On Wed, 28 Apr 2021 09:32:08 +0200
Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote:
> Basically the TI TSC2046 touchscreen controller is 8 channel ADC optimized for
> the touchscreen use case. By implementing it as an IIO ADC device, we can
> make use of resistive-adc-touch and iio-hwmon drivers.
>
> Polled readings are currently not implemented to keep this patch small, so
> iio-hwmon will not work out of the box for now.
>
> So far, this driver was tested with a custom version of resistive-adc-touch driver,
> since it needs to be extended to make use of Z1 and Z2 channels. The X/Y
> are working without additional changes.
>
> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
A few really small things inline that I'm happy to clean up whilst applying,
or can get rolled into a v7 if you have to do one due to review from others.
...
> +
> +static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx,
> + u32 *effective_speed_hz)
> +{
> + struct spi_transfer xfer;
> + struct spi_message msg;
> + int ret;
> +
> + memset(&xfer, 0, sizeof(xfer));
> + priv->tx_one->cmd = tsc2046_adc_get_cmd(priv, ch_idx, false);
> + priv->tx_one->data = 0;
> + xfer.tx_buf = priv->tx_one;
> + xfer.rx_buf = priv->rx_one;
> + xfer.len = sizeof(*priv->tx_one);
> + spi_message_init(&msg);
> + spi_message_add_tail(&xfer, &msg);
Slight preference for
spi_message_init_with_transfers(&msg, &xfer, 1);
Same elsewhere where we get this pattern.
> +
> + /*
> + * We aren't using spi_write_then_read() because we need to be able
> + * to get hold of the effective_speed_hz from the xfer
> + */
> + ret = spi_sync(priv->spi, &msg);
> + if (ret) {
> + dev_err_ratelimited(&priv->spi->dev, "SPI transfer failed %pe\n",
> + ERR_PTR(ret));
> + return ret;
> + }
> +
> + if (effective_speed_hz)
> + *effective_speed_hz = xfer.effective_speed_hz;
> +
> + return tsc2046_adc_get_value(priv->rx_one);
> +}
> +
...
> +static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv)
> +{
> + unsigned int ch_idx;
> + size_t size;
> + int ret;
> +
> + priv->tx_one = devm_kzalloc(&priv->spi->dev, sizeof(*priv->tx_one),
> + GFP_KERNEL);
> + if (!priv->tx_one)
> + return -ENOMEM;
> +
> + priv->rx_one = devm_kzalloc(&priv->spi->dev, sizeof(*priv->rx_one),
> + GFP_KERNEL);
> + if (!priv->rx_one)
> + return -ENOMEM;
> +
> + /*
> + * Make dummy read to set initial power state and get real SPI clock
> + * freq. It seems to be not important which channel is used for this
> + * case.
> + */
> + ret = tsc2046_adc_read_one(priv, TI_TSC2046_ADDR_TEMP0,
> + &priv->effective_speed_hz);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * In case SPI controller do not report effective_speed_hz, use
> + * configure value and hope it will match.
> + */
> + if (!priv->effective_speed_hz)
> + priv->effective_speed_hz = priv->spi->max_speed_hz;
> +
> +
> + priv->scan_interval_us = TI_TSC2046_SAMPLE_INTERVAL_US;
> + priv->time_per_bit_ns = DIV_ROUND_UP(NSEC_PER_SEC,
> + priv->effective_speed_hz);
> +
> + /*
> + * Calculate and allocate maximal size buffer if all channels are
> + * enabled.
> + */
> + size = 0;
> + for (ch_idx = 0; ch_idx < priv->dcfg->num_channels; ch_idx++)
> + size += tsc2046_adc_group_set_layout(priv, ch_idx, ch_idx);
> +
> + priv->tx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL);
> + if (!priv->tx)
> + return -ENOMEM;
> +
> + priv->rx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL);
> + if (!priv->rx)
> + return -ENOMEM;
> +
> + spi_message_init(&priv->msg);
> + priv->msg.context = priv;
Why is this set as we never set priv->msg.complete?
I can drop this whilst merging if we aren't going around again.
> +
> + priv->xfer.tx_buf = priv->tx;
> + priv->xfer.rx_buf = priv->rx;
> + priv->xfer.len = size;
> + spi_message_add_tail(&priv->xfer, &priv->msg);
Having dropped the above, can also change to
spi_message_init_with_transfers()
> +
> + return 0;
> +}
> +
...
> +static int tsc2046_adc_probe(struct spi_device *spi)
> +{
> + const struct tsc2046_adc_dcfg *dcfg;
> + struct device *dev = &spi->dev;
> + struct tsc2046_adc_priv *priv;
> + struct iio_dev *indio_dev;
> + struct iio_trigger *trig;
> + int ret;
> +
> + if (spi->max_speed_hz > TI_TSC2046_MAX_CLK_FREQ) {
> + dev_err(dev, "SPI max_speed_hz is too high: %d Hz. Max supported freq is %zu Hz\n",
> + spi->max_speed_hz, TI_TSC2046_MAX_CLK_FREQ);
> + return -EINVAL;
> + }
> +
> + dcfg = device_get_match_data(dev);
> + if (!dcfg)
> + return -EINVAL;
> +
> + spi->bits_per_word = 8;
> + spi->mode &= ~SPI_MODE_X_MASK;
> + spi->mode |= SPI_MODE_0;
> + ret = spi_setup(spi);
> + if (ret < 0)
> + return dev_err_probe(dev, ret, "Error in SPI setup\n");
> +
> + indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + priv = iio_priv(indio_dev);
> + priv->dcfg = dcfg;
> +
> + spi_set_drvdata(spi, indio_dev);
> +
> + priv->spi = spi;
> +
> + indio_dev->name = TI_TSC2046_NAME;
> + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
> + indio_dev->channels = dcfg->channels;
> + indio_dev->num_channels = dcfg->num_channels;
> + indio_dev->info = &tsc2046_adc_info;
> +
> + tsc2046_adc_parse_fwnode(priv);
> +
> + ret = tsc2046_adc_setup_spi_msg(priv);
> + if (ret)
> + return ret;
> +
> + mutex_init(&priv->slock);
> +
> + /* TODO: remove IRQ_NOAUTOEN after needed patches are mainline */
> + irq_set_status_flags(spi->irq, IRQ_NOAUTOEN);
They are now but I can do this whilst merging if that's all we have to change.
> + ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
> + 0, indio_dev->name, indio_dev);
> + if (ret)
> + return ret;
> +
> + trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name);
> + if (!trig)
> + return -ENOMEM;
> +
> + priv->trig = trig;
> + iio_trigger_set_drvdata(trig, indio_dev);
> + trig->ops = &tsc2046_adc_trigger_ops;
> +
> + spin_lock_init(&priv->trig_lock);
> + hrtimer_init(&priv->trig_timer, CLOCK_MONOTONIC,
> + HRTIMER_MODE_REL_SOFT);
> + priv->trig_timer.function = tsc2046_adc_trig_more;
> +
> + ret = devm_iio_trigger_register(dev, trig);
> + if (ret) {
> + dev_err(dev, "failed to register trigger\n");
> + return ret;
> + }
> +
> + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
> + &tsc2046_adc_trigger_handler, NULL);
> + if (ret) {
> + dev_err(dev, "Failed to setup triggered buffer\n");
> + return ret;
> + }
> +
> + /* set default trigger */
> + indio_dev->trig = iio_trigger_get(priv->trig);
> +
> + return devm_iio_device_register(dev, indio_dev);
> +}
> +
thanks,
J
