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gpio: sysfs: move irq trigger flags to class-device data

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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: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Johan Hovold 2015-05-04 17:10:48 +02:00 committed by Linus Walleij
parent 427fdeef50
commit cef1717b7f
2 changed files with 24 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/gpio/gpiolib-sysfs.c
View File

@ -10,12 +10,18 @@
#include "gpiolib.h" #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 gpiod_data {
struct gpio_desc *desc; struct gpio_desc *desc;
struct mutex mutex; struct mutex mutex;
struct kernfs_node *value_kn; struct kernfs_node *value_kn;
int irq; int irq;
unsigned char irq_flags;
bool direction_can_change; bool direction_can_change;
}; };
@ -143,7 +149,7 @@ static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
} }
/* Caller holds gpiod-data mutex. */ /* 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 gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc; 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; return -ENODEV;
irq_flags = IRQF_SHARED; 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) ? irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 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) ? irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; 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) if (ret < 0)
goto err_unlock; goto err_unlock;
desc->flags |= gpio_flags; data->irq_flags = flags;
return 0; return 0;
@ -204,7 +210,7 @@ static void gpio_sysfs_free_irq(struct device *dev)
struct gpiod_data *data = dev_get_drvdata(dev); struct gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc; struct gpio_desc *desc = data->desc;
desc->flags &= ~GPIO_TRIGGER_MASK; data->irq_flags = 0;
free_irq(data->irq, data); free_irq(data->irq, data);
gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc)); gpiochip_unlock_as_irq(desc->chip, gpio_chip_hwgpio(desc));
sysfs_put(data->value_kn); sysfs_put(data->value_kn);
@ -212,28 +218,25 @@ static void gpio_sysfs_free_irq(struct device *dev)
static const struct { static const struct {
const char *name; const char *name;
unsigned long flags; unsigned char flags;
} trigger_types[] = { } trigger_types[] = {
{ "none", 0 }, { "none", 0 },
{ "falling", BIT(FLAG_TRIG_FALL) }, { "falling", GPIO_IRQF_TRIGGER_FALLING },
{ "rising", BIT(FLAG_TRIG_RISE) }, { "rising", GPIO_IRQF_TRIGGER_RISING },
{ "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) }, { "both", GPIO_IRQF_TRIGGER_BOTH },
}; };
static ssize_t edge_show(struct device *dev, static ssize_t edge_show(struct device *dev,
struct device_attribute *attr, char *buf) struct device_attribute *attr, char *buf)
{ {
struct gpiod_data *data = dev_get_drvdata(dev); struct gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc;
unsigned long mask;
ssize_t status = 0; ssize_t status = 0;
int i; int i;
mutex_lock(&data->mutex); mutex_lock(&data->mutex);
for (i = 0; i < ARRAY_SIZE(trigger_types); i++) { for (i = 0; i < ARRAY_SIZE(trigger_types); i++) {
mask = desc->flags & GPIO_TRIGGER_MASK; if (data->irq_flags == trigger_types[i].flags) {
if (mask == trigger_types[i].flags) {
status = sprintf(buf, "%s\n", trigger_types[i].name); status = sprintf(buf, "%s\n", trigger_types[i].name);
break; break;
} }
@ -248,8 +251,7 @@ static ssize_t edge_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t size) struct device_attribute *attr, const char *buf, size_t size)
{ {
struct gpiod_data *data = dev_get_drvdata(dev); struct gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc; unsigned char flags;
unsigned long flags;
ssize_t status = size; ssize_t status = size;
int i; int i;
@ -265,12 +267,12 @@ static ssize_t edge_store(struct device *dev,
mutex_lock(&data->mutex); mutex_lock(&data->mutex);
if ((desc->flags & GPIO_TRIGGER_MASK) == flags) { if (flags == data->irq_flags) {
status = size; status = size;
goto out_unlock; goto out_unlock;
} }
if (desc->flags & GPIO_TRIGGER_MASK) if (data->irq_flags)
gpio_sysfs_free_irq(dev); gpio_sysfs_free_irq(dev);
if (flags) { 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 gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc; struct gpio_desc *desc = data->desc;
int status = 0; int status = 0;
unsigned int flags = data->irq_flags;
if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value) if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
return 0; 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); clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
/* reconfigure poll(2) support if enabled on one edge only */ /* reconfigure poll(2) support if enabled on one edge only */
if (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ if (flags == GPIO_IRQF_TRIGGER_FALLING ||
!!test_bit(FLAG_TRIG_FALL, &desc->flags)) { flags == GPIO_IRQF_TRIGGER_RISING) {
unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
gpio_sysfs_free_irq(dev); gpio_sysfs_free_irq(dev);
status = gpio_sysfs_request_irq(dev, trigger_flags); status = gpio_sysfs_request_irq(dev, flags);
} }
return status; return status;
@ -700,7 +701,7 @@ void gpiod_unexport(struct gpio_desc *desc)
/* /*
* Release irq after deregistration to prevent race with edge_store. * 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); gpio_sysfs_free_irq(dev);
mutex_unlock(&sysfs_lock); mutex_unlock(&sysfs_lock);

4
drivers/gpio/gpiolib.h
View File

@ -83,16 +83,12 @@ struct gpio_desc {
#define FLAG_IS_OUT 1 #define FLAG_IS_OUT 1
#define FLAG_EXPORT 2 /* protected by sysfs_lock */ #define FLAG_EXPORT 2 /* protected by sysfs_lock */
#define FLAG_SYSFS 3 /* exported via /sys/class/gpio/control */ #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_ACTIVE_LOW 6 /* value has active low */
#define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */ #define FLAG_OPEN_DRAIN 7 /* Gpio is open drain type */
#define FLAG_OPEN_SOURCE 8 /* Gpio is open source 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_USED_AS_IRQ 9 /* GPIO is connected to an IRQ */
#define FLAG_IS_HOGGED 11 /* GPIO is hogged */ #define FLAG_IS_HOGGED 11 /* GPIO is hogged */
#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
const char *label; const char *label;
}; };