1 files changed, 91 insertions, 42 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b747c76..d407f904 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -622,14 +622,31 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
 		struct gpio_desc *desc = &gdev->descs[i];
 
 		desc->gdev = gdev;
-
-		/* REVISIT: most hardware initializes GPIOs as inputs (often
-		 * with pullups enabled) so power usage is minimized. Linux
-		 * code should set the gpio direction first thing; but until
-		 * it does, and in case chip->get_direction is not set, we may
-		 * expose the wrong direction in sysfs.
+		/*
+		 * REVISIT: most hardware initializes GPIOs as inputs
+		 * (often with pullups enabled) so power usage is
+		 * minimized. Linux code should set the gpio direction
+		 * first thing; but until it does, and in case
+		 * chip->get_direction is not set, we may expose the
+		 * wrong direction in sysfs.
 		 */
-		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
+
+		if (chip->get_direction) {
+			/*
+			 * If we have .get_direction, set up the initial
+			 * direction flag from the hardware.
+			 */
+			int dir = chip->get_direction(chip, i);
+
+			if (!dir)
+				set_bit(FLAG_IS_OUT, &desc->flags);
+		} else if (!chip->direction_input) {
+			/*
+			 * If the chip lacks the .direction_input callback
+			 * we logically assume all lines are outputs.
+			 */
+			set_bit(FLAG_IS_OUT, &desc->flags);
+		}
 	}
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
@@ -1547,8 +1564,8 @@ EXPORT_SYMBOL_GPL(gpiod_direction_input);
 
 static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 {
-	struct gpio_chip	*chip;
-	int			status = -EINVAL;
+	struct gpio_chip *gc = desc->gdev->chip;
+	int ret;
 
 	/* GPIOs used for IRQs shall not be set as output */
 	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
@@ -1558,28 +1575,50 @@ static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 		return -EIO;
 	}
 
-	/* Open drain pin should not be driven to 1 */
-	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
-		return gpiod_direction_input(desc);
-
-	/* Open source pin should not be driven to 0 */
-	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
-		return gpiod_direction_input(desc);
+	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
+		/* First see if we can enable open drain in hardware */
+		if (gc->set_single_ended) {
+			ret = gc->set_single_ended(gc, gpio_chip_hwgpio(desc),
+						   LINE_MODE_OPEN_DRAIN);
+			if (!ret)
+				goto set_output_value;
+		}
+		/* Emulate open drain by not actively driving the line high */
+		if (value)
+			return gpiod_direction_input(desc);
+	}
+	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
+		if (gc->set_single_ended) {
+			ret = gc->set_single_ended(gc, gpio_chip_hwgpio(desc),
+						   LINE_MODE_OPEN_SOURCE);
+			if (!ret)
+				goto set_output_value;
+		}
+		/* Emulate open source by not actively driving the line low */
+		if (!value)
+			return gpiod_direction_input(desc);
+	} else {
+		/* Make sure to disable open drain/source hardware, if any */
+		if (gc->set_single_ended)
+			gc->set_single_ended(gc,
+					     gpio_chip_hwgpio(desc),
+					     LINE_MODE_PUSH_PULL);
+	}
 
-	chip = desc->gdev->chip;
-	if (!chip->set || !chip->direction_output) {
+set_output_value:
+	if (!gc->set || !gc->direction_output) {
 		gpiod_warn(desc,
 		       "%s: missing set() or direction_output() operations\n",
 		       __func__);
 		return -EIO;
 	}
 
-	status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
-	if (status == 0)
+	ret = gc->direction_output(gc, gpio_chip_hwgpio(desc), value);
+	if (!ret)
 		set_bit(FLAG_IS_OUT, &desc->flags);
 	trace_gpio_value(desc_to_gpio(desc), 0, value);
-	trace_gpio_direction(desc_to_gpio(desc), 0, status);
-	return status;
+	trace_gpio_direction(desc_to_gpio(desc), 0, ret);
+	return ret;
 }
 
