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From b08ea35a3296ee25c4cb53a977b752266dafa2c2 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Thu, 3 Dec 2015 15:14:13 +0100
Subject: [PATCH] gpio: add a data pointer to gpio_chip
This adds a void * pointer to gpio_chip so that driver can
assign and retrieve some states. This is done to get rid of
container_of() calls for gpio_chips embedded inside state
containers, so we can remove the need to have the gpio_chip
or later (planned) struct gpio_device be dynamically allocated
at registration time, so that its struct device can be properly
reference counted and not bound to its parent device (e.g.
a platform_device) but instead live on after unregistration
if it is opened by e.g. a char device or sysfs.
The data is added with the new function gpiochip_add_data()
and for compatibility we add static inline wrapper function
gpiochip_add() that will call gpiochip_add_data() with
NULL as argument. The latter will be removed once we have
exorcised gpiochip_add() from the kernel.
gpiochip_get_data() is added as a static inline accessor
for drivers to quickly get their data out.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/gpio/gpiolib.c | 10 ++++++----
include/linux/gpio/driver.h | 14 +++++++++++++-
2 files changed, 19 insertions(+), 5 deletions(-)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -280,7 +280,7 @@ static int gpiochip_set_desc_names(struc
}
/**
- * gpiochip_add() - register a gpio_chip
+ * gpiochip_add_data() - register a gpio_chip
* @chip: the chip to register, with chip->base initialized
* Context: potentially before irqs will work
*
@@ -288,7 +288,7 @@ static int gpiochip_set_desc_names(struc
* because the chip->base is invalid or already associated with a
* different chip. Otherwise it returns zero as a success code.
*
- * When gpiochip_add() is called very early during boot, so that GPIOs
+ * When gpiochip_add_data() is called very early during boot, so that GPIOs
* can be freely used, the chip->dev device must be registered before
* the gpio framework's arch_initcall(). Otherwise sysfs initialization
* for GPIOs will fail rudely.
@@ -296,7 +296,7 @@ static int gpiochip_set_desc_names(struc
* If chip->base is negative, this requests dynamic assignment of
* a range of valid GPIOs.
*/
-int gpiochip_add(struct gpio_chip *chip)
+int gpiochip_add_data(struct gpio_chip *chip, void *data)
{
unsigned long flags;
int status = 0;
@@ -308,6 +308,8 @@ int gpiochip_add(struct gpio_chip *chip)
if (!descs)
return -ENOMEM;
+ chip->data = data;
+
spin_lock_irqsave(&gpio_lock, flags);
if (base < 0) {
@@ -389,7 +391,7 @@ err_free_descs:
chip->label ? : "generic");
return status;
}
-EXPORT_SYMBOL_GPL(gpiochip_add);
+EXPORT_SYMBOL_GPL(gpiochip_add_data);
/**
* gpiochip_remove() - unregister a gpio_chip
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -23,6 +23,7 @@ struct seq_file;
* @dev: optional device providing the GPIOs
* @cdev: class device used by sysfs interface (may be NULL)
* @owner: helps prevent removal of modules exporting active GPIOs
+ * @data: per-instance data assigned by the driver
* @list: links gpio_chips together for traversal
* @request: optional hook for chip-specific activation, such as
* enabling module power and clock; may sleep
@@ -92,6 +93,7 @@ struct gpio_chip {
struct device *dev;
struct device *cdev;
struct module *owner;
+ void *data;
struct list_head list;
int (*request)(struct gpio_chip *chip,
@@ -166,7 +168,11 @@ extern const char *gpiochip_is_requested
unsigned offset);
/* add/remove chips */
-extern int gpiochip_add(struct gpio_chip *chip);
+extern int gpiochip_add_data(struct gpio_chip *chip, void *data);
+static inline int gpiochip_add(struct gpio_chip *chip)
+{
+ return gpiochip_add_data(chip, NULL);
+}
extern void gpiochip_remove(struct gpio_chip *chip);
extern struct gpio_chip *gpiochip_find(void *data,
int (*match)(struct gpio_chip *chip, void *data));
@@ -175,6 +181,12 @@ extern struct gpio_chip *gpiochip_find(v
int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset);
void gpiochip_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
+/* get driver data */
+static inline void *gpiochip_get_data(struct gpio_chip *chip)
+{
+ return chip->data;
+}
+
struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
#ifdef CONFIG_GPIOLIB_IRQCHIP
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