[Linux-stm32] [PATCH 1/1] pinctrl: stmfx: fix valid_mask init sequence

[Amelie DELAUNAY]

On 11/5/19 3:32 PM, Linus Walleij wrote:
> On Mon, Nov 4, 2019 at 11:09 AM Amelie Delaunay <amelie.delaunay at st.com> 
> wrote:
> 
>> With stmfx_pinctrl_gpio_init_valid_mask callback, gpio_valid_mask was used
>> to initialize gpiochip valid_mask for gpiolib. But gpio_valid_mask was not
>> yet initialized. gpio_valid_mask required gpio-ranges to be registered,
>> this is the case after gpiochip_add_data call. But init_valid_mask
>> callback is also called under gpiochip_add_data. gpio_valid_mask
>> initialization cannot be moved before gpiochip_add_data because
>> gpio-ranges are not registered.
> 
> Sorry but this doesn't add up, look at this call graph:
> 
> gpiochip_add_data()
>    gpiochip_add_data_with_key()
>      gpiochip_alloc_valid_mask()
>      of_gpiochip_add()
>      of_gpiochip_add_pin_range()
>      gpiochip_init_valid_mask()
> 
> So the .initi_valid_mask() is clearly called *after*
> of_gpiochip_add_pin_range() so this cannot be the real reason,
> provided that the ranges come from the device tree. AFAICT that
> is the case with the stmfx.
> 
> Can you check and see if the problem is something else?
>

stmfx_pinctrl_gpio_init_valid_mask uses pctl->gpio_valid_mask to 
initialize gpiochip valid_mask.

pctl->gpio_valid_mask is initialized in 
stmfx_pinctrl_gpio_function_enable depending on gpio ranges.

stmfx_pinctrl_gpio_function_enable is called after gpiochip_add_data 
because it requires gpio ranges to be registered.

So, in stmfx driver the call graph is

stmfx_pinctrl_probe
   gpiochip_add_data()
     gpiochip_add_data_with_key()
       gpiochip_alloc_valid_mask()
       of_gpiochip_add()
       of_gpiochip_add_pin_range()
       gpiochip_init_valid_mask()
         stmfx_pinctrl_gpio_init_valid_mask (but pctl->gpio_valid_mask 
is not yet initialized so gpiochip valid_mask is wrong)
   stmfx_pinctrl_gpio_function_enable (pctl->gpio_valid_mask is going to 
be initialized thanks to gpio ranges)

When consumer tries to take a pin (it is the case for the joystick on 
stm32mp157c-ev1), it gets the following issue:
[    3.347391] irq: :soc:i2c at 40013000:stmfx at 42:stmfx-pin-controller 
didn't like hwirq-0x0 to VIRQ92 mapping (rc=-6)
[    3.356418] irq: :soc:i2c at 40013000:stmfx at 42:stmfx-pin-controller 
didn't like hwirq-0x1 to VIRQ92 mapping (rc=-6)
[    3.366512] irq: :soc:i2c at 40013000:stmfx at 42:stmfx-pin-controller 
didn't like hwirq-0x2 to VIRQ92 mapping (rc=-6)
[    3.376671] irq: :soc:i2c at 40013000:stmfx at 42:stmfx-pin-controller 
didn't like hwirq-0x3 to VIRQ92 mapping (rc=-6)
[    3.387169] irq: :soc:i2c at 40013000:stmfx at 42:stmfx-pin-controller 
didn't like hwirq-0x4 to VIRQ92 mapping (rc=-6)
[    3.397065] gpio-keys joystick: Found button without gpio or irq
[    3.403041] gpio-keys: probe of joystick failed with error -22

I can reword the commit message to make it clearer.

Regards,
Amelie