 /**
@@ -1841,10 +1880,10 @@ static void gpio_chip_set_multiple(struct gpio_chip *chip,
 	}
 }
 
-static void gpiod_set_array_value_priv(bool raw, bool can_sleep,
-				       unsigned int array_size,
-				       struct gpio_desc **desc_array,
-				       int *value_array)
+void gpiod_set_array_value_complex(bool raw, bool can_sleep,
+				   unsigned int array_size,
+				   struct gpio_desc **desc_array,
+				   int *value_array)
 {
 	int i = 0;
 
@@ -1950,8 +1989,8 @@ void gpiod_set_raw_array_value(unsigned int array_size,
 {
 	if (!desc_array)
 		return;
-	gpiod_set_array_value_priv(true, false, array_size, desc_array,
-				   value_array);
+	gpiod_set_array_value_complex(true, false, array_size, desc_array,
+				      value_array);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_value);
 
@@ -1972,8 +2011,8 @@ void gpiod_set_array_value(unsigned int array_size,
 {
 	if (!desc_array)
 		return;
-	gpiod_set_array_value_priv(false, false, array_size, desc_array,
-				   value_array);
+	gpiod_set_array_value_complex(false, false, array_size, desc_array,
+				      value_array);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_array_value);
 
@@ -1998,13 +2037,22 @@ EXPORT_SYMBOL_GPL(gpiod_cansleep);
  */
 int gpiod_to_irq(const struct gpio_desc *desc)
 {
-	struct gpio_chip	*chip;
-	int			offset;
+	struct gpio_chip *chip;
+	int offset;
 
 	VALIDATE_DESC(desc);
 	chip = desc->gdev->chip;
 	offset = gpio_chip_hwgpio(desc);
-	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
+	if (chip->to_irq) {
+		int retirq = chip->to_irq(chip, offset);
+
+		/* Zero means NO_IRQ */
+		if (!retirq)
+			return -ENXIO;
+
+		return retirq;
+	}
+	return -ENXIO;
 }
 EXPORT_SYMBOL_GPL(gpiod_to_irq);
 
@@ -2176,8 +2224,8 @@ void gpiod_set_raw_array_value_cansleep(unsigned int array_size,
 	might_sleep_if(extra_checks);
 	if (!desc_array)
 		return;
-	gpiod_set_array_value_priv(true, true, array_size, desc_array,
-				   value_array);
+	gpiod_set_array_value_complex(true, true, array_size, desc_array,
+				      value_array);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_value_cansleep);
 
@@ -2199,8 +2247,8 @@ void gpiod_set_array_value_cansleep(unsigned int array_size,
 	might_sleep_if(extra_checks);
 	if (!desc_array)
 		return;
-	gpiod_set_array_value_priv(false, true, array_size, desc_array,
-				   value_array);
+	gpiod_set_array_value_complex(false, true, array_size, desc_array,
+				      value_array);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_array_value_cansleep);
 
@@ -2726,15 +2774,16 @@ int gpiod_hog(struct gpio_desc *desc, const char *name,
 
 	local_desc = gpiochip_request_own_desc(chip, hwnum, name);
 	if (IS_ERR(local_desc)) {
-		pr_err("requesting hog GPIO %s (chip %s, offset %d) failed\n",
-		       name, chip->label, hwnum);
-		return PTR_ERR(local_desc);
+		status = PTR_ERR(local_desc);
+		pr_err("requesting hog GPIO %s (chip %s, offset %d) failed, %d\n",
+		       name, chip->label, hwnum, status);
+		return status;
 	}
 
 	status = gpiod_configure_flags(desc, name, dflags);
 	if (status < 0) {
-		pr_err("setup of hog GPIO %s (chip %s, offset %d) failed\n",
-		       name, chip->label, hwnum);
+		pr_err("setup of hog GPIO %s (chip %s, offset %d) failed, %d\n",
+		       name, chip->label, hwnum, status);
 		gpiochip_free_own_desc(desc);
 		return status;
 	}