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Date:   Sat, 16 Mar 2019 07:20:23 -0700
From:   Guenter Roeck <linux@roeck-us.net>
To:     Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Frank Rowand <frowand.list@gmail.com>,
        linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Jan =?iso-8859-1?Q?Kundr=E1t?= <jan.kundrat@cesnet.cz>
Subject: Re: [PATCH v2 3/5] gpio: use new gpio_set_config() helper in more
 places
Message-ID: <20190316142023.GA10494@roeck-us.net>
References: <20190207162859.26252-1-thomas.petazzoni@bootlin.com>
 <20190207162859.26252-4-thomas.petazzoni@bootlin.com>
 <20190316014352.GA6124@roeck-us.net>
 <20190316144519.07805478@windsurf>
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In-Reply-To: <20190316144519.07805478@windsurf>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
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On Sat, Mar 16, 2019 at 02:45:19PM +0100, Thomas Petazzoni wrote:
> Hello,
> 
> On Fri, 15 Mar 2019 18:43:52 -0700
> Guenter Roeck <linux@roeck-us.net> wrote:
> 
> > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > > index cf8a4402fef1..9762a836fec9 100644
> > > --- a/drivers/gpio/gpiolib.c
> > > +++ b/drivers/gpio/gpiolib.c
> > > @@ -2762,7 +2762,7 @@ int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
> > >  	}
> > >  
> > >  	config = pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, debounce);
> > > -	return chip->set_config(chip, gpio_chip_hwgpio(desc), config);
> > > +	return gpio_set_config(chip, gpio_chip_hwgpio(desc), config);  
> > 
> > Are you sure this is correct ? This patch results in a number of tracebacks
> > in mainline. Reverting it fixes the problem.
> > 
> > gpio_set_config() seems to pack config, but it is already packed above.
> > That seems a bit suspicious.
> 
> I'll have a look. In the mean time, I'm fine with the patch being
> reverted.
> 

I don't know the code well enough to make a recommendation one way or another
(meaning I am not entirely sure if the aspeed code generating the traceback code
is correct). However, the attached does fix the problem for me, suggesting that
gpio_set_config() might be missing an argument.

Guenter

---

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 144af0733581..e972836e8d8f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2563,9 +2563,9 @@ EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
  */
 
 static int gpio_set_config(struct gpio_chip *gc, unsigned offset,
-			   enum pin_config_param mode)
+			   enum pin_config_param mode, u32 argument)
 {
-	unsigned long config = { PIN_CONF_PACKED(mode, 0) };
+	unsigned long config = { PIN_CONF_PACKED(mode, argument) };
 
 	return gc->set_config ? gc->set_config(gc, offset, config) : -ENOTSUPP;
 }
@@ -2619,10 +2619,10 @@ int gpiod_direction_input(struct gpio_desc *desc)
 
 	if (test_bit(FLAG_PULL_UP, &desc->flags))
 		gpio_set_config(chip, gpio_chip_hwgpio(desc),
-				PIN_CONFIG_BIAS_PULL_UP);
+				PIN_CONFIG_BIAS_PULL_UP, 0);
 	else if (test_bit(FLAG_PULL_DOWN, &desc->flags))
 		gpio_set_config(chip, gpio_chip_hwgpio(desc),
-				PIN_CONFIG_BIAS_PULL_DOWN);
+				PIN_CONFIG_BIAS_PULL_DOWN, 0);
 
 	trace_gpio_direction(desc_to_gpio(desc), 1, status);
 
@@ -2727,7 +2727,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
 		/* First see if we can enable open drain in hardware */
 		ret = gpio_set_config(gc, gpio_chip_hwgpio(desc),
-				      PIN_CONFIG_DRIVE_OPEN_DRAIN);
+				      PIN_CONFIG_DRIVE_OPEN_DRAIN, 0);
 		if (!ret)
 			goto set_output_value;
 		/* Emulate open drain by not actively driving the line high */
@@ -2736,7 +2736,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 	}
 	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
 		ret = gpio_set_config(gc, gpio_chip_hwgpio(desc),
-				      PIN_CONFIG_DRIVE_OPEN_SOURCE);
+				      PIN_CONFIG_DRIVE_OPEN_SOURCE, 0);
 		if (!ret)
 			goto set_output_value;
 		/* Emulate open source by not actively driving the line low */
@@ -2744,7 +2744,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 			return gpiod_direction_input(desc);
 	} else {
 		gpio_set_config(gc, gpio_chip_hwgpio(desc),
-				PIN_CONFIG_DRIVE_PUSH_PULL);
+				PIN_CONFIG_DRIVE_PUSH_PULL, 0);
 	}
 
 set_output_value:
@@ -2764,19 +2764,11 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output);
 int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 {
 	struct gpio_chip	*chip;
-	unsigned long		config;
 
 	VALIDATE_DESC(desc);
 	chip = desc->gdev->chip;
-	if (!chip->set || !chip->set_config) {
-		gpiod_dbg(desc,
-			  "%s: missing set() or set_config() operations\n",
-			  __func__);
-		return -ENOTSUPP;
-	}
-
-	config = pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, debounce);
-	return gpio_set_config(chip, gpio_chip_hwgpio(desc), config);
+	return gpio_set_config(chip, gpio_chip_hwgpio(desc),
+			       PIN_CONFIG_INPUT_DEBOUNCE, debounce);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
 
@@ -2791,7 +2783,6 @@ EXPORT_SYMBOL_GPL(gpiod_set_debounce);
 int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
 {
 	struct gpio_chip *chip;
-	unsigned long packed;
 	int gpio;
 	int rc;
 
@@ -2807,13 +2798,8 @@ int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
 
 	/* If the driver supports it, set the persistence state now */
 	chip = desc->gdev->chip;
-	if (!chip->set_config)
-		return 0;
-
-	packed = pinconf_to_config_packed(PIN_CONFIG_PERSIST_STATE,
-					  !transitory);
 	gpio = gpio_chip_hwgpio(desc);
-	rc = gpio_set_config(chip, gpio, packed);
+	rc = gpio_set_config(chip, gpio, PIN_CONFIG_PERSIST_STATE, !transitory);
 	if (rc == -ENOTSUPP) {
 		dev_dbg(&desc->gdev->dev, "Persistence not supported for GPIO %d\n",
 				gpio);