2014-11-25 19:55:57

by Timur Tabi

[permalink] [raw]
Subject: Re: [PATCH v2 1/3] pinctrl: Add Qualcomm TLMM driver

On Thu, Dec 5, 2013 at 8:10 PM, Bjorn Andersson
<[email protected]> wrote:
>
> +static int msm_gpio_init(struct msm_pinctrl *pctrl)
> +{
> + struct gpio_chip *chip;
> + int irq;
> + int ret;
> + int i;
> + int r;
> +
> + chip = &pctrl->chip;
> + chip->base = 0;
> + chip->ngpio = pctrl->soc->ngpios;

I know this patch is a year old, but I'm wondering if this line is correct.

The original version of your patch from 11/23/13 said this:

+ chip->ngpio = pctrl->soc->gpio_range->npins;

and today, the line is this:

unsigned ngpio = pctrl->soc->ngpios;

I'm wondering if this line should be instead:

unsigned ngpio = pctrl->soc->npins;

I'm confused about the difference between msm_pinctrl_soc_data.npins
and msm_pinctrl_soc_data.ngpios. Variable "ngpio" is used by
gpiochip_add(), so I think it's not concerned with pin control.
msm_pinctrl_soc_data.npins appears to be the number of GPIOs, whereas
msm_pinctrl_soc_data.ngpios appears to be the number of pin groups.

--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.


2014-11-26 17:41:22

by Bjorn Andersson

[permalink] [raw]
Subject: Re: [PATCH v2 1/3] pinctrl: Add Qualcomm TLMM driver

On Tue, Nov 25, 2014 at 11:55 AM, Timur Tabi <[email protected]> wrote:
> On Thu, Dec 5, 2013 at 8:10 PM, Bjorn Andersson
> <[email protected]> wrote:
>>
>> +static int msm_gpio_init(struct msm_pinctrl *pctrl)
>> +{
>> + struct gpio_chip *chip;
>> + int irq;
>> + int ret;
>> + int i;
>> + int r;
>> +
>> + chip = &pctrl->chip;
>> + chip->base = 0;
>> + chip->ngpio = pctrl->soc->ngpios;
>
> I know this patch is a year old, but I'm wondering if this line is correct.
>

Hi Timur,

It's always good to review old code, so don't worry about its age of
the patch or code.

> The original version of your patch from 11/23/13 said this:
>
> + chip->ngpio = pctrl->soc->gpio_range->npins;
>

If you look in patchset 2 (the addition of 8974) you can see that I
passed a pinctrl_gpio_range from the 8974 driver to the common driver;
but I only use this to pass the number of gpios (NUM_GPIO_PINGROUPS).

> and today, the line is this:
>
> unsigned ngpio = pctrl->soc->ngpios;
>

Most likely based on some review comments this was replaced with just
an unsigned 'ngpios'.

> I'm wondering if this line should be instead:
>
> unsigned ngpio = pctrl->soc->npins;
>
> I'm confused about the difference between msm_pinctrl_soc_data.npins
> and msm_pinctrl_soc_data.ngpios. Variable "ngpio" is used by
> gpiochip_add(), so I think it's not concerned with pin control.
> msm_pinctrl_soc_data.npins appears to be the number of GPIOs, whereas
> msm_pinctrl_soc_data.ngpios appears to be the number of pin groups.
>

The 'ngpio' specifies how many gpio pins/groups (they are 1:1 in the
qcom case) the tlmm block sports, while 'npins' specifies how many
pingroups can be controlled by pinctrl/pinconf/pinmux.

So 'npins' will be 'ngpio' plus the other things that can be
controlled, e.g. sdcc.


The original patch assigns ngpio to be "the number of pinctrl pins in
the gpio range", i.e. a subset of all pins.

Regards,
Bjorn