Commit 4b90432d authored by Simon Guinot's avatar Simon Guinot Committed by Jacek Anaszewski
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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: default avatarSimon Guinot <simon.guinot@sequanux.org>
Signed-off-by: default avatarVincent Donnefort <vdonnefort@gmail.com>
Signed-off-by: default avatarJacek Anaszewski <j.anaszewski@samsung.com>
parent f7fafd08

drivers/leds/leds-ns2.c

+51 −24
Original line number Diff line number Diff line
@@ -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) {

	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

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