linux-kernel - Re: [PATCH v5 6/7] iio: add MEMSensing MSA311 3-axis accelerometer driver

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Date:   Mon, 15 Aug 2022 14:01:13 +0000
From:   Dmitry Rokosov <DDRokosov@...rdevices.ru>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
CC:     "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "jic23@...nel.org" <jic23@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "andriy.shevchenko@...ux.intel.com" 
        <andriy.shevchenko@...ux.intel.com>,
        "christophe.jaillet@...adoo.fr" <christophe.jaillet@...adoo.fr>,
        "stano.jakubek@...il.com" <stano.jakubek@...il.com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "stephan@...hold.net" <stephan@...hold.net>,
        "daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>,
        "wsa@...nel.org" <wsa@...nel.org>,
        "lars@...afoo.de" <lars@...afoo.de>,
        "Michael.Hennerich@...log.com" <Michael.Hennerich@...log.com>,
        "jbhayana@...gle.com" <jbhayana@...gle.com>,
        "lucas.demarchi@...el.com" <lucas.demarchi@...el.com>,
        "jani.nikula@...el.com" <jani.nikula@...el.com>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        kernel <kernel@...rdevices.ru>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 6/7] iio: add MEMSensing MSA311 3-axis accelerometer
 driver

On Sat, Aug 13, 2022 at 01:34:40AM +0300, Andy Shevchenko wrote:

[...]

> > Spec: https://cdn-shop.adafruit.com/product-files/5309/MSA311-V1.1-ENG.pdf
> 
> Can you use Datasheet: tag below (just before your SoB tag)?

Sure, I can move it on the previous line beforce SoB tag.
But with Datasheet: tag this line will be over the commit msg line limit.
If you don't mind I will stay with Spec: tag instead of Datasheet:

[...]

> > +static const struct {
> > +       int val;
> > +       int val2;
> > +} msa311_fs_table[] = {
> > +       {0, 9580}, {0, 19160}, {0, 38320}, {0, 76641}
> > +};
> 
> At least you may deduplicate the type definition for these data structures, like
> 
> struct iio_float {
>   int integer;
>   int fract;
> };

Agreed. I will make deduplication of this type inside msa311 driver
only.

[...]

> > +               dev_err(dev,
> > +                       "cannot set odr %u.%luHz, not available in %s mode\n",
> > +                       msa311_odr_table[odr].val,
> > +                       msa311_odr_table[odr].val2 / MILLIHZ_PER_HZ,
> 
> Logically it's MICROHZ_PER_MILLIHZ.
> 

You are right. But I think it would be better to print the original val2
value with zero-padding.

[...]

> > +       freq_uhz = msa311_odr_table[odr].val * MICROHZ_PER_HZ +
> > +                  msa311_odr_table[odr].val2;
> > +       wait_ms = (MICROHZ_PER_HZ / freq_uhz) * MSEC_PER_SEC;
> 
> On the contrary this seems correct.

Good

> > +       err = iio_device_claim_direct_mode(indio_dev);
> > +       if (err)
> > +               return err;
> > +
> > +       mutex_lock(&msa311->lock);
> > +       err = msa311_get_axis(msa311, chan, &axis);
> > +       mutex_unlock(&msa311->lock);
> > +
> > +       iio_device_release_direct_mode(indio_dev);
> > +
> > +       if (err) {
> > +               dev_err(dev, "cannot get axis %s (%pe)\n",
> > +                       chan->datasheet_name, ERR_PTR(err));
> > +               return err;
> > +       }
> > +
> > +       pm_runtime_mark_last_busy(dev);
> > +       pm_runtime_put_autosuspend(dev);
> 
> All error cases above miss the PM restoration. Is it on purpose?
> Otherwise fix it here and check everywhere else.

Nice catch! This is a bug. I'll fix it in v6

> > +       used = scnprintf(msa311->chip_name, sizeof(msa311->chip_name),
> > +                        "msa311-%hhx", partid);
> 
> > +       msa311->chip_name[used] = '\0';
> 
> What is this for exactly?
> 

Ah, you are right, scnprintf() makes null terminating inside.

> > +       /* Disable all interrupts by default */
> > +       err = regmap_write(msa311->regs, MSA311_INT_SET_0_REG, 0);
> > +       if (err)
> > +               return dev_err_probe(dev, err,
> > +                                    "cannot disable set0 interrupts\n");
> > +
> > +       err = regmap_write(msa311->regs, MSA311_INT_SET_1_REG, 0);
> > +       if (err)
> > +               return dev_err_probe(dev, err,
> > +                                    "cannot disable set1 interrupts\n");
> 
> Wondering if the above can be combined to bulk write.
> 

I will try and rework this place if it's workable.

> > +       /* Unmap all INT1 interrupts by default */
> > +       err = regmap_write(msa311->regs, MSA311_INT_MAP_0_REG, 0);
> > +       if (err)
> > +               return dev_err_probe(dev, err,
> > +                                    "failed to unmap map0 interrupts\n");
> > +
> > +       err = regmap_write(msa311->regs, MSA311_INT_MAP_1_REG, 0);
> > +       if (err)
> > +               return dev_err_probe(dev, err,
> > +                                    "failed to unmap map1 interrupts\n");
> 
> Ditto.

The same as above.

[...]

-- 
Thank you,
Dmitry