On the board n090401 (Seagate NAS 4-Bay), some of the LEDs are handled
by the leds-ns2 driver. This LEDs are connected to an I2C GPIO expander
(PCA95554PW) which means that GPIO access may sleep. This patch makes
leds-ns2 compatible with such GPIOs by using the *_cansleep() variant of
the GPIO functions. As a drawback this functions can't be used safely in
a timer context (with the timer LED trigger for example). To fix this
issue, a workqueue mechanism (copied from the leds-gpio driver) is used.
Note that this patch also updates slightly the ns2_led_sata_store
function. The LED state is now retrieved from cached values instead of
reading the GPIOs previously. This prevents ns2_led_sata_store from
working with a stale LED state (which may happen when a delayed work
is pending).
Signed-off-by: Simon Guinot <simon.guinot@xxxxxxxxxxxx>
Signed-off-by: Vincent Donnefort <vdonnefort@xxxxxxxxx>
---
drivers/leds/leds-ns2.c | 75 +++++++++++++++++++++++++++++++++----------------
1 file changed, 51 insertions(+), 24 deletions(-)
Changes for v2:
- Fix gpio_{get,set}_*_cansleep() usage while holding a spinlock:
Holding a spinlock at this places was not needed.
diff --git a/drivers/leds/leds-ns2.c b/drivers/leds/leds-ns2.c
index b0bc03539dbb..b33514d9f427 100644
--- a/drivers/leds/leds-ns2.c
+++ b/drivers/leds/leds-ns2.c
@@ -31,6 +31,7 @@
#include <linux/platform_data/leds-kirkwood-ns2.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
+#include "leds.h"
/*
* The Network Space v2 dual-GPIO LED is wired to a CPLD. Three different LED
@@ -43,12 +44,25 @@ struct ns2_led_data {
struct led_classdev cdev;
unsigned cmd;
unsigned slow;
+ bool can_sleep;
+ int mode_index;
unsigned char sata; /* True when SATA mode active. */
rwlock_t rw_lock; /* Lock GPIOs. */
+ struct work_struct work;
int num_modes;
struct ns2_led_modval *modval;
};
+static void ns2_led_work(struct work_struct *work)
+{
+ struct ns2_led_data *led_dat =
+ container_of(work, struct ns2_led_data, work);
+ int i = led_dat->mode_index;
+
+ gpio_set_value_cansleep(led_dat->cmd, led_dat->modval[i].cmd_level);
+ gpio_set_value_cansleep(led_dat->slow, led_dat->modval[i].slow_level);
+}
+
static int ns2_led_get_mode(struct ns2_led_data *led_dat,
enum ns2_led_modes *mode)
{
@@ -57,10 +71,8 @@ static int ns2_led_get_mode(struct ns2_led_data *led_dat,
int cmd_level;
int slow_level;
- read_lock_irq(&led_dat->rw_lock);
-
- cmd_level = gpio_get_value(led_dat->cmd);
- slow_level = gpio_get_value(led_dat->slow);
+ cmd_level = gpio_get_value_cansleep(led_dat->cmd);
+ slow_level = gpio_get_value_cansleep(led_dat->slow);
for (i = 0; i < led_dat->num_modes; i++) {
if (cmd_level == led_dat->modval[i].cmd_level &&
@@ -71,8 +83,6 @@ static int ns2_led_get_mode(struct ns2_led_data *led_dat,
}
}
- read_unlock_irq(&led_dat->rw_lock);
-
return ret;
}
@@ -80,19 +90,32 @@ static void ns2_led_set_mode(struct ns2_led_data *led_dat,
enum ns2_led_modes mode)
{
int i;
+ bool found = false;
unsigned long flags;
- write_lock_irqsave(&led_dat->rw_lock, flags);
-
- for (i = 0; i < led_dat->num_modes; i++) {
+ for (i = 0; i < led_dat->num_modes; i++)
if (mode == led_dat->modval[i].mode) {
- gpio_set_value(led_dat->cmd,
- led_dat->modval[i].cmd_level);
- gpio_set_value(led_dat->slow,
- led_dat->modval[i].slow_level);
+ found = true;
+ break;
}
+
+ if (!found)
+ return;
+
+ write_lock_irqsave(&led_dat->rw_lock, flags);
+
+ if (!led_dat->can_sleep) {
+ gpio_set_value(led_dat->cmd,
+ led_dat->modval[i].cmd_level);
+ gpio_set_value(led_dat->slow,
+ led_dat->modval[i].slow_level);
+ goto exit_unlock;
}
+ led_dat->mode_index = i;
+ schedule_work(&led_dat->work);
+
+exit_unlock:
write_unlock_irqrestore(&led_dat->rw_lock, flags);
}
@@ -122,7 +145,6 @@ static ssize_t ns2_led_sata_store(struct device *dev,
container_of(led_cdev, struct ns2_led_data, cdev);
int ret;
unsigned long enable;
- enum ns2_led_modes mode;
ret = kstrtoul(buff, 10, &enable);
if (ret < 0)
@@ -131,19 +153,19 @@ static ssize_t ns2_led_sata_store(struct device *dev,
enable = !!enable;
if (led_dat->sata == enable)
- return count;
+ goto exit;
- ret = ns2_led_get_mode(led_dat, &mode);
- if (ret < 0)
- return ret;
+ led_dat->sata = enable;
+
+ if (!led_get_brightness(led_cdev))
+ goto exit;
- if (enable && mode == NS_V2_LED_ON)
+ if (enable)
ns2_led_set_mode(led_dat, NS_V2_LED_SATA);
- if (!enable && mode == NS_V2_LED_SATA)
+ else
ns2_led_set_mode(led_dat, NS_V2_LED_ON);
- led_dat->sata = enable;
-
+exit:
return count;
}
@@ -173,7 +195,7 @@ create_ns2_led(struct platform_device *pdev, struct ns2_led_data *led_dat,
enum ns2_led_modes mode;
ret = devm_gpio_request_one(&pdev->dev, template->cmd,
- gpio_get_value(template->cmd) ?
+ gpio_get_value_cansleep(template->cmd) ?
GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
template->name);
if (ret) {
@@ -183,7 +205,7 @@ create_ns2_led(struct platform_device *pdev, struct ns2_led_data *led_dat,
}
ret = devm_gpio_request_one(&pdev->dev, template->slow,
- gpio_get_value(template->slow) ?
+ gpio_get_value_cansleep(template->slow) ?
GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
template->name);
if (ret) {
@@ -202,6 +224,8 @@ create_ns2_led(struct platform_device *pdev, struct ns2_led_data *led_dat,
led_dat->cdev.groups = ns2_led_groups;
led_dat->cmd = template->cmd;
led_dat->slow = template->slow;
+ led_dat->can_sleep = gpio_cansleep(led_dat->cmd) |
+ gpio_cansleep(led_dat->slow);
led_dat->modval = template->modval;
led_dat->num_modes = template->num_modes;
@@ -214,6 +238,8 @@ create_ns2_led(struct platform_device *pdev, struct ns2_led_data *led_dat,
led_dat->cdev.brightness =
(mode == NS_V2_LED_OFF) ? LED_OFF : LED_FULL;
+ INIT_WORK(&led_dat->work, ns2_led_work);
+
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0)
return ret;
@@ -224,6 +250,7 @@ create_ns2_led(struct platform_device *pdev, struct ns2_led_data *led_dat,
static void delete_ns2_led(struct ns2_led_data *led_dat)
{
led_classdev_unregister(&led_dat->cdev);
+ cancel_work_sync(&led_dat->work);
}
#ifdef CONFIG_OF_GPIO
--
2.1.4
--
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