Re: [PATCH v7 2/4] iio: adc: Add Xilinx AMS driver

Lars-Peter Clausen
2021-10-23T12:36:41Z

On 10/19/21 5:20 PM, Anand Ashok Dumbre wrote:
> [....]
> +struct ams {
> + void __iomem *base;
> + void __iomem *ps_base;
> + void __iomem *pl_base;
> + struct clk *clk;
> + struct device *dev;
> + /* check kernel doc above */
> + struct mutex lock;
> + /* check kernel doc above */
Do we need this comment?
> + spinlock_t intr_lock;
> + unsigned int alarm_mask;
> + unsigned int masked_alarm;
> + u64 intr_mask;
> + int irq;
The irq field is only ever used in the probe function. Could be made a
local variable.
> + struct delayed_work ams_unmask_work;
> +};
> [...]
>
> +static void ams_enable_channel_sequence(struct iio_dev *indio_dev)
> +{
> + int i;
> + unsigned long long scan_mask;
> + struct ams *ams = iio_priv(indio_dev);
> +
> + /*
> + * Enable channel sequence. First 22 bits of scan_mask represent
> + * PS channels, and next remaining bits represent PL channels.
> + */
> +
> + /* Run calibration of PS & PL as part of the sequence */
> + scan_mask = 0x1 | BIT(AMS_PS_SEQ_MAX);
> + for (i = 0; i < indio_dev->num_channels; i++)
> + scan_mask |= BIT_ULL(indio_dev->channels[i].scan_index);

There are channels with a scan index > 63. These need to be skipped here
to avoid undefined behavior. UBSAN is reporting an error here.
> [...]
> + if (ams->pl_base) {
> + /* put sysmon in a soft reset to change the sequence */
> + ams_pl_update_reg(ams, AMS_REG_CONFIG1, AMS_CONF1_SEQ_MASK,
> + AMS_CONF1_SEQ_DEFAULT);
> +
> + /* configure basic channels */
> + scan_mask = FIELD_GET(AMS_PL_SEQ_MASK, scan_mask);
> + writel(FIELD_GET(AMS_REG_SEQ0_MASK, scan_mask),
> + ams->pl_base + AMS_REG_SEQ_CH0);
> + writel(FIELD_GET(AMS_REG_SEQ2_MASK, scan_mask),
> + ams->pl_base + AMS_REG_SEQ_CH2);
> + writel(FIELD_GET(AMS_REG_SEQ1_MASK, scan_mask),
> + ams->pl_base + AMS_REG_SEQ_CH1);
Hm, the ordering is a bit strange here: 0, 2, 1.
> +
> + /* set continuous sequence mode */
> + ams_pl_update_reg(ams, AMS_REG_CONFIG1, AMS_CONF1_SEQ_MASK,
> + AMS_CONF1_SEQ_CONTINUOUS);
> + }
> +}
> +
>
> +
> [...]
> +
> +static int ams_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct ams *ams = iio_priv(indio_dev);
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&ams->lock);
> + if (chan->scan_index >= (AMS_PS_SEQ_MAX * 3)) {
This AMS_PS_SEQ_MAX * 3 really deserves a define. AMS_CTRL_SEQ_BASE or
something like that.
> + ret = ams_read_vcc_reg(ams, chan->address, val);
> + if (ret) {
> + mutex_unlock(&ams->lock);
> + return -EINVAL;
> + }
> + ams_enable_channel_sequence(indio_dev);
> + } else if (chan->scan_index >= AMS_PS_SEQ_MAX)
> + *val = readl(ams->pl_base + chan->address);
> + else
> + *val = readl(ams->ps_base + chan->address);
> + mutex_unlock(&ams->lock);
> +
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->type) {
> + case IIO_VOLTAGE:
> + switch (chan->address) {
> + case AMS_SUPPLY1:
> + case AMS_SUPPLY2:
> + case AMS_SUPPLY3:
> + case AMS_SUPPLY4:
> + *val = AMS_SUPPLY_SCALE_3VOLT;
> + break;
> + case AMS_SUPPLY5:
> + case AMS_SUPPLY6:
> + if (chan->scan_index < AMS_PS_SEQ_MAX)
> + *val = AMS_SUPPLY_SCALE_6VOLT;
> + else
> + *val = AMS_SUPPLY_SCALE_3VOLT;
> + break;
> + case AMS_SUPPLY7:
> + case AMS_SUPPLY8:
> + *val = AMS_SUPPLY_SCALE_6VOLT;
> + break;
> + case AMS_SUPPLY9:
> + case AMS_SUPPLY10:
> + if (chan->scan_index < AMS_PS_SEQ_MAX)
> + *val = AMS_SUPPLY_SCALE_3VOLT;
> + else
> + *val = AMS_SUPPLY_SCALE_6VOLT;
> + break;
For the PL the range of supply 7 to 10 depends on the CONFIG_REG4 and
can be either 3V or 6V. Might be worth checking that register, rather
than hardcoding the value.
> + case AMS_VCC_PSPLL0:
> + case AMS_VCC_PSPLL3:
> + case AMS_VCCINT:
> + case AMS_VCCBRAM:
> + case AMS_VCCAUX:
> + case AMS_PSDDRPLL:
> + case AMS_PSINTFPDDR:

