linux-kernel - pinctrl: sx150x bug

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Date:   Wed, 5 Aug 2020 11:28:11 +0200
From:   Martin DEVERA <devik@...labs.cz>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: pinctrl: sx150x bug

Hello,

I encountered bug in SX1502 expander driver in 5.7.7. Here is relevant 
DTS part:

compatible = "semtech,sx1502q";
gpio4_cfg_pins: gpio2-cfg {
                         pins = "gpio5";
                         output-high;
     };

And part of OOPS:

[    0.673996] [<c023cfa6>] (gpiochip_get_data) from [<c023b235>] 
(sx150x_gpio_direction_output+0xd)
[    0.683259] [<c023b235>] (sx150x_gpio_direction_output) from 
[<c023b363>] (sx150x_pinconf_set+0x)
[    0.692796] [<c023b363>] (sx150x_pinconf_set) from [<c0238fef>] 
(pinconf_apply_setting+0x39/0x7e)
[    0.701635] [<c0238fef>] (pinconf_apply_setting) from [<c0236c77>] 
(pinctrl_commit_state+0xa5/0x)
[    0.710648] [<c0236c77>] (pinctrl_commit_state) from [<c0237e03>] 
(pinctrl_enable+0xff/0x1d4)
[    0.719139] [<c0237e03>] (pinctrl_enable) from [<c023b791>] 
(sx150x_probe+0x1a3/0x358)
[    0.727027] [<c023b791>] (sx150x_probe) from [<c02c38bf>] 
(i2c_device_probe+0x1bb/0x1dc)

The problem is that sx150x_pinconf_set uses sx150x_gpio_direction_output 
but gpio is not
setup yet. Patch below fixes it but I'm not sure whether is it correct:

diff --git a/drivers/pinctrl/pinctrl-sx150x.c 
b/drivers/pinctrl/pinctrl-sx150x.c
index 6e74bd87d959..3f5651edd336 100644
--- a/drivers/pinctrl/pinctrl-sx150x.c
+++ b/drivers/pinctrl/pinctrl-sx150x.c
@@ -1154,12 +1154,6 @@ static int sx150x_probe(struct i2c_client *client,
                 return ret;
         }

-       ret = pinctrl_enable(pctl->pctldev);
-       if (ret) {
-               dev_err(dev, "Failed to enable pinctrl device\n");
-               return ret;
-       }
-
         /* Register GPIO controller */
         pctl->gpio.base = -1;
         pctl->gpio.ngpio = pctl->data->npins;
@@ -1191,6 +1185,12 @@ static int sx150x_probe(struct i2c_client *client,
         if (ret)
                 return ret;

+       ret = pinctrl_enable(pctl->pctldev);
+       if (ret) {
+               dev_err(dev, "Failed to enable pinctrl device\n");
+               return ret;
+       }
+
         ret = gpiochip_add_pin_range(&pctl->gpio, dev_name(dev),
                                      0, 0, pctl->data->npins);
         if (ret)