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Commit cef1717b authored by Johan Hovold's avatar Johan Hovold Committed by Linus Walleij
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gpio: sysfs: move irq trigger flags to class-device data 



Move irq trigger flags, which as sysfs-interface specific, to the class
device data.

This avoids accessing the gpio-descriptor flags field using non-atomic
operations without any locking, and allows for a more clear separation
of the sysfs interface from gpiolib core.

Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Reviewed-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 427fdeef

drivers/gpio/gpiolib-sysfs.c

+24 −23
Original line number Diff line number Diff line
@@ -10,12 +10,18 @@ 


#include "gpiolib.h"



#define GPIO_IRQF_TRIGGER_FALLING	BIT(0)

#define GPIO_IRQF_TRIGGER_RISING	BIT(1)

#define GPIO_IRQF_TRIGGER_BOTH		(GPIO_IRQF_TRIGGER_FALLING | \

					 GPIO_IRQF_TRIGGER_RISING)



struct gpiod_data {

	struct gpio_desc *desc;



	struct mutex mutex;

	struct kernfs_node *value_kn;

	int irq;

	unsigned char irq_flags;



	bool direction_can_change;

};
@@ -143,7 +149,7 @@ static irqreturn_t gpio_sysfs_irq(int irq, void *priv) 
}



/* Caller holds gpiod-data mutex. */

static int gpio_sysfs_request_irq(struct device *dev, unsigned long gpio_flags)

static int gpio_sysfs_request_irq(struct device *dev, unsigned char flags)

{

	struct gpiod_data	*data = dev_get_drvdata(dev);

	struct gpio_desc	*desc = data->desc;
@@ -159,10 +165,10 @@ static int gpio_sysfs_request_irq(struct device *dev, unsigned long gpio_flags) 
		return -ENODEV;



	irq_flags = IRQF_SHARED;

	if (test_bit(FLAG_TRIG_FALL, &gpio_flags))

	if (flags & GPIO_IRQF_TRIGGER_FALLING)

		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?

			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;

	if (test_bit(FLAG_TRIG_RISE, &gpio_flags))

	if (flags & GPIO_IRQF_TRIGGER_RISING)

		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?

			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
@@ -183,7 +189,7 @@ static int gpio_sysfs_request_irq(struct device *dev, unsigned long gpio_flags) 
	if (ret < 0)

		goto err_unlock;



	desc->flags |= gpio_flags;

	data->irq_flags = flags;



	return 0;
@@ -204,7 +210,7 @@ static void gpio_sysfs_free_irq(struct device *dev) 
	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;



	desc->flags &= ~GPIO_TRIGGER_MASK;

	data->irq_flags = 0;

	free_irq(data->irq, data);

	gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc));

	sysfs_put(data->value_kn);
@@ -212,28 +218,25 @@ static void gpio_sysfs_free_irq(struct device *dev) 


static const struct {

	const char *name;

	unsigned long flags;

	unsigned char flags;

} trigger_types[] = {

	{ "none",    0 },

	{ "falling", BIT(FLAG_TRIG_FALL) },

	{ "rising",  BIT(FLAG_TRIG_RISE) },

	{ "both",    BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },

	{ "falling", GPIO_IRQF_TRIGGER_FALLING },

	{ "rising",  GPIO_IRQF_TRIGGER_RISING },

	{ "both",    GPIO_IRQF_TRIGGER_BOTH },

};



static ssize_t edge_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	unsigned long mask;

	ssize_t	status = 0;

	int i;



	mutex_lock(&data->mutex);



	for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {

		mask = desc->flags & GPIO_TRIGGER_MASK;

		if (mask == trigger_types[i].flags) {

		if (data->irq_flags == trigger_types[i].flags) {

			status = sprintf(buf, "%s\n", trigger_types[i].name);

			break;

		}
@@ -248,8 +251,7 @@ static ssize_t edge_store(struct device *dev, 
		struct device_attribute *attr, const char *buf, size_t size)

{

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	unsigned long flags;

	unsigned char flags;

	ssize_t	status = size;

	int i;
@@ -265,12 +267,12 @@ static ssize_t edge_store(struct device *dev, 


	mutex_lock(&data->mutex);



	if ((desc->flags & GPIO_TRIGGER_MASK) == flags) {

	if (flags == data->irq_flags) {

		status = size;

		goto out_unlock;

	}



	if (desc->flags & GPIO_TRIGGER_MASK)

	if (data->irq_flags)

		gpio_sysfs_free_irq(dev);



	if (flags) {
@@ -292,6 +294,7 @@ static int gpio_sysfs_set_active_low(struct device *dev, int value) 
	struct gpiod_data	*data = dev_get_drvdata(dev);

	struct gpio_desc	*desc = data->desc;

	int			status = 0;

	unsigned int		flags = data->irq_flags;



	if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)

		return 0;
@@ -302,12 +305,10 @@ static int gpio_sysfs_set_active_low(struct device *dev, int value) 
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);



	/* reconfigure poll(2) support if enabled on one edge only */

	if (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^

				!!test_bit(FLAG_TRIG_FALL, &desc->flags)) {

		unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;



	if (flags == GPIO_IRQF_TRIGGER_FALLING ||

					flags == GPIO_IRQF_TRIGGER_RISING) {

		gpio_sysfs_free_irq(dev);

		status = gpio_sysfs_request_irq(dev, trigger_flags);

		status = gpio_sysfs_request_irq(dev, flags);

	}



	return status;
@@ -700,7 +701,7 @@ void gpiod_unexport(struct gpio_desc *desc) 
	/*

	 * Release irq after deregistration to prevent race with edge_store.

	 */

	if (desc->flags & GPIO_TRIGGER_MASK)

	if (data->irq_flags)

		gpio_sysfs_free_irq(dev);



	mutex_unlock(&sysfs_lock);

drivers/gpio/gpiolib.h

+0 −4
Original line number Diff line number Diff line
@@ -83,16 +83,12 @@ struct gpio_desc { 
#define FLAG_IS_OUT	1

#define FLAG_EXPORT	2	/* protected by sysfs_lock */

#define FLAG_SYSFS	3	/* exported via /sys/class/gpio/control */

#define FLAG_TRIG_FALL	4	/* trigger on falling edge */

#define FLAG_TRIG_RISE	5	/* trigger on rising edge */

#define FLAG_ACTIVE_LOW	6	/* value has active low */

#define FLAG_OPEN_DRAIN	7	/* Gpio is open drain type */

#define FLAG_OPEN_SOURCE 8	/* Gpio is open source type */

#define FLAG_USED_AS_IRQ 9	/* GPIO is connected to an IRQ */

#define FLAG_IS_HOGGED	11	/* GPIO is hogged */



#define GPIO_TRIGGER_MASK	(BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))



	const char		*label;

};