Re: [PATCH v5 1/2] gpio: Add driver for PC Engines APU boards

[Florian Eckert]

> /*
>  * Multi-line comments
>  * have this style
>  */

fixed


> > +#include <linux/kernel.h>
>
> kbuild bot complains for absence of
>
> #include <linux/mod_devicetable.h>
>
> here.

fixed

> > +static int gpio_apu_get_dir(struct gpio_chip *chip, unsigned int 
> > offset)
> > +{
> > +       u32 val;
> > +       struct apu_gpio_pdata *apu_gpio = gpiochip_get_data(chip);
> > +
> > +       spin_lock(&apu_gpio->lock);
> > +
>
> > +       val = ~ioread32(apu_gpio->addr[offset]);
>
> There is no need to do ~ under spin lock.

fixed

> > +
> > +       spin_unlock(&apu_gpio->lock);
> > +
> > +       return !!(val & BIT(APU_GPIO_BIT_DIR));
> > +}
>
> > +       if (dmi_check_system(apu3_gpio_dmi_table)) {
>
> (1)
>
> > +               apu_gpio->addr = devm_kzalloc(&pdev->dev,
> > +                               sizeof(apu3_gpio_offset),
> > +                               GFP_KERNEL);
>
> > +
>
> No need to have this blank line. Same for the other cases.

fixed

> > +               if (!apu_gpio->addr)
> > +                       return -ENOMEM;
>
> > +       } else if (dmi_check_system(apu2_gpio_dmi_table)) {
>
> (2)
>
> I think I have already told about (1) and (2). You may create two
> callbacks and utilize .callback member in DMI table.

Done but I do not seen any advantage. I used the following driver as 
basis.
https://github.com/torvalds/linux/blob/master/drivers/leds/leds-clevo-mail.c

> > +       }
>
> > +static int __init apu_gpio_init(void)
> > +{
>
> > +       if (!(dmi_check_system(apu2_gpio_dmi_table)) &&
> > +               !(dmi_check_system(apu3_gpio_dmi_table))) {
> > +               pr_err("No PC Engines board detected\n");
> > +               return -ENODEV;
> > +       }
>
> I don't think we need this.

see below


> > +}
> > +
> > +module_init(apu_gpio_init);
> > +module_exit(apu_gpio_exit);

> After removing unneeded checks why not to simple use
> module_platform_driver()
> ?

I have fixed all the above hints from you now but using 
"module_platform_driver" is no option.
I played around with them but the driver does not find any device. So I 
need the init function
to add a platform device. Only if I do this way driver and device will 
find and match. And I
see the gpios under /sys/class/gpio. So I think I need this?
I have not find any driver who has the same problems
I used the following drivers as my basis:
https://github.com/torvalds/linux/blob/master/drivers/leds/leds-apu.c
https://github.com/torvalds/linux/blob/master/drivers/leds/leds-clevo-mail.c
They all use dmi and need init/exit for platform device register and 
unregister