This is missing AMS_VCCAMS, AMS_VREFP, AMS_VREFN. They all use the 3V scale.

The only ones on a 1V scale are the external channels.

Maye it is easier to write this as

case AMS_VP_VN:
case AMS_REG_VAUX ... AMS_REG_VAUX(15):
*val = AMS_SUPPLY_SCALE_1VOLT;
break;
default:
*val = AMS_SUPPLY_SCALE_3VOLT;
break;

> + *val = AMS_SUPPLY_SCALE_3VOLT;
> + break;
> + default:
> + *val = AMS_SUPPLY_SCALE_1VOLT;
> + break;
> + }
> + *val2 = AMS_SUPPLY_SCALE_DIV_BIT;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + case IIO_TEMP:
> + *val = AMS_TEMP_SCALE;
> + *val2 = AMS_TEMP_SCALE_DIV_BIT;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + default:
> + return -EINVAL;
> + }
> + case IIO_CHAN_INFO_OFFSET:
> + /* Only the temperature channel has an offset */
> + *val = AMS_TEMP_OFFSET;
> + return IIO_VAL_INT;
> + }
> +
> + return -EINVAL;
> +}
> +
> [...]
>
> +static int ams_init_module(struct iio_dev *indio_dev, struct device_node *np,
> + struct iio_chan_spec *channels)
> +{
> + struct ams *ams = iio_priv(indio_dev);
> + int num_channels = 0;
> +
> + if (of_device_is_compatible(np, "xlnx,zynqmp-ams-ps")) {
> + ams->ps_base = of_iomap(np, 0);
No unmap anywhere in the driver. Same for the other base addresses.
> [...]
> +
> + return num_channels;
> +}
> [...]
> +static int ams_probe(struct platform_device *pdev)
> +{
> [...]
> + ams->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(ams->clk))
> + return PTR_ERR(ams->clk);
> + clk_prepare_enable(ams->clk);
> + devm_add_action_or_reset(&pdev->dev, ams_clk_disable_unprepare,
> + ams->clk);
Needs to check for errors. Same for other users of
devm_add_action_or_reset().
> +
> + INIT_DELAYED_WORK(&ams->ams_unmask_work, ams_unmask_worker);
> + devm_add_action_or_reset(&pdev->dev, ams_cancel_delayed_work,
> + &ams->ams_unmask_work);
> +
> + ret = ams_init_device(ams);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to initialize AMS\n");
> + return ret;
> + }
> +
> + ret = ams_parse_dt(indio_dev, pdev);
> + if (ret) {
> + dev_err(&pdev->dev, "failure in parsing DT\n");
> + return ret;
> + }
> +
> + ams_enable_channel_sequence(indio_dev);
> +
> + ams->irq = platform_get_irq(pdev, 0);
> + if (ams->irq == -EPROBE_DEFER) {
What about other errors? E.g. if the interrupt is not specified int he
devicetree we'll pass the invalid irq number to request_irq().
> + ret = -EPROBE_DEFER;
> + return ret;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, ams->irq, &ams_irq, 0, "ams-irq",
> + indio_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to register interrupt\n");
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, indio_dev);
> +
> + ret = devm_iio_device_register(&pdev->dev, indio_dev);
> +
> + return ret;
> +}