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