Re: [PATCH v2 3/7] pinctrl: armada-37xx: Add pin controller support for Armada 37xx

[Gregory CLEMENT <gregory.clement@free-electrons.com>]

Hi Linus,
 
 On lun., mars 27 2017, Linus Walleij <linus.walleij@linaro.org> wrote:

> On Tue, Mar 21, 2017 at 7:28 PM, Gregory CLEMENT
> <gregory.clement@free-electrons.com> wrote:
>
>> The Armada 37xx SoC come with 2 pin controllers: one on the south
>> bridge (managing 28 pins) and one on the north bridge (managing 36 pins).
>>
>> At the hardware level the controller configure the pins by group and not
>> pin by pin. This constraint is reflected in the design of the driver:
>> only the group related functions are implemented.
>
> Interesting!
>
>> +static int armada_37xx_pmx_direction_input(struct armada_37xx_pinctrl *info,
>> +                                          unsigned int offset)
>> +{
>> +       unsigned int reg = OUTPUT_EN;
>> +       unsigned int mask;
>> +
>> +       if (offset >= GPIO_PER_REG) {
>> +               offset -= GPIO_PER_REG;
>> +               reg += sizeof(u32);
>> +       }
>> +       mask = BIT(offset);
>> +
>> +       return regmap_update_bits(info->regmap, reg, mask, 0);
>> +}
>> +
>> +
>> +
>
> A bit of excess whitespace, OK nitpicking.
>

As I need to send a v4, I will fix it in the same time.

> Then this stuff:
>
>> +static int armada_37xx_add_function(struct armada_37xx_pmx_func *funcs,
>> +                                   int *funcsize, const char *name)
>> +{
>> +       int i = 0;
>> +
>> +       if (*funcsize <= 0)
>> +               return -EOVERFLOW;
>> +
>> +       while (funcs->ngroups) {
>> +               /* function already there */
>> +               if (strcmp(funcs->name, name) == 0) {
>> +                       funcs->ngroups++;
>> +
>> +                       return -EEXIST;
>> +               }
>> +               funcs++;
>> +               i++;
>> +       }
>> +
>> +       /* append new unique function */
>> +       funcs->name = name;
>> +       funcs->ngroups = 1;
>> +       (*funcsize)--;
>> +
>> +       return 0;
>> +}
>> +
>> +static int armada_37xx_fill_group(struct armada_37xx_pinctrl *info, int base)
>> +{
>> +       int n, num = 0, funcsize = info->data->nr_pins;
>> +
>> +       for (n = 0; n < info->ngroups; n++) {
>> +               struct armada_37xx_pin_group *grp = &info->groups[n];
>> +               int i, j, f;
>> +
>> +               grp->pins = devm_kzalloc(info->dev,
>> +                                        (grp->npins + grp->extra_npins) *
>> +                                        sizeof(*grp->pins), GFP_KERNEL);
>> +               if (!grp->pins)
>> +                       return -ENOMEM;
>> +
>> +               for (i = 0; i < grp->npins; i++)
>> +                       grp->pins[i] = grp->start_pin + base + i;
>> +
>> +               for (j = 0; j < grp->extra_npins; j++)
>> +                       grp->pins[i+j] = grp->extra_pin + base + j;
>> +
>> +               for (f = 0; f < NB_FUNCS; f++) {
>> +                       int ret;
>> +                       /* check for unique functions and count groups */
>> +                       ret = armada_37xx_add_function(info->funcs, &funcsize,
>> +                                           grp->funcs[f]);
>> +                       if (ret == -EOVERFLOW)
>> +                               dev_err(info->dev,
>> +                                       "More functions than pins(%d)\n",
>> +                                       info->data->nr_pins);
>> +                       if (ret < 0)
>> +                               continue;
>> +                       num++;
>> +               }
>> +       }
>> +
>> +       info->nfuncs = num;
>> +
>> +       return 0;
>> +}
>> +
>> +static int armada_37xx_fill_func(struct armada_37xx_pinctrl *info)
>> +{
>> +       struct armada_37xx_pmx_func *funcs = info->funcs;
>> +       int n;
>> +
>> +       for (n = 0; n < info->nfuncs; n++) {
>> +               const char *name = funcs[n].name;
>> +               const char **groups;
>> +               int g;
>> +
>> +               funcs[n].groups = devm_kzalloc(info->dev, funcs[n].ngroups *
>> +                                              sizeof(*(funcs[n].groups)),
>> +                                              GFP_KERNEL);
>> +               if (!funcs[n].groups)
>> +                       return -ENOMEM;
>> +
>> +               groups = funcs[n].groups;
>> +
>> +               for (g = 0; g < info->ngroups; g++) {
>> +                       struct armada_37xx_pin_group *gp = &info->groups[g];
>> +                       int f;
>> +
>> +                       for (f = 0; f < NB_FUNCS; f++) {
>> +                               if (strcmp(gp->funcs[f], name) == 0) {
>> +                                       *groups = gp->name;
>> +                                       groups++;
>> +                               }
>> +                       }
>> +               }
>> +       }
>> +       return 0;
>> +}
>
> I would be happy if you add kerneldoc to these functions and explain
> what they do. Because I don't get it. I guess they are filling in the data
> structures but yeah. Hard to follow.

OK

>
>> +       match = of_match_node(armada_37xx_pinctrl_of_match, np);
>> +       info->data = (struct armada_37xx_pin_data *)match->data;
>
> Use of_device_get_match_data()

OK

>
>
>> +static struct platform_driver armada_37xx_pinctrl_driver = {
>> +       .driver = {
>> +               .name = "armada-37xx-pinctrl",
>> +               .of_match_table = armada_37xx_pinctrl_of_match,
>> +       },
>> +       .probe = armada_37xx_pinctrl_probe,
>> +};
>> +
>> +builtin_platform_driver(armada_37xx_pinctrl_driver);
>
> It almost looks like your could use builting_platform_driver_probe() actually,
> and tag the costly initfunctions with __init so they get dicarded
> after probe.

Sure, I will do it

Thanks,

Gregory

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com