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Date: Fri, 1 Jul 2022 12:04:42 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: cy_huang <u0084500@...il.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Lars-Peter Clausen <lars@...afoo.de>,
cy_huang <cy_huang@...htek.com>,
linux-iio <linux-iio@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] iio: adc: Add rtq6056 support
On Wed, Jun 29, 2022 at 4:23 AM cy_huang <u0084500@...il.com> wrote:
> Add Richtek rtq6056 supporting.
>
> It can be used for the system to monitor load current and power with 16-bit
> resolution.
...
> +static int rtq6056_adc_read_channel(struct rtq6056_priv *priv,
> + struct iio_chan_spec const *ch,
> + int *val)
> +{
> + struct device *dev = priv->dev;
> + unsigned int addr = ch->address;
> + unsigned int regval;
> + int ret;
> +
> + pm_runtime_get_sync(dev);
> +
> + ret = regmap_read(priv->regmap, addr, ®val);
> + if (ret) {
> + pm_runtime_put(dev);
> + return ret;
> + }
You can optimize this to
pm_runtime_get_sync(dev);
ret = regmap_read(priv->regmap, addr, ®val);
pm_runtime_mark_last_busy(dev);
pm_runtime_put(dev);
if (ret)
return ret;
> + /* Power and VBUS is unsigned 16-bit, others are signed 16-bit */
> + if (addr == RTQ6056_REG_BUSVOLT || addr == RTQ6056_REG_POWER)
> + *val = regval;
> + else
> + *val = sign_extend32(regval, 16);
> + pm_runtime_mark_last_busy(dev);
> + pm_runtime_put(dev);
...and get rid of these.
> + return IIO_VAL_INT;
> +}
...
> + *val2 = 1000000000;
NANO ?
...
> + *val2 = 1000;
MILLI ?
> + *val = DIV_ROUND_UP(1000000, sample_time);
USEC_PER_SEC ?
> +
> + return IIO_VAL_INT;
> +}
...
> +static int rtq6056_adc_read_label(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + char *label)
> +{
> + return sysfs_emit(label, "%s\n", rtq6056_channel_labels[chan->channel]);
> +}
...
> + /* calibration = 5120000 / (Rshunt (uohm) * current lsb (1mA)) */
uOhm
...
> +static ssize_t shunt_resistor_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct rtq6056_priv *priv = iio_priv(dev_to_iio_dev(dev));
> + int vals[2] = { priv->shunt_resistor_uohm, 1000000 };
MICRO ?
> + return iio_format_value(buf, IIO_VAL_FRACTIONAL, 1, vals);
> +}
...
> + ret = rtq6056_set_shunt_resistor(priv, val * 1000000 + val_fract);
MICRO ?
> + if (ret)
> + return ret;
...
> + struct {
> + u16 vals[RTQ6056_MAX_CHANNEL];
> + int64_t timestamp;
> + } data __aligned(8);
Hmm... alignment of this struct will be at least 4 bytes, but
shouldn't we rather be sure that the timestamp member is aligned
properly? Otherwise this seems fragile and dependent on
RTQ6056_MAX_CHANNEL % 4 == 0.
...
> + pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC);
> + pm_runtime_use_autosuspend(dev);
> + pm_runtime_set_active(dev);
> + pm_runtime_mark_last_busy(dev);
> + pm_runtime_enable(dev);
> +
> + /* By default, use 2000 micro-ohm resistor */
> + shunt_resistor_uohm = 2000;
> + device_property_read_u32(dev, "shunt-resistor-micro-ohms",
> + &shunt_resistor_uohm);
> +
> + ret = rtq6056_set_shunt_resistor(priv, shunt_resistor_uohm);
> + if (ret) {
> + dev_err(dev, "Failed to init shunt resistor\n");
> + goto err_probe;
return dev_err_probe();
(see below how)
> + }
> +
> + indio_dev->name = "rtq6056";
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = rtq6056_channels;
> + indio_dev->num_channels = ARRAY_SIZE(rtq6056_channels);
> + indio_dev->info = &rtq6056_info;
> +
> + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
> + rtq6056_buffer_trigger_handler,
> + NULL);
> + if (ret) {
> + dev_err(dev, "Failed to allocate iio trigger buffer\n");
Ditto.
> + goto err_probe;
It is a sign of wrong ordering, either do not use devm_ calls after
non-devm_ or make the latter wrapped into devm_add_action_or_reset().
See below for additional information.
> + }
> +
> + ret = devm_iio_device_register(dev, indio_dev);
> + if (ret) {
> + dev_err(dev, "Failed to allocate iio device\n");
> + goto err_probe;
> + }
> +
> + return 0;
> +
> +err_probe:
> + pm_runtime_dont_use_autosuspend(dev);
> + pm_runtime_disable(dev);
> + pm_runtime_set_suspended(dev);
> +
> + return ret;
...
> +static int rtq6056_remove(struct i2c_client *i2c)
> +{
> + struct device *dev = &i2c->dev;
Another (but usually not good option) is to call devm_..._unregister() here.
> + pm_runtime_dont_use_autosuspend(dev);
> + pm_runtime_disable(dev);
> + pm_runtime_set_suspended(dev);
> +
> + return 0;
> +}
...
> +static const struct dev_pm_ops rtq6056_pm_ops = {
> + SET_RUNTIME_PM_OPS(rtq6056_runtime_suspend, rtq6056_runtime_resume, NULL)
RUNTIME_PM_OPS()
> +};
...
> +static const struct of_device_id rtq6056_device_match[] = {
> + { .compatible = "richtek,rtq6056", },
In this case the inner comma is not needed.
> + {}
> +};
...
> +static struct i2c_driver rtq6056_driver = {
> + .driver = {
> + .name = "rtq6056",
> + .of_match_table = rtq6056_device_match,
> + .pm = &rtq6056_pm_ops,
pm_ptr()
> + },
--
With Best Regards,
Andy Shevchenko
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