Re: [PATCH v2 1/1] iio: adc: qcom-spmi-adc5: Fix the channel name

[Konrad Dybcio <konrad.dybcio@linaro.org>]

On 22.01.2023 18:24, Jonathan Cameron wrote:
> On Wed, 18 Jan 2023 12:06:23 +0200
> Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> 
>> The node name can contain an address part which is unused
>> by the driver. Moreover, this string is propagated into
>> the userspace label, sysfs filenames *and breaking ABI*.
>>
>> Cut the address part out before assigning the channel name.
>>
>> Fixes: 4f47a236a23d ("iio: adc: qcom-spmi-adc5: convert to device properties")
>> Reported-by: Marijn Suijten <marijn.suijten@somainline.org>
>> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> LGTM, but given it will have ABI impact, I'd like to hear from 
> Andy, Bjorn or Konrad as maintainers and /or Dmitry as someone
> who has touched this driver fairly recently.
+ Doug

Unless the Chromium folks relied on the old names (they're the
only ones I can think of that actually could have tapped into
this), I say green light!

Konrad
> 
> Mostly I want to be sure they know this exists before it causes surprise.
> 
> Jonathan
> 
>> ---
>> v2: rephrased commit message (Marijn), fixed compilation issue (Marijin)
>>  drivers/iio/adc/qcom-spmi-adc5.c | 10 +++++++++-
>>  1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/adc/qcom-spmi-adc5.c b/drivers/iio/adc/qcom-spmi-adc5.c
>> index e90c299c913a..c2d5e06f137a 100644
>> --- a/drivers/iio/adc/qcom-spmi-adc5.c
>> +++ b/drivers/iio/adc/qcom-spmi-adc5.c
>> @@ -628,12 +628,20 @@ static int adc5_get_fw_channel_data(struct adc5_chip *adc,
>>  				    struct fwnode_handle *fwnode,
>>  				    const struct adc5_data *data)
>>  {
>> -	const char *name = fwnode_get_name(fwnode), *channel_name;
>> +	const char *channel_name;
>> +	char *name;
>>  	u32 chan, value, varr[2];
>>  	u32 sid = 0;
>>  	int ret;
>>  	struct device *dev = adc->dev;
>>  
>> +	name = devm_kasprintf(dev, GFP_KERNEL, "%pfwP", fwnode);
>> +	if (!name)
>> +		return -ENOMEM;
>> +
>> +	/* Cut the address part */
>> +	name[strchrnul(name, '@') - name] = '\0';
>> +
>>  	ret = fwnode_property_read_u32(fwnode, "reg", &chan);
>>  	if (ret) {
>>  		dev_err(dev, "invalid channel number %s\n", name);
>