linux-kernel - Re: [PATCH v4 4/4] iio: vcnl4000: Add buffer support for VCNL4010/20.

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Date:   Tue, 21 Apr 2020 15:27:14 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Mathieu Othacehe <m.othacehe@...il.com>
Cc:     Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald <pmeerw@...erw.net>,
        linux-iio <linux-iio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 4/4] iio: vcnl4000: Add buffer support for VCNL4010/20.

On Tue, Apr 21, 2020 at 10:59 AM Mathieu Othacehe <m.othacehe@...il.com> wrote:
>
> The VCNL4010 and VCNL4020 chips are able to raise interrupts on data ready.
> Use it to provide triggered buffer support for proximity data.
>
> Those two chips also provide ambient light data. However, they are sampled
> at different rate than proximity data. As this is not handled by the IIO
> framework for now, and the sample frequencies of ambient light data are
> very low, do add buffer support for them.

...

> +static irqreturn_t vcnl4010_trigger_handler(int irq, void *p)
> +{
> +       struct iio_poll_func *pf = p;
> +       struct iio_dev *indio_dev = pf->indio_dev;
> +       struct vcnl4000_data *data = iio_priv(indio_dev);
> +       const unsigned long *active_scan_mask = indio_dev->active_scan_mask;
> +       u16 buffer[8] = {0}; /* 1x16-bit + ts */
> +       bool data_read = false;
> +       unsigned long isr;
> +       int val = 0;
> +       int ret;
> +
> +       ret = i2c_smbus_read_byte_data(data->client, VCNL4010_ISR);
> +       if (ret < 0)
> +               goto end;
> +
> +       isr = ret;
> +
> +       if (test_bit(0, active_scan_mask)) {
> +               if (test_bit(VCNL4010_INT_PROXIMITY, &isr)) {
> +                       ret = vcnl4000_read_data(data,
> +                                                VCNL4000_PS_RESULT_HI,
> +                                                &val);
> +                       if (ret < 0)
> +                               goto end;
> +
> +                       buffer[0] = val;
> +                       data_read = true;
> +               }
> +       }
> +
> +       ret = i2c_smbus_write_byte_data(data->client, VCNL4010_ISR,
> +                                       isr & VCNL4010_INT_DRDY);

> +       if (ret < 0 || !data_read)

I would split them, because they are logically different checks.

> +               goto end;
> +
> +       iio_push_to_buffers_with_timestamp(indio_dev, buffer,
> +                                          iio_get_time_ns(indio_dev));
> +
>  end:
> +       iio_trigger_notify_done(indio_dev->trig);
>         return IRQ_HANDLED;
>  }

...

> +static int vcnl4010_buffer_predisable(struct iio_dev *indio_dev)
> +{
> +       struct vcnl4000_data *data = iio_priv(indio_dev);
> +       int ret, ret_disable;
> +
> +       ret = i2c_smbus_write_byte_data(data->client, VCNL4010_INT_CTRL, 0);
> +       if (ret < 0)
> +               goto end;
> +
> +       ret = i2c_smbus_write_byte_data(data->client, VCNL4000_COMMAND, 0);
> +
> +end:

> +       ret_disable = iio_triggered_buffer_predisable(indio_dev);
> +       if (ret == 0)
> +               ret = ret_disable;

What is this?

Can't you rather call IIO API first, and then try to handle the rest?

> +       return ret;
> +}

-- 
With Best Regards,
Andy Shevchenko