Messages in this thread | | | Date | Thu, 23 Mar 2023 06:07:36 -0700 | Subject | Re: [PATCH 1/2] iio: max597x: Add support for max597x | From | Lars-Peter Clausen <> |
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On 3/23/23 05:01, Naresh Solanki wrote: > Hi, > > On 22-03-2023 09:28 pm, Lars-Peter Clausen wrote: >> Hi, >> >> This looks really good. A few minor comments inline. >> >> On 3/22/23 05:43, Naresh Solanki wrote: >>> [...] >>> +static int max597x_iio_read_raw(struct iio_dev *iio_dev, >>> + struct iio_chan_spec const *chan, >>> + int *val, int *val2, long info) >>> +{ >>> + int ret; >>> + struct max597x_iio *data = iio_priv(iio_dev); >>> + unsigned int reg_l, reg_h; >>> + >>> + switch (info) { >>> + case IIO_CHAN_INFO_RAW: >>> + ret = regmap_read(data->regmap, chan->address, ®_l); >>> + if (ret < 0) >>> + return ret; >>> + ret = regmap_read(data->regmap, chan->address - 1, ®_h); >>> + if (ret < 0) >>> + return ret; >> Is there any chance of a race condition of getting inconsistent data >> when splitting this over two reads? I.e. registers being updated with >> new values in between the two reads. > yes, reg_l holds lower 2 bits. due to latency in reads, value may differ. >>> + *val = (reg_h << 2) | (reg_l & 3); >>> + >>> + return IIO_VAL_INT; >>> + case IIO_CHAN_INFO_SCALE: >>> + >>> + switch (chan->address) { >>> + case MAX5970_REG_CURRENT_L(0): >>> + fallthrough; >> >> `fallthrough` should not be needed for multiple case statements right >> on top of each other with no code in between. Same below > Sure. >> >>> + case MAX5970_REG_CURRENT_L(1): >>> + /* in A, convert to mA */ >>> + *val = data->irng[chan->channel] * 1000; >>> + *val2 = >>> + data->shunt_micro_ohms[chan->channel] * ADC_MASK; >> ADC_MASK should really have a MAX5970_ prefix, but I guess it is >> defined in max597x.h > Yes its taken from max597x.h >>> + return IIO_VAL_FRACTIONAL; >>> + >>> + case MAX5970_REG_VOLTAGE_L(0): >>> + fallthrough; >>> + case MAX5970_REG_VOLTAGE_L(1): >>> + /* in uV, convert to mV */ >>> + *val = data->mon_rng[chan->channel]; >>> + *val2 = ADC_MASK * 1000; >>> + return IIO_VAL_FRACTIONAL; >>> + } >>> + >>> + break; >>> + } >>> + return -EINVAL; >>> +} >>> [..] >>> +static int max597x_iio_probe(struct platform_device *pdev) >>> +{ >>> + struct max597x_data *max597x = dev_get_drvdata(pdev->dev.parent); >>> + struct i2c_client *i2c = to_i2c_client(pdev->dev.parent); >>> + struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL); >>> + struct iio_dev *indio_dev; >>> + struct max597x_iio *priv; >>> + int ret, i; >>> + >>> + if (!regmap) >>> + return -EPROBE_DEFER; >>> + >>> + if (!max597x || !max597x->num_switches) >>> + return -EPROBE_DEFER; >>> + >>> + /* registering iio */ >>> + indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*priv)); >> For the devm allocations we should be using &pdev->dev and not the >> I2C device, since this is the device to which the allocations belong >> and where they should be freed when the device is removed. > Sure. Will use &pdev->dev >>> + if (!indio_dev) { >>> + dev_err(&i2c->dev, "failed allocating iio device\n"); >> Consider using dev_err_probe() for error message printing. This will >> give a consistent formatting of the messages. Also again use >> &pdev->dev instead of I2C device to get the right device listed in >> the error messages. > Sure. Will use > dev_err_probe(&pdev->dev, ret, "could not register iio device"); >>> + return -ENOMEM; >>> + } >>> + indio_dev->name = dev_name(&i2c->dev); >> The IIO ABI wants the type of the chip for the name. E.g. "max5970", >> using dev_name() of the parent I2C device will result in something else. > Sure. Will make it: > indio_dev->name = dev_name(&pdev->dev); > dev_name() in general should not be used for indio_dev->name, it does not meet the ABI requirements for the IIO ABI. Move this into the switch block below and then assign "max5970" or "max5978" depending on the device type.
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