[PATCH 1/2] Add pin list based GPIO ranges

[Christian Ruppert]

Traditionally, GPIO ranges are based on consecutive ranges of both GPIO
and pin numbers. This patch allows for GPIO ranges with arbitrary lists
of pin numbers.

Signed-off-by: Christian Ruppert <christian.ruppert@xxxxxxxxxx>
---
 drivers/pinctrl/core.c          |   59 ++++++++++++++++++++++++++++++++------
 include/linux/pinctrl/pinctrl.h |    4 ++-
 2 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 5327f35..25bb17e 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -280,6 +280,29 @@ static int pinctrl_register_pins(struct pinctrl_dev *pctldev,
 }
 
 /**
+ * gpio_to_pin() - GPIO range GPIO number to pin number translation
+ * @range: GPIO range used for the translation
+ * @gpio: gpio pin to translate to a pin number
+ *
+ * Finds the pin number for a given GPIO using the specified GPIO range
+ * as a base for translation. The distinction between linear GPIO ranges
+ * and pin list based GPIO ranges is managed correctly by this function.
+ *
+ * This function assumes the gpio is part of the specified GPIO range, use
+ * only after making sure this is the case (e.g. by calling it on the
+ * result of successful pinctrl_get_device_gpio_range calls)!
+ */
+static inline int gpio_to_pin(struct pinctrl_gpio_range *range,
+				unsigned int gpio)
+{
+	unsigned int offset = gpio - range->base;
+	if (range->pins)
+		return range->pins[offset];
+	else
+		return range->pin_base + offset;
+}
+
+/**
  * pinctrl_match_gpio_range() - check if a certain GPIO pin is in range
  * @pctldev: pin controller device to check
  * @gpio: gpio pin to check taken from the global GPIO pin space
@@ -444,8 +467,14 @@ pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
 	/* Loop over the ranges */
 	list_for_each_entry(range, &pctldev->gpio_ranges, node) {
 		/* Check if we're in the valid range */
-		if (pin >= range->pin_base &&
-		    pin < range->pin_base + range->npins) {
+		if (range->pins) {
+			int a;
+			for (a = 0; a < range->npins; a++) {
+				if (range->pins[a] == pin)
+					return range;
+			}
+		} else if (pin >= range->pin_base &&
+			   pin < range->pin_base + range->npins) {
 			mutex_unlock(&pctldev->mutex);
 			return range;
 		}
@@ -528,7 +557,7 @@ int pinctrl_request_gpio(unsigned gpio)
 	}
 
 	/* Convert to the pin controllers number space */
-	pin = gpio - range->base + range->pin_base;
+	pin = gpio_to_pin(range, gpio);
 
 	ret = pinmux_request_gpio(pctldev, range, pin, gpio);
 
@@ -562,7 +591,7 @@ void pinctrl_free_gpio(unsigned gpio)
 	mutex_lock(&pctldev->mutex);
 
 	/* Convert to the pin controllers number space */
-	pin = gpio - range->base + range->pin_base;
+	pin = gpio_to_pin(range, gpio);
 
 	pinmux_free_gpio(pctldev, pin, range);
 
@@ -589,7 +618,7 @@ static int pinctrl_gpio_direction(unsigned gpio, bool input)
 	mutex_lock(&pctldev->mutex);
 
 	/* Convert to the pin controllers number space */
-	pin = gpio - range->base + range->pin_base;
+	pin = gpio_to_pin(range, gpio);
 	ret = pinmux_gpio_direction(pctldev, range, pin, input);
 
 	mutex_unlock(&pctldev->mutex);
@@ -1296,11 +1325,21 @@ static int pinctrl_gpioranges_show(struct seq_file *s, void *what)
 
 	/* Loop over the ranges */
 	list_for_each_entry(range, &pctldev->gpio_ranges, node) {
-		seq_printf(s, "%u: %s GPIOS [%u - %u] PINS [%u - %u]\n",
-			   range->id, range->name,
-			   range->base, (range->base + range->npins - 1),
-			   range->pin_base,
-			   (range->pin_base + range->npins - 1));
+		if (range->pins) {
+			int a;
+			seq_printf(s, "%u: %s GPIOS [%u - %u] PINS {",
+				range->id, range->name,
+				range->base, (range->base + range->npins - 1));
+			for (a = 0; a < range->npins - 1; a++)
+				seq_printf(s, "%u, ", range->pins[a]);
+			seq_printf(s, "%u}\n", range->pins[a]);
+		}
+		else
+			seq_printf(s, "%u: %s GPIOS [%u - %u] PINS [%u - %u]\n",
+				range->id, range->name,
+				range->base, (range->base + range->npins - 1),
+				range->pin_base,
+				(range->pin_base + range->npins - 1));
 	}
 
 	mutex_unlock(&pctldev->mutex);
diff --git a/include/linux/pinctrl/pinctrl.h b/include/linux/pinctrl/pinctrl.h
index 2c2a9e8..176a6c1 100644
--- a/include/linux/pinctrl/pinctrl.h
+++ b/include/linux/pinctrl/pinctrl.h
@@ -49,7 +49,8 @@ struct pinctrl_pin_desc {
  * @name: a name for the chip in this range
  * @id: an ID number for the chip in this range
  * @base: base offset of the GPIO range
- * @pin_base: base pin number of the GPIO range
+ * @pin_base: base pin number of the GPIO range if pins != NULL
+ * @pins: enumeration of pins in GPIO range or NULL
  * @npins: number of pins in the GPIO range, including the base number
  * @gc: an optional pointer to a gpio_chip
  */
@@ -59,6 +60,7 @@ struct pinctrl_gpio_range {
 	unsigned int id;
 	unsigned int base;
 	unsigned int pin_base;
+	unsigned const *pins;
 	unsigned int npins;
 	struct gpio_chip *gc;
 };
-- 
1.7.1

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