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leds: leds-ns2: handle can_sleep GPIOs 

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@sequanux.org>
Signed-off-by: Vincent Donnefort <vdonnefort@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
This commit is contained in:
Simon Guinot 2015-07-02 19:56:42 +02:00 committed by Jacek Anaszewski
parent f7fafd083c
commit 4b90432dc1
1 changed files with 53 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
drivers/leds/leds-ns2.c
View File

@ -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;
for (i = 0; i < led_dat->num_modes; i++)
if (mode == led_dat->modval[i].mode) {
found = true;
break;
}
if (!found)
return;
write_lock_irqsave(&led_dat->rw_lock, flags);
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);
}
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;
ret = ns2_led_get_mode(led_dat, &mode);
if (ret < 0)
return ret;
if (enable && mode == NS_V2_LED_ON)
ns2_led_set_mode(led_dat, NS_V2_LED_SATA);
if (!enable && mode == NS_V2_LED_SATA)
ns2_led_set_mode(led_dat, NS_V2_LED_ON);
goto exit;
led_dat->sata = enable;
if (!led_get_brightness(led_cdev))
goto exit;
if (enable)
ns2_led_set_mode(led_dat, NS_V2_LED_SATA);
else
ns2_led_set_mode(led_dat, NS_V2_LED_ON);
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