From 4b90432dc1edca6cfc0bb338794beed46af3a472 Mon Sep 17 00:00:00 2001 From: Simon Guinot Date: Thu, 2 Jul 2015 19:56:42 +0200 Subject: [PATCH] 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 Signed-off-by: Vincent Donnefort Signed-off-by: Jacek Anaszewski --- drivers/leds/leds-ns2.c | 75 +++++++++++++++++++++++++++++++++---------------- 1 file changed, 51 insertions(+), 24 deletions(-) diff --git a/drivers/leds/leds-ns2.c b/drivers/leds/leds-ns2.c index b0bc035..b33514d 100644 --- a/drivers/leds/leds-ns2.c +++ b/drivers/leds/leds-ns2.c @@ -31,6 +31,7 @@ #include #include #include +#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 -- 2.7.4