gpio-controller;
};
+2.1) gpio-controller and pinctrl subsystem
+------------------------------------------
+gpio-controller on a SOC might be tightly coupled with the pinctrl
+subsystem, in the sense that the pins can be used by other functions
+together with optional gpio feature.
+
+While the pin allocation is totally managed by the pin ctrl subsystem,
+gpio (under gpiolib) is still maintained by gpio drivers. It may happen
+that different pin ranges in a SoC is managed by different gpio drivers.
+
+This makes it logical to let gpio drivers announce their pin ranges to
+the pin ctrl subsystem and call 'pinctrl_request_gpio' in order to
+request the corresponding pin before any gpio usage.
+
+For this, the gpio controller can use a pinctrl phandle and pins to
+announce the pinrange to the pin ctrl subsystem. For example,
+
+ qe_pio_e: gpio-controller@1460 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
+ reg = <0x1460 0x18>;
+ gpio-controller;
+ gpio-ranges = <&pinctrl1 20 10>, <&pinctrl2 50 20>;
+
+ }
+
+where,
+ &pinctrl1 and &pinctrl2 is the phandle to the pinctrl DT node.
+
+ Next values specify the base pin and number of pins for the range
+ handled by 'qe_pio_e' gpio. In the given example from base pin 20 to
+ pin 29 under pinctrl1 and pin 50 to pin 69 under pinctrl2 is handled
+ by this gpio controller.
+
+The pinctrl node must have "#gpio-range-cells" property to show number of
+arguments to pass with phandle from gpio controllers node.
signaling rate accordingly.
+GPIO controllers and the pinctrl subsystem
+------------------------------------------
+
+A GPIO controller on a SOC might be tightly coupled with the pinctrl
+subsystem, in the sense that the pins can be used by other functions
+together with an optional gpio feature. We have already covered the
+case where e.g. a GPIO controller need to reserve a pin or set the
+direction of a pin by calling any of:
+
+pinctrl_request_gpio()
+pinctrl_free_gpio()
+pinctrl_gpio_direction_input()
+pinctrl_gpio_direction_output()
+
+But how does the pin control subsystem cross-correlate the GPIO
+numbers (which are a global business) to a certain pin on a certain
+pin controller?
+
+This is done by registering "ranges" of pins, which are essentially
+cross-reference tables. These are described in
+Documentation/pinctrl.txt
+
+While the pin allocation is totally managed by the pinctrl subsystem,
+gpio (under gpiolib) is still maintained by gpio drivers. It may happen
+that different pin ranges in a SoC is managed by different gpio drivers.
+
+This makes it logical to let gpio drivers announce their pin ranges to
+the pin ctrl subsystem before it will call 'pinctrl_request_gpio' in order
+to request the corresponding pin to be prepared by the pinctrl subsystem
+before any gpio usage.
+
+For this, the gpio controller can register its pin range with pinctrl
+subsystem. There are two ways of doing it currently: with or without DT.
+
+For with DT support refer to Documentation/devicetree/bindings/gpio/gpio.txt.
+
+For non-DT support, user can call gpiochip_add_pin_range() with appropriate
+parameters to register a range of gpio pins with a pinctrl driver. For this
+exact name string of pinctrl device has to be passed as one of the
+argument to this routine.
+
+
What do these conventions omit?
===============================
One of the biggest things these conventions omit is pin multiplexing, since
the range ID value, so that the pin controller knows which range it should
deal with.
+Calling pinctrl_add_gpio_range from pinctrl driver is DEPRECATED. Please see
+section 2.1 of Documentation/devicetree/bindings/gpio/gpio.txt on how to bind
+pinctrl and gpio drivers.
PINMUX interfaces
=================
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
+#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
/* Private data structure for of_gpiochip_find_and_xlate */
}
EXPORT_SYMBOL(of_mm_gpiochip_add);
+#ifdef CONFIG_PINCTRL
+void of_gpiochip_add_pin_range(struct gpio_chip *chip)
+{
+ struct device_node *np = chip->of_node;
+ struct gpio_pin_range *pin_range;
+ struct of_phandle_args pinspec;
+ int index = 0, ret;
+
+ if (!np)
+ return;
+
+ do {
+ ret = of_parse_phandle_with_args(np, "gpio-ranges",
+ "#gpio-range-cells", index, &pinspec);
+ if (ret)
+ break;
+
+ pin_range = devm_kzalloc(chip->dev, sizeof(*pin_range),
+ GFP_KERNEL);
+ if (!pin_range) {
+ pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
+ chip->label);
+ break;
+ }
+
+ pin_range->range.name = chip->label;
+ pin_range->range.base = chip->base;
+ pin_range->range.pin_base = pinspec.args[0];
+ pin_range->range.npins = pinspec.args[1];
+ pin_range->pctldev = of_pinctrl_add_gpio_range(pinspec.np,
+ &pin_range->range);
+
+ list_add_tail(&pin_range->node, &chip->pin_ranges);
+
+ } while (index++);
+}
+
+void of_gpiochip_remove_pin_range(struct gpio_chip *chip)
+{
+ struct gpio_pin_range *pin_range, *tmp;
+
+ list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
+ list_del(&pin_range->node);
+ pinctrl_remove_gpio_range(pin_range->pctldev,
+ &pin_range->range);
+ }
+}
+#else
+void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
+void of_gpiochip_remove_pin_range(struct gpio_chip *chip) {}
+#endif
+
void of_gpiochip_add(struct gpio_chip *chip)
{
if ((!chip->of_node) && (chip->dev))
chip->of_xlate = of_gpio_simple_xlate;
}
+ of_gpiochip_add_pin_range(chip);
of_node_get(chip->of_node);
}
void of_gpiochip_remove(struct gpio_chip *chip)
{
+ of_gpiochip_remove_pin_range(chip);
+
if (chip->of_node)
of_node_put(chip->of_node);
}
}
}
+#ifdef CONFIG_PINCTRL
+ INIT_LIST_HEAD(&chip->pin_ranges);
+#endif
+
of_gpiochip_add(chip);
unlock:
}
EXPORT_SYMBOL_GPL(gpiochip_find);
+#ifdef CONFIG_PINCTRL
+void gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
+ unsigned int pin_base, unsigned int npins)
+{
+ struct gpio_pin_range *pin_range;
+
+ pin_range = devm_kzalloc(chip->dev, sizeof(*pin_range), GFP_KERNEL);
+ if (!pin_range) {
+ pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
+ chip->label);
+ return;
+ }
+
+ pin_range->range.name = chip->label;
+ pin_range->range.base = chip->base;
+ 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);
+
+ list_add_tail(&pin_range->node, &chip->pin_ranges);
+}
+
+void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
+{
+ struct gpio_pin_range *pin_range, *tmp;
+
+ list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
+ list_del(&pin_range->node);
+ pinctrl_remove_gpio_range(pin_range->pctldev,
+ &pin_range->range);
+ }
+}
+#else
+void gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
+ unsigned int pin_base, unsigned int npins) {}
+void gpiochip_remove_pin_ranges(struct gpio_chip *chip) {}
+#endif
+
/* These "optional" allocation calls help prevent drivers from stomping
* on each other, and help provide better diagnostics in debugfs.
* They're called even less than the "set direction" calls.
}
EXPORT_SYMBOL_GPL(pinctrl_add_gpio_ranges);
+struct pinctrl_dev *find_pinctrl_and_add_gpio_range(const char *devname,
+ struct pinctrl_gpio_range *range)
+{
+ struct pinctrl_dev *pctldev = get_pinctrl_dev_from_devname(devname);
+
+ if (!pctldev)
+ return NULL;
+
+ pinctrl_add_gpio_range(pctldev, range);
+ return pctldev;
+}
+EXPORT_SYMBOL_GPL(find_pinctrl_and_add_gpio_range);
+
/**
* pinctrl_remove_gpio_range() - remove a range of GPIOs fro a pin controller
* @pctldev: pin controller device to remove the range from
return NULL;
}
+struct pinctrl_dev *of_pinctrl_add_gpio_range(struct device_node *np,
+ struct pinctrl_gpio_range *range)
+{
+ struct pinctrl_dev *pctldev;
+
+ pctldev = find_pinctrl_by_of_node(np);
+ if (!pctldev)
+ return NULL;
+
+ pinctrl_add_gpio_range(pctldev, range);
+ return pctldev;
+}
+
static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
struct device_node *np_config)
{
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/of.h>
+#include <linux/pinctrl/pinctrl.h>
#ifdef CONFIG_GPIOLIB
struct module;
struct device_node;
+#ifdef CONFIG_PINCTRL
+/**
+ * struct gpio_pin_range - pin range controlled by a gpio chip
+ * @head: list for maintaining set of pin ranges, used internally
+ * @pctldev: pinctrl device which handles corresponding pins
+ * @range: actual range of pins controlled by a gpio controller
+ */
+
+struct gpio_pin_range {
+ struct list_head node;
+ struct pinctrl_dev *pctldev;
+ struct pinctrl_gpio_range range;
+};
+#endif
+
/**
* struct gpio_chip - abstract a GPIO controller
* @label: for diagnostics
int (*of_xlate)(struct gpio_chip *gc,
const struct of_phandle_args *gpiospec, u32 *flags);
#endif
+#ifdef CONFIG_PINCTRL
+ /*
+ * If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
+ * describe the actual pin range which they serve in an SoC. This
+ * information would be used by pinctrl subsystem to configure
+ * corresponding pins for gpio usage.
+ */
+ struct list_head pin_ranges;
+#endif
};
extern const char *gpiochip_is_requested(struct gpio_chip *chip,
return -EINVAL;
}
+void gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
+ unsigned int pin_base, unsigned int npins);
+void gpiochip_remove_pin_ranges(struct gpio_chip *chip);
#endif
#endif /* __LINUX_GPIO_H */
unsigned nranges);
extern void pinctrl_remove_gpio_range(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range);
+
+extern struct pinctrl_dev *find_pinctrl_and_add_gpio_range(const char *devname,
+ struct pinctrl_gpio_range *range);
+
+#ifdef CONFIG_OF
+extern struct pinctrl_dev *of_pinctrl_add_gpio_range(struct device_node *np,
+ struct pinctrl_gpio_range *range);
+#else
+static inline
+struct pinctrl_dev *of_pinctrl_add_gpio_range(struct device_node *np,
+ struct pinctrl_gpio_range *range)
+{
+ return NULL;
+}
+
+#endif /* CONFIG_OF */
+
extern const char *pinctrl_dev_get_name(struct pinctrl_dev *pctldev);
extern void *pinctrl_dev_get_drvdata(struct pinctrl_dev *pctldev);
#else
projects / can-eth-gw-linux.git / commitdiff