Re: [PATCH v6 1/2] gpio: loongson: add gpio driver support

[Yinbo Zhu]

在 2022/11/24 6:14, Linus Walleij 写道:
> On Wed, Nov 23, 2022 at 9:04 AM Yinbo Zhu <zhuyinbo@xxxxxxxxxxx> wrote:
>
> > The Loongson platforms GPIO controller contains 60 GPIO pins in total,
> > 4 of which are dedicated GPIO pins, and the remaining 56 are reused
> > with other functions. Each GPIO can set input/output and has the
> > interrupt capability.
> >
> > This driver added support for Loongson GPIO controller and support to
> > use DTS or ACPI to descibe GPIO device resources.
> >
> > Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> > Signed-off-by: Hongchen Zhang <zhanghongchen@xxxxxxxxxxx>
> > Signed-off-by: Liu Peibao <liupeibao@xxxxxxxxxxx>
> > Signed-off-by: Juxin Gao <gaojuxin@xxxxxxxxxxx>
> > Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> > ---
> > Change in v6:
> This is way better :)
>
> I guess you notice how the driver gets smaller and smaller.
> This is a good sign!
It's thanks to your advice！
> > +static int loongson_gpio_request(
> > +                       struct gpio_chip *chip, unsigned int pin)
> > +{
> > +       if (pin >= chip->ngpio)
> > +               return -EINVAL;
> > +
> > +       return 0;
> > +}
> Drop this altogether as discussed in my other reply.
okay , I got it.
> > +static inline void __set_direction(struct loongson_gpio_chip *lgpio,
> > +                       unsigned int pin, int input)
> > +static void __set_level(struct loongson_gpio_chip *lgpio, unsigned int pin,
> > +                       int high)
> I missed this before. Also the use of __underscore for inner functions
> is a bad habit IMO (because __underscore is also used for compiler
> primitives such as __init which is confusing) The signature of these
> functions is too generic. Name them loongson_commit_direction() or
> loongson_commit_level() or something.
okay , I got it.
> > +static int loongson_gpio_get_direction(
> > +                               struct gpio_chip *chip, unsigned int pin)
> thanks for implementing this!
>
> > +       if (lgpio->p_data->mode == BIT_CTRL_MODE) {
> > +               ret = bgpio_init(&lgpio->chip, dev, 8,
> > +                               LOONGSON_GPIO_IN(lgpio),
> > +                               LOONGSON_GPIO_OUT(lgpio), 0,
> > +                               LOONGSON_GPIO_OEN(lgpio), NULL, 0);
> > +               if (ret) {
> > +                       dev_err(dev, "unable to init generic GPIO\n");
> > +                       return ret;
> > +               }
> > +               lgpio->chip.ngpio = ngpios;
> Neat!
>
> > +               lgpio->chip.base = 0;
> Drop this. It is good that the base is unpredictable so
> people don't start to rely on it. (drivers/gpio/TODO)
okay, I got it.
> > +       rval = device_property_read_u16_array(dev, "gsi_idx_map", NULL, 0);
> But this gsi_idx_map is missing from your device tree bindings,
> is it not?
>
> Or what am I missing here? Sorry I might overlook something...

gsi_idx_map is for acpi, the dts doesn't use it, and acpi should be 
follow dts,

so remove it.

> > +static int loongson_gpio_probe(struct platform_device *pdev)
> > +{
> > +       void __iomem *reg_base;
> > +       struct loongson_gpio_chip *lgpio;
> > +       struct device_node *np = pdev->dev.of_node;
> > +       struct device *dev = &pdev->dev;
> > +
> > +       lgpio = devm_kzalloc(dev, sizeof(*lgpio), GFP_KERNEL);
> > +       if (!lgpio)
> > +               return -ENOMEM;
> > +
> > +       loongson_gpio_get_props(pdev, lgpio);
> > +
> > +       lgpio->p_data = device_get_match_data(&pdev->dev);
> lgpio->p_data = device_get_match_data(dev);
>
>
> > +static int __init loongson_gpio_setup(void)
> > +{
> > +       return platform_driver_register(&loongson_gpio_driver);
> > +}
> > +postcore_initcall(loongson_gpio_setup);
> Why does this have to be postcore_initcall()?

it was refer other gpio driver. other perpherial driver will use gpio, 
the gpio driver

 should be loaded as early as possible,so use postcore_initcall();

> Yours,
> Linus Walleij