304,
>
> Keep sorted by value?
>
I'd rather leave it as is simply because order here matches order in
sensor datasheet.
> > +};
>
> ...
>
> > + ret = i2c_master_send(client, txbuf, txsize);
>
> > + if (ret != txsize)
> > + return ret < 0 ? ret : -EIO;
>
> Wouldn't be better
>
> if (ret < 0)
> return ret;
> if (ret != txsize)
> return -EIO;
>
> ?
>
Hmm, okay. Perhaps slightly easier to read.
> > + if (!rxbuf)
> > + return 0;
> > +
> > + ret = i2c_master_recv(client, rxbuf, rxsize);
>
> > + if (ret != rxsize)
> > + return ret < 0 ? ret : -EIO;
>
> Ditto.
>
> ...
>
> > +static int scd30_i2c_command(struct scd30_state *state, enum scd30_cmd cmd,
> > + u16 arg, void *response, int size)
> > +{
> > + char crc, buf[SCD30_I2C_MAX_BUF_SIZE], *rsp = response;
> > + int i, ret;
>
> i -> offset ?
>
'i' is shorter and I am lazy :).
> > + put_unaligned_be16(scd30_i2c_cmd_lookup_tbl[cmd], buf);
> > + i = 2;
> > +
> > + if (rsp) {
> > + /* each two bytes are followed by a crc8 */
> > + size += size / 2;
> > + } else {
> > + put_unaligned_be16(arg, buf + i);
> > + crc = crc8(scd30_i2c_crc8_tbl, buf + i, 2, CRC8_INIT_VALUE);
> > + i += 2;
>
> > + buf[i] = crc;
> > + i += 1;
>
> buf[offset++] = crc; ?
>
I'd rather stick to what I have now. It looks more consistent.
> > + /* commands below don't take an argument */
> > + if ((cmd == CMD_STOP_MEAS) || (cmd == CMD_RESET))
> > + i -= 3;
> > + }
> > +
> > + ret = scd30_i2c_xfer(state, buf, i, buf, size);
> > + if (ret)
> > + return ret;
> > +
> > + /* validate received data and strip off crc bytes */
> > + for (i = 0; i < size; i += 3) {
> > + crc = crc8(scd30_i2c_crc8_tbl, buf + i, 2, CRC8_INIT_VALUE);
> > + if (crc != buf[i + 2]) {
> > + dev_err(state->dev, "data integrity check failed\n");
> > + return -EIO;
> > + }
> > +
>
> > + *rsp++ = buf[i];
>
> + 0 (for the sake of consistency?
>
Adding 0 is a little bit odd.
> > + *rsp++ = buf[i + 1];
> > + }
> > +
> > + return 0;
> > +}
>
> ...
>
> > +static struct i2c_driver scd30_i2c_driver = {
> > + .driver = {
>
> > + .name = KBUILD_MODNAME,
>
> Better to hard code.
>
I seriously doubt anyone will ever want to change module name. What for?
> > + .of_match_table = scd30_i2c_of_match,
> > + .pm = &scd30_pm_ops,
> > + },
> > + .probe_new = scd30_i2c_probe,
> > +};
>
> --
> With Best Regards,
> Andy Shevchenko
