| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CADiBU3_sU8bj29x2Qs9y9fM2YDYcKvNBkBuzfpzuCkAjSeTu+Q@mail.gmail.com>
Date: Mon, 4 Jul 2022 15:27:09 +0800
From: ChiYuan Huang <u0084500@...il.com>
To: Andy Shevchenko <andy.shevchenko@...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
ChiYuan Huang <u0084500@...il.com> 於 2022年7月4日 週一 上午11:16寫道：
>
> Andy Shevchenko <andy.shevchenko@...il.com> 於 2022年7月1日 週五 下午6:05寫道：
> >
> > 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 ?
> >
> Yes, unit is 2.5 microvolt. I have all listed all unit comments in the
> source code.a
Sorry, I found this scale is wrong.
For voltage channel, standard binding uses millivolt as the reported value.
>From this case, It must be (val * 2500) /1000000
So the '*val2' must equal to 1000000
> > ...
> >
> > > + *val2 = 1000;
> >
> > MILLI ?
> >
> Yes.
As the above one. Must be millivolt as the unit.
Channel unit is 2.5mV.
This value is correct and equal to (val * 2500) / 1000
> > > + *val = DIV_ROUND_UP(1000000, sample_time);
> >
> > USEC_PER_SEC ?
> >
> No, sample time is (vshunt convesion time + vbus conversion time) *
> average sample.
> And the sample freq returns the unit by HZ (sample frequency per second)
>
The 'sample time' is unit by micro-second like as you mentioned.
> > > +
> > > + 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 ?
> >
> Yes, for this kind of sense resistor, it will choose 2 milli-Ohm, 1
> milli-Ohms,, 0.5 milli-Ohms, or less.
> > > + return iio_format_value(buf, IIO_VAL_FRACTIONAL, 1, vals);
> > > +}
> >
> > ...
> >
> > > + ret = rtq6056_set_shunt_resistor(priv, val * 1000000 + val_fract);
> >
> > MICRO ?
> >
> Yes
> > > + 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.
> >
> Yap, from the 'max channel', it already guarantee this struct will be
> aligned at lease 4.
> Actually, It can be removed.
> > ...
> >
> > > + 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.
> >
> I think the another way is to register all using devm_ and to call the
> pm_runtime at the last.
> > > + }
> > > +
> > > + 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
Powered by blists - more mailing lists