[U-Boot] rockchip: missing request op in common pinctrl driver resulting kernel boot failure

[U-Boot] rockchip: missing request op in common pinctrl driver resulting kernel boot failure

[Levin Du]

Hi all,

I try U-Boot v2019.04 on the Firefly-RK3399 board and the kernel failed during
loading. After doing some `git bisect`, I find the commit
e7ae4cf27a6d5837cb5e868712cdaa61d3ceb5e0 (which is adding common rockchip
pinctrl driver) is where the problem starts to emerge.

After some trial and error, it seems that the new pinctrl driver has got rid
of the request op. But in board/rockchip/evb_rk3399/evb-rk3399.c:


       /* Enable pwm0 for panel backlight */                                                                                                      
       ret = pinctrl_request_noflags(pinctrl, PERIPH_ID_PWM0);                                                                                    
       if (ret) {                                                                                                                                 
               debug("%s PWM0 pinctrl init fail! (ret=%d)\n", __func__, ret);                                                                     
               goto out;                                                                                                                          
       }                                                                                                                                          
                                                                                                                                                  

The pinctrl_request_noflags call will fail and end, skiping the regulator
operations in normal flow.

Adding a dummy request function (return 0) to rockchip_pinctrl_ops solves the
kernel hang: 

+static int rockchip_pinctrl_request(struct udevice *dev, int func, int flags)
+{
+       struct rockchip_pinctrl_priv *priv = dev_get_priv(dev);
+
+       debug("%s: func=%x, flags=%x\n", __func__, func, flags);
+       return 0;
+}
+
 const struct pinctrl_ops rockchip_pinctrl_ops = {
+        .request                      = rockchip_pinctrl_request,
        .set_state                      = rockchip_pinctrl_set_state,
        .get_gpio_mux                   = rockchip_pinctrl_get_gpio_mux,
 };

But I wonder why no other RK3399 boards experience the same problem. If I'd
like to write a patch to address this, a dummy request function is not proper
IMO. I'm seeking your advice. Thanks in advance.

Best Regards,
-- 
Levin Du

[U-Boot] rockchip: missing request op in common pinctrl driver resulting kernel boot failure

[Mark Kettenis]

> From: Levin Du <djw@t-chip.com.cn>
> Date: Fri, 14 Jun 2019 17:09:43 +0800
> 
> Hi all,
> 
> I try U-Boot v2019.04 on the Firefly-RK3399 board and the kernel failed during
> loading. After doing some `git bisect`, I find the commit
> e7ae4cf27a6d5837cb5e868712cdaa61d3ceb5e0 (which is adding common rockchip
> pinctrl driver) is where the problem starts to emerge.
> 
> After some trial and error, it seems that the new pinctrl driver has got rid
> of the request op. But in board/rockchip/evb_rk3399/evb-rk3399.c:
> 
> 
>        /* Enable pwm0 for panel backlight */                                                                                                      
>        ret = pinctrl_request_noflags(pinctrl, PERIPH_ID_PWM0);                                                                                    
>        if (ret) {                                                                                                                                 
>                debug("%s PWM0 pinctrl init fail! (ret=%d)\n", __func__, ret);                                                                     
>                goto out;                                                                                                                          
>        }                                                                                                                                          
>                                                                              > 
> The pinctrl_request_noflags call will fail and end, skiping the regulator
> operations in normal flow.
> 
> Adding a dummy request function (return 0) to rockchip_pinctrl_ops solves the
> kernel hang: 
> 
> +static int rockchip_pinctrl_request(struct udevice *dev, int func, int flags)
> +{
> +       struct rockchip_pinctrl_priv *priv = dev_get_priv(dev);
> +
> +       debug("%s: func=%x, flags=%x\n", __func__, func, flags);
> +       return 0;
> +}
> +
>  const struct pinctrl_ops rockchip_pinctrl_ops = {
> +        .request                      = rockchip_pinctrl_request,
>         .set_state                      = rockchip_pinctrl_set_state,
>         .get_gpio_mux                   = rockchip_pinctrl_get_gpio_mux,
>  };
> 
> But I wonder why no other RK3399 boards experience the same problem. If I'd
> like to write a patch to address this, a dummy request function is not proper
> IMO. I'm seeking your advice. Thanks in advance.

Thanks for tracking this down!  I had noticed that something broke but
I didn't find the time to track this down yet.

I suspect that since CONFIG_PINCTRL_FULL is enabled all the
pinctrl_request() and pinctrl_request_noflags() calls are no longer
necessary and should probably be removed.  Hopefully somebody who is
more knowledgeable in this area can confirm?

[U-Boot] rockchip: missing request op in common pinctrl driver resulting kernel boot failure

[djw at t-chip.com.cn]

Since this request is a no-op, it is best to drop the
pinctrl_request_noflags(pinctrl, PERIPH_ID_PWM?) lines in
board/rockchip/evb_rk3399/evb-rk3399.c (there're no such code lines in other
rk3399 board files), which is tested to work with the Firefly-RK3399 board.

Therefore, are the PERIPH_ID_PWM? taken care of somewhere in other places?

--
Best Regards,
Levin Du