Re: [PATCH v2 1/1] intel-mid: Fix sfi get_platform_data() return value issues

[sathyanarayanan kuppuswamy]

Thanks for the review Andy. Please check my comments inline.


On 09/08/2016 05:51 AM, Andy Shevchenko wrote:
> On Wed, 2016-09-07 at 17:05 -0700, Kuppuswamy Sathyanarayanan wrote:
> > According to the intel_mid_sfi_get_pdata() function definition,
> "function" is implied, remove the word.
Will be fixed in next version.
> > get_platform_data() function
> Ditto.
Same as above.
> > should returns NULL on no platform
> returns -> return
Same as above.
> > data scenario and return ERR_PTR on platform data initialization
> > failures. But current device platform initialization code does not
> > follow this requirement. This patch fixes the return values issues
> > in various sfi device libs code.
> sfi -> SFI
Same as above.
> Looking into patch I would consider to split it to series:
>
> 1. Rewrite GPIO expander logic to cover dynamic allocation. You have to
> check how it supposed to be in GPIO framework. IIRC gpio_base = -1
I checked the expander driver logic. As long as we return platform data 
as NULL, it by default falls back to dynamic allocation. So I think 
returning NULL on gpio_base == -1 is itself enough to support the 
dynamic allocation.

file: a/drivers/gpio/gpio-pca953x.c

755         pdata = dev_get_platdata(&client->dev);
756         if (pdata) {
757                 irq_base = pdata->irq_base;
758                 chip->gpio_start = pdata->gpio_base;
759                 invert = pdata->invert;
760                 chip->names = pdata->names;
761         } else {
762                 chip->gpio_start = -1;
763                 irq_base = 0;
764         }

> (perhaps a defined constant) will do the trick.
> 2. Fix the actual return codes (maybe with changes to sfi.c).
> 3. Fix and add error messages.
I can split the patch into two. One for return code fix and another for 
adding error messages.
> 4+ (in the future) Address code duplication
Agreed.
> > --- a/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
> > +++ b/arch/x86/platform/intel-mid/device_libs/platform_max7315.c
> > @@ -29,9 +29,9 @@ static void __init *max7315_platform_data(void
> > *info)
> >   	char intr_pin_name[SFI_NAME_LEN + 1];
> >   
> >   	if (nr == MAX7315_NUM) {
> > -		pr_err("too many max7315s, we only support %d\n",
> > -				MAX7315_NUM);
> > -		return NULL;
> > +		pr_err("%s: too many max7315s, we only support %d\n",
> > +		       __func__, MAX7315_NUM);
> Use the same as for PCAL9555A:
>
> pr_err("%s: Too many instances, only %d supported\n",
Will be fixed in next version.
> > @@ -48,8 +48,12 @@ static void __init *max7315_platform_data(void
> > *info)
> >   	gpio_base = get_gpio_by_name(base_pin_name);
> >   	intr = get_gpio_by_name(intr_pin_name);
> >   
> > -	if (gpio_base < 0)
> > +	if (gpio_base < 0) {
> > +		pr_err("%s: Unknown GPIO base number, falling back
> > to"
> > +		       "dynamic allocation\n", __func__);
> Don't split literals.
>
> pr_err("...long literal...\n",
>         args...);
>
> No. This not just the message you show and abort initialization, in case
> of dynamic allocation you have to proceed initialization.
How about we go with following warning message. Since using dynamic gpio 
allocation is not an error, I think a warning message is more than 
enough here. Also , I don't see any value in adding "Unknown gpio base 
number" to the error message. So we can remove it to fit the log message 
into one line.

+       if (gpio_base == -1) {
+               pr_warn("%s: falling back to dynamic gpio allocation\n",
+                       __func__);

> > index ee22864..4b33aab 100644
> > --- a/arch/x86/platform/intel-mid/device_libs/platform_mpu3050.c
> > +++ b/arch/x86/platform/intel-mid/device_libs/platform_mpu3050.c
> > @@ -14,15 +14,21 @@
> >   
> >   	i2c_info->irq = intr + INTEL_MID_IRQ_OFFSET;
> > +
> >   	return NULL;
> This change doesn't belong to the series.
Submitting a separate patch to fix this this single style issue seems to 
be over kill. Will it be ok if I add this to my debug message patch ?
> >   }
> >   
> > diff --git a/arch/x86/platform/intel-
> > mid/device_libs/platform_pcal9555a.c b/arch/x86/platform/intel-
> > mid/device_libs/platform_pcal9555a.c
> > index 429a941..190b2d2 100644
> > --- a/arch/x86/platform/intel-mid/device_libs/platform_pcal9555a.c
> > +++ b/arch/x86/platform/intel-mid/device_libs/platform_pcal9555a.c
> > @@ -41,13 +41,16 @@ static void __init *pcal9555a_platform_data(void
> > *info)
> >   	intr = get_gpio_by_name(intr_pin_name);
> >   
> >   	/* Check if the SFI record valid */
> > -	if (gpio_base == -1)
> > +	if (gpio_base == -1) {
> > +		pr_err("%s: Unknown GPIO base number, falling back to
> > dynamic"
> > +		       "allocation\n", __func__);
> >   		return NULL;
> Same comment as above for gpio_base.
Will be fixed in next version.
> > --- a/arch/x86/platform/intel-mid/device_libs/platform_tca6416.c
> > +++ b/arch/x86/platform/intel-mid/device_libs/platform_tca6416.c
> > @@ -34,8 +34,12 @@ static void *tca6416_platform_data(void *info)
> >   	gpio_base = get_gpio_by_name(base_pin_name);
> >   	intr = get_gpio_by_name(intr_pin_name);
> >   
> > -	if (gpio_base < 0)
> > +	if (gpio_base < 0) {
> > +		pr_err("%s: Unknown GPIO base number, falling back to
> > dynamic"
> > +		       "allocation\n", __func__);
> Ditto.

--
Sathyanarayanan Kuppuswamy
Android kernel developer