Re: [PATCH v2 2/2] iio: potentiometer: Add driver support for AD5110
From: Mugilraj Dhavachelvan
Date: Wed Aug 11 2021 - 01:46:21 EST
On Tue, Aug 10, 2021 at 03:49:52PM +0300, Andy Shevchenko wrote:
> On Mon, Aug 9, 2021 at 10:59 AM Mugilraj Dhavachelvan
> <dmugil2000@xxxxxxxxx> wrote:
> >
> > The AD5110/AD5112/AD5114 provide a nonvolatile solution
> > for 128-/64-/32-position adjustment applications, offering
> > guaranteed low resistor tolerance errors of ±8% and up to
> > ±6 mA current density.
>
> ...
>
> > +/*
> > + * Analog Devices AD5110 digital potentiometer driver
> > + *
> > + * Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@xxxxxxxxx>
> > + *
> > + * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
>
> > + *
>
> Redundant blank line.
>
fixed in v3
> > + */
>
> ...
>
> > +#define WIPER_RESISTANCE 70
>
> Missed prefix?
>
fixed in v3
> ...
>
> > +static const struct iio_chan_spec ad5110_channels[] = {
> > + {
> > + .type = IIO_RESISTANCE,
> > + .output = 1,
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_OFFSET) |
> > + BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_ENABLE),
> > + }
>
> + comma.
>
fixed in v3
> > +};
>
> ...
>
> > + ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
> > + if (ret != sizeof(data->buf)) {
>
> > + ret = -EIO;
>
> Shadowed error code when ret < 0.
>
fixed in v3
> > + goto error;
> > + }
>
> ...
>
> > + ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
> > + if (ret != sizeof(data->buf))
> > + ret = -EIO;
>
> Ditto.
>
fixed in v3
> > + mutex_unlock(&data->lock);
> > +
> > + return ret < 0 ? ret : 0;
> > +}
>
> ...
>
> > + data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
> > + if (!(val & BIT(7)))
> > + data->tol *= -1;
>
> Shouldn't you simple use corresponding sign_extend*()?
>
I'm not able see any sign_extend for 16 bit. Is there any other way?
> ...
>
> > + ret = ad5110_write(data, AD5110_EEPROM_WR, 0);
> > + if (ret) {
> > + dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");
> > + return ret;
> > + }
>
>
> > + msleep(20);
>
> Each long sleeps like this must be explained.
>
fixed in v3
> ...
>
> > +static IIO_DEVICE_ATTR(store_eeprom, 0644,
> > + ad5110_eeprom_read,
> > + ad5110_eeprom_write, 0);
>
> IIO_DEVICE_ATTR_RW() ?
>
fixed in v3
> ...
>
> > +static struct attribute *ad5110_attributes[] = {
> > + &iio_dev_attr_store_eeprom.dev_attr.attr,
> > + NULL,
>
> No comma for a terminator line.
>
fixed in v3
> > +};
>
> ...
>
> > + data->cfg = device_get_match_data(dev);
>
> > + if (!data->cfg)
> > + data->cfg = &ad5110_cfg[i2c_match_id(ad5110_id, client)->driver_data];
>
> Not sure this is not a dead code since you are using ->probe_new().
>
Even I'm suspecting that and also removing id_table. But I'm not sure of
it so just left as it is.
> ...
>
> > +static struct i2c_driver ad5110_driver = {
> > + .driver = {
> > + .name = "ad5110",
> > + .of_match_table = ad5110_of_match,
> > + },
> > + .probe_new = ad5110_probe,
> > + .id_table = ad5110_id,
> > +};
>
> > +
>
> Redundant blank line
fixed in v3.
>
> > +module_i2c_driver(ad5110_driver);
>
Thanks for the feedback :)
> --
> With Best Regards,
> Andy Shevchenko