gpiolib: let gpiochip_add_pin_range() specify offset

Like with commit 3c739ad0df5eb41cd7adad879eda6aa09879eb76
it is not always enough to specify all the pins of a gpio_chip
from offset zero to be added to a pin map range, since the
mapping from GPIO to pin controller may not be linear at all,
but need to be broken into a few consecutive sub-ranges or
1-pin entries for complicated cases. The ranges may also be
sparse.

This alters the signature of the function to accept offsets
into both the GPIO-chip local pinspace and the pin controller
local pinspace.

Reviewed-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index a40cd84c5c107bb69c8bb07ae5ff4916ebf0e7f0..d542a141811a00b2f49589ba8db583b7b30c0ac0 100644 (file)
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -238,8 +238,20 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
                if (!pctldev)
                        break;
 
+               /*
+                * This assumes that the n GPIO pins are consecutive in the
+                * GPIO number space, and that the pins are also consecutive
+                * in their local number space. Currently it is not possible
+                * to add different ranges for one and the same GPIO chip,
+                * as the code assumes that we have one consecutive range
+                * on both, mapping 1-to-1.
+                *
+                * TODO: make the OF bindings handle multiple sparse ranges
+                * on the same GPIO chip.
+                */
                ret = gpiochip_add_pin_range(chip,
                                             pinctrl_dev_get_name(pctldev),
+                                            0, /* offset in gpiochip */
                                             pinspec.args[0],
                                             pinspec.args[1]);
 

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c5f650095faafa9e3f1b1a71759671c411bb17c6..6d13bea4778ac80e772eb7d6da4e734ffabb4e1f 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1187,24 +1187,45 @@ EXPORT_SYMBOL_GPL(gpiochip_find);
 
 #ifdef CONFIG_PINCTRL
 
+/**
+ * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
+ * @chip: the gpiochip to add the range for
+ * @pinctrl_name: the dev_name() of the pin controller to map to
+ * @offset: the start offset in the current gpio_chip number space
+ * @pin_base: the start offset in the pin controller number space
+ * @npins: the number of pins from the offset of each pin space (GPIO and
+ *     pin controller) to accumulate in this range
+ */
 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
-                          unsigned int pin_base, unsigned int npins)
+                          unsigned int offset, unsigned int pin_base,
+                          unsigned int npins)
 {
        struct gpio_pin_range *pin_range;
 
-       pin_range = devm_kzalloc(chip->dev, sizeof(*pin_range), GFP_KERNEL);
+       pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
        if (!pin_range) {
                pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
                                chip->label);
                return -ENOMEM;
        }
 
+       /* Use local offset as range ID */
+       pin_range->range.id = offset;
+       pin_range->range.gc = chip;
        pin_range->range.name = chip->label;
-       pin_range->range.base = chip->base;
+       pin_range->range.base = chip->base + offset;
        pin_range->range.pin_base = pin_base;
        pin_range->range.npins = npins;
        pin_range->pctldev = find_pinctrl_and_add_gpio_range(pinctl_name,
                        &pin_range->range);
+       if (!pin_range->pctldev) {
+               pr_err("%s: GPIO chip: could not create pin range\n",
+                      chip->label);
+               kfree(pin_range);
+       }
+       pr_debug("%s: GPIO chip: created GPIO range %d->%d ==> PIN %d->%d\n",
+                chip->label, offset, offset + npins - 1,
+                pin_base, pin_base + npins - 1);
 
        list_add_tail(&pin_range->node, &chip->pin_ranges);
 
@@ -1212,6 +1233,10 @@ int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
 
+/**
+ * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
+ * @chip: the chip to remove all the mappings for
+ */
 void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
 {
        struct gpio_pin_range *pin_range, *tmp;
@@ -1220,6 +1245,7 @@ void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
                list_del(&pin_range->node);
                pinctrl_remove_gpio_range(pin_range->pctldev,
                                &pin_range->range);
+               kfree(pin_range);
        }
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 2b84fc32fae2bf9f861104ebd8d8c0adc4d9006a..ec58fdbddb59604b5679ff907257d8f92b7bef3f 100644 (file)
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -283,14 +283,16 @@ struct gpio_pin_range {
 };
 
 int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
-                          unsigned int pin_base, unsigned int npins);
+                          unsigned int offset, unsigned int pin_base,
+                          unsigned int npins);
 void gpiochip_remove_pin_ranges(struct gpio_chip *chip);
 
 #else
 
 static inline int
 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
-                      unsigned int pin_base, unsigned int npins)
+                      unsigned int offset, unsigned int pin_base,
+                      unsigned int npins)
 {
        return 0;
 }

diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 7ba2762abbc912428b02d3836c44fbf147315231..99861c65dd8b4fc2893f3e3e127e225563330982 100644 (file)
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -233,7 +233,8 @@ static inline int irq_to_gpio(unsigned irq)
 
 static inline int
 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
-                      unsigned int pin_base, unsigned int npins)
+                      unsigned int offset, unsigned int pin_base,
+                      unsigned int npins)
 {
        WARN_ON(1);
        return -EINVAL;