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Message-ID: <CAHp75VfHFo41S=Bhs2MB6Te6VAn+yCteys6XcYgciNZu9VppJg@mail.gmail.com>
Date: Wed, 26 Aug 2020 19:10:03 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Nishant Malpani <nish.malpani25@...il.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
"Bogdan, Dragos" <dragos.bogdan@...log.com>,
darius.berghe@...log.com,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-iio <linux-iio@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>
Subject: Re: [PATCH 1/3] iio: gyro: adxrs290: Add triggered buffer support
On Tue, Aug 25, 2020 at 4:11 PM Nishant Malpani
<nish.malpani25@...il.com> wrote:
>
> Provide a way for continuous data capture by setting up buffer support. The
> data ready signal exposed at the SYNC pin of the ADXRS290 is exploited as
> a hardware interrupt which triggers to fill the buffer.
>
> Triggered buffer setup was tested with both hardware trigger (DATA_RDY) and
> software triggers (sysfs-trig & hrtimer).
...
> +static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
> +{
> + struct adxrs290_state *st = iio_priv(indio_dev);
> + int val, ret;
> +
> + mutex_lock(&st->lock);
> +
> + if (st->mode == mode) {
> + ret = 0;
Can be done outside of mutex.
> + goto done;
> + }
> +
> + val = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
> + if (val < 0) {
> + ret = val;
> + goto done;
> + }
Consider other way around
ret = ...
...
val = ret;
> + switch (mode) {
> + case ADXRS290_MODE_STANDBY:
> + val &= ~ADXRS290_MEASUREMENT;
> + break;
> + case ADXRS290_MODE_MEASUREMENT:
> + val |= ADXRS290_MEASUREMENT;
> + break;
> + default:
> + ret = -EINVAL;
> + goto done;
> + }
> +
> + ret = adxrs290_spi_write_reg(st->spi,
> + ADXRS290_REG_POWER_CTL,
> + val);
> + if (ret < 0) {
> + dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
> + goto done;
> + }
> +
> + /* update cached mode */
> + st->mode = mode;
> +
> +done:
> + mutex_unlock(&st->lock);
> + return ret;
> +}
...
> + goto err_release;
>
> - return IIO_VAL_INT;
> + ret = IIO_VAL_INT;
> + break;
> default:
> - return -EINVAL;
> + ret = -EINVAL;
> + break;
> }
> +err_release:
I didn't get the purpose of this. Wasn't the break statement enough?
> + iio_device_release_direct_mode(indio_dev);
> + return ret;
> case IIO_CHAN_INFO_SCALE:
> switch (chan->type) {
> case IIO_ANGL_VEL:
...
> + goto err_release;
Ditto.
> + }
> +
> /* caching the updated state of the high-pass filter */
> st->hpf_3db_freq_idx = hpf_idx;
> /* retrieving the current state of the low-pass filter */
> lpf_idx = st->lpf_3db_freq_idx;
> - return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> + ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> + break;
> +
> + default:
> + ret = -EINVAL;
> + break;
> }
>
> - return -EINVAL;
> +err_release:
> + iio_device_release_direct_mode(indio_dev);
> + return ret;
> }
...
> + val = (state ? ADXRS290_SYNC(ADXRS290_DATA_RDY_OUT) : 0);
Purpose of outer parentheses?
...
> +static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
> +{
> + struct adxrs290_state *st = iio_priv(indio_dev);
> + int ret;
> +
> + if (!st->spi->irq) {
> + dev_info(&st->spi->dev, "no irq, using polling\n");
> + return 0;
> + }
> +
> + st->dready_trig = devm_iio_trigger_alloc(&st->spi->dev,
> + "%s-dev%d",
> + indio_dev->name,
> + indio_dev->id);
> + if (!st->dready_trig)
> + return -ENOMEM;
> +
> + st->dready_trig->dev.parent = &st->spi->dev;
> + st->dready_trig->ops = &adxrs290_trigger_ops;
> + iio_trigger_set_drvdata(st->dready_trig, indio_dev);
> +
> + ret = devm_request_irq(&st->spi->dev, st->spi->irq,
> + &iio_trigger_generic_data_rdy_poll,
> + IRQF_ONESHOT,
> + "adxrs290_irq", st->dready_trig);
> + if (ret < 0) {
> + dev_err(&st->spi->dev, "request irq %d failed\n", st->spi->irq);
> + return ret;
return dev_err_probe(...);
> + }
> +
> + ret = devm_iio_trigger_register(&st->spi->dev, st->dready_trig);
> + if (ret) {
> + dev_err(&st->spi->dev, "iio trigger register failed\n");
> + return ret;
return dev_err_probe(...);
> + }
> +
> + indio_dev->trig = iio_trigger_get(st->dready_trig);
> +
> + return 0;
> +}
...
> + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
> + &iio_pollfunc_store_time,
> + &adxrs290_trigger_handler, NULL);
> + if (ret < 0) {
> + dev_err(&spi->dev, "iio triggered buffer setup failed\n");
> + return ret;
return dev_err_probe(...);
> + }
--
With Best Regards,
Andy Shevchenko